/* assets/css/style.css */
:root {
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  --color-bg: #ffffff;
  --color-text: #1d1d1f;
  --color-text-secondary: #6e6e73;
  --color-accent: #0071e3;
  --color-border: #d2d2d7;
  --color-card-bg: #f5f5f7;
  --max-width: 1200px;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-sans);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--color-accent); text-decoration: none; }
a:hover { text-decoration: underline; }

/* Navigation */
.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: 52px;
  background: rgba(255,255,255,0.8);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 24px;
  z-index: 100;
}

.nav-title { font-size: 16px; font-weight: 600; }

.nav-links { display: flex; gap: 20px; align-items: center; }
.nav-links a { font-size: 13px; color: var(--color-text); }

.nav-lang-btn {
  border: 1px solid var(--color-border);
  border-radius: 14px;
  padding: 4px 14px;
  font-size: 13px;
  background: transparent;
  cursor: pointer;
  color: var(--color-text);
}
.nav-lang-btn:hover { background: var(--color-card-bg); }

body { padding-top: 52px; }

/* Hero Section */
.hero {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 96px 24px 64px;
  text-align: center;
}
.hero h1 { font-size: 48px; font-weight: 700; letter-spacing: -0.02em; margin-bottom: 12px; }
.hero p { font-size: 20px; color: var(--color-text-secondary); margin-bottom: 8px; }
.hero .hero-meta { font-size: 14px; color: var(--color-text-secondary); }

.section {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 48px 24px;
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
  scroll-margin-top: 52px;
}
.section.visible { opacity: 1; transform: translateY(0); }

.section-title { font-size: 32px; font-weight: 700; margin-bottom: 4px; }
.section-count { font-size: 14px; color: var(--color-text-secondary); margin-bottom: 24px; }

/* Card Grid */
.card-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
}
@media (max-width: 1024px) { .card-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 640px) { .card-grid { grid-template-columns: 1fr; } }

.card {
  background: var(--color-card-bg);
  border-radius: 16px;
  overflow: hidden;
  transition: box-shadow 0.2s ease;
}
.card:hover { box-shadow: 0 4px 16px rgba(0,0,0,0.08); }

.card-header { padding: 20px; cursor: pointer; }
.card-header h3 { font-size: 18px; font-weight: 600; margin-bottom: 2px; }
.card-header .card-en-name { font-size: 13px; color: var(--color-text-secondary); margin-bottom: 8px; }
.card-header .card-summary { font-size: 14px; color: var(--color-text); }

.card-body {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease;
  padding: 0 20px;
}
.card.expanded .card-body { max-height: 480px; padding: 0 20px 20px; }

.card-body .what-it-does { font-size: 13px; margin-bottom: 12px; }
.tag {
  display: inline-block;
  font-size: 12px;
  background: #e8e8ed;
  border-radius: 10px;
  padding: 2px 10px;
  margin: 0 6px 6px 0;
}
.card-expand-btn {
  display: inline-block;
  margin-top: 8px;
  font-size: 13px;
  font-weight: 500;
}

/* Detail Page */
.breadcrumb { max-width: var(--max-width); margin: 24px auto 0; padding: 0 24px; font-size: 13px; color: var(--color-text-secondary); }
.breadcrumb a { color: var(--color-text-secondary); }

.detail-header { max-width: var(--max-width); margin: 0 auto; padding: 24px 24px 32px; }
.detail-header h1 { font-size: 40px; font-weight: 700; margin-bottom: 4px; }
.detail-header .detail-en-name { font-size: 18px; color: var(--color-text-secondary); margin-bottom: 12px; }
.detail-header .github-link {
  display: inline-block;
  border: 1px solid var(--color-border);
  border-radius: 14px;
  padding: 6px 16px;
  font-size: 13px;
  margin-top: 12px;
}

.detail-body {
  max-width: 720px;
  margin: 0 auto;
  padding: 0 24px 64px;
  font-size: 16px;
}
.detail-body h2 { font-size: 24px; margin: 32px 0 12px; }
.detail-body p { margin-bottom: 16px; }
.detail-body ul, .detail-body ol { margin: 0 0 16px 20px; }
.detail-body li { margin-bottom: 6px; }
.detail-body pre {
  background: #1d1d1f;
  color: #f5f5f7;
  border-radius: 12px;
  padding: 16px;
  overflow-x: auto;
  margin-bottom: 16px;
  font-size: 13px;
}
.detail-body code { font-family: "SF Mono", Consolas, monospace; }
.detail-body blockquote {
  border-left: 3px solid var(--color-accent);
  padding-left: 16px;
  color: var(--color-text-secondary);
  margin-bottom: 16px;
}

.related-cases { max-width: var(--max-width); margin: 0 auto; padding: 0 24px 64px; }
.related-cases h2 { font-size: 20px; margin-bottom: 16px; }
.back-link { display: inline-block; margin: 32px 24px 0; font-size: 14px; }

/* Footer */
.footer {
  border-top: 1px solid var(--color-border);
  padding: 32px 24px;
  text-align: center;
  font-size: 13px;
  color: var(--color-text-secondary);
  margin-top: 32px;
}