:root {
  --bg: #f6f7fb;
  --surface: #ffffff;
  --border: #e6e8f0;
  --text: #1f2335;
  --muted: #5c6380;
  --primary: #6c5ce7;
  --primary-soft: rgba(108, 92, 231, 0.1);
  --accent: #00c2ff;
  --success: #22c55e;
  --warning: #f59e0b;
  --radius-lg: 20px;
  --radius-md: 14px;
  --shadow-lg: 0 18px 40px rgba(63, 63, 94, 0.12);
  --shadow-md: 0 10px 24px rgba(99, 105, 144, 0.12);
  --font-body: -apple-system, BlinkMacSystemFont, 'SF Pro Text', 'Segoe UI', Roboto, Helvetica, Arial,
    'PingFang SC', 'Microsoft YaHei', 'Noto Sans CJK SC', sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, 'Liberation Mono', 'Courier New',
    monospace;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html,
body {
  height: 100%;
}

body {
  margin: 0;
  background: linear-gradient(135deg, #eef1ff 0%, #f7f7ff 48%, #f1fbff 100%);
  color: var(--text);
  font-family: var(--font-body);
  line-height: 1.6;
}

a,
button {
  font-family: var(--font-body);
}

a {
  color: var(--primary);
  text-decoration: none;
}

button {
  border: none;
  background: none;
  padding: 0;
  cursor: pointer;
}

.page {
  max-width: 1100px;
  margin: 32px auto;
  padding: 0 20px 48px;
}

.shell {
  background: var(--surface);
  border-radius: var(--radius-lg);
  border: 1px solid rgba(230, 232, 240, 0.6);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
}

header.hero {
  padding: 32px clamp(20px, 4vw, 48px);
  background: linear-gradient(120deg, rgba(108, 92, 231, 0.08), rgba(0, 194, 255, 0.08));
  border-bottom: 1px solid rgba(230, 232, 240, 0.7);
}

.hero h1 {
  margin: 0 0 12px;
  font-size: clamp(26px, 4.4vw, 36px);
  letter-spacing: 0.6px;
}

.hero .subtitle {
  margin: 0;
  font-size: 15px;
  color: var(--muted);
}

.hero-nav {
  margin-top: 18px;
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.hero-chip {
  appearance: none;
  border: 1px solid rgba(108, 92, 231, 0.14);
  background: rgba(255, 255, 255, 0.78);
  color: var(--muted);
  padding: 8px 14px;
  border-radius: 999px;
  font-size: 13px;
  font-family: inherit;
  cursor: pointer;
  transition: background 0.18s ease, color 0.18s ease, border-color 0.18s ease, box-shadow 0.18s ease;
}

.hero-chip:hover {
  border-color: rgba(108, 92, 231, 0.3);
  color: var(--primary);
}

.hero-chip.is-active {
  background: var(--primary);
  color: #fff;
  border-color: rgba(108, 92, 231, 0.9);
  box-shadow: 0 12px 24px rgba(108, 92, 231, 0.28);
}

.hero-chip:focus-visible {
  outline: 2px solid rgba(108, 92, 231, 0.85);
  outline-offset: 2px;
}

.chip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.7);
  border: 1px solid rgba(108, 92, 231, 0.15);
  font-size: 13px;
  color: var(--muted);
}

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

.content {
  padding: clamp(20px, 4.6vw, 42px);
  display: grid;
  gap: clamp(24px, 3vw, 36px);
}

.topics {
  display: grid;
  gap: 16px;
}

.topics h2 {
  margin: 0 0 4px;
  font-size: 18px;
}

.topics p {
  margin: 0;
  font-size: 14px;
  color: var(--muted);
}

.toolbar {
  margin-top: 18px;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.search-box {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px 16px;
  border-radius: 14px;
  border: 1px solid rgba(108, 92, 231, 0.18);
  background: rgba(255, 255, 255, 0.84);
  box-shadow: 0 10px 24px rgba(108, 92, 231, 0.08);
}

.search-box input {
  flex: 1;
  border: none;
  background: transparent;
  font-size: 14px;
  color: var(--text);
  outline: none;
}

.search-box input::placeholder {
  color: rgba(92, 99, 128, 0.7);
}

.search-icon {
  font-size: 15px;
}

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

.hero-filters {
  display: none;
}

@media (max-width: 640px) {
  .hero-nav {
    display: none;
  }

  .hero-filters {
    display: flex;
  }
}

.filter {
  padding: 8px 14px;
  border-radius: 999px;
  border: 1px solid rgba(108, 92, 231, 0.12);
  background: rgba(255, 255, 255, 0.78);
  font-size: 13px;
  color: var(--muted);
  transition: background 0.18s ease, color 0.18s ease, border-color 0.18s ease, box-shadow 0.18s ease;
}

.filter:hover {
  border-color: rgba(108, 92, 231, 0.26);
  color: var(--primary);
}

.filter.is-active {
  background: var(--primary);
  color: #fff;
  border-color: rgba(108, 92, 231, 0.9);
  box-shadow: 0 12px 24px rgba(108, 92, 231, 0.28);
}

.recommendations {
  margin-top: 24px;
  padding: 20px 22px;
  border-radius: var(--radius-lg);
  background: linear-gradient(130deg, rgba(108, 92, 231, 0.08), rgba(0, 194, 255, 0.08));
  border: 1px solid rgba(108, 92, 231, 0.18);
  display: grid;
  gap: 18px;
}

.recommend-header {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

.recommend-header h3 {
  margin: 0;
  font-size: 17px;
}

.recommend-header span {
  font-size: 13px;
  color: var(--muted);
}

.recommend-grid {
  display: grid;
  gap: 12px;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

.category-sections {
  display: grid;
  gap: 28px;
  margin-top: 16px;
}

.category-section {
  display: grid;
  gap: 14px;
}

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

.category-section__header h3 {
  margin: 0;
  font-size: 16px;
  color: var(--text);
}

.category-section__action {
  appearance: none;
  border: none;
  background: none;
  color: var(--primary);
  font-size: 13px;
  cursor: pointer;
  padding: 4px 6px;
  border-radius: 6px;
  transition: background 0.18s ease;
}

.category-section__action:hover,
.category-section__action:focus-visible {
  background: rgba(108, 92, 231, 0.12);
  outline: none;
}

.category-section__grid {
  display: grid;
  gap: 12px;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

.topic-grid {
  margin-top: 18px;
  display: grid;
  gap: 14px;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

.topic-card {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 16px 18px;
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  background: rgba(255, 255, 255, 0.82);
  box-shadow: var(--shadow-md);
  transition: transform 0.18s ease, box-shadow 0.18s ease, border-color 0.18s ease;
  text-align: left;
  text-decoration: none;
  color: inherit;
}

.topic-card[aria-current='true'],
.topic-card:hover {
  transform: translateY(-3px);
  border-color: rgba(108, 92, 231, 0.16);
  box-shadow: 0 16px 32px rgba(108, 92, 231, 0.18);
}

.topic-card small {
  font-size: 12px;
  color: var(--muted);
}

.topic-card h3 {
  margin: 0;
  font-size: 16px;
  line-height: 1.4;
}

.topic-card .tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.topic-card--recommend {
  border-color: rgba(108, 92, 231, 0.18);
}

.topic-card--recommend[aria-current='true'],
.topic-card--recommend:hover {
  border-color: rgba(108, 92, 231, 0.38);
  box-shadow: 0 16px 32px rgba(108, 92, 231, 0.22);
}

.topic-card:focus-visible {
  outline: 2px solid var(--primary);
  outline-offset: 2px;
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 4px 9px;
  font-size: 12px;
  border-radius: 999px;
  background: var(--primary-soft);
  color: var(--primary);
}

.result-summary {
  margin: 8px 0 0;
  font-size: 13px;
  color: var(--muted);
}

.empty {
  margin: 12px 0 0;
  font-size: 14px;
  color: var(--muted);
  text-align: center;
}

.detail {
  border: 1px solid rgba(230, 232, 240, 0.8);
  border-radius: var(--radius-lg);
  background: rgba(255, 255, 255, 0.95);
  box-shadow: var(--shadow-md);
  padding: clamp(22px, 3.8vw, 40px);
}

.detail header {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 20px;
}

.detail .category {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  color: var(--muted);
}

.detail h2 {
  margin: 0;
  font-size: clamp(22px, 3.6vw, 30px);
}

.detail .intro {
  margin: 0;
  font-size: 14px;
  color: var(--muted);
}

.facts {
  margin-top: 18px;
  display: grid;
  gap: 12px;
  grid-template-columns: repeat(auto-fit, minmax(130px, 1fr));
}

.fact {
  background: rgba(247, 248, 255, 0.88);
  border: 1px solid rgba(108, 92, 231, 0.12);
  border-radius: var(--radius-md);
  padding: 12px 14px;
  font-size: 13px;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.fact span {
  font-size: 12px;
  color: var(--muted);
}

.fact strong {
  font-size: 15px;
  font-weight: 600;
}

.block {
  display: grid;
  gap: 12px;
  margin-top: 24px;
}

.block h3 {
  margin: 0;
  font-size: 18px;
}

.list {
  margin: 0;
  padding-left: 20px;
}

.list li {
  margin-bottom: 8px;
  color: var(--muted);
  font-size: 14px;
}

.list li strong {
  color: var(--text);
}

.callout {
  border-radius: var(--radius-md);
  padding: 16px;
  border: 1px solid rgba(34, 197, 94, 0.26);
  background: rgba(34, 197, 94, 0.08);
  color: #066a36;
  font-size: 14px;
}

.callout[data-variant='warning'] {
  background: rgba(245, 158, 11, 0.1);
  border-color: rgba(245, 158, 11, 0.25);
  color: #824200;
}

.extras {
  display: grid;
  gap: 14px;
  margin-top: 20px;
}

.extra-card {
  border-radius: var(--radius-md);
  padding: 16px;
  background: rgba(255, 255, 255, 0.9);
  border: 1px solid rgba(230, 232, 240, 0.8);
  box-shadow: var(--shadow-md);
}

.extra-card h4 {
  margin: 0 0 8px;
  font-size: 16px;
}

.extra-card p {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
}

.resources {
  display: grid;
  gap: 10px;
  margin-top: 12px;
}

.resource-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
}

.resource-link span {
  color: var(--muted);
}

.footer {
  margin-top: 12px;
  padding-top: 18px;
  border-top: 1px solid rgba(230, 232, 240, 0.7);
  font-size: 12px;
  color: var(--muted);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 10px;
}

.footer .mono {
  font-family: var(--font-mono);
  color: var(--text);
}

@media (max-width: 720px) {
  .page {
    margin: 20px auto 32px;
    padding: 0 16px 32px;
  }

  .shell {
    border-radius: 18px;
  }

  .toolbar {
    gap: 12px;
  }

  .recommend-grid,
  .topic-grid {
    grid-template-columns: 1fr;
  }

  .detail {
    padding: 20px;
  }

  .block {
    gap: 10px;
  }
}