:root {
  --bg: #f3efe4;
  --bg-alt: #e6ddc8;
  --panel: rgba(255, 250, 240, 0.84);
  --panel-strong: #fffaf0;
  --line: rgba(78, 59, 35, 0.12);
  --ink: #2a2117;
  --ink-soft: #6b5a46;
  --accent: #b0522a;
  --accent-strong: #8f3f1d;
  --accent-wash: rgba(176, 82, 42, 0.12);
  --success: #276749;
  --success-wash: rgba(39, 103, 73, 0.12);
  --danger: #9b2c2c;
  --danger-wash: rgba(155, 44, 44, 0.12);
  --shadow: 0 18px 50px rgba(74, 57, 32, 0.12);
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  min-height: 100%;
}

body {
  font-family: "Avenir Next", "PingFang SC", "Hiragino Sans GB", "Source Han Sans SC", sans-serif;
  color: var(--ink);
  background:
    radial-gradient(circle at top left, rgba(176, 82, 42, 0.18), transparent 22%),
    radial-gradient(circle at bottom right, rgba(39, 103, 73, 0.16), transparent 20%),
    linear-gradient(135deg, #f7f1e2 0%, #efe6d0 44%, #e4d7be 100%);
}

.shell {
  display: grid;
  grid-template-columns: 340px minmax(0, 1fr);
  min-height: 100vh;
}

.sidebar {
  padding: 28px 22px;
  border-right: 1px solid var(--line);
  background: rgba(255, 248, 234, 0.72);
  backdrop-filter: blur(18px);
}

.brand h1,
.hero h2,
.quiz-card h3,
.completion-state h3,
.empty-state h3 {
  font-family: "Iowan Old Style", "Palatino Linotype", "Times New Roman", serif;
  letter-spacing: -0.03em;
}

.eyebrow {
  margin: 0 0 8px;
  font-size: 12px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent-strong);
}

.brand h1 {
  margin: 0;
  font-size: 40px;
  line-height: 1;
}

.brand-copy {
  margin: 14px 0 0;
  color: var(--ink-soft);
  line-height: 1.7;
}

.sidebar-block {
  margin-top: 26px;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 20px;
  background: var(--panel);
  box-shadow: var(--shadow);
}

.sidebar-block h2 {
  margin: 0 0 14px;
  font-size: 16px;
}

.rule-list {
  margin: 0;
  padding-left: 18px;
  color: var(--ink-soft);
  line-height: 1.75;
}

.block-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.deck-list {
  display: grid;
  gap: 12px;
}

.deck-item {
  width: 100%;
  padding: 14px 14px 12px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.55);
  color: inherit;
  text-align: left;
  cursor: pointer;
  transition: transform 180ms ease, border-color 180ms ease, background 180ms ease;
}

.deck-item:hover,
.deck-item:focus-visible {
  transform: translateY(-1px);
  border-color: rgba(176, 82, 42, 0.35);
  outline: none;
}

.deck-item.active {
  border-color: rgba(176, 82, 42, 0.5);
  background: linear-gradient(135deg, rgba(176, 82, 42, 0.14), rgba(255, 255, 255, 0.85));
}

.deck-item-head,
.deck-item-foot {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
}

.deck-item-head strong {
  font-size: 15px;
}

.deck-item p {
  margin: 8px 0 12px;
  color: var(--ink-soft);
  line-height: 1.6;
  font-size: 13px;
}

.status-pill,
.mini-pill,
.type-badge,
.date-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 999px;
  font-size: 12px;
  padding: 6px 10px;
  white-space: nowrap;
}

.status-pill.due,
.type-badge.due {
  background: var(--accent-wash);
  color: var(--accent-strong);
}

.status-pill.done {
  background: var(--success-wash);
  color: var(--success);
}

.mini-pill {
  background: rgba(42, 33, 23, 0.06);
  color: var(--ink-soft);
}

.main {
  padding: 30px;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 24px;
  align-items: end;
}

.hero h2 {
  margin: 0;
  font-size: clamp(36px, 4vw, 58px);
  line-height: 0.98;
}

.hero-copy {
  margin: 14px 0 0;
  color: var(--ink-soft);
  font-size: 17px;
  line-height: 1.75;
  max-width: 820px;
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(3, minmax(120px, 1fr));
  gap: 12px;
}

.stat-card,
.deck-meta,
.quiz-card,
.completion-state,
.empty-state {
  border: 1px solid var(--line);
  border-radius: 24px;
  background: var(--panel-strong);
  box-shadow: var(--shadow);
}

.stat-card {
  min-width: 120px;
  padding: 16px;
}

.stat-label {
  display: block;
  margin-bottom: 10px;
  font-size: 12px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-soft);
}

.stat-card strong {
  font-size: 32px;
}

.deck-meta {
  margin-top: 22px;
  padding: 18px 20px;
  display: grid;
  gap: 8px;
}

.deck-meta h3 {
  margin: 0;
  font-size: 24px;
}

.deck-meta p {
  margin: 0;
  color: var(--ink-soft);
  line-height: 1.7;
}

.tag-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.tag {
  display: inline-flex;
  padding: 6px 10px;
  border-radius: 999px;
  background: rgba(42, 33, 23, 0.06);
  color: var(--ink-soft);
  font-size: 12px;
}

.card-stage {
  margin-top: 24px;
}

.quiz-card,
.completion-state,
.empty-state {
  padding: 28px;
}

.card-topline {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.date-badge {
  background: rgba(42, 33, 23, 0.06);
  color: var(--ink-soft);
}

.type-badge {
  background: rgba(176, 82, 42, 0.12);
  color: var(--accent-strong);
}

.progress-wrap {
  margin-top: 18px;
}

.progress-copy {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  font-size: 13px;
  color: var(--ink-soft);
}

.progress-bar {
  margin-top: 10px;
  height: 10px;
  border-radius: 999px;
  background: rgba(42, 33, 23, 0.08);
  overflow: hidden;
}

.progress-value {
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, #c56a39 0%, #8f3f1d 100%);
  width: 0;
  transition: width 220ms ease;
}

.card-prompt {
  margin: 22px 0 8px;
  font-size: clamp(28px, 3vw, 40px);
  line-height: 1.15;
}

.card-hint {
  margin: 0 0 20px;
  color: var(--ink-soft);
  line-height: 1.7;
}

.options-grid {
  display: grid;
  gap: 12px;
}

.option-btn {
  width: 100%;
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 14px;
  align-items: start;
  padding: 16px 18px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: #fffdf8;
  color: inherit;
  text-align: left;
  cursor: pointer;
  transition: transform 180ms ease, border-color 180ms ease, background 180ms ease;
}

.option-btn:hover,
.option-btn:focus-visible {
  transform: translateY(-1px);
  border-color: rgba(176, 82, 42, 0.35);
  outline: none;
}

.option-btn.locked {
  cursor: default;
}

.option-btn.correct {
  border-color: rgba(39, 103, 73, 0.38);
  background: rgba(39, 103, 73, 0.08);
}

.option-btn.wrong {
  border-color: rgba(155, 44, 44, 0.38);
  background: rgba(155, 44, 44, 0.08);
}

.option-key {
  width: 30px;
  height: 30px;
  border-radius: 50%;
  background: rgba(42, 33, 23, 0.06);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 13px;
  color: var(--ink-soft);
}

.option-btn p {
  margin: 0;
  color: var(--ink);
  line-height: 1.65;
}

.feedback-panel {
  margin-top: 20px;
  padding: 18px 20px;
  border-radius: 20px;
  background: linear-gradient(135deg, rgba(255, 246, 231, 0.96), rgba(248, 241, 224, 0.96));
  border: 1px solid rgba(176, 82, 42, 0.14);
}

.feedback-panel.success {
  background: linear-gradient(135deg, rgba(235, 251, 239, 0.96), rgba(245, 255, 247, 0.96));
  border-color: rgba(39, 103, 73, 0.18);
}

.feedback-panel.error {
  background: linear-gradient(135deg, rgba(255, 241, 241, 0.96), rgba(255, 250, 250, 0.96));
  border-color: rgba(155, 44, 44, 0.16);
}

.feedback-title {
  margin: 0 0 8px;
  font-weight: 700;
}

.feedback-reason,
.feedback-usage {
  margin: 0;
  color: var(--ink-soft);
  line-height: 1.7;
}

.feedback-usage {
  margin-top: 8px;
}

.card-actions,
.completion-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 22px;
}

.primary-btn,
.ghost-btn {
  appearance: none;
  border-radius: 999px;
  padding: 11px 18px;
  font: inherit;
  cursor: pointer;
  transition: transform 180ms ease, box-shadow 180ms ease, border-color 180ms ease;
}

.primary-btn {
  border: 1px solid transparent;
  background: linear-gradient(135deg, #b0522a, #8f3f1d);
  color: #fff9f2;
  box-shadow: 0 10px 24px rgba(143, 63, 29, 0.18);
}

.ghost-btn {
  border: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.66);
  color: var(--ink);
}

.primary-btn:hover,
.primary-btn:focus-visible,
.ghost-btn:hover,
.ghost-btn:focus-visible {
  transform: translateY(-1px);
  outline: none;
}

.completion-state p,
.empty-state p {
  margin: 0;
  color: var(--ink-soft);
  line-height: 1.7;
}

.completion-state h3,
.empty-state h3 {
  margin: 8px 0 12px;
  font-size: clamp(28px, 3vw, 42px);
}

@media (max-width: 1080px) {
  .shell {
    grid-template-columns: 1fr;
  }

  .sidebar {
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

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

@media (max-width: 640px) {
  .main,
  .sidebar {
    padding: 18px;
  }

  .hero-stats {
    grid-template-columns: 1fr;
  }

  .quiz-card,
  .completion-state,
  .empty-state {
    padding: 20px;
  }

  .card-prompt {
    font-size: 28px;
  }
}