/* ============================================================
   BH Academy — course content standard
   · .cb-*  content blocks (content-blocks.jsx)
   · .rd-*  course reader layout (page-course-reader.jsx)
   Same language as styles.css: hairlines, navy rules, Everett for
   figures and titles, minimal radii, tokens only (dark mode ready).
   Motion: short, eased, purposeful; disabled under prefers-reduced-motion.
   ============================================================ */

:root {
  --ease-out: cubic-bezier(.22, 1, .36, 1);
  --ease-in-out: cubic-bezier(.65, 0, .35, 1);
  --t-fast: .18s;
  --t-med: .45s;
  --t-slow: .7s;
}

/* ---------- Flow & reveal ---------- */
.cb-flow { display: flex; flex-direction: column; gap: 32px; }
.cb-item--p + .cb-item--p, .cb-item--lead + .cb-item--p { margin-top: -14px; }
.cb-item--h { margin-top: 16px; }
.cb-item--h + .cb-item { margin-top: -10px; }

.cb-item { transition: opacity var(--t-slow) var(--ease-out), transform var(--t-slow) var(--ease-out); }
.cb-item[data-visible="false"] { opacity: 0; transform: translateY(18px); }
.cb-stagger { transition: opacity var(--t-med) var(--ease-out), transform var(--t-med) var(--ease-out), border-color var(--t-fast), background-color var(--t-fast), box-shadow var(--t-fast); transition-delay: calc(var(--i, 0) * 70ms + 120ms), calc(var(--i, 0) * 70ms + 120ms), 0s, 0s, 0s; }
.cb-item[data-visible="false"] .cb-stagger { opacity: 0; transform: translateY(12px); }

/* ---------- Text ---------- */
.cb-lead { margin: 0; font-size: 20px; line-height: 1.6; color: var(--text-strong); font-weight: 400; letter-spacing: -0.005em; text-wrap: pretty; }
.cb-p { margin: 0; font-size: 16.5px; line-height: 1.78; color: var(--text); text-wrap: pretty; }
.cb-p strong, .cb-lead strong, .cb-list strong, .cb-card-text strong, .cb-concept-text strong, .cb-callout-text strong, .cb-compare-text strong, .cb-step-title strong, .cb-tabs-panel-text strong, .cb-summary strong { color: var(--text-strong); font-weight: 600; }
.cb-lead strong { font-weight: 600; box-shadow: inset 0 -.38em 0 var(--primary-50); }

.cb-ref {
  display: inline-block; margin: 0 1px; padding: 0 5px;
  font: 500 11px/1.65 var(--font-mono); vertical-align: 1px; letter-spacing: 0;
  color: var(--bh-ocean); background: var(--primary-50); border-radius: var(--r-xs);
  white-space: nowrap; transition: background-color var(--t-fast), color var(--t-fast);
}
.cb-ref[title] { cursor: help; }
.cb-ref[title]:hover { background: var(--bh-ocean); color: #fff; }
[data-theme="dark"] .cb-ref { color: var(--bh-sky); }

.cb-h h3 { margin: 0; font-family: var(--font-display); font-weight: 500; font-size: 26px; letter-spacing: -0.018em; line-height: 1.18; color: var(--text-strong); text-wrap: balance; }
.cb-kicker { display: flex; align-items: center; gap: 10px; font-size: 12.5px; font-weight: 600; color: var(--bh-ocean); margin-bottom: 10px; }
.cb-kicker::before { content: ""; width: 18px; height: 2px; background: currentColor; }
[data-theme="dark"] .cb-kicker { color: var(--bh-sky); }
.cb-block-title { display: block; font-size: 13.5px; font-weight: 600; color: var(--text-strong); margin-bottom: 14px; }

.cb-list { margin: 0; padding-left: 20px; display: flex; flex-direction: column; gap: 8px; font-size: 16px; line-height: 1.65; }
.cb-list li::marker { color: var(--bh-ocean); }
.cb-list--tight { gap: 6px; font-size: 14.5px; line-height: 1.55; padding-left: 18px; }

/* ---------- Concepts ---------- */
.cb-concepts { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 24px 28px; }
.cb-concepts--single { grid-template-columns: minmax(0, 1fr); }
.cb-concept { position: relative; padding-top: 18px; }
.cb-concept::before { content: ""; position: absolute; top: 0; left: 0; right: 0; height: 2px; background: var(--border); }
.cb-concept::after { content: ""; position: absolute; top: 0; left: 0; height: 2px; width: 100%; background: var(--bh-navy); transform-origin: left; transition: transform .9s var(--ease-out); transition-delay: calc(var(--i, 0) * 120ms + 200ms); }
.cb-item[data-visible="false"] .cb-concept::after { transform: scaleX(0); }
[data-theme="dark"] .cb-concept::after { background: var(--bh-sky); }
.cb-concept-term { font-family: var(--font-display); font-size: 20px; font-weight: 500; color: var(--text-strong); letter-spacing: -0.012em; margin-bottom: 8px; line-height: 1.25; }
.cb-concept-text { font-size: 15px; line-height: 1.68; color: var(--text); }

/* ---------- Cards ---------- */
.cb-cards { display: grid; grid-template-columns: repeat(var(--cb-cols, 3), minmax(0, 1fr)); gap: 14px; }
.cb-card {
  background: var(--surface); border: 1px solid transparent; border-radius: var(--r-md);
  padding: 22px; display: flex; flex-direction: column; gap: 8px;
}
.cb-card:hover { border-color: var(--border-strong); background: var(--bg-elev); }
.cb-card-top { display: flex; align-items: flex-start; justify-content: space-between; gap: 8px; margin-bottom: 8px; }
.cb-card-icon { width: 40px; height: 40px; border-radius: var(--r-md); display: grid; place-items: center; background: var(--bh-navy); color: #fff; flex-shrink: 0; transition: transform var(--t-med) var(--ease-out); }
.cb-card:hover .cb-card-icon { transform: rotate(-6deg) scale(1.06); }
[data-theme="dark"] .cb-card-icon { background: var(--bh-sky); color: var(--bh-navy); }
.cb-card-tag { font-size: 11.5px; font-weight: 600; color: var(--bh-ocean); text-align: right; line-height: 1.3; padding-top: 2px; }
[data-theme="dark"] .cb-card-tag { color: var(--bh-sky); }
.cb-card-title { font-size: 16px; font-weight: 600; color: var(--text-strong); line-height: 1.35; }
.cb-card-text { font-size: 14.5px; line-height: 1.62; color: var(--text); }
.cb-cards--compact .cb-card { padding: 18px; }
.cb-cards--compact .cb-card-icon { width: 34px; height: 34px; background: var(--primary-50); color: var(--bh-ocean); }
.cb-cards--compact .cb-card-title { font-size: 15px; }
.cb-cards--compact .cb-card-text { font-size: 14px; }

/* ---------- Tabs (interactive) ---------- */
.cb-tabs { border: 1px solid var(--border); border-radius: var(--r-md); overflow: hidden; background: var(--bg-elev); }
.cb-tabs-list {
  position: relative; display: grid; grid-template-columns: repeat(var(--n), minmax(0, 1fr));
  background: var(--surface); border-bottom: 1px solid var(--border);
}
.cb-tabs-indicator {
  position: absolute; left: 0; bottom: -1px; height: 2px; width: calc(100% / var(--n));
  background: var(--bh-navy); transform: translateX(calc(100% * var(--a)));
  transition: transform var(--t-med) var(--ease-out);
}
[data-theme="dark"] .cb-tabs-indicator { background: var(--bh-sky); }
.cb-tabs-tab {
  position: relative; display: flex; align-items: center; justify-content: center; gap: 8px;
  min-width: 0; padding: 14px 12px; background: transparent; border: 0;
  font: 500 14px var(--font-sans); color: var(--text-muted);
  transition: color var(--t-fast), background-color var(--t-fast);
}
.cb-tabs-tab span { white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.cb-tabs-tab + .cb-tabs-tab { box-shadow: inset 1px 0 0 var(--border); }
.cb-tabs-tab:hover { color: var(--text-strong); background: var(--bg-elev); }
.cb-tabs-tab[aria-selected="true"] { color: var(--text-strong); background: var(--bg-elev); font-weight: 600; }
.cb-tabs-tab[aria-selected="true"] svg { color: var(--bh-ocean); }
[data-theme="dark"] .cb-tabs-tab[aria-selected="true"] svg { color: var(--bh-sky); }
.cb-tabs-tab:focus-visible { outline-offset: -3px; }
.cb-tabs-panel { display: grid; grid-template-columns: 56px 1fr; gap: 20px; padding: 26px 28px 28px; animation: cb-panel-in var(--t-med) var(--ease-out); }
.cb-tabs-panel-icon { width: 56px; height: 56px; border-radius: 50%; display: grid; place-items: center; background: var(--bh-navy); color: #fff; animation: cb-pop var(--t-med) var(--ease-out); }
[data-theme="dark"] .cb-tabs-panel-icon { background: var(--bh-sky); color: var(--bh-navy); }
.cb-tabs-panel-kicker { display: flex; align-items: center; gap: 12px; font-size: 12.5px; font-weight: 600; color: var(--bh-ocean); margin-bottom: 4px; }
[data-theme="dark"] .cb-tabs-panel-kicker { color: var(--bh-sky); }
.cb-tabs-panel-count { margin-left: auto; font: 500 12px var(--font-mono); color: var(--text-subtle); }
.cb-tabs-panel-title { font-family: var(--font-display); font-size: 22px; font-weight: 500; letter-spacing: -0.015em; line-height: 1.25; color: var(--text-strong); margin-bottom: 8px; }
.cb-tabs-panel-text { font-size: 15.5px; line-height: 1.7; color: var(--text); }
@keyframes cb-panel-in { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: none; } }
@keyframes cb-pop { from { transform: scale(.7); opacity: 0; } to { transform: scale(1); opacity: 1; } }

/* ---------- Figures ---------- */
.cb-figures { display: grid; grid-template-columns: repeat(var(--cb-cols, 3), minmax(0, 1fr)); border-top: 1px solid var(--bh-navy); border-bottom: 1px solid var(--border); }
[data-theme="dark"] .cb-figures { border-top-color: rgba(255,255,255,.5); }
.cb-figure { padding: 20px 20px 20px 0; }
.cb-figure + .cb-figure { padding-left: 20px; border-left: 1px solid var(--border); }
.cb-figure-value { font-family: var(--font-display); font-size: 36px; font-weight: 400; letter-spacing: -0.035em; line-height: 1.05; color: var(--text-strong); font-variant-numeric: tabular-nums; white-space: nowrap; }
.cb-figure-label { margin-top: 10px; font-size: 13.5px; line-height: 1.45; color: var(--text-muted); }

/* ---------- Timeline (interactive) ---------- */
.cb-timeline { border: 1px solid var(--border); border-radius: var(--r-md); padding: 22px 24px 24px; background: var(--bg-elev); }
.cb-timeline-head { display: flex; align-items: center; justify-content: space-between; gap: 16px; margin-bottom: 10px; }
.cb-timeline-head .cb-block-title { margin: 0; }
.cb-timeline-nav { display: flex; gap: 6px; margin-left: auto; }
.cb-timeline-nav button {
  width: 34px; height: 34px; display: grid; place-items: center; border-radius: 50%;
  border: 1px solid var(--border-strong); background: var(--bg-elev); color: var(--text-strong);
  transition: border-color var(--t-fast), background-color var(--t-fast), color var(--t-fast);
}
.cb-timeline-nav button:hover:not(:disabled) { background: var(--bh-navy); border-color: var(--bh-navy); color: #fff; }
.cb-timeline-nav button:disabled { opacity: .35; cursor: default; }
.cb-timeline-track { position: relative; }
.cb-timeline-line { position: absolute; top: 18px; left: calc(100% / (var(--n) * 2)); width: calc(100% - 100% / var(--n)); height: 2px; background: var(--border); pointer-events: none; }
.cb-timeline-line span { display: block; height: 100%; background: var(--bh-ocean); transition: width var(--t-slow) var(--ease-out); }
.cb-timeline-rail { position: relative; display: grid; grid-template-columns: repeat(var(--n), minmax(44px, 1fr)); overflow-x: auto; scrollbar-width: none; }
.cb-timeline-rail::-webkit-scrollbar { display: none; }
.cb-timeline-stop { display: flex; flex-direction: column; align-items: center; gap: 8px; padding: 12px 2px 4px; background: none; border: 0; color: var(--text-muted); font: inherit; }
.cb-timeline-dot {
  width: 14px; height: 14px; border-radius: 50%; background: var(--bg-elev); box-shadow: inset 0 0 0 2px var(--border-strong);
  transition: transform var(--t-med) var(--ease-out), background-color var(--t-fast), box-shadow var(--t-fast);
}
.cb-timeline-stop[data-state="past"] .cb-timeline-dot { background: var(--bh-ocean); box-shadow: none; }
.cb-timeline-stop[data-state="active"] .cb-timeline-dot { background: var(--bh-navy); box-shadow: 0 0 0 5px var(--primary-100); transform: scale(1.25); }
[data-theme="dark"] .cb-timeline-stop[data-state="active"] .cb-timeline-dot { background: var(--bh-sky); box-shadow: 0 0 0 5px rgba(155,220,245,.18); }
.cb-timeline-stop:hover .cb-timeline-dot { transform: scale(1.2); }
.cb-timeline-year { font-family: var(--font-display); font-size: 14px; font-weight: 500; font-variant-numeric: tabular-nums; transition: color var(--t-fast); }
.cb-timeline-stop[data-state="active"] .cb-timeline-year { color: var(--text-strong); font-weight: 700; }
.cb-timeline-panel {
  display: grid; grid-template-columns: auto 1fr; gap: 20px; align-items: baseline;
  margin-top: 16px; padding: 18px 20px; background: var(--surface); border-radius: var(--r-md);
  animation: cb-panel-in var(--t-med) var(--ease-out);
}
.cb-timeline-panel-year { font-family: var(--font-display); font-size: 34px; letter-spacing: -0.03em; line-height: 1; color: var(--bh-ocean); }
[data-theme="dark"] .cb-timeline-panel-year { color: var(--bh-sky); }
.cb-timeline-panel-text { font-size: 16.5px; line-height: 1.5; color: var(--text-strong); font-weight: 500; }

/* ---------- Steps ---------- */
.cb-steps { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; position: relative; }
.cb-steps li { display: grid; grid-template-columns: 32px 1fr; gap: 16px; padding: 13px 0; position: relative; }
.cb-steps li + li { border-top: 1px solid var(--border); }
.cb-step-num {
  width: 30px; height: 30px; border-radius: 50%; display: grid; place-items: center;
  background: var(--bh-navy); color: #fff; font: 600 13px var(--font-sans); font-variant-numeric: tabular-nums;
}
[data-theme="dark"] .cb-step-num { background: var(--bh-sky); color: var(--bh-navy); }
.cb-steps li:hover .cb-step-num { background: var(--bh-ocean); }
.cb-step-title { font-size: 15.5px; line-height: 1.5; color: var(--text-strong); padding-top: 4px; }
.cb-step-text { font-size: 14.5px; line-height: 1.6; color: var(--text-muted); margin-top: 3px; }

/* ---------- Compare ---------- */
.cb-compare { display: grid; grid-template-columns: minmax(0, 1fr) 44px minmax(0, 1fr); border: 1px solid var(--border); border-radius: var(--r-md); overflow: hidden; }
.cb-compare--goodbad { grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); }
.cb-compare-side { padding: 22px; display: flex; flex-direction: column; gap: 8px; }
.cb-compare--goodbad .cb-compare-side + .cb-compare-side { border-left: 1px solid var(--border); }
.cb-compare-side--bad { background: var(--contrast-soft); }
.cb-compare-side--good { background: var(--success-soft); }
.cb-compare-label { display: flex; align-items: center; gap: 8px; font-size: 12.5px; font-weight: 600; color: var(--bh-ocean); }
[data-theme="dark"] .cb-compare-label { color: var(--bh-sky); }
.cb-compare-mark { width: 20px; height: 20px; border-radius: 50%; display: grid; place-items: center; color: #fff; }
.cb-compare-side--bad .cb-compare-label { color: var(--contrast); }
.cb-compare-side--bad .cb-compare-mark { background: var(--contrast); }
.cb-compare-side--good .cb-compare-label { color: var(--success); }
.cb-compare-side--good .cb-compare-mark { background: var(--success); }
[data-theme="dark"] .cb-compare-side--good .cb-compare-label { color: #8CC79B; }
[data-theme="dark"] .cb-compare-side--bad .cb-compare-label { color: #F2A19B; }
.cb-compare-title { font-family: var(--font-display); font-size: 19px; font-weight: 500; color: var(--text-strong); letter-spacing: -0.012em; line-height: 1.25; }
.cb-compare-text { font-size: 15px; line-height: 1.62; color: var(--text); }
.cb-compare-vs { position: relative; display: grid; place-items: center; background: var(--surface); }
.cb-compare-vs::before { content: ""; position: absolute; top: 0; bottom: 0; left: 50%; width: 1px; background: var(--border); }
.cb-compare-vs span { position: relative; width: 30px; height: 30px; border-radius: 50%; display: grid; place-items: center; background: var(--bh-navy); color: #fff; font: 600 10.5px var(--font-mono); text-transform: uppercase; letter-spacing: .04em; }
[data-theme="dark"] .cb-compare-vs span { background: var(--bh-sky); color: var(--bh-navy); }

/* ---------- Table ---------- */
.cb-table-scroll { overflow-x: auto; border: 1px solid var(--border); border-radius: var(--r-md); }
.cb-table { width: 100%; border-collapse: collapse; font-size: 14px; line-height: 1.5; }
.cb-table th { text-align: left; font-weight: 600; font-size: 12.5px; color: #fff; background: var(--bh-navy); padding: 11px 16px; white-space: nowrap; }
.cb-table td { padding: 12px 16px; border-top: 1px solid var(--border); vertical-align: top; color: var(--text); min-width: 150px; transition: background-color var(--t-fast); }
.cb-table td:first-child { font-weight: 600; color: var(--text-strong); min-width: 0; }
.cb-table tbody tr:hover td { background: var(--primary-50); }

/* ---------- Chips ---------- */
.cb-chips { display: flex; flex-wrap: wrap; gap: 8px; }
.cb-chip { display: inline-flex; align-items: stretch; border: 1px solid var(--border-strong); border-radius: var(--r-md); overflow: hidden; font-size: 13.5px; background: var(--bg-elev); }
.cb-chip:hover { border-color: var(--bh-navy); }
.cb-chip-code { display: grid; place-items: center; min-width: 36px; padding: 6px 10px; background: var(--bh-navy); color: #fff; font: 600 12px var(--font-mono); }
[data-theme="dark"] .cb-chip-code { background: var(--bh-sky); color: var(--bh-navy); }
.cb-chip-label { padding: 6px 12px; color: var(--text-strong); display: flex; align-items: center; }

/* ---------- Quote ---------- */
.cb-quote { position: relative; margin: 8px 0; padding: 6px 0 6px 64px; }
.cb-quote-mark { position: absolute; left: 0; top: -14px; font-family: var(--font-display); font-size: 96px; line-height: 1; color: var(--bh-blue); }
.cb-quote blockquote { margin: 0; font-family: var(--font-display); font-size: 24px; line-height: 1.35; letter-spacing: -0.016em; color: var(--text-strong); font-weight: 400; text-wrap: pretty; }
.cb-quote figcaption { display: flex; align-items: center; gap: 10px; margin-top: 14px; font-size: 13px; color: var(--text-muted); }
.cb-quote figcaption::before { content: ""; width: 24px; height: 1px; background: var(--border-strong); }

/* ---------- Callout ---------- */
.cb-callout { display: grid; grid-template-columns: 22px 1fr; gap: 14px; padding: 18px 20px; border-left: 3px solid var(--bh-ocean); background: var(--surface); border-radius: 0 var(--r-md) var(--r-md) 0; }
.cb-callout-icon { color: var(--bh-ocean); padding-top: 1px; }
.cb-callout-title { font-size: 13px; font-weight: 600; color: var(--text-strong); margin-bottom: 4px; }
.cb-callout-text { font-size: 15px; line-height: 1.65; color: var(--text); }
.cb-callout--key { border-left-color: var(--bh-navy); background: var(--primary-50); }
.cb-callout--key .cb-callout-icon { color: var(--bh-navy); }
[data-theme="dark"] .cb-callout--key { border-left-color: var(--bh-sky); }
[data-theme="dark"] .cb-callout-icon, [data-theme="dark"] .cb-callout--key .cb-callout-icon { color: var(--bh-sky); }
.cb-callout--warn { border-left-color: var(--emphasis); background: var(--emphasis-soft); }
.cb-callout--warn .cb-callout-icon { color: var(--emphasis); }
.cb-item[data-visible="true"] .cb-callout-icon { animation: cb-pop var(--t-med) var(--ease-out) .25s both; }

/* ---------- Case (interactive) ---------- */
.cb-case {
  position: relative; overflow: hidden;
  background: var(--bh-navy); color: rgba(255,255,255,.88); border-radius: var(--r-md); padding: 24px 26px;
  background-image: radial-gradient(circle at 105% -10%, rgba(62,152,255,.24), transparent 45%);
}
[data-theme="dark"] .cb-case { background-color: var(--surface-2); }
.cb-case-head { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; margin-bottom: 12px; font-size: 13px; }
.cb-case-tag { width: 24px; height: 24px; display: grid; place-items: center; border-radius: var(--r-xs); background: var(--bh-blue); color: #fff; font: 600 12px var(--font-mono); }
.cb-case-label { font-weight: 600; color: #fff; }
.cb-case-title { color: var(--bh-sky); }
.cb-case-title::before { content: "·"; margin-right: 10px; color: rgba(255,255,255,.4); }
.cb-case-text { margin: 0; font-size: 16.5px; line-height: 1.7; }
.cb-case-text strong, .cb-case-questions strong { color: #fff; }
.cb-case .cb-ref { background: rgba(255,255,255,.1); color: var(--bh-sky); }
.cb-case-toggle {
  display: inline-flex; align-items: center; gap: 8px; margin-top: 18px; padding: 8px 14px;
  border: 1px solid rgba(255,255,255,.3); border-radius: var(--r-md); background: transparent; color: #fff;
  font: 500 13.5px var(--font-sans); transition: background-color var(--t-fast), border-color var(--t-fast);
}
.cb-case-toggle:hover { background: rgba(255,255,255,.08); border-color: #fff; }
.cb-case-toggle svg { transition: transform var(--t-med) var(--ease-out); }
.cb-case[data-open="true"] .cb-case-toggle svg { transform: rotate(180deg); }
.cb-case-keys { display: grid; grid-template-rows: 0fr; transition: grid-template-rows var(--t-med) var(--ease-out); }
.cb-case-keys > div { overflow: hidden; }
.cb-case[data-open="true"] .cb-case-keys { grid-template-rows: 1fr; }
.cb-case-questions { margin: 16px 0 0; padding: 16px 0 0; border-top: 1px solid rgba(255,255,255,.14); list-style: none; display: flex; flex-direction: column; gap: 10px; font-size: 15px; line-height: 1.55; }
.cb-case-questions li { position: relative; padding-left: 22px; opacity: 0; transform: translateX(-6px); transition: opacity var(--t-med) var(--ease-out), transform var(--t-med) var(--ease-out); }
.cb-case-questions li::before { content: ""; position: absolute; left: 2px; top: .62em; width: 8px; height: 8px; border-radius: 50%; box-shadow: inset 0 0 0 2px var(--bh-sky); }
.cb-case[data-open="true"] .cb-case-questions li { opacity: 1; transform: none; transition-delay: calc(var(--i) * 60ms + 120ms); }

/* ---------- Myth cards (flip) ---------- */
.cb-myths { display: grid; grid-template-columns: repeat(var(--cb-cols, 2), minmax(0, 1fr)); gap: 14px; }
.cb-myth { display: block; padding: 0; border: 0; background: none; text-align: left; font: inherit; color: inherit; perspective: 1200px; }
.cb-myth-inner { display: grid; height: 100%; transition: transform var(--t-slow) var(--ease-in-out); transform-style: preserve-3d; }
.cb-myth[data-open="true"] .cb-myth-inner { transform: rotateY(180deg); }
.cb-myth-face {
  grid-area: 1 / 1; display: flex; flex-direction: column; gap: 12px; min-height: 176px;
  padding: 22px; border-radius: var(--r-md); backface-visibility: hidden; -webkit-backface-visibility: hidden;
}
.cb-myth-front { border: 1px dashed var(--border-strong); background: var(--bg-elev); transition: border-color var(--t-fast); }
.cb-myth:hover .cb-myth-front { border-color: var(--bh-ocean); }
.cb-myth-back { transform: rotateY(180deg); background: var(--success-soft); border: 1px solid var(--success); }
.cb-myth-label { display: inline-flex; align-items: center; gap: 6px; font-size: 12.5px; font-weight: 600; color: var(--emphasis); }
.cb-myth-back .cb-myth-label { color: var(--success); }
[data-theme="dark"] .cb-myth-back .cb-myth-label { color: #8CC79B; }
.cb-myth-text { flex: 1; font-family: var(--font-display); font-size: 19px; line-height: 1.38; color: var(--text-strong); letter-spacing: -0.012em; }
.cb-myth-fact { flex: 1; font-size: 15px; line-height: 1.62; color: var(--text); }
.cb-myth-hint { display: inline-flex; align-items: center; gap: 6px; font-size: 12.5px; font-weight: 500; color: var(--bh-ocean); }
[data-theme="dark"] .cb-myth-hint { color: var(--bh-sky); }
.cb-myth-back .cb-myth-hint { color: var(--text-muted); }
.cb-myth:focus-visible { outline: none; }
.cb-myth:focus-visible .cb-myth-face { outline: 2px solid var(--bh-ocean); outline-offset: 2px; }

/* ---------- Summary ---------- */
.cb-summary { background: var(--surface); border-top: 3px solid var(--bh-navy); padding: 24px 26px; border-radius: 0 0 var(--r-md) var(--r-md); }
[data-theme="dark"] .cb-summary { border-top-color: var(--bh-sky); }
.cb-summary-head { display: flex; align-items: center; gap: 8px; font-size: 13px; font-weight: 600; color: var(--text-strong); margin-bottom: 16px; }
.cb-summary ul { margin: 0; padding: 0; list-style: none; display: flex; flex-direction: column; gap: 12px; font-size: 15.5px; line-height: 1.55; }
.cb-summary li { display: grid; grid-template-columns: 22px 1fr; gap: 12px; align-items: start; }
.cb-summary-check { width: 22px; height: 22px; border-radius: 50%; display: grid; place-items: center; background: var(--bh-ocean); color: #fff; margin-top: 1px; }
.cb-summary-sources { margin-top: 18px; padding-top: 14px; border-top: 1px solid var(--border); font-size: 13px; color: var(--text-muted); line-height: 2; }
.cb-summary-sources > span:first-child { font-weight: 600; color: var(--text-strong); margin-right: 6px; }

/* ---------- Blocks · small screens ---------- */
@media (max-width: 720px) {
  .cb-flow { gap: 28px; }
  .cb-concepts, .cb-myths, .cb-compare, .cb-compare--goodbad, .cb-cards { grid-template-columns: minmax(0, 1fr); }
  .cb-cards--compact, .cb-figures { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .cb-figures[style*="--cb-cols: 3"] { grid-template-columns: minmax(0, 1fr); }
  .cb-figures .cb-figure { padding: 16px 12px 16px 0; border-left: 0; }
  .cb-figures .cb-figure:nth-child(even) { padding-left: 16px; border-left: 1px solid var(--border); }
  .cb-figures .cb-figure:nth-child(n+3) { border-top: 1px solid var(--border); }
  .cb-figures[style*="--cb-cols: 3"] .cb-figure { padding-left: 0; border-left: 0; }
  .cb-figures[style*="--cb-cols: 3"] .cb-figure + .cb-figure { border-top: 1px solid var(--border); }
  .cb-figure-value { font-size: 30px; white-space: normal; }
  .cb-compare-vs { height: 44px; }
  .cb-compare-vs::before { top: 50%; bottom: auto; left: 0; right: 0; width: auto; height: 1px; }
  .cb-compare--goodbad .cb-compare-side + .cb-compare-side { border-left: 0; border-top: 1px solid var(--border); }
  .cb-tabs-list { display: flex; overflow-x: auto; scrollbar-width: none; }
  .cb-tabs-indicator { display: none; }
  .cb-tabs-tab { flex: 1 0 auto; padding: 12px 14px; }
  .cb-tabs-tab[aria-selected="true"] { box-shadow: inset 0 -2px 0 var(--bh-navy); }
  .cb-tabs-tab svg { display: none; }
  .cb-tabs-panel { grid-template-columns: minmax(0, 1fr); gap: 14px; padding: 20px; }
  .cb-tabs-panel-icon { width: 44px; height: 44px; }
  .cb-timeline { padding: 18px; }
  .cb-timeline-rail { grid-template-columns: repeat(var(--n), 64px); }
  .cb-timeline-line { left: 32px; width: calc(64px * (var(--n) - 1)); }
  .cb-timeline-panel { grid-template-columns: minmax(0, 1fr); gap: 6px; }
  .cb-timeline-panel-year { font-size: 28px; }
  .cb-quote { padding-left: 44px; }
  .cb-quote-mark { font-size: 72px; top: -10px; }
  .cb-quote blockquote { font-size: 20px; }
  .cb-lead { font-size: 18px; }
  .cb-p { font-size: 16px; }
  .cb-case { padding: 20px; }
  .cb-h h3 { font-size: 23px; }
}

/* ============================================================
   Course reader
   ============================================================ */
.rd { min-height: 100vh; background: var(--bg); }
.rd-bar {
  position: sticky; top: 0; z-index: 30; height: 60px;
  display: flex; align-items: center; gap: 18px; padding: 0 20px;
  background: var(--inverse-bg); color: #fff;
}
.rd-reading { position: absolute; left: 0; right: 0; bottom: 0; height: 2px; background: var(--bh-blue); transform-origin: left; transition: transform .08s linear; }
.rd-bar-menu { display: none; background: none; border: 0; color: #fff; width: 36px; height: 36px; place-items: center; border-radius: var(--r-md); flex-shrink: 0; }
.rd-bar-menu:hover { background: rgba(255,255,255,.08); }
.rd-bar-back { display: inline-flex; align-items: center; gap: 6px; font-size: 13px; color: rgba(255,255,255,.75); white-space: nowrap; transition: color var(--t-fast); }
.rd-bar-back:hover { color: #fff; }
.rd-bar-back svg { transition: transform var(--t-fast) var(--ease-out); }
.rd-bar-back:hover svg { transform: translateX(-3px); }
.rd-bar-title { flex: 1; min-width: 0; display: flex; flex-direction: column; padding-left: 18px; border-left: 1px solid rgba(255,255,255,.18); line-height: 1.35; }
.rd-bar-course { font-size: 12px; color: rgba(255,255,255,.6); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.rd-bar-item { font-size: 14px; font-weight: 500; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.rd-bar-progress { display: flex; align-items: center; gap: 10px; width: 180px; font-size: 13px; font-weight: 600; flex-shrink: 0; font-variant-numeric: tabular-nums; }
.rd-bar-progress .gs-progress { background: rgba(255,255,255,.18); }
.rd-bar-progress .gs-progress-fill { background: var(--bh-sky); transition: width .6s var(--ease-out); }

.rd-body { display: grid; grid-template-columns: 304px minmax(0, 1fr); }
.rd-body[data-notes-open="true"] { grid-template-columns: 248px minmax(0, 1fr) clamp(340px, 30vw, 480px); }
.rd-body[data-notes-open="true"] .rd-main { padding: 36px 28px 80px; }
.rd-bar-tool[data-active="true"] { background: rgba(255,255,255,.15); border-color: rgba(255,255,255,.65); }
.rd-notes { position: sticky; top: 60px; height: calc(100dvh - 60px); min-width: 0; min-height: 0; display: flex; flex-direction: column; border-left: 1px solid var(--border); background: var(--bg-elev); }
.rd-notes[hidden] { display: none; }
.rd-notes-head { display: flex; align-items: center; justify-content: space-between; gap: 12px; padding: 22px 22px 0; }
.rd-notes-head .cb-kicker { margin: 0; font-size: 10px; }
.rd-notes-head h2 { margin: 6px 0 0; font: 500 24px/1.2 var(--font-display); letter-spacing: -.03em; color: var(--text-strong); }
.rd-notes-course { margin: 10px 22px 0; color: var(--text-muted); font-size: 12px; line-height: 1.5; }
.rd-notes-hint { margin: 6px 22px 18px; display: flex; align-items: center; gap: 5px; color: var(--text-subtle); font-size: 11px; }
.rd-notes iframe { display: block; width: 100%; flex: 1; min-height: 0; border: 0; background: var(--bg-elev); }
@media (min-width: 981px) and (max-width: 1190px) {
  .rd-body[data-notes-open="true"] { grid-template-columns: 210px minmax(0, 1fr) 330px; }
  .rd-body[data-notes-open="true"] .rd-main { padding-left: 20px; padding-right: 20px; }
  .rd[data-notes-open="true"] .rd-bar-progress { width: auto; }
  .rd[data-notes-open="true"] .rd-bar-progress .gs-progress { display: none; }
}
.rd-nav { position: sticky; top: 60px; height: calc(100vh - 60px); overflow-y: auto; border-right: 1px solid var(--border); background: var(--bg-elev); scrollbar-width: thin; }
.rd-outline { padding: 6px 0 48px; }
.rd-outline-group { padding: 18px 16px 10px; border-bottom: 1px solid var(--border); }
.rd-outline-group[data-current="true"] { background: linear-gradient(var(--surface), var(--bg-elev) 120px); }
.rd-outline-head { display: flex; justify-content: space-between; align-items: center; font-size: 12px; font-weight: 600; color: var(--bh-ocean); }
[data-theme="dark"] .rd-outline-head { color: var(--bh-sky); }
.rd-outline-ring { display: inline-flex; align-items: center; gap: 6px; color: var(--text-muted); font-weight: 500; font-variant-numeric: tabular-nums; font-size: 11.5px; }
.rd-outline-ring svg { width: 16px; height: 16px; transform: rotate(-90deg); }
.rd-outline-ring circle { fill: none; stroke-width: 3; }
.rd-outline-ring circle:first-child { stroke: var(--surface-2); }
.rd-outline-ring circle:last-child { stroke: var(--bh-ocean); stroke-dasharray: 50.27; stroke-dashoffset: calc(50.27 * (1 - var(--p))); stroke-linecap: round; transition: stroke-dashoffset .6s var(--ease-out); }
.rd-outline-title { font-size: 14px; font-weight: 600; color: var(--text-strong); margin: 4px 0 10px; line-height: 1.35; }
.rd-outline ol { list-style: none; margin: 0 -8px; padding: 0; }
.rd-outline-item {
  position: relative; display: grid; grid-template-columns: 18px 1fr auto; gap: 10px; align-items: start;
  padding: 7px 8px; border-radius: var(--r-sm); font-size: 13px; line-height: 1.42; color: var(--text);
  transition: background-color var(--t-fast), color var(--t-fast);
}
.rd-outline-item:hover { background: var(--surface); color: var(--text-strong); }
.rd-outline-item[data-active="true"] { background: var(--primary-50); color: var(--text-strong); font-weight: 600; }
.rd-outline-item[data-active="true"]::before { content: ""; position: absolute; left: -8px; top: 6px; bottom: 6px; width: 2px; background: var(--bh-navy); border-radius: 2px; }
[data-theme="dark"] .rd-outline-item[data-active="true"]::before { background: var(--bh-sky); }
.rd-outline-dot { width: 18px; height: 18px; border-radius: 50%; border: 1.5px solid var(--border-strong); display: grid; place-items: center; color: var(--text-muted); margin-top: 1px; transition: background-color var(--t-fast), border-color var(--t-fast); }
.rd-outline-item[data-quiz="true"] .rd-outline-dot { border-style: dashed; }
.rd-outline-item[data-active="true"] .rd-outline-dot { border-color: var(--bh-ocean); color: var(--bh-ocean); border-style: solid; }
.rd-outline-item[data-done="true"] .rd-outline-dot { background: var(--bh-ocean); border-color: var(--bh-ocean); border-style: solid; color: #fff; animation: cb-pop var(--t-med) var(--ease-out); }
.rd-outline-num { font-family: var(--font-mono); font-size: 11.5px; color: var(--text-muted); margin-right: 6px; font-weight: 500; }
.rd-outline-min { font-size: 11.5px; color: var(--text-subtle); font-variant-numeric: tabular-nums; padding-top: 1px; }

.rd-main { min-width: 0; padding: 52px 40px 96px; }
.rd-article { max-width: 760px; margin: 0 auto; animation: rd-enter .55s var(--ease-out); }
@keyframes rd-enter { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: none; } }

.rd-head { padding-bottom: 28px; margin-bottom: 36px; border-bottom: 1px solid var(--border); }
.rd-kicker { display: flex; align-items: center; font-size: 13px; font-weight: 600; color: var(--bh-ocean); margin-bottom: 14px; }
.rd-kicker-sep { width: 4px; height: 4px; border-radius: 50%; background: var(--border-strong); margin: 0 10px; }
[data-theme="dark"] .rd-kicker { color: var(--bh-sky); }
.rd-page-dots { display: flex; align-items: center; gap: 6px; margin: -4px 0 18px; }
.rd-page-dots > span:not(.rd-page-dots-test) { width: 28px; height: 4px; border-radius: 2px; background: var(--surface-2); transition: background-color var(--t-med), width var(--t-med) var(--ease-out); }
.rd-page-dots > span[data-state="past"] { background: var(--bh-ocean); }
.rd-page-dots > span[data-state="active"] { width: 44px; background: var(--bh-navy); }
[data-theme="dark"] .rd-page-dots > span[data-state="active"] { background: var(--bh-sky); }
.rd-page-dots-test { display: grid; place-items: center; width: 20px; height: 20px; margin-left: 2px; border-radius: 50%; border: 1px dashed var(--border-strong); color: var(--text-subtle); }
.rd-title { margin: 0; font-family: var(--font-display); font-weight: 500; font-size: clamp(30px, 3.6vw, 44px); line-height: 1.08; letter-spacing: -0.03em; color: var(--text-strong); text-wrap: balance; }
.rd-meta { display: flex; flex-wrap: wrap; gap: 8px 22px; margin-top: 18px; font-size: 13.5px; color: var(--text-muted); }
.rd-meta span { display: inline-flex; align-items: center; gap: 7px; }

/* Unit opener */
.rd-unit-card {
  position: relative; overflow: hidden; isolation: isolate;
  display: grid; grid-template-columns: auto 1fr; gap: 28px;
  padding: 30px 32px; margin-bottom: 40px; border-radius: var(--r-md);
  background: var(--bh-navy); color: rgba(255,255,255,.85);
  animation: rd-enter .7s var(--ease-out) .1s both;
}
.rd-unit-rings { position: absolute; inset: 0; width: 100%; height: 100%; z-index: -1; pointer-events: none; }
.rd-unit-ring { fill: none; stroke-width: 1; stroke: rgba(255,255,255,.08); transform-box: view-box; transform-origin: 360px 360px; animation: bh-orbit 120s linear infinite; }
.rd-unit-ring--1 { stroke: rgba(62,152,255,.25); animation-duration: 180s; animation-direction: reverse; }
.rd-unit-card-num { font-family: var(--font-display); font-size: 72px; line-height: .85; font-weight: 400; color: var(--bh-blue); letter-spacing: -0.045em; }
.rd-unit-card-label { font-size: 12.5px; font-weight: 600; color: var(--bh-sky); margin-bottom: 8px; }
.rd-unit-card-q { margin: 0; font-family: var(--font-display); font-size: 22px; line-height: 1.35; color: #fff; letter-spacing: -0.014em; text-wrap: pretty; }
.rd-unit-card-grid { display: grid; grid-template-columns: 1.7fr 1fr; gap: 24px; margin-top: 20px; padding-top: 18px; border-top: 1px solid rgba(255,255,255,.14); font-size: 13.5px; line-height: 1.55; }
.rd-unit-card-grid span { display: block; font-size: 12px; font-weight: 600; color: rgba(255,255,255,.55); margin-bottom: 4px; }

/* End of page */
.rd-end {
  display: grid; grid-template-columns: 48px 1fr auto; gap: 18px; align-items: center;
  margin-top: 56px; padding: 22px 24px; border: 1px solid var(--border); border-radius: var(--r-md); background: var(--surface);
  transition: background-color var(--t-med), border-color var(--t-med);
}
.rd-end[data-done="true"] { background: var(--success-soft); border-color: var(--success); }
.rd-end-icon { width: 48px; height: 48px; border-radius: 50%; display: grid; place-items: center; background: var(--bg-elev); color: var(--text-muted); box-shadow: inset 0 0 0 1px var(--border-strong); transition: background-color var(--t-med), color var(--t-med), box-shadow var(--t-med); }
.rd-end[data-done="true"] .rd-end-icon { background: var(--success); color: #fff; box-shadow: none; animation: cb-pop .5s var(--ease-out); }
.rd-end-title { font-family: var(--font-display); font-size: 19px; font-weight: 500; letter-spacing: -0.012em; color: var(--text-strong); }
.rd-end-text { margin-top: 2px; font-size: 14px; line-height: 1.5; color: var(--text-muted); }
.rd-end-actions { display: flex; align-items: center; gap: 12px; }
.rd-end-undo { background: none; border: 0; padding: 0; font-size: 13px; color: var(--text-muted); text-decoration: underline; text-underline-offset: 3px; }
.rd-end-undo:hover { color: var(--text-strong); }

/* Pager — two equal cards */
.rd-pager { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 14px; margin-top: 20px; }
.rd-pager-link {
  display: grid; grid-template-columns: auto 1fr; gap: 14px; align-items: center; min-width: 0;
  padding: 16px 18px; border: 1px solid var(--border); border-radius: var(--r-md); background: var(--bg-elev);
  transition: border-color var(--t-fast), background-color var(--t-fast);
}
.rd-pager-link--next { grid-template-columns: 1fr auto; text-align: right; }
.rd-pager-link--next .rd-pager-arrow { order: 2; }
.rd-pager-link:hover { border-color: var(--text-strong); }
.rd-pager-arrow { width: 36px; height: 36px; border-radius: 50%; display: grid; place-items: center; background: var(--surface); color: var(--text-strong); transition: background-color var(--t-fast), color var(--t-fast), transform var(--t-med) var(--ease-out); }
.rd-pager-link:hover .rd-pager-arrow { background: var(--bh-navy); color: #fff; }
.rd-pager-link--prev:hover .rd-pager-arrow { transform: translateX(-3px); }
.rd-pager-link--next:hover .rd-pager-arrow { transform: translateX(3px); }
.rd-pager-copy { display: flex; flex-direction: column; gap: 3px; min-width: 0; }
.rd-pager-dir { font-size: 12px; font-weight: 500; color: var(--text-muted); }
.rd-pager-title { font-size: 14.5px; font-weight: 600; line-height: 1.4; color: var(--text-strong); overflow: hidden; display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; }

/* ---------- Quiz ---------- */
.rd-quiz-state { padding: 48px 20px; text-align: center; color: var(--text-muted); }
.rd-spinner { display: inline-block; width: 16px; height: 16px; margin-right: 8px; border: 2px solid var(--border); border-top-color: var(--bh-ocean); border-radius: 50%; animation: rd-spin .8s linear infinite; vertical-align: middle; }
@keyframes rd-spin { to { transform: rotate(360deg); } }
.rd-toast { position: fixed; bottom: 24px; left: 50%; transform: translateX(-50%); z-index: 999; display: flex; align-items: center; gap: 20px; width: max-content; max-width: calc(100% - 32px); padding: 16px 20px; border: 1px solid var(--border-strong); border-radius: var(--r-md); background: var(--bg-elev); color: var(--text-strong); box-shadow: 0 8px 32px #0002; font-size: 14px; }
.rd-toast button { border: 0; background: transparent; color: inherit; font-size: 24px; cursor: pointer; }
/* Each quiz screen is a "plane" that fits the viewport: header, content, and an
   action bar pinned to the bottom of the screen. */
.rd-article[data-kind="quiz"], .rd-article[data-kind="exam"] { max-width: 960px; }
.rd-main:has(.rd-qz) { padding-top: 28px; }
.rd-qz { --qz-gap: 18px; display: flex; flex-direction: column; gap: var(--qz-gap); min-height: calc(100dvh - 60px - 56px); margin-bottom: 28px; }
.rd-qz-head { display: flex; align-items: flex-end; justify-content: space-between; gap: 16px; padding-bottom: 16px; border-bottom: 1px solid var(--border); }
.rd-qz-head .rd-kicker { margin-bottom: 8px; }
.rd-qz-title { margin: 0; color: var(--text-strong); font: 500 clamp(24px, 3vw, 32px)/1.15 var(--font-display); letter-spacing: -0.02em; text-wrap: balance; }

/* Stat strip — equal cells, hairline dividers in any column count */
.rd-qz-stats { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 1px; margin: 0; overflow: hidden; border: 1px solid var(--border); border-radius: var(--r-md); background: var(--border); }
.rd-qz-stat { padding: 13px 18px 14px; background: var(--bg-elev); animation: rd-rise .5s var(--ease-out) both; animation-delay: calc(var(--i) * 60ms + 80ms); }
.rd-qz-stat dt { display: flex; align-items: center; gap: 6px; font-size: 12px; font-weight: 500; color: var(--text-muted); }
.rd-qz-stat dt svg { color: var(--text-subtle); }
.rd-qz-stat dd { margin: 5px 0 0; color: var(--text-strong); font: 500 26px/1.1 var(--font-display); letter-spacing: -0.02em; font-variant-numeric: tabular-nums; }
.rd-qz-stat dd small { margin-left: 1px; font-size: 15px; letter-spacing: 0; color: var(--text-muted); }
.rd-qz-stat[data-tone="right"] dt, .rd-qz-stat[data-tone="right"] dt svg { color: var(--success); }
.rd-qz-stat[data-tone="wrong"] dt, .rd-qz-stat[data-tone="wrong"] dt svg { color: var(--contrast); }

/* Cards */
.rd-qz-grid { display: grid; grid-template-columns: minmax(0, 1.05fr) minmax(0, 1fr); gap: var(--qz-gap); align-items: stretch; }
.rd-qz-card { min-width: 0; padding: 18px 20px 20px; border: 1px solid var(--border); border-radius: var(--r-md); background: var(--bg-elev); animation: rd-rise .5s var(--ease-out) .2s both; }
.rd-qz-card-head { display: flex; align-items: center; justify-content: space-between; gap: 12px; min-height: 24px; margin-bottom: 14px; }
.rd-qz-card-title { margin: 0; color: var(--text-strong); font: 600 15px/1.3 var(--font-sans); }

.rd-rules ul { list-style: none; margin: 0; padding: 0; display: grid; gap: 12px; }
.rd-rules li { display: grid; grid-template-columns: 32px minmax(0, 1fr); gap: 12px; align-items: start; }
.rd-rules-icon { width: 32px; height: 32px; border-radius: 50%; display: grid; place-items: center; background: var(--surface); color: var(--bh-ocean); }
[data-theme="dark"] .rd-rules-icon { color: var(--bh-sky); }
.rd-rules li strong { display: block; padding-top: 1px; font-size: 14px; line-height: 1.4; font-weight: 600; color: var(--text-strong); }
.rd-rules li div > span { display: block; margin-top: 1px; font-size: 12.5px; line-height: 1.5; color: var(--text-muted); text-wrap: pretty; }

.rd-prep { display: flex; flex-direction: column; }
.rd-prep-status, .rd-qz-chip, .rd-rstate { display: inline-flex; align-items: center; gap: 5px; padding: 3px 9px; border-radius: 999px; font-size: 12px; font-weight: 600; line-height: 1.4; white-space: nowrap; font-variant-numeric: tabular-nums; }
.rd-prep-status { background: var(--emphasis-soft); color: var(--emphasis); }
.rd-prep-status[data-ok="true"] { background: var(--success-soft); color: var(--success); }
.rd-prep-list { list-style: none; margin: 0 -6px; padding: 0; }
.rd-prep-list a { display: grid; grid-template-columns: 18px 32px minmax(0, 1fr) auto; gap: 10px; align-items: center; padding: 8px 6px; border-top: 1px solid var(--border); font-size: 13.5px; color: var(--text); transition: background-color var(--t-fast); }
.rd-prep-list li:first-child a { border-top: 0; }
.rd-prep-list a:hover { background: var(--surface); }
.rd-prep-dot { width: 18px; height: 18px; border-radius: 50%; border: 1.5px solid var(--border-strong); display: grid; place-items: center; color: #fff; }
.rd-prep-list a[data-done="true"] .rd-prep-dot { background: var(--bh-ocean); border-color: var(--bh-ocean); }
.rd-prep-label { font: 500 12px var(--font-mono); color: var(--text-muted); }
.rd-prep-title { overflow: hidden; white-space: nowrap; text-overflow: ellipsis; font-weight: 500; color: var(--text-strong); }
.rd-prep-meta { font-size: 12px; color: var(--text-muted); font-variant-numeric: tabular-nums; }
.rd-prep-summary { margin-top: auto; padding-top: 14px; }
.rd-prep-summary summary { list-style: none; display: flex; align-items: center; gap: 7px; padding: 10px 12px; border-radius: var(--r-md); background: var(--surface); font-size: 13px; font-weight: 600; color: var(--text-strong); cursor: pointer; }
.rd-prep-summary summary::-webkit-details-marker { display: none; }
.rd-prep-summary summary > svg:first-child { color: var(--bh-ocean); }
.rd-prep-chev { margin-left: auto; color: var(--text-muted); transition: transform var(--t-fast) var(--ease-out); }
.rd-prep-summary[open] .rd-prep-chev { transform: rotate(90deg); }
.rd-prep-summary ul { margin: 10px 0 0; padding: 0 8px 0 30px; display: grid; gap: 5px; font-size: 13.5px; line-height: 1.55; }
.rd-prep-summary li::marker { color: var(--bh-ocean); }

/* Action bar — always the last row of the plane */
.rd-qz-foot { margin-top: auto; display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 14px 20px; padding-top: 18px; border-top: 1px solid var(--border); }
.rd-qz-foot-copy { display: flex; flex-direction: column; gap: 8px; min-width: 0; font-size: 14px; color: var(--text-muted); }
.rd-qz-foot-copy strong { color: var(--text-strong); }
.rd-qz-foot-actions { display: flex; flex-wrap: wrap; gap: 10px; margin-left: auto; }
.rd-qz-history { display: flex; flex-wrap: wrap; gap: 6px; }
.rd-qz-chip { font-weight: 500; border: 1px solid var(--border); background: var(--surface); color: var(--text-muted); }
.rd-qz-chip[data-pass="true"] { border-color: transparent; background: var(--success-soft); color: var(--success); }

/* ---- Run & review ---- */
.rd-qz--run { gap: 0; }
.rd-runbar { position: sticky; top: 72px; z-index: 6; display: flex; align-items: center; gap: 18px; padding: 14px 18px; overflow: hidden; border: 1px solid var(--border); border-radius: var(--r-md); background: var(--bg-elev); }
.rd-runbar-count, .rd-timer, .rd-runbar-close { flex: 0 0 140px; }
.rd-runbar-count { white-space: nowrap; font-size: 14px; color: var(--text-muted); font-variant-numeric: tabular-nums; }
.rd-runbar-count strong { color: var(--text-strong); }
.rd-runbar-pips { flex: 1; display: flex; flex-wrap: wrap; justify-content: center; gap: 7px; }
.rd-runbar-pips button { width: 14px; height: 14px; padding: 0; border: 1.5px solid var(--border-strong); border-radius: 50%; background: transparent; cursor: pointer; transition: background-color var(--t-fast), border-color var(--t-fast), transform var(--t-fast) var(--ease-out); }
.rd-runbar-pips button:hover:not(:disabled) { transform: scale(1.18); border-color: var(--text-strong); }
.rd-runbar-pips button[data-on="true"] { border-color: var(--bh-ocean); background: var(--bh-ocean); }
.rd-runbar-pips button[data-result="right"] { border-color: var(--success); background: var(--success); }
.rd-runbar-pips button[data-result="wrong"] { border-color: var(--contrast); background: var(--contrast); }
.rd-runbar-pips button[data-result="blank"] { border-style: dashed; }
.rd-runbar-pips button[data-current="true"] { box-shadow: 0 0 0 2px var(--bg-elev), 0 0 0 3.5px var(--text-strong); }
.rd-timer { display: inline-flex; align-items: center; justify-content: flex-end; gap: 8px; color: var(--text-strong); font: 600 18px/1 var(--font-mono); font-variant-numeric: tabular-nums; transition: color var(--t-med); }
.rd-timer svg { color: var(--text-muted); }
.rd-runbar[data-low="true"] .rd-timer, .rd-runbar[data-low="true"] .rd-timer svg { color: var(--emphasis); }
.rd-runbar[data-critical="true"] .rd-timer, .rd-runbar[data-critical="true"] .rd-timer svg { color: var(--contrast); }
.rd-runbar[data-critical="true"] .rd-timer span { animation: rd-blink 1s steps(2, start) infinite; }
.rd-runbar-time { position: absolute; left: 0; bottom: 0; width: 100%; height: 3px; background: var(--bh-ocean); transform-origin: left; transition: transform .25s linear, background-color var(--t-med); }
.rd-runbar[data-low="true"] .rd-runbar-time { background: var(--emphasis); }
.rd-runbar[data-critical="true"] .rd-runbar-time { background: var(--contrast); }
.rd-runbar-close { display: inline-flex; align-items: center; justify-content: flex-end; gap: 6px; padding: 0; border: 0; background: none; font-size: 13px; font-weight: 500; color: var(--text-muted); cursor: pointer; }
.rd-runbar-close:hover { color: var(--text-strong); }

.rd-qscreen, .rd-rscreen { flex: 1; padding: 30px 0 26px; animation: rd-qin .35s var(--ease-out); }
.rd-qscreen-kicker { display: flex; align-items: center; justify-content: space-between; gap: 10px; min-height: 24px; margin-bottom: 12px; font-size: 12px; font-weight: 600; letter-spacing: .05em; text-transform: uppercase; color: var(--text-muted); }
.rd-save { display: inline-flex; align-items: center; gap: 6px; font-size: 12.5px; font-weight: 500; letter-spacing: 0; text-transform: none; color: var(--text-subtle); transition: color var(--t-med); }
.rd-save[data-state="saving"] { color: var(--text-muted); }
.rd-save[data-state="saved"] { color: var(--success); }
.rd-save[data-state="error"] { color: var(--contrast); }
.rd-save-dot { width: 6px; height: 6px; border-radius: 50%; background: currentColor; animation: rd-blink .8s ease-in-out infinite alternate; }
.rd-rstate { letter-spacing: 0; text-transform: none; }
.rd-rstate[data-state="right"] { background: var(--success-soft); color: var(--success); }
.rd-rstate[data-state="wrong"] { background: var(--contrast-soft); color: var(--contrast); }
.rd-rstate[data-state="blank"] { background: var(--surface); color: var(--text-muted); }
.rd-qscreen-text { max-width: 46em; margin: 0 0 22px; color: var(--text-strong); font: 500 clamp(19px, 2.4vw, 24px)/1.4 var(--font-display); letter-spacing: -0.01em; text-wrap: pretty; }

.rd-options { display: flex; flex-direction: column; gap: 10px; }
.rd-option {
  display: grid; grid-template-columns: 30px minmax(0, 1fr) 20px; gap: 14px; align-items: center;
  width: 100%; min-height: 56px; padding: 12px 16px; text-align: left;
  border: 1px solid var(--border-strong); border-radius: var(--r-md); background: var(--bg-elev);
  color: var(--text); font: 15px/1.5 var(--font-sans);
  transition: border-color var(--t-fast), background-color var(--t-fast), box-shadow var(--t-fast), transform var(--t-fast) var(--ease-out);
  animation: rd-rise .4s var(--ease-out) both; animation-delay: calc(var(--i, 0) * 40ms + 60ms);
}
button.rd-option { cursor: pointer; }
button.rd-option:hover:not(:disabled) { border-color: var(--text-strong); background: var(--surface); }
button.rd-option:active:not(:disabled) { transform: scale(.995); }
button.rd-option:focus-visible { outline: 2px solid var(--bh-ocean); outline-offset: 2px; }
.rd-option-letter { width: 30px; height: 30px; border-radius: 50%; display: grid; place-items: center; border: 1px solid var(--border-strong); font: 600 12px var(--font-mono); color: var(--text-muted); transition: background-color var(--t-fast), color var(--t-fast), border-color var(--t-fast); }
.rd-option-mark { display: grid; place-items: center; }
.rd-option-yours { display: inline-block; margin-left: 10px; padding: 1px 7px; border-radius: 999px; background: var(--surface-2); color: var(--text-muted); font-size: 11px; font-weight: 600; vertical-align: 1px; white-space: nowrap; }
.rd-option[data-state="selected"] { border-color: var(--bh-navy); background: var(--primary-50); color: var(--text-strong); box-shadow: inset 0 0 0 1px var(--bh-navy); }
.rd-option[data-state="selected"] .rd-option-letter { border-color: var(--bh-navy); background: var(--bh-navy); color: #fff; animation: cb-pop .3s var(--ease-out); }
.rd-option[data-state="selected"] .rd-option-mark { color: var(--bh-navy); }
[data-theme="dark"] .rd-option[data-state="selected"] { border-color: var(--bh-sky); box-shadow: inset 0 0 0 1px var(--bh-sky); }
[data-theme="dark"] .rd-option[data-state="selected"] .rd-option-letter { border-color: var(--bh-sky); background: var(--bh-sky); color: var(--bh-navy); }
[data-theme="dark"] .rd-option[data-state="selected"] .rd-option-mark { color: var(--bh-sky); }
.rd-option[data-state="correct"] { border-color: var(--success); background: var(--success-soft); color: var(--text-strong); }
.rd-option[data-state="correct"] .rd-option-letter { border-color: var(--success); background: var(--success); color: #fff; }
.rd-option[data-state="correct"] .rd-option-mark { color: var(--success); }
.rd-option[data-state="incorrect"] { border-color: var(--contrast); background: var(--contrast-soft); }
.rd-option[data-state="incorrect"] .rd-option-letter { border-color: var(--contrast); background: var(--contrast); color: #fff; }
.rd-option[data-state="incorrect"] .rd-option-mark { color: var(--contrast); }
div.rd-option[data-state="idle"] { opacity: .6; }
.rd-why { margin: 16px 0 0; padding: 12px 16px; border-left: 3px solid var(--border-strong); border-radius: 0 var(--r-md) var(--r-md) 0; background: var(--surface); font-size: 14px; line-height: 1.6; color: var(--text); animation: rd-rise .4s var(--ease-out) .25s both; }
.rd-why[data-state="right"] { border-left-color: var(--success); }
.rd-why[data-state="wrong"], .rd-why[data-state="blank"] { border-left-color: var(--contrast); }
.rd-why--muted { color: var(--text-muted); font-size: 13.5px; }
.rd-why-label { display: block; margin-bottom: 2px; font-size: 12.5px; font-weight: 600; color: var(--text-strong); }
.rd-why[data-state="right"] .rd-why-label { color: var(--success); }
.rd-why[data-state="wrong"] .rd-why-label, .rd-why[data-state="blank"] .rd-why-label { color: var(--contrast); }

.rd-qnav { display: grid; grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr); align-items: center; gap: 16px; padding-top: 18px; border-top: 1px solid var(--border); }
.rd-qnav > :first-child { justify-self: start; }
.rd-qnav > :last-child { justify-self: end; }
.rd-qnav-hint { text-align: center; font-size: 12px; color: var(--text-subtle); white-space: nowrap; }
.rd-qnav-hint kbd { display: inline-grid; place-items: center; min-width: 20px; height: 20px; margin: 0 1px; padding: 0 5px; border: 1px solid var(--border-strong); border-bottom-width: 2px; border-radius: 4px; background: var(--bg-elev); font: 500 11px var(--font-mono); color: var(--text-muted); }

/* Hand-in dialog */
.rd-modal { position: fixed; inset: 0; z-index: 60; display: grid; place-items: center; padding: 16px; background: rgba(10,30,51,.46); backdrop-filter: blur(2px); animation: rd-fade .2s ease-out; }
.rd-confirm { width: min(440px, 100%); padding: 28px; text-align: center; border-radius: var(--r-md); background: var(--bg-elev); box-shadow: var(--shadow-lg); animation: rd-pop-in .28s var(--ease-out); }
.rd-confirm-icon { width: 48px; height: 48px; margin: 0 auto 14px; border-radius: 50%; display: grid; place-items: center; background: var(--primary-50); color: var(--bh-ocean); }
.rd-confirm-title { margin: 0; color: var(--text-strong); font: 500 22px/1.25 var(--font-display); letter-spacing: -0.015em; }
.rd-confirm-meter { max-width: 220px; height: 6px; margin: 16px auto 0; overflow: hidden; border-radius: 3px; background: var(--surface-2); }
.rd-confirm-meter span { display: block; height: 100%; border-radius: 3px; background: var(--bh-ocean); transition: width .4s var(--ease-out); }
.rd-confirm p { margin: 12px 0 0; font-size: 14px; line-height: 1.6; color: var(--text-muted); }
.rd-confirm p strong { color: var(--text-strong); }
.rd-confirm-actions { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; margin-top: 22px; }
.rd-confirm-actions .gs-btn { justify-content: center; }

/* ---- Result ---- */
.rd-verdict {
  --verdict-bg: var(--emphasis-soft); --verdict-ink: var(--emphasis);
  position: relative; display: grid; grid-template-columns: auto minmax(0, 1fr); gap: 32px; align-items: center;
  padding: 24px 28px; border: 1px solid color-mix(in srgb, var(--verdict-ink) 40%, transparent); border-radius: var(--r-md);
  background: var(--verdict-bg); animation: rd-rise .5s var(--ease-out) both;
}
.rd-qz--result[data-pass="true"] .rd-verdict { --verdict-bg: var(--success-soft); --verdict-ink: var(--success); }
[data-theme="dark"] .rd-qz--result[data-pass="true"] .rd-verdict { --verdict-ink: #8CC79B; }
.rd-verdict-copy > * { animation: rd-rise .5s var(--ease-out) both; }
.rd-verdict-copy > :nth-child(1) { animation-delay: .25s; }
.rd-verdict-copy > :nth-child(2) { animation-delay: .35s; }
.rd-verdict-copy > :nth-child(3) { animation-delay: .45s; }
.rd-verdict-badge { display: inline-flex; align-items: center; gap: 6px; padding: 4px 10px; border-radius: 999px; background: var(--verdict-ink); color: #fff; font-size: 12px; font-weight: 600; line-height: 1.4; }
[data-theme="dark"] .rd-qz--result[data-pass="true"] .rd-verdict-badge { color: var(--bh-navy); }
.rd-verdict-sep { width: 3px; height: 3px; margin: 0 2px; border-radius: 50%; background: currentColor; opacity: .7; }
.rd-result-title { margin: 10px 0 6px; color: var(--text-strong); font: 500 clamp(22px, 2.6vw, 28px)/1.15 var(--font-display); letter-spacing: -0.02em; }
.rd-verdict p { max-width: 60ch; margin: 0; font-size: 14.5px; line-height: 1.6; color: var(--text); text-wrap: pretty; }

.rd-ring { position: relative; width: 136px; height: 136px; flex-shrink: 0; }
.rd-ring svg { display: block; width: 100%; height: 100%; overflow: visible; }
.rd-ring circle { fill: none; stroke-width: 8; }
.rd-ring-track { stroke: rgba(10,30,51,.09); }
[data-theme="dark"] .rd-ring-track { stroke: rgba(255,255,255,.12); }
.rd-ring-fill { stroke: var(--verdict-ink); stroke-linecap: round; transition: stroke-dashoffset 1.1s cubic-bezier(.2,.7,.2,1) .15s; }
.rd-ring-tick { stroke: var(--text-strong); stroke-width: 2; stroke-linecap: round; opacity: .45; }
.rd-ring-label { position: absolute; inset: 0; display: flex; flex-direction: column; align-items: center; justify-content: center; line-height: 1; }
.rd-ring-score { display: flex; align-items: baseline; color: var(--text-strong); font-family: var(--font-display); font-variant-numeric: tabular-nums; }
.rd-ring-score strong { font-size: 40px; font-weight: 500; letter-spacing: -0.04em; }
.rd-ring-score span { font-size: 16px; color: var(--text-muted); }
.rd-ring-caption { margin-top: 6px; font-size: 10.5px; font-weight: 600; letter-spacing: .08em; text-transform: uppercase; color: var(--text-muted); }
.rd-ring-badge { position: absolute; right: 2px; bottom: 2px; width: 34px; height: 34px; border-radius: 50%; display: grid; place-items: center; background: var(--verdict-ink); color: #fff; box-shadow: 0 0 0 4px var(--verdict-bg); transform: scale(0); }
.rd-ring[data-on="true"] .rd-ring-badge { animation: rd-badge .55s cubic-bezier(.3,1.6,.5,1) 1.15s both; }
.rd-ring-halo { position: absolute; inset: 4px; border-radius: 50%; border: 2px solid var(--verdict-ink); opacity: 0; pointer-events: none; }
.rd-ring[data-pass="true"][data-on="true"] .rd-ring-halo { animation: rd-halo 1.3s var(--ease-out) 1.25s 2; }

.rd-answers-legend { display: flex; flex-wrap: wrap; gap: 14px; font-size: 12px; color: var(--text-muted); }
.rd-answers-legend span { display: inline-flex; align-items: center; gap: 6px; }
.rd-answers-legend span::before { content: ""; width: 10px; height: 10px; border-radius: 2px; }
.rd-answers-legend [data-result="right"]::before { background: var(--success); }
.rd-answers-legend [data-result="wrong"]::before { background: var(--contrast); }
.rd-answers-legend [data-result="blank"]::before { border: 1.5px dashed var(--border-strong); }
.rd-answers-grid { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(auto-fill, minmax(54px, 1fr)); gap: 8px; }
.rd-answers-grid button {
  width: 100%; height: 44px; display: flex; align-items: center; justify-content: center; gap: 5px;
  border: 1px solid transparent; border-radius: var(--r-md); font: 600 14px var(--font-sans); font-variant-numeric: tabular-nums; cursor: pointer;
  transition: transform var(--t-fast) var(--ease-out), box-shadow var(--t-fast);
  animation: rd-tile .4s var(--ease-out) both; animation-delay: calc(var(--i) * 30ms + 450ms);
}
.rd-answers-grid button:hover { transform: translateY(-2px); box-shadow: var(--shadow-lg); }
.rd-answers-grid button:focus-visible { outline: 2px solid var(--bh-ocean); outline-offset: 2px; }
.rd-answers-grid button[data-result="right"] { background: var(--success-soft); color: var(--success); }
.rd-answers-grid button[data-result="wrong"] { background: var(--contrast-soft); color: var(--contrast); }
.rd-answers-grid button[data-result="blank"] { border: 1.5px dashed var(--border-strong); background: transparent; color: var(--text-muted); }
[data-theme="dark"] .rd-answers-grid button[data-result="right"] { color: #8CC79B; }
.rd-answers-grid i { width: 8px; height: 2px; background: currentColor; }
.rd-answers-note { display: flex; align-items: center; gap: 6px; margin: 14px 0 0; font-size: 12.5px; color: var(--text-muted); }

@keyframes rd-rise { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }
@keyframes rd-qin { from { opacity: 0; transform: translateX(14px); } to { opacity: 1; transform: none; } }
@keyframes rd-fade { from { opacity: 0; } to { opacity: 1; } }
@keyframes rd-pop-in { from { opacity: 0; transform: translateY(10px) scale(.98); } to { opacity: 1; transform: none; } }
@keyframes rd-tile { from { opacity: 0; transform: scale(.85); } to { opacity: 1; transform: none; } }
@keyframes rd-badge { from { transform: scale(0) rotate(-40deg); } to { transform: scale(1) rotate(0); } }
@keyframes rd-halo { from { opacity: .55; transform: scale(1); } to { opacity: 0; transform: scale(1.32); } }
@keyframes rd-blink { from { opacity: 1; } to { opacity: .35; } }

/* ---- Locked content ---- */
.rd-locked { display: flex; flex-direction: column; align-items: flex-start; margin: 6vh 0 32px; padding: 40px; border: 1px dashed var(--border-strong); border-radius: var(--r-md); background: var(--bg-elev); }
.rd-locked-icon { width: 52px; height: 52px; margin-bottom: 20px; border-radius: 50%; display: grid; place-items: center; background: var(--surface); color: var(--text-muted); }
.rd-locked .rd-title { margin: 0 0 12px; }
.rd-locked-text { max-width: 54ch; margin: 0 0 24px; font-size: 15.5px; line-height: 1.6; color: var(--text-muted); }
.rd-locked-text strong { color: var(--text-strong); font-weight: 600; }
.rd-outline-item[data-locked="true"] { color: var(--text-subtle); cursor: not-allowed; }
.rd-outline-item[data-locked="true"]:hover { background: transparent; color: var(--text-subtle); }
.rd-outline-item[data-locked="true"] .rd-outline-dot { border-style: solid; border-color: var(--border); color: var(--text-subtle); }
.rd-outline-item[data-locked="true"] .rd-outline-num { color: var(--text-subtle); }
.rd-pager-link[data-locked="true"] { border-style: dashed; cursor: not-allowed; }
.rd-pager-link[data-locked="true"]:hover { border-color: var(--border); }
.rd-pager-link[data-locked="true"] .rd-pager-title, .rd-pager-link[data-locked="true"] .rd-pager-arrow { color: var(--text-subtle); }
.rd-pager-link[data-locked="true"]:hover .rd-pager-arrow { background: var(--surface); color: var(--text-subtle); transform: none; }
.rd-drawer-locked { color: var(--text-subtle) !important; }

@media (max-width: 980px) {
  .rd-main:has(.rd-qz) { padding-top: 20px; }
  .rd-qz { min-height: calc(100dvh - 60px - 40px); }
}
@media (max-width: 720px) {
  .rd-qz { --qz-gap: 14px; }
  .rd-qz-head { padding-bottom: 12px; }
  .rd-qz-title { font-size: 23px; }
  .rd-qz-stats { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .rd-qz-stat { padding: 9px 12px 10px; }
  .rd-qz-stat dd { margin-top: 3px; font-size: 20px; }
  .rd-ring { width: 108px; height: 108px; }
  .rd-ring-score strong { font-size: 32px; }
  .rd-ring-badge { width: 28px; height: 28px; }
  .rd-result-title { margin-top: 8px; }
  .rd-verdict p { font-size: 14px; }
  .rd-answers-legend { display: none; }
  .rd-answers-grid { grid-template-columns: repeat(5, minmax(0, 1fr)); gap: 6px; }
  .rd-answers-grid button { height: 38px; }
  .rd-qz-grid { grid-template-columns: minmax(0, 1fr); }
  .rd-qz-card { padding: 16px; }
  .rd-verdict { grid-template-columns: minmax(0, 1fr); justify-items: center; gap: 12px; padding: 18px 16px; text-align: center; }
  .rd-verdict p { margin: 0 auto; }
  .rd-runbar { flex-wrap: wrap; top: 68px; gap: 12px; padding: 12px 14px; }
  .rd-runbar-count, .rd-timer, .rd-runbar-close { flex: 1 1 auto; }
  .rd-runbar-pips { order: 3; flex-basis: 100%; justify-content: flex-start; gap: 8px; }
  .rd-qscreen, .rd-rscreen { padding: 22px 0 20px; }
  .rd-option { gap: 10px; min-height: 52px; padding: 12px; font-size: 14.5px; }
  .rd-qnav { grid-template-columns: 1fr 1fr; }
  .rd-qnav-hint { display: none; }
  .rd-qz-foot > .gs-btn, .rd-qz-foot-actions { width: 100%; }
  .rd-qz-foot > .gs-btn, .rd-qz-foot-actions .gs-btn { flex: 1; justify-content: center; }
  .rd-confirm-actions { grid-template-columns: minmax(0, 1fr); }
  .rd-locked { padding: 28px 20px; }
}
@media (prefers-reduced-motion: reduce) {
  .rd-qz-stat, .rd-qz-card, .rd-qscreen, .rd-rscreen, .rd-option, .rd-why, .rd-modal, .rd-confirm, .rd-verdict, .rd-verdict-copy > *,
  .rd-answers-grid button, .rd-ring-halo, .rd-save-dot, .rd-timer span { animation: none !important; }
  .rd-ring-badge { animation: none !important; transform: none; }
  .rd-runbar-time { transition: none; }
}



/* Enrol gate */
.rd-gate { min-height: 100vh; display: grid; place-items: center; padding: 32px 16px; background: var(--surface); }
.rd-gate-card { max-width: 560px; width: 100%; background: var(--bg-elev); border: 1px solid var(--border); border-radius: var(--r-md); padding: 40px; animation: rd-enter .6s var(--ease-out); }
.rd-gate-lead { font-size: 16px; line-height: 1.6; color: var(--text-muted); margin: 14px 0 0; }

.rd-scrim { display: none; }

/* ---------- Reader · tablet & phone ---------- */
@media (max-width: 980px) {
  .rd-body { grid-template-columns: minmax(0, 1fr); }
  .rd-body[data-notes-open="true"] { grid-template-columns: minmax(0, 1fr) 330px; }
  .rd-body[data-notes-open="true"] .rd-nav { display: none; position: static; width: 100%; height: auto; max-height: 35dvh; transform: none; visibility: visible; grid-column: 1 / -1; box-shadow: none; }
  .rd-body[data-notes-open="true"] .rd-nav[data-open="true"] { display: block; }
  .rd-body[data-notes-open="true"] .rd-scrim { display: none; }
  .rd-body[data-notes-open="true"] .rd-main { padding: 28px 20px 60px; }
  .rd-bar-menu { display: grid; }
  .rd-bar-back span { display: none; }
  .rd-bar { gap: 10px; padding: 0 12px; }
  .rd-bar-title { padding-left: 10px; }
  .rd-bar-progress { width: auto; }
  .rd-bar-progress .gs-progress { display: none; }
  .rd-nav {
    position: fixed; top: 60px; left: 0; bottom: 0; height: auto; width: min(320px, 86vw); z-index: 25;
    transform: translateX(-100%); transition: transform .35s var(--ease-out); visibility: hidden;
  }
  .rd-nav[data-open="true"] { transform: none; box-shadow: var(--shadow-lg); visibility: visible; }
  .rd-scrim { display: block; position: fixed; inset: 60px 0 0; background: rgba(10,30,51,.4); z-index: 20; opacity: 0; pointer-events: none; transition: opacity .3s; }
  .rd-scrim[data-open="true"] { opacity: 1; pointer-events: auto; }
  .rd-main { padding: 32px 16px 72px; }
  .rd-unit-card { grid-template-columns: minmax(0, 1fr); gap: 12px; padding: 24px 22px; }
  .rd-unit-card-num { font-size: 48px; }
  .rd-unit-card-q { font-size: 19px; }
  .rd-unit-card-grid { grid-template-columns: minmax(0, 1fr); gap: 12px; }
  .rd-end { grid-template-columns: 40px 1fr; padding: 20px; }
  .rd-end-icon { width: 40px; height: 40px; }
  .rd-end > .gs-btn, .rd-end-actions { grid-column: 1 / -1; }
  .rd-end > .gs-btn { width: 100%; }
  .rd-end-actions { justify-content: space-between; }
  .rd-gate-card { padding: 28px 20px; }
}

/* Small screens keep both working surfaces visible in a vertical split.
   Neither the editor nor the expanded outline covers the reading pane. */
@media (max-width: 760px) {
  .rd-body[data-notes-open="true"] { display: flex; flex-direction: column; height: calc(100dvh - 60px); overflow: hidden; }
  .rd-body[data-notes-open="true"] .rd-main { flex: 1; min-height: 100px; overflow-y: auto; padding: 24px 16px 48px; }
  .rd-body[data-notes-open="true"] .rd-notes { position: static; height: 48%; min-height: 270px; flex-shrink: 0; border-left: 0; border-top: 1px solid var(--border-strong); }
  .rd-body[data-notes-open="true"] .rd-nav { flex-shrink: 0; max-height: 22dvh; border-bottom: 1px solid var(--border); }
  .rd-notes-head { padding: 12px 16px 0; }
  .rd-notes-head h2 { font-size: 20px; margin-top: 2px; }
  .rd-notes-head .cb-kicker, .rd-notes-course { display: none; }
  .rd-notes-hint { margin: 5px 16px 10px; }
  .rd[data-notes-open="true"] .rd-runbar { top: 0; }
}
@media (max-width: 640px) {
  .rd-pager { grid-template-columns: minmax(0, 1fr); }
  .rd-pager-empty { display: none; }
}

/* ============================================================
   Hypertext layer — refs, glossary terms, cross-links, sources
   ============================================================ */
button.cb-ref { border: 0; font: 500 11px/1.65 var(--font-mono); cursor: pointer; }
button.cb-ref:hover, button.cb-ref[aria-expanded="true"] { background: var(--bh-ocean); color: #fff; }
.cb-ref--static { cursor: default; }

.cb-term {
  display: inline; padding: 0; border: 0; background: none; font: inherit; color: inherit; cursor: help;
  text-decoration: underline dotted; text-decoration-color: var(--bh-ocean); text-decoration-thickness: 1.5px; text-underline-offset: 4px;
  transition: background-color var(--t-fast), text-decoration-color var(--t-fast);
  border-radius: 2px;
}
.cb-term:hover, .cb-term[aria-expanded="true"] { background: var(--primary-50); text-decoration-style: solid; }
[data-theme="dark"] .cb-term { text-decoration-color: var(--bh-sky); }
.cb-case .cb-term { text-decoration-color: var(--bh-sky); }
.cb-case .cb-term:hover, .cb-case .cb-term[aria-expanded="true"] { background: rgba(255,255,255,.1); }

.cb-xref { color: var(--bh-ocean); font-weight: 500; text-decoration: underline; text-decoration-color: color-mix(in srgb, currentColor 35%, transparent); text-underline-offset: 3px; transition: text-decoration-color var(--t-fast); }
.cb-xref:hover { text-decoration-color: currentColor; }
.cb-xref::after { content: "↗"; display: inline-block; margin-left: 2px; font-size: .8em; transform: translateY(-1px); }
[data-theme="dark"] .cb-xref, .cb-case .cb-xref { color: var(--bh-sky); }

/* Popover card */
.cb-pop {
  position: fixed; z-index: 200; padding: 16px 18px;
  background: var(--bg-elev); color: var(--text); border: 1px solid var(--border); border-radius: var(--r-md);
  box-shadow: 0 18px 48px rgba(10,30,51,.18), 0 2px 6px rgba(10,30,51,.08);
  animation: cb-pop-in .2s var(--ease-out);
}
.cb-pop::before {
  content: ""; position: absolute; left: calc(var(--arrow) - 6px); width: 12px; height: 12px; background: var(--bg-elev);
  border: 1px solid var(--border); transform: rotate(45deg);
}
.cb-pop[data-side="below"]::before { top: -7px; border-right: 0; border-bottom: 0; }
.cb-pop[data-side="above"]::before { bottom: -7px; border-left: 0; border-top: 0; }
@keyframes cb-pop-in { from { opacity: 0; transform: translateY(4px) scale(.98); } to { opacity: 1; transform: none; } }
.cb-pop-kicker { display: flex; align-items: center; gap: 6px; font-size: 11.5px; font-weight: 600; color: var(--bh-ocean); margin-bottom: 8px; }
[data-theme="dark"] .cb-pop-kicker { color: var(--bh-sky); }
.cb-pop-term { font-family: var(--font-display); font-size: 19px; font-weight: 500; letter-spacing: -0.012em; color: var(--text-strong); margin-bottom: 6px; }
.cb-pop-def { margin: 0; font-size: 14px; line-height: 1.6; }
.cb-pop-actions { display: flex; align-items: center; justify-content: space-between; gap: 12px; flex-wrap: wrap; margin-top: 12px; padding-top: 10px; border-top: 1px solid var(--border); }
.cb-pop-link { display: inline-flex; align-items: center; gap: 4px; font-size: 13px; font-weight: 600; color: var(--bh-ocean); }
.cb-pop-link:hover { text-decoration: underline; text-underline-offset: 3px; }
[data-theme="dark"] .cb-pop-link { color: var(--bh-sky); }
.cb-pop-ghost { background: none; border: 0; padding: 0; font: 500 13px var(--font-sans); color: var(--text-muted); }
.cb-pop-ghost:hover { color: var(--text-strong); text-decoration: underline; text-underline-offset: 3px; }
.cb-pop-sources { display: flex; flex-direction: column; gap: 14px; }
.cb-pop-source { display: grid; grid-template-columns: auto 1fr; gap: 12px; align-items: start; }
.cb-pop-source + .cb-pop-source { padding-top: 14px; border-top: 1px solid var(--border); }
.cb-pop-code { display: inline-grid; place-items: center; min-width: 38px; height: 24px; padding: 0 6px; border-radius: var(--r-sm); font: 600 11.5px var(--font-mono); background: var(--bh-navy); color: #fff; }
.cb-pop-code[data-type="I"] { background: var(--bh-ocean); }
.cb-pop-code[data-type="A"] { background: var(--surface-2); color: var(--text-strong); }
.cb-pop-title { font-size: 14px; font-weight: 600; line-height: 1.4; color: var(--text-strong); }
.cb-pop-type { margin-top: 2px; font-size: 12.5px; color: var(--text-muted); }
.cb-pop-source .cb-pop-link { margin-top: 8px; }

/* Sources at the end of a page */
.cb-sources { margin-top: 48px; padding-top: 28px; border-top: 1px solid var(--border); }
.cb-sources-head { display: flex; align-items: flex-end; justify-content: space-between; gap: 16px; margin-bottom: 16px; }
.cb-sources-head h3 { margin: 0; font-family: var(--font-display); font-size: 22px; font-weight: 500; letter-spacing: -0.015em; color: var(--text-strong); }
.cb-sources-count { font: 500 12px var(--font-mono); color: var(--text-muted); padding: 3px 8px; border: 1px solid var(--border); border-radius: var(--r-full); }
.cb-sources ul { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 8px; }
.cb-sources-item {
  display: grid; grid-template-columns: auto 1fr auto; gap: 12px; align-items: start; height: 100%;
  padding: 12px 14px; border: 1px solid var(--border); border-radius: var(--r-md); background: var(--bg-elev);
  transition: border-color var(--t-fast), background-color var(--t-fast);
}
a.cb-sources-item:hover { border-color: var(--text-strong); }
.cb-sources-copy { display: flex; flex-direction: column; gap: 2px; min-width: 0; }
.cb-sources-title { font-size: 13.5px; font-weight: 600; line-height: 1.4; color: var(--text-strong); }
.cb-sources-type { font-size: 12px; color: var(--text-muted); }
.cb-sources-go { color: var(--text-subtle); transition: color var(--t-fast), transform var(--t-fast) var(--ease-out); }
a.cb-sources-item:hover .cb-sources-go { color: var(--bh-ocean); transform: translate(2px, -2px); }

/* ============================================================
   Reader tools — glossary, bookmarks, shortcuts, test prep
   ============================================================ */
.rd-bar-tool {
  display: inline-flex; align-items: center; gap: 8px; height: 34px; padding: 0 12px; flex-shrink: 0;
  border: 1px solid rgba(255,255,255,.22); border-radius: var(--r-md); background: transparent; color: #fff; font: 500 13px var(--font-sans);
  transition: background-color var(--t-fast), border-color var(--t-fast);
}
.rd-bar-tool:hover { background: rgba(255,255,255,.08); border-color: rgba(255,255,255,.5); }

.rd-head-row { display: flex; align-items: center; justify-content: space-between; gap: 16px; flex-wrap: wrap; margin-top: 18px; }
.rd-head-row .rd-meta { margin-top: 0; }
.rd-mark {
  display: inline-flex; align-items: center; gap: 7px; height: 32px; padding: 0 12px;
  border: 1px solid var(--border-strong); border-radius: var(--r-full); background: var(--bg-elev); color: var(--text-strong);
  font: 500 13px var(--font-sans); transition: border-color var(--t-fast), background-color var(--t-fast), color var(--t-fast);
}
.rd-mark:hover { border-color: var(--text-strong); }
.rd-mark[data-on="true"] { background: var(--bh-navy); border-color: var(--bh-navy); color: #fff; }
.rd-mark[data-on="true"] svg { animation: cb-pop .35s var(--ease-out); }
[data-theme="dark"] .rd-mark[data-on="true"] { background: var(--bh-sky); border-color: var(--bh-sky); color: var(--bh-navy); }
.rd-outline-min { display: inline-flex; align-items: center; gap: 5px; }
.rd-outline-mark { color: var(--bh-ocean); }
[data-theme="dark"] .rd-outline-mark { color: var(--bh-sky); }

.rd-shortcuts { display: flex; justify-content: center; flex-wrap: wrap; gap: 6px 20px; margin-top: 22px; font-size: 12.5px; color: var(--text-subtle); }
.rd-shortcuts kbd {
  display: inline-grid; place-items: center; min-width: 22px; height: 22px; padding: 0 5px; margin-right: 4px;
  border: 1px solid var(--border-strong); border-bottom-width: 2px; border-radius: var(--r-sm);
  font: 500 11.5px var(--font-sans); color: var(--text-muted); background: var(--bg-elev);
}

/* Glossary drawer */
.rd-drawer { position: fixed; inset: 0; z-index: 150; }
.rd-drawer-scrim { position: absolute; inset: 0; background: rgba(10,30,51,.42); animation: rd-fade .25s ease both; }
.rd-drawer-panel {
  position: absolute; top: 0; right: 0; bottom: 0; width: min(460px, 100vw);
  display: flex; flex-direction: column; background: var(--bg-elev); box-shadow: -24px 0 60px rgba(10,30,51,.2);
  animation: rd-slide .32s var(--ease-out) both;
}
.rd-drawer[data-closing="true"] .rd-drawer-scrim { animation: rd-fade .22s ease reverse both; }
.rd-drawer[data-closing="true"] .rd-drawer-panel { animation: rd-slide .22s var(--ease-in-out) reverse both; }
@keyframes rd-fade { from { opacity: 0; } to { opacity: 1; } }
@keyframes rd-slide { from { transform: translateX(100%); } to { transform: none; } }
.rd-drawer-head { display: flex; align-items: flex-start; justify-content: space-between; gap: 16px; padding: 26px 26px 16px; }
.rd-drawer-head h2 { margin: 0; font-family: var(--font-display); font-size: 26px; font-weight: 500; letter-spacing: -0.02em; color: var(--text-strong); }
.rd-drawer-close { width: 36px; height: 36px; display: grid; place-items: center; border-radius: 50%; border: 1px solid var(--border); background: var(--bg-elev); color: var(--text-strong); }
.rd-drawer-close:hover { border-color: var(--text-strong); }
.rd-drawer-search {
  display: flex; align-items: center; gap: 10px; margin: 0 26px 8px; height: 44px; padding: 0 14px;
  border: 1px solid var(--border-strong); border-radius: var(--r-md); color: var(--text-muted);
}
.rd-drawer-search:focus-within { border-color: var(--bh-ocean); box-shadow: var(--ring); }
.rd-drawer-search input { flex: 1; min-width: 0; height: 100%; border: 0; outline: 0; background: transparent; font: 15px var(--font-sans); color: var(--text-strong); }
.rd-drawer-search button { display: grid; place-items: center; width: 24px; height: 24px; border: 0; border-radius: 50%; background: var(--surface-2); color: var(--text-muted); }
.rd-drawer-list { flex: 1; overflow-y: auto; padding: 4px 26px 40px; }
.rd-drawer-letter { position: sticky; top: 0; z-index: 1; padding: 14px 0 6px; background: var(--bg-elev); font-family: var(--font-display); font-size: 20px; color: var(--bh-ocean); border-bottom: 1px solid var(--border); }
[data-theme="dark"] .rd-drawer-letter { color: var(--bh-sky); }
.rd-drawer-entry { padding: 14px 0; border-bottom: 1px solid var(--border); scroll-margin-top: 56px; transition: background-color .6s; }
.rd-drawer-entry[data-focus="true"] { background: var(--primary-50); margin: 0 -12px; padding: 14px 12px; border-radius: var(--r-md); }
.rd-drawer-entry h3 { margin: 0 0 4px; font-size: 15.5px; font-weight: 600; color: var(--text-strong); }
.rd-drawer-entry p { margin: 0; font-size: 14px; line-height: 1.6; color: var(--text); }
.rd-drawer-entry a, .rd-drawer-here { display: inline-flex; align-items: center; gap: 4px; margin-top: 8px; font-size: 12.5px; font-weight: 600; color: var(--bh-ocean); }
.rd-drawer-entry a:hover { text-decoration: underline; text-underline-offset: 3px; }
.rd-drawer-here { color: var(--text-muted); font-weight: 500; }
.rd-drawer-empty { color: var(--text-muted); font-size: 14px; padding: 24px 0; }

.rd-end-text strong { color: var(--text-strong); font-weight: 600; }

@media (max-width: 980px) {
  .rd-bar-tool span { display: none; }
  .rd-bar-tool { width: 36px; padding: 0; justify-content: center; }
  .rd-shortcuts { display: none; }
}
@media (max-width: 720px) {
  .cb-sources ul { grid-template-columns: minmax(0, 1fr); }
  .rd-mark span { display: none; }
  .rd-mark { width: 34px; padding: 0; justify-content: center; }
  .rd-drawer-head, .rd-drawer-list { padding-left: 18px; padding-right: 18px; }
  .rd-drawer-search { margin: 0 18px 8px; }
}

/* ---------- Reduced motion ---------- */
@media (prefers-reduced-motion: reduce) {
  .cb-item, .cb-stagger, .cb-concept::after, .cb-myth-inner, .cb-case-keys, .cb-case-questions li,
  .cb-tabs-indicator, .cb-timeline-line span, .rd-ring-fill, .rd-nav, .rd-reading { transition: none !important; }
  .cb-tabs-panel, .cb-tabs-panel-icon, .cb-timeline-panel, .rd-article, .rd-unit-card, .rd-question, .rd-result,
  .rd-gate-card, .rd-why, .rd-outline-item .rd-outline-dot, .rd-end-icon, .rd-option-letter, .cb-callout-icon, .rd-unit-ring, .cb-pop, .rd-drawer-scrim, .rd-drawer-panel, .rd-mark svg { animation: none !important; }
  .cb-myth-inner { transform: none !important; }
  .cb-myth-face { backface-visibility: visible; }
  .cb-myth-back { transform: none; display: none; }
  .cb-myth[data-open="true"] .cb-myth-front { display: none; }
  .cb-myth[data-open="true"] .cb-myth-back { display: flex; }
}

/* The same notebook stays mounted in all three sizes, including full page. */
.rd-notes-actions { display: flex; align-items: center; gap: 8px; flex-shrink: 0; }
.rd-notes-sizes { display: flex; gap: 2px; padding: 3px; border: 1px solid var(--border); border-radius: 7px; background: var(--surface); }
.rd-notes-sizes button { display: grid; place-items: center; width: 27px; height: 27px; padding: 0; border: 0; border-radius: 4px; color: var(--text-muted); background: transparent; }
.rd-notes-sizes button:hover { color: var(--text-strong); }
.rd-notes-sizes button[aria-pressed="true"] { color: var(--bh-ocean); background: var(--bg-elev); box-shadow: 0 1px 4px #0a1e331a; }
.rd-body[data-notes-open="true"][data-notes-mode="wide"] { grid-template-columns: minmax(0, 1fr) clamp(460px, 48vw, 820px); }
.rd-body[data-notes-open="true"][data-notes-mode="wide"] .rd-nav,
.rd-body[data-notes-open="true"][data-notes-mode="wide"] .rd-scrim,
.rd-body[data-notes-open="true"][data-notes-mode="full"] .rd-nav,
.rd-body[data-notes-open="true"][data-notes-mode="full"] .rd-scrim,
.rd-body[data-notes-open="true"][data-notes-mode="full"] .rd-main { display: none; }
.rd-body[data-notes-open="true"][data-notes-mode="full"] { display: grid; grid-template-columns: minmax(0, 1fr); height: calc(100dvh - 60px); overflow: hidden; }
.rd-body[data-notes-open="true"][data-notes-mode="full"] .rd-notes { position: static; height: 100%; border-left: 0; }
.rd[data-notes-open="true"][data-notes-mode="full"] .rd-bar-menu,
.rd[data-notes-open="true"][data-notes-mode="wide"] .rd-bar-menu { display: none; }
@media (min-width: 761px) and (max-width: 980px) {
  .rd-body[data-notes-open="true"][data-notes-mode="wide"] { grid-template-columns: minmax(0, 1fr) minmax(380px, 52vw); }
}
@media (max-width: 760px) {
  .rd-notes-actions { gap: 5px; }
  .rd-notes-sizes button { width: 25px; height: 25px; }
  .rd-body[data-notes-open="true"][data-notes-mode="wide"] .rd-notes { height: 65%; }
}