:root {
  --primary-start: #3a7bd5;
  --primary-end: #4b6cb7;
  --bg: #f5f7fa;
  --text: #1a202c;
  --text-muted: #718096;
  --card-bg: #ffffff;
  --accent: #3a7bd5;
  --accent-dark: #2f5fa8;
  --border: #e2e8f0;
  --shadow-card: 0 4px 24px rgba(58, 123, 213, 0.1);
  --max-width: 640px;
  --radius: 12px;
  --radius-card: 20px;
  --icon-tint-1: #e8f2ff;
  --icon-tint-2: #e8faf0;
  --icon-tint-3: #fff4e6;
  --icon-tint-4: #f3e8ff;
  --icon-tint-5: #ffe8f0;
  --icon-tint-6: #e6fffa;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
}

/* ===== Home page ===== */
.home-page {
  background: var(--bg);
}

.home-hero {
  background: linear-gradient(180deg, var(--primary-start) 0%, var(--primary-end) 100%);
  color: #fff;
  padding: 28px 20px 24px;
  text-align: center;
}

.home-title {
  font-size: 1.375rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  margin-bottom: 16px;
}

.home-intro {
  font-size: 0.8125rem;
  line-height: 1.7;
  color: rgba(255, 255, 255, 0.92);
  text-align: left;
  max-width: var(--max-width);
  margin: 0 auto;
}

.home-stats-wrap {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 16px 8px;
}

.home-stats {
  display: flex;
  justify-content: center;
  padding: 16px;
  background: var(--card-bg);
  border-radius: var(--radius-card);
  box-shadow: var(--shadow-card);
}

.stat-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
}

.stat-item:not(:last-child)::after {
  display: none;
}

.stat-value {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--accent);
  line-height: 1.2;
}

.stat-label {
  font-size: 0.6875rem;
  color: var(--text-muted);
}

.home-main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 16px 16px 12px;
}

.home-card {
  background: var(--card-bg);
  border-radius: var(--radius-card);
  box-shadow: var(--shadow-card);
  padding: 18px 14px 22px;
}

.section-title {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 1rem;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 18px;
  padding: 0 4px;
}

.section-bar {
  display: inline-block;
  width: 4px;
  height: 16px;
  background: var(--accent);
  border-radius: 2px;
  flex-shrink: 0;
}

.home-page .icon-grid {
  --grid-col-gap: 8px;
  --grid-cols: 3;
  --icon-max: 56px;
  padding: 0;
}

.home-page .grid-item {
  gap: 10px;
}

.home-page .icon-box {
  width: 56px;
  height: 56px;
  max-width: 56px;
  aspect-ratio: 1;
  border-radius: 50%;
  border: none;
  box-shadow: none;
}

.home-page .grid-item:nth-child(6n + 1) .icon-box { background: var(--icon-tint-1); }
.home-page .grid-item:nth-child(6n + 2) .icon-box { background: var(--icon-tint-2); }
.home-page .grid-item:nth-child(6n + 3) .icon-box { background: var(--icon-tint-3); }
.home-page .grid-item:nth-child(6n + 4) .icon-box { background: var(--icon-tint-4); }
.home-page .grid-item:nth-child(6n + 5) .icon-box { background: var(--icon-tint-5); }
.home-page .grid-item:nth-child(6n + 6) .icon-box { background: var(--icon-tint-6); }

.home-page .grid-label {
  font-size: 0.75rem;
  color: var(--text);
  font-weight: 500;
}

.home-page .grid-item:hover .icon-box {
  box-shadow: 0 4px 12px rgba(58, 123, 213, 0.18);
}

.home-footer {
  background: var(--bg);
  border-top: none;
  margin-top: 0;
  padding-top: 8px;
  color: var(--text-muted);
}

.home-footer a {
  color: var(--accent);
}

a {
  color: inherit;
  text-decoration: none;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 16px 32px;
}

/* Legacy header (detail pages) */
.site-header {
  padding: 20px 0 12px;
  text-align: left;
  font-size: 0.875rem;
  color: var(--text-muted);
  line-height: 1.5;
}

/* Grid (detail / fallback) */
.icon-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px 12px;
  padding: 8px 0 24px;
}

.grid-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  cursor: pointer;
  transition: transform 0.2s ease;
}

.grid-item:hover {
  transform: translateY(-2px);
}

.grid-item:active {
  transform: scale(0.97);
}

.icon-box {
  width: 100%;
  aspect-ratio: 1;
  max-width: 96px;
  background: var(--icon-tint-1);
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  border: none;
  overflow: hidden;
}

.icon-box svg {
  width: 72%;
  height: 72%;
}

.grid-label {
  font-size: 0.8125rem;
  text-align: center;
  color: var(--text);
  line-height: 1.3;
}

/* Footer */
.site-footer {
  text-align: center;
  padding: 24px 16px 32px;
  font-size: 0.75rem;
  color: var(--text-muted);
  line-height: 1.8;
  border-top: 1px solid var(--border);
  margin-top: 8px;
}

.site-footer a {
  color: #5a7a9a;
}

/* Detail page */
.detail-page {
  padding-bottom: 48px;
}

.back-link {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 16px 0 8px;
  font-size: 0.875rem;
  color: var(--accent);
}

.back-link:hover {
  opacity: 0.8;
}

.detail-hero {
  text-align: center;
  padding: 16px 0 24px;
}

.detail-icon-link {
  display: block;
  width: fit-content;
  margin: 0 auto 12px;
}

.detail-icon-link:hover .detail-icon {
  border-color: var(--accent);
}

.detail-icon {
  width: 88px;
  height: 88px;
  margin: 0 auto;
  background: var(--card-bg);
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--border);
}

.detail-icon svg {
  width: 64%;
  height: 64%;
}

.detail-title {
  font-size: 1.5rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.detail-subtitle {
  font-size: 0.875rem;
  color: var(--text-muted);
}

.content-section {
  margin-bottom: 28px;
}

.content-section h2 {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--accent);
  margin-bottom: 12px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--border);
}

.content-section p {
  margin-bottom: 12px;
  text-align: justify;
}

.content-section p strong {
  color: var(--text);
  font-size: 1rem;
}

.content-section .school-title {
  font-size: 1.0625rem;
  font-weight: 600;
  color: var(--accent);
  margin: 24px 0 12px;
  padding-left: 10px;
  border-left: 3px solid var(--accent);
}

.content-section ol,
.content-section ul {
  padding-left: 1.25rem;
  margin-bottom: 12px;
}

.content-section li {
  margin-bottom: 8px;
}

.content-section li::marker {
  color: var(--accent);
}

.analysis-flow {
  list-style: decimal;
  padding-left: 1.5rem;
  margin-bottom: 16px;
}

.analysis-flow li {
  margin-bottom: 12px;
  padding-left: 4px;
}

.analysis-flow li strong {
  color: var(--accent);
}

.step-list {
  list-style: none;
  padding-left: 0;
  counter-reset: step;
}

.step-list li {
  counter-increment: step;
  padding-left: 2rem;
  position: relative;
  margin-bottom: 14px;
}

.step-list li::before {
  content: counter(step);
  position: absolute;
  left: 0;
  top: 0;
  width: 1.5rem;
  height: 1.5rem;
  background: var(--accent);
  color: #fff;
  border-radius: 50%;
  font-size: 0.75rem;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
}

.tag-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 12px;
}

.tag {
  font-size: 0.75rem;
  padding: 4px 10px;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 20px;
  color: var(--text-muted);
}

@media (min-width: 480px) {
  .home-page .icon-grid {
    --icon-max: 64px;
  }

  .home-page .icon-box {
    width: 64px;
    height: 64px;
    max-width: 64px;
  }

  .home-page .grid-label {
    font-size: 0.8125rem;
  }

  .icon-box {
    max-width: 110px;
  }

  .grid-label {
    font-size: 0.875rem;
  }
}