:root {
  color-scheme: light;
  --paper: #eef6fb;
  --ink: #172033;
  --muted: #5f6b7d;
  --line: #cbd8e6;
  --panel: #ffffff;
  --button: #f8fbff;
  --button-hover: #edf6ff;
  --blue: #2563eb;
  --green: #07936b;
  --red: #dc3d4a;
  --cyan: #0891b2;
  --magenta: #b13a8f;
  --amber: #b45f06;
  --grid: #e2eaf3;
  --shadow: 0 18px 45px rgba(15, 23, 42, 0.12), 0 2px 10px rgba(8, 145, 178, 0.08);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  color: var(--ink);
  background:
    linear-gradient(135deg, #e7f8ff 0%, #f8fbff 50%, #eff6ff 100%);
}

button,
input {
  font: inherit;
}

button {
  min-height: 42px;
  border: 1px solid var(--line);
  border-radius: 8px;
  color: var(--ink);
  background: var(--button);
  cursor: pointer;
  transition: background 160ms ease, border-color 160ms ease, box-shadow 160ms ease, transform 160ms ease;
}

button:not(:disabled):hover {
  border-color: #8ccde0;
  background: var(--button-hover);
  box-shadow: 0 5px 14px rgba(8, 145, 178, 0.13);
  transform: translateY(-1px);
}

button:disabled {
  cursor: default;
  opacity: 0.88;
}

button:focus-visible,
input:focus-visible {
  outline: 3px solid rgba(37, 87, 199, 0.24);
  outline-offset: 2px;
}

.app-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 300px;
  gap: 20px;
  min-height: 100vh;
  padding: 18px;
}

.play-area {
  display: flex;
  flex-direction: column;
  min-width: 0;
  border: 1px solid var(--line);
  border-top: 4px solid var(--cyan);
  border-radius: 8px;
  background: var(--panel);
  box-shadow: var(--shadow);
  overflow: hidden;
}

.top-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  padding: 16px 20px 12px;
  border-bottom: 1px solid var(--line);
  background: linear-gradient(90deg, rgba(8, 145, 178, 0.10), rgba(37, 99, 235, 0.07));
}

.eyebrow {
  margin: 0 0 3px;
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

h1 {
  margin: 0;
  font-size: clamp(1.55rem, 2.9vw, 2.65rem);
  line-height: 1.05;
}

.score-strip {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
  color: var(--muted);
  white-space: nowrap;
}

.score-strip span {
  padding: 7px 10px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.82);
}

.canvas-wrap {
  min-height: 0;
  padding: 12px 14px 6px;
}

canvas {
  display: block;
  width: 100%;
  aspect-ratio: 5 / 3;
  max-height: min(56vh, calc(100vh - 265px));
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #ffffff;
}

.question-row {
  display: grid;
  grid-template-columns: minmax(220px, 1fr) minmax(260px, 480px);
  gap: 16px;
  align-items: center;
  padding: 12px 20px 14px;
}

.question-row p {
  margin: 0;
  font-size: 1.05rem;
  font-weight: 700;
}

.answer-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 8px;
}

.answer-button {
  font-weight: 800;
}

.answer-button.correct {
  border-color: rgba(35, 131, 79, 0.65);
  color: #075b43;
  background: rgba(7, 147, 107, 0.14);
  box-shadow: inset 0 -3px 0 rgba(7, 147, 107, 0.24);
}

.answer-button.incorrect {
  border-color: rgba(211, 56, 56, 0.65);
  color: #8f1722;
  background: rgba(220, 61, 74, 0.13);
  box-shadow: inset 0 -3px 0 rgba(220, 61, 74, 0.20);
}

.reveal-panel {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  padding: 18px 20px;
  border-top: 1px solid var(--line);
  background: #f6fbff;
}

.reveal-panel.is-correct {
  background: linear-gradient(90deg, rgba(7, 147, 107, 0.18), #f6fbff 72%);
}

.reveal-panel.is-incorrect {
  background: linear-gradient(90deg, rgba(220, 61, 74, 0.14), #f6fbff 72%);
}

.verdict-burst {
  min-width: 0;
  animation: verdict-pop 360ms ease-out;
}

.verdict-burst.is-correct .result-text {
  color: var(--green);
}

.verdict-burst.is-incorrect .result-text {
  color: var(--red);
}

.result-label {
  margin: 0 0 4px;
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 800;
  text-transform: uppercase;
}

.result-text {
  margin: 0;
  font-size: clamp(2rem, 5vw, 4.2rem);
  font-weight: 900;
  line-height: 0.95;
}

.result-detail {
  margin: 8px 0 0;
  color: var(--muted);
  font-size: 1rem;
  font-weight: 750;
}

.primary-button {
  min-width: 132px;
  border-color: #0e7490;
  color: #fff;
  background: #0e7490;
  font-weight: 800;
}

.side-panel {
  display: flex;
  flex-direction: column;
  gap: 14px;
  min-width: 0;
}

.score-card,
.control-group,
.answer-key,
.history {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  padding: 14px;
}

.score-main {
  display: grid;
  gap: 2px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--line);
}

.score-main span:first-child {
  font-size: clamp(2.4rem, 8vw, 4.1rem);
  font-weight: 900;
  line-height: 0.9;
}

.score-main span:last-child,
.score-grid span {
  color: var(--muted);
  font-size: 0.76rem;
  font-weight: 800;
  text-transform: uppercase;
}

.score-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  margin-top: 14px;
}

.score-grid p {
  display: grid;
  gap: 2px;
  margin: 0;
  padding: 10px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #f8fbff;
}

.score-grid strong {
  font-size: 1.5rem;
  line-height: 1;
}

.control-group {
  display: grid;
  gap: 12px;
}

.control-group label {
  color: var(--muted);
  font-size: 0.9rem;
  font-weight: 750;
}

.switch-row {
  display: grid;
  grid-template-columns: 18px 1fr;
  gap: 10px;
  align-items: center;
  color: var(--ink) !important;
}

.switch-row input {
  width: 18px;
  height: 18px;
  margin: 0;
}

input[type="range"] {
  width: 100%;
  accent-color: var(--blue);
}

.compact-buttons {
  grid-template-columns: 1fr 1fr;
}

.legend {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 12px;
  color: var(--muted);
  font-size: 0.88rem;
  font-weight: 750;
}

.swatch {
  display: inline-block;
  width: 18px;
  height: 4px;
  margin-right: 6px;
  vertical-align: middle;
  border-radius: 2px;
}

.swatch.red {
  background: var(--red);
}

.swatch.blue {
  background: var(--blue);
}

.swatch.green {
  background: var(--green);
}

dl {
  display: grid;
  gap: 8px;
  margin: 0;
}

dl div {
  display: grid;
  grid-template-columns: 70px 1fr;
  gap: 8px;
}

dt {
  color: var(--muted);
  font-weight: 800;
}

dd {
  margin: 0;
  font-weight: 700;
}

.history {
  min-height: 130px;
}

.history h2 {
  margin: 0 0 10px;
  font-size: 1rem;
}

.history ol {
  display: grid;
  gap: 8px;
  margin: 0;
  padding-left: 22px;
  color: var(--muted);
}

.history li.correct {
  color: var(--green);
}

.history li.incorrect {
  color: var(--amber);
}

.reading-nav {
  margin-top: auto;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  padding: 14px;
}

.reading-nav a,
.back-link a {
  color: #0e7490;
  font-weight: 850;
  text-decoration: none;
}

.reading-nav a:hover,
.back-link a:hover {
  text-decoration: underline;
}

.reading-shell {
  min-height: 100vh;
  padding: 24px;
}

.reading-page {
  max-width: 860px;
  margin: 0 auto;
  border: 1px solid var(--line);
  border-top: 4px solid var(--cyan);
  border-radius: 8px;
  background: var(--panel);
  box-shadow: var(--shadow);
  padding: clamp(22px, 4vw, 44px);
}

.reading-page h1 {
  margin-bottom: 18px;
}

.reading-page h2 {
  margin: 28px 0 8px;
  font-size: 1.18rem;
}

.reading-page p {
  margin: 0 0 14px;
  color: var(--ink);
  font-size: 1rem;
  line-height: 1.65;
}

.reading-page .lede {
  color: var(--muted);
  font-size: 1.08rem;
  font-weight: 650;
}

.resource-list {
  display: grid;
  gap: 10px;
  margin: 0;
  padding-left: 22px;
}

.resource-list li {
  line-height: 1.55;
}

.resource-list a {
  color: #0e7490;
  font-weight: 850;
}

.back-link {
  margin-top: 30px !important;
}

@keyframes verdict-pop {
  0% {
    opacity: 0;
    transform: translateY(10px) scale(0.96);
  }

  70% {
    transform: translateY(0) scale(1.03);
  }

  100% {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}

[hidden] {
  display: none !important;
}

@media (max-width: 900px) {
  .app-shell {
    grid-template-columns: 1fr;
    padding: 10px;
  }

  .side-panel {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .score-card,
  .answer-key,
  .history {
    grid-column: 1 / -1;
  }
}

@media (max-width: 660px) {
  .top-bar,
  .reveal-panel {
    align-items: stretch;
    flex-direction: column;
  }

  .question-row {
    grid-template-columns: 1fr;
  }

  .answer-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .score-strip {
    justify-content: space-between;
  }

  .side-panel {
    grid-template-columns: 1fr;
  }

  canvas {
    aspect-ratio: 4 / 3;
    max-height: none;
  }
}