:root {
  color-scheme: light;
  --ink: #141414;
  --muted: #5d6572;
  --line: #d9dde5;
  --panel: #ffffff;
  --paper: #f5f6f8;
  --accent: #b21d2a;
  --accent-dark: #7f121d;
  --good: #167348;
  --bad: #ad2f2f;
  --focus: #1d5fd1;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: var(--paper);
  color: var(--ink);
}

button,
select {
  font: inherit;
}

button {
  cursor: pointer;
}

.shell {
  width: min(1180px, calc(100vw - 32px));
  margin: 0 auto;
  padding: 24px 0;
}

.topbar {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 20px;
  padding: 16px 0 20px;
}

.eyebrow {
  margin: 0 0 6px;
  color: var(--accent);
  font-size: 0.82rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  margin-bottom: 0;
  font-size: clamp(2rem, 4vw, 4rem);
  line-height: 0.96;
}

.scorebox {
  display: grid;
  gap: 4px;
  min-width: 150px;
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  text-align: right;
}

.scorebox span,
.scorebox strong {
  display: block;
}

.scorebox span {
  color: var(--muted);
  font-size: 0.9rem;
}

.layout {
  display: grid;
  grid-template-columns: 320px 1fr;
  gap: 18px;
  align-items: start;
}

.panel,
.card {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
}

.panel {
  position: sticky;
  top: 16px;
  padding: 16px;
}

.field {
  display: grid;
  gap: 8px;
}

label {
  color: var(--muted);
  font-size: 0.86rem;
  font-weight: 700;
}

select {
  width: 100%;
  padding: 10px 12px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: #fff;
}

.stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 8px;
  margin: 16px 0;
}

.stats div {
  min-width: 0;
  padding: 10px 8px;
  border: 1px solid var(--line);
  border-radius: 6px;
}

.stats span {
  display: block;
  color: var(--muted);
  font-size: 0.72rem;
}

.stats strong {
  display: block;
  margin-top: 4px;
  font-size: 1.1rem;
}

.actions {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 8px;
  margin-bottom: 14px;
}

.actions button,
.pager button,
.answer-btn {
  min-height: 44px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: #fff;
  color: var(--ink);
  font-weight: 800;
}

.actions button:hover,
.pager button:hover,
.answer-btn:hover {
  border-color: var(--accent);
}

.question-nav {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 6px;
}

.question-nav button {
  aspect-ratio: 1;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: #fff;
  color: var(--muted);
  font-size: 0.82rem;
  font-weight: 800;
}

.question-nav button.active {
  border-color: var(--accent);
  color: var(--accent);
}

.question-nav button.answered {
  background: #f0f7f3;
  color: var(--good);
}

.question-nav button.wrong {
  background: #fff1f1;
  color: var(--bad);
}

.workspace {
  display: grid;
  gap: 14px;
}

.question-card {
  min-height: 320px;
  padding: 28px;
}

.question-meta {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  color: var(--muted);
  font-weight: 800;
  font-size: 0.88rem;
}

#questionText {
  margin: 34px 0;
  font-size: clamp(1.35rem, 3vw, 2.45rem);
  line-height: 1.14;
  letter-spacing: 0;
}

.answer-row {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.answer-btn {
  min-height: 64px;
  font-size: 1.05rem;
}

.answer-btn.selected {
  border-color: var(--accent);
  background: var(--accent);
  color: #fff;
}

.feedback {
  padding: 22px;
}

.result-line {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 12px;
}

.result-line strong {
  font-size: 1.2rem;
}

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

.feedback.correct .result-line strong {
  color: var(--good);
}

.feedback.incorrect .result-line strong {
  color: var(--bad);
}

.flashcard {
  margin-top: 16px;
  padding: 16px;
  border: 1px solid #cfd8e7;
  border-radius: 8px;
  background: #f8fbff;
}

.flashcard span {
  display: block;
  margin-bottom: 6px;
  color: var(--focus);
  font-size: 0.78rem;
  font-weight: 900;
  text-transform: uppercase;
}

.flashcard h3 {
  margin-bottom: 8px;
  font-size: 1rem;
}

.flashcard blockquote {
  margin: 10px 0 12px;
  padding: 12px 14px;
  border-left: 4px solid var(--focus);
  border-radius: 0 6px 6px 0;
  background: #ffffff;
  color: #283548;
  line-height: 1.45;
}

.flashcard a {
  color: var(--focus);
  font-size: 0.88rem;
  font-weight: 800;
}

.pager {
  display: flex;
  justify-content: space-between;
  gap: 10px;
}

.pager button {
  min-width: 132px;
  padding: 0 18px;
}

button:focus-visible,
select:focus-visible {
  outline: 3px solid rgba(29, 95, 209, 0.35);
  outline-offset: 2px;
}

@media (max-width: 860px) {
  .shell {
    width: min(100vw - 20px, 720px);
    padding-top: 10px;
  }

  .topbar {
    align-items: stretch;
    flex-direction: column;
  }

  .scorebox {
    text-align: left;
  }

  .layout {
    grid-template-columns: 1fr;
  }

  .panel {
    position: static;
  }

  .question-nav {
    grid-template-columns: repeat(10, 1fr);
  }

  .question-card {
    min-height: auto;
    padding: 20px;
  }
}

@media (max-width: 520px) {
  .stats {
    grid-template-columns: 1fr;
  }

  .question-nav {
    grid-template-columns: repeat(5, 1fr);
  }

  .answer-row,
  .actions {
    grid-template-columns: 1fr;
  }

  .result-line,
  .pager {
    align-items: stretch;
    flex-direction: column;
  }

  .pager button {
    width: 100%;
  }
}