:root {
  color-scheme: dark;
  --bg: #07101e;
  --bg2: #101b30;
  --surface: rgba(15, 27, 48, .74);
  --surface-solid: #111e34;
  --surface-soft: rgba(255, 255, 255, .045);
  --card: #f8f6ef;
  --card-2: #fffdf8;
  --ink: #101827;
  --muted-ink: #697386;
  --text: #f6f8fc;
  --muted: #9faac0;
  --line: rgba(255, 255, 255, .11);
  --line-card: rgba(16, 24, 39, .10);
  --accent: #6ea8ff;
  --accent2: #8b7cff;
  --tech: #54d9cc;
  --good: #4ade80;
  --review: #fbbf24;
  --bad: #fb7185;
  --shadow: 0 34px 80px rgba(0, 0, 0, .42);
  --radius: 28px;
  --ease: cubic-bezier(.2, .75, .25, 1);
  --sans: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --mono: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
html { min-width: 320px; min-height: 100%; background: var(--bg); }
body {
  margin: 0;
  min-height: 100vh;
  overflow-x: hidden;
  color: var(--text);
  font-family: var(--sans);
  background:
    radial-gradient(900px 600px at 15% -10%, rgba(61, 116, 205, .24), transparent 60%),
    radial-gradient(820px 640px at 95% 20%, rgba(124, 58, 237, .13), transparent 55%),
    linear-gradient(145deg, var(--bg), var(--bg2));
}
body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  opacity: .28;
  background-image: radial-gradient(rgba(255, 255, 255, .14) .7px, transparent .7px);
  background-size: 26px 26px;
  mask-image: linear-gradient(to bottom, rgba(0,0,0,.45), transparent 75%);
}
button, input, select { font: inherit; }
button, a, select, input { -webkit-tap-highlight-color: transparent; }
a { color: inherit; }
button:focus-visible, select:focus-visible, input:focus-visible, article:focus-visible, a:focus-visible, summary:focus-visible {
  outline: 3px solid rgba(110, 168, 255, .5);
  outline-offset: 3px;
}

.page-shell, .topbar { width: min(1060px, calc(100% - 44px)); margin-inline: auto; }
.topbar {
  min-height: 76px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  position: relative;
  z-index: 20;
}
.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--text);
  text-decoration: none;
  font-weight: 780;
  letter-spacing: -.02em;
}
.brand-mark {
  width: 42px;
  height: 42px;
  padding: 10px;
  display: flex;
  align-items: flex-end;
  justify-content: center;
  gap: 3px;
  border: 1px solid rgba(255,255,255,.16);
  border-radius: 14px;
  background: linear-gradient(145deg, #2b64b8, #152b50);
  box-shadow: inset 0 1px rgba(255,255,255,.15), 0 8px 24px rgba(0,0,0,.18);
}
.brand-mark i { display: block; width: 4px; border-radius: 2px; background: #dce9ff; }
.brand-mark i:nth-child(1) { height: 8px; opacity: .7; }
.brand-mark i:nth-child(2) { height: 16px; }
.brand-mark i:nth-child(3) { height: 12px; opacity: .85; }
.brand-dot { color: var(--accent); }
.breadcrumb { display: flex; gap: 9px; align-items: center; color: var(--muted); font: 700 10px var(--mono); text-transform: uppercase; letter-spacing: .08em; }
.breadcrumb a { text-decoration: none; }
.breadcrumb a:hover { color: var(--text); }
.breadcrumb strong { color: var(--text); }

.page-head {
  padding: 10px 0 18px;
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 24px;
}
.page-head > div:first-child { min-width: 0; }
.eyebrow, .kicker, .face-label {
  margin: 0;
  color: var(--muted);
  font: 800 10px var(--mono);
  letter-spacing: .14em;
  text-transform: uppercase;
}
.page-head h1 {
  margin: 7px 0 0;
  font-size: clamp(30px, 4.5vw, 46px);
  line-height: 1.02;
  letter-spacing: -.045em;
  font-weight: 790;
}
.deck-summary {
  max-width: 690px;
  margin: 9px 0 0;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.55;
}
.mode-tabs {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 6px;
  min-width: min(300px, 100%);
  padding: 5px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--surface);
  backdrop-filter: blur(16px);
}
.mode-tab {
  border: 0;
  border-radius: 11px;
  padding: 9px 14px;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  font: 760 12px var(--sans);
  transition: background .18s var(--ease), color .18s var(--ease), transform .18s var(--ease);
}
.mode-tab:hover { color: var(--text); }
.mode-tab.active {
  color: var(--text);
  background: rgba(110,168,255,.16);
  box-shadow: inset 0 0 0 1px rgba(110,168,255,.20);
}

.metric-strip {
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
  padding: 0 0 14px;
}
.metric-strip div {
  display: inline-flex;
  align-items: baseline;
  gap: 6px;
  padding: 7px 10px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: rgba(255,255,255,.025);
  color: var(--muted);
}
.metric-strip strong { color: var(--text); font: 800 11px var(--mono); }
.metric-strip span { font: 700 9px var(--mono); text-transform: uppercase; letter-spacing: .05em; }

.study-view { padding: 0 0 48px; }
.study-layout {
  display: grid;
  grid-template-columns: minmax(0, 680px) minmax(250px, 1fr);
  gap: 24px;
  align-items: start;
  justify-content: center;
}
.card-stage { min-width: 0; }
.card-stack { position: relative; padding: 0 0 22px; }
.card-stack::before, .card-stack::after {
  content: "";
  position: absolute;
  inset: 12px 18px 10px;
  z-index: -1;
  border: 1px solid rgba(255,255,255,.07);
  border-radius: var(--radius);
  background: rgba(255,255,255,.10);
}
.card-stack::after { inset: 22px 34px 0; z-index: -2; opacity: .5; }
.flashcard {
  position: relative;
  z-index: 2;
  min-height: 465px;
  padding: 34px clamp(28px, 5vw, 52px) 30px;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  border: 1px solid rgba(17,24,39,.08);
  border-radius: var(--radius);
  outline: none;
  cursor: pointer;
  user-select: none;
  color: var(--ink);
  background: linear-gradient(160deg, var(--card-2) 0%, var(--card) 100%);
  box-shadow: var(--shadow);
  transition: transform .2s var(--ease), box-shadow .2s var(--ease);
}
.flashcard::before {
  content: "";
  position: absolute;
  inset: 0 0 auto;
  height: 6px;
  background: linear-gradient(90deg, #4b82d4, #776fdc 52%, #4ccbbb);
}
.flashcard:hover { transform: translateY(-2px); }
.flashcard:focus-visible { box-shadow: 0 0 0 4px rgba(110,168,255,.18), var(--shadow); }
.card-topline {
  min-height: 30px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}
.card-topline > div { display: flex; flex-wrap: wrap; gap: 7px; }
.topic-chip, .source-badge, .card-number {
  display: inline-flex;
  align-items: center;
  min-height: 27px;
  padding: 6px 10px;
  border-radius: 999px;
  font: 800 10px var(--sans);
  letter-spacing: .04em;
}
.topic-chip { color: #365b91; background: rgba(54,91,145,.08); }
.source-badge { color: #277052; background: rgba(39,112,82,.08); }
.source-badge[data-status="needs_verification"] { color: #8b681f; background: rgba(139,104,31,.10); }
.card-number { color: #3b5f98; letter-spacing: .10em; }
.card-number::before { content: "CARD "; }
.question-face {
  flex: 1;
  padding: 22px 0 28px;
  display: grid;
  place-items: center;
  text-align: center;
}
.question-face .face-label { display: none; }
.question-face h2 {
  max-width: 570px;
  margin: 0;
  color: var(--ink);
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(28px, 4.2vw, 39px);
  font-weight: 700;
  line-height: 1.18;
  letter-spacing: -.025em;
  text-wrap: balance;
}
.tap-hint {
  align-self: end;
  margin: 0;
  color: #778295;
  font-size: 12px;
  text-align: center;
}
.tap-hint::before {
  content: "↵";
  width: 18px;
  height: 18px;
  margin-right: 7px;
  display: inline-grid;
  place-items: center;
  border: 1px solid rgba(16,24,39,.14);
  border-radius: 6px;
  font-size: 10px;
}
.answer-panel {
  margin-top: auto;
  padding-top: 20px;
  border-top: 1px solid var(--line-card);
  text-align: center;
}
.answer-panel .face-label { color: #5a76a2; font-size: 10px; }
.answer-text {
  max-width: 580px;
  margin: 13px auto 0;
  color: var(--ink);
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(24px, 3.6vw, 34px);
  font-weight: 700;
  line-height: 1.18;
  letter-spacing: -.022em;
  text-wrap: balance;
}
.explanation-text {
  max-width: 600px;
  margin: 12px auto 0;
  color: var(--muted-ink);
  font-size: 12px;
  line-height: 1.55;
}
.source-details {
  margin-top: 17px;
  padding: 11px 13px;
  border: 1px solid rgba(16,24,39,.09);
  border-radius: 14px;
  background: rgba(16,24,39,.025);
  color: var(--muted-ink);
  font-size: 11px;
  text-align: left;
}
.source-details summary { color: #38567d; cursor: pointer; font-weight: 800; }
.source-details p { line-height: 1.5; }
.source-reference { font: 10px var(--mono); }
.source-links { display: flex; flex-wrap: wrap; gap: 6px; }
.source-links a {
  padding: 5px 7px;
  border: 1px solid rgba(49,95,186,.18);
  border-radius: 8px;
  color: #3b5f98;
  text-decoration: none;
  font-size: 10px;
}

.study-controls {
  position: sticky;
  top: 18px;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 22px;
  background: var(--surface);
  backdrop-filter: blur(18px);
  box-shadow: 0 18px 40px rgba(0,0,0,.16);
}
.progress-block > div:first-child {
  display: flex;
  justify-content: space-between;
  gap: 15px;
  color: var(--muted);
  font: 700 10px var(--mono);
  text-transform: uppercase;
  letter-spacing: .05em;
}
.progress-track {
  height: 5px;
  margin-top: 12px;
  overflow: hidden;
  border-radius: 999px;
  background: rgba(255,255,255,.09);
}
.progress-track i {
  display: block;
  width: 0;
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, #5c93ee, #9a8cff);
  transition: width .35s var(--ease);
}
.progress-track.wide { width: 100%; margin: 12px 0 18px; }

.primary-button, .secondary-button, .rating-button {
  border-radius: 13px;
  cursor: pointer;
  transition: transform .18s var(--ease), border-color .18s, background .18s, filter .18s;
}
.primary-button {
  border: 1px solid transparent;
  padding: 11px 13px;
  color: white;
  background: linear-gradient(135deg, #4d7fd1, #6a66d8);
  box-shadow: 0 12px 28px rgba(58,92,180,.22);
  font-weight: 780;
}
.secondary-button {
  border: 1px solid var(--line);
  padding: 11px 13px;
  color: var(--text);
  background: rgba(255,255,255,.035);
  font-weight: 720;
}
.primary-button:hover:not(:disabled), .secondary-button:hover:not(:disabled), .rating-button:hover:not(:disabled) { transform: translateY(-1px); }
.primary-button:hover:not(:disabled) { filter: brightness(1.06); }
.secondary-button:hover:not(:disabled), .rating-button:hover:not(:disabled) { border-color: rgba(110,168,255,.45); }
.primary-button:disabled, .secondary-button:disabled, .rating-button:disabled { cursor: not-allowed; opacity: .45; transform: none; }
.full { width: 100%; }

.primary-controls { display: flex; gap: 8px; margin-top: 20px; }
.primary-controls button { flex: 1; }
.rating-row { display: grid; grid-template-columns: repeat(3, 1fr); gap: 7px; margin-top: 9px; }
.rating-button {
  min-width: 0;
  display: grid;
  gap: 3px;
  padding: 10px;
  border: 1px solid var(--line);
  background: rgba(255,255,255,.025);
  color: var(--text);
  text-align: left;
}
.rating-button strong { font-size: 12px; }
.rating-button span { color: var(--muted); font-size: 9px; line-height: 1.3; }
.rating-button.again[aria-pressed="true"] { border-color: rgba(251,113,133,.7); background: rgba(251,113,133,.10); }
.rating-button.hard[aria-pressed="true"] { border-color: rgba(251,191,36,.65); background: rgba(251,191,36,.10); }
.rating-button.got-it[aria-pressed="true"] { border-color: rgba(74,222,128,.65); background: rgba(74,222,128,.10); }
.quick-tools { display: grid; grid-template-columns: 1fr auto; gap: 8px; margin-top: 10px; }
.quick-toggle {
  display: flex;
  align-items: center;
  gap: 9px;
  padding: 9px 11px;
  border: 1px solid var(--line);
  border-radius: 13px;
  background: rgba(255,255,255,.025);
  cursor: pointer;
}
.quick-toggle input { width: 17px; height: 17px; accent-color: var(--accent); }
.quick-toggle span { display: grid; gap: 1px; }
.quick-toggle strong { font-size: 11px; }
.quick-toggle small { color: var(--muted); font-size: 9px; }
.jump-row {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-top: 15px;
  padding-top: 15px;
  border-top: 1px solid var(--line);
}
.jump-row label { color: var(--muted); font: 700 10px var(--mono); text-transform: uppercase; }
.jump-row input {
  width: 72px;
  min-width: 0;
  padding: 10px;
  border: 1px solid var(--line);
  border-radius: 12px;
  outline: none;
  background: rgba(255,255,255,.04);
  color: var(--text);
}
.study-options {
  margin-top: 12px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: rgba(255,255,255,.02);
}
.study-options summary {
  padding: 12px 13px;
  cursor: pointer;
  color: var(--text);
  font-size: 11px;
  font-weight: 760;
}
.options-body { display: grid; gap: 10px; padding: 0 12px 12px; }
.options-body label, .setup-card > label {
  display: grid;
  gap: 6px;
  color: var(--muted);
  font-size: 10px;
  font-weight: 760;
  text-transform: uppercase;
  letter-spacing: .04em;
}
select {
  width: 100%;
  padding: 10px 31px 10px 11px;
  border: 1px solid var(--line);
  border-radius: 12px;
  outline: none;
  color: var(--text);
  background: var(--surface-solid);
  cursor: pointer;
  text-transform: none;
  letter-spacing: normal;
}
.text-button {
  justify-self: start;
  border: 0;
  padding: 4px 0;
  background: none;
  color: var(--accent);
  cursor: pointer;
  font: 700 10px var(--mono);
  text-transform: uppercase;
}
.shortcut-copy { margin: 13px 0 0; color: var(--muted); font: 600 9px/1.6 var(--mono); }
.empty-panel {
  min-height: 300px;
  display: grid;
  place-content: center;
  padding: 32px;
  border: 1px dashed var(--line);
  border-radius: var(--radius);
  background: rgba(255,255,255,.02);
  text-align: center;
}
.empty-panel h2 { margin: 0 0 7px; }
.empty-panel p { max-width: 440px; margin: 0; color: var(--muted); }

.check-row {
  display: flex !important;
  align-items: center;
  gap: 10px !important;
  padding: 10px 11px;
  border: 1px solid var(--line);
  border-radius: 13px;
  background: rgba(255,255,255,.025);
  cursor: pointer;
}
.check-row input { width: 17px; height: 17px; accent-color: var(--accent); }
.check-row span { display: grid; gap: 2px; }
.check-row strong { color: var(--text); font-size: 11px; text-transform: none; letter-spacing: 0; }
.check-row small { color: var(--muted); font-size: 9px; font-weight: 500; text-transform: none; letter-spacing: 0; }

.test-setup {
  max-width: 820px;
  margin: 12px auto 48px;
  padding: clamp(26px, 5vw, 44px);
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(280px, .9fr);
  gap: 28px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: linear-gradient(155deg, rgba(18,34,59,.96), rgba(12,23,42,.98));
  box-shadow: var(--shadow);
}
.setup-copy h2 {
  margin: 9px 0 12px;
  font-size: clamp(30px, 5vw, 42px);
  line-height: 1.04;
  letter-spacing: -.035em;
}
.setup-copy > p:not(.eyebrow) { color: var(--muted); line-height: 1.6; }
.test-policy { display: grid; gap: 7px; padding-left: 18px; color: var(--muted); font-size: 12px; line-height: 1.45; }
.test-policy li::marker { color: var(--accent); }
.setup-card { align-self: start; display: grid; gap: 12px; }
.eligible-summary { margin: 0; color: var(--text); font-size: 12px; line-height: 1.5; }
.last-result { margin: 0; padding-top: 12px; border-top: 1px solid var(--line); color: var(--muted); font: 10px/1.5 var(--mono); }

.test-run { width: min(820px, 100%); margin: 0 auto; padding: 12px 0 48px; }
.test-run-head { display: flex; align-items: end; justify-content: space-between; gap: 16px; margin-bottom: 4px; }
.test-run-head p { margin-bottom: 5px; }
.test-run-head strong { font: 800 13px var(--mono); }
.test-time { display: grid; justify-items: end; color: var(--muted); font: 700 9px var(--mono); text-transform: uppercase; letter-spacing: .08em; }
.test-time strong { color: var(--text); font-size: 13px; }
.test-question-card {
  position: relative;
  min-height: 430px;
  padding: clamp(26px, 5vw, 44px);
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: linear-gradient(155deg, rgba(18,34,59,.96), rgba(12,23,42,.98));
  box-shadow: var(--shadow);
}
.test-question-card::after {
  content: "";
  position: absolute;
  width: 220px;
  height: 220px;
  right: -90px;
  top: -90px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(110,168,255,.15), transparent 68%);
  pointer-events: none;
}
.test-question-card .card-number { color: var(--accent); }
.test-question-card .card-number::before { content: "SOURCE "; }
.test-question-card .topic-chip { color: #b8d3ff; background: rgba(110,168,255,.11); }
.test-question-card .face-label { display: block; margin-top: 18px; }
.test-question-card h2 {
  max-width: 690px;
  margin: 10px 0 28px;
  color: var(--text);
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(25px, 4vw, 34px);
  font-weight: 700;
  line-height: 1.32;
  letter-spacing: -.025em;
}
.choice-list { display: grid; gap: 10px; margin-top: 24px; }
.choice-button {
  width: 100%;
  display: grid;
  grid-template-columns: 34px 1fr;
  align-items: center;
  gap: 12px;
  padding: 13px 14px;
  border: 1px solid var(--line);
  border-radius: 15px;
  background: rgba(255,255,255,.045);
  color: var(--text);
  text-align: left;
  cursor: pointer;
  line-height: 1.4;
  transition: .18s var(--ease);
}
.choice-button:hover { transform: translateY(-1px); border-color: rgba(110,168,255,.45); }
.choice-button[aria-pressed="true"] { border-color: rgba(110,168,255,.62); background: rgba(110,168,255,.12); box-shadow: inset 0 0 0 1px rgba(110,168,255,.12); }
.choice-marker {
  width: 30px;
  height: 30px;
  display: grid;
  place-items: center;
  border: 1px solid var(--line);
  border-radius: 9px;
  color: var(--muted);
  font: 800 10px var(--mono);
}
.choice-button[aria-pressed="true"] .choice-marker { border-color: var(--accent); background: var(--accent); color: #081426; }
.test-controls { display: grid; grid-template-columns: auto 1fr auto auto; align-items: center; gap: 8px; margin-top: 10px; }
.test-controls span { justify-self: center; color: var(--muted); font: 700 10px var(--mono); }

.results-view { width: min(900px, 100%); margin: 0 auto; padding: 12px 0 48px; }
.results-head {
  display: grid;
  grid-template-columns: 220px 1fr;
  align-items: center;
  gap: 28px;
  padding: 20px 0 28px;
}
.final-score { display: block; color: var(--accent); font: 900 clamp(48px, 9vw, 76px)/.9 var(--sans); letter-spacing: -.06em; }
.results-head h2 { margin: 0; font-size: clamp(24px, 4vw, 36px); letter-spacing: -.03em; }
.results-head p { color: var(--muted); }
.results-grid { display: grid; grid-template-columns: minmax(240px, .65fr) minmax(0, 1.35fr); gap: 10px; align-items: start; }
.result-panel {
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: var(--surface);
  backdrop-filter: blur(16px);
}
.result-panel > h2 { margin: 0 0 12px; font-size: 15px; }
.topic-result { display: flex; align-items: center; justify-content: space-between; gap: 12px; padding: 10px 0; border-top: 1px solid var(--line); font-size: 11px; }
.topic-result strong { font: 800 10px var(--mono); }
.missed-panel { max-height: 660px; overflow: auto; }
.missed-card { padding: 12px 0; border-top: 1px solid var(--line); }
.missed-card h3 { margin: 0 0 7px; font-size: 13px; line-height: 1.4; }
.missed-card p { margin: 4px 0; color: var(--muted); font-size: 11px; line-height: 1.5; }
.missed-card .correct-answer, .all-correct { color: var(--good); }
.results-actions { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 10px; }

.state-panel { display: grid; justify-items: center; gap: 10px; padding: 20vh 16px; color: var(--muted); }
.loading-mark { width: 28px; height: 28px; border: 2px solid var(--line); border-top-color: var(--accent); border-radius: 50%; animation: spin .8s linear infinite; }
.error-panel { color: var(--bad); text-align: center; }
@keyframes spin { to { transform: rotate(360deg); } }
.footer {
  min-height: 90px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  color: var(--muted);
  font: 700 10px var(--mono);
}
.footer a { text-decoration: none; }
.sr-only { position: absolute !important; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0; }

@media (max-width: 820px) {
  .page-head { align-items: start; flex-direction: column; }
  .mode-tabs { width: min(360px, 100%); }
  .study-layout { grid-template-columns: 1fr; }
  .study-controls { position: static; }
  .test-setup { grid-template-columns: 1fr; }
  .results-head, .results-grid { grid-template-columns: 1fr; }
  .results-head { gap: 10px; }
}

@media (max-width: 560px) {
  .page-shell, .topbar { width: min(100% - 26px, 1060px); }
  .topbar { min-height: 68px; }
  .brand-mark { width: 38px; height: 38px; border-radius: 12px; }
  .breadcrumb { display: none; }
  .page-head { padding-top: 4px; gap: 14px; }
  .page-head h1 { font-size: 30px; }
  .deck-summary { font-size: 12px; }
  .mode-tabs { width: 100%; }
  .metric-strip { gap: 5px; padding-bottom: 10px; }
  .metric-strip div { padding: 6px 8px; }
  .metric-strip div:nth-child(3) { display: none; }
  .study-layout { gap: 14px; }
  .card-stack { padding-bottom: 16px; }
  .card-stack::before { inset: 8px 12px 7px; }
  .card-stack::after { inset: 15px 22px 0; }
  .flashcard { min-height: 405px; padding: 24px 20px 22px; border-radius: 24px; }
  .question-face { padding: 20px 0 22px; }
  .question-face h2 { font-size: clamp(26px, 8vw, 33px); }
  .answer-text { font-size: clamp(23px, 7vw, 30px); }
  .topic-chip, .source-badge { max-width: 180px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
  .source-badge { display: none; }
  .study-controls { padding: 14px; border-radius: 20px; }
  .primary-controls { gap: 6px; }
  .primary-controls button { padding-inline: 8px; font-size: 11px; }
  .rating-row { grid-template-columns: repeat(3, 1fr); gap: 6px; }
  .rating-button { padding: 9px 7px; text-align: center; }
  .rating-button span { display: none; }
  .quick-tools { grid-template-columns: 1fr auto; }
  .shortcut-copy { display: none; }
  .test-setup, .test-question-card { padding: 22px 18px; border-radius: 24px; }
  .test-question-card { min-height: 0; }
  .test-controls { grid-template-columns: 1fr 1fr; }
  .test-controls span { grid-column: 1 / -1; grid-row: 1; }
  .test-controls .primary-button { grid-column: 1 / -1; }
  .results-actions { display: grid; }
  .footer { align-items: flex-start; flex-direction: column; justify-content: center; gap: 6px; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; animation-duration: .01ms !important; transition-duration: .01ms !important; }
}

/* Source evidence and provenance must remain readable on narrow screens. */
.source-links > p, .source-original { flex-basis: 100%; min-width: 0; }
.source-links a, .source-original p { overflow-wrap: anywhere; }
.source-links a small { display: inline-block; line-height: 1.5; margin-top: 4px; }
.source-original { padding-top: 8px; }
.source-original summary { cursor: pointer; font-weight: 700; }
.source-scope { font-size: 12px; line-height: 1.5; }

@media (max-width: 560px) {
  [data-source-audit="true"] .source-badge { display: inline-block; }
  [data-source-audit="true"] .metric-strip div:nth-child(3) { display: flex; }
  [data-source-audit="true"] .card-topline > div { display: flex; flex-direction: column; align-items: flex-start; gap: 6px; }
}