@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&family=JetBrains+Mono:wght@400;500&display=swap');

:root {
  --color-bg: #ffffff;
  --color-bg-secondary: #f8fafc;
  --color-bg-tertiary: #f1f5f9;
  --color-text: #0f172a;
  --color-text-secondary: #475569;
  --color-text-muted: #64748b;
  --color-border: #e2e8f0;
  --color-primary: #2563eb;
  --color-primary-hover: #1d4ed8;
  --color-primary-light: #dbeafe;
  --color-accent: #06b6d4;
  --color-success: #10b981;
  --color-warning: #f59e0b;
  --color-danger: #ef4444;
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --font-sans: 'Inter', 'PingFang SC', 'Microsoft YaHei', system-ui, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'SF Mono', Consolas, monospace;
  --header-height: 64px;
  --transition: all 0.2s ease;
}

[data-theme="dark"] {
  --color-bg: #0a0a0f;
  --color-bg-secondary: #12121a;
  --color-bg-tertiary: #1a1a25;
  --color-text: #f1f5f9;
  --color-text-secondary: #94a3b8;
  --color-text-muted: #64748b;
  --color-border: #27273a;
  --color-primary: #3b82f6;
  --color-primary-hover: #60a5fa;
  --color-primary-light: rgba(59, 130, 246, 0.15);
  --color-accent: #22d3ee;
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.3);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.4), 0 2px 4px -2px rgb(0 0 0 / 0.4);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.5), 0 4px 6px -4px rgb(0 0 0 / 0.5);
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; scroll-padding-top: calc(var(--header-height) + 24px); }
body {
  font-family: var(--font-sans);
  background-color: var(--color-bg);
  color: var(--color-text);
  line-height: 1.7;
  font-size: 15px;
  transition: background-color 0.3s ease, color 0.3s ease;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

/* Header */
.header {
  position: fixed; top: 0; left: 0; right: 0; height: var(--header-height);
  background: rgba(255,255,255,0.85); backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border); z-index: 1000;
  display: flex; align-items: center; justify-content: space-between; padding: 0 24px;
  transition: var(--transition);
}
[data-theme="dark"] .header { background: rgba(10,10,15,0.85); }

.header-left, .header-right { display: flex; align-items: center; gap: 16px; }

.logo { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 18px; color: var(--color-text); text-decoration: none; }
.logo:hover { text-decoration: none; color: var(--color-text); }
.logo-icon {
  width: 32px; height: 32px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  border-radius: var(--radius-sm); display: flex; align-items: center; justify-content: center;
  color: white; font-size: 14px; font-weight: 700;
}

.header-btn {
  display: flex; align-items: center; gap: 6px; padding: 8px 14px; border-radius: var(--radius-sm);
  font-size: 13px; font-weight: 500; color: var(--color-text-secondary); background: transparent;
  border: 1px solid transparent; cursor: pointer; transition: var(--transition); text-decoration: none;
}
.header-btn:hover { background: var(--color-bg-tertiary); color: var(--color-text); text-decoration: none; }
.theme-toggle { width: 40px; height: 40px; padding: 0; display: flex; align-items: center; justify-content: center; }

.kbd {
  display: inline-flex; align-items: center; justify-content: center; min-width: 24px; padding: 2px 6px;
  background: var(--color-bg-tertiary); border: 1px solid var(--color-border); border-radius: 4px;
  font-family: var(--font-mono); font-size: 12px; color: var(--color-text-secondary); box-shadow: 0 1px 0 var(--color-border);
}

/* Main */
.main { margin-top: var(--header-height); }

/* Hero */
.hero {
  position: relative; overflow: hidden;
  padding: 80px 24px 48px; text-align: center;
}
.hero::before {
  content: ''; position: absolute; inset: 0;
  background: radial-gradient(ellipse at 50% 0%, var(--color-primary-light) 0%, transparent 60%);
  opacity: 0.6; pointer-events: none;
}
.hero-inner { position: relative; max-width: 800px; margin: 0 auto; }
.hero-title {
  font-size: 52px; font-weight: 800; letter-spacing: -0.03em; line-height: 1.1; margin-bottom: 20px;
  background: linear-gradient(135deg, var(--color-text) 0%, var(--color-primary) 100%);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text;
}
[data-theme="dark"] .hero-title { background: linear-gradient(135deg, #f1f5f9 0%, var(--color-accent) 100%); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
.hero-desc { font-size: 18px; color: var(--color-text-secondary); line-height: 1.7; max-width: 640px; margin: 0 auto 28px; }
.hero-actions { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }

.button {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: 10px 18px; border-radius: var(--radius-sm); font-size: 14px; font-weight: 500;
  cursor: pointer; transition: var(--transition); border: none; text-decoration: none;
}
.button-primary { background: var(--color-primary); color: white; }
.button-primary:hover { background: var(--color-primary-hover); text-decoration: none; color: white; }
.button-secondary { background: var(--color-bg-tertiary); color: var(--color-text); border: 1px solid var(--color-border); }
.button-secondary:hover { background: var(--color-border); text-decoration: none; color: var(--color-text); }

/* Search bar in hero */
.hero-search { position: relative; max-width: 520px; margin: 0 auto 32px; }
.hero-search-input {
  width: 100%; padding: 14px 18px 14px 48px; border-radius: var(--radius-lg);
  border: 1px solid var(--color-border); background: var(--color-bg);
  color: var(--color-text); font-size: 15px; outline: none; transition: var(--transition);
  box-shadow: var(--shadow-sm);
}
.hero-search-input:focus { border-color: var(--color-primary); box-shadow: 0 0 0 3px var(--color-primary-light); }
.hero-search-icon { position: absolute; left: 16px; top: 50%; transform: translateY(-50%); color: var(--color-text-muted); width: 18px; height: 18px; }

/* Section blocks */
.section { padding: 0 24px 64px; max-width: 1200px; margin: 0 auto; }
.section-block { position: relative; }
.section-block + .section-block { padding-top: 48px; }
.section-block + .section-block::before {
  content: ''; position: absolute; top: 0; left: 24px; right: 24px; height: 1px;
  background: linear-gradient(90deg, transparent, var(--color-border) 20%, var(--color-border) 80%, transparent);
}

.section-header { display: flex; align-items: center; gap: 12px; margin-bottom: 24px; }
.section-header-icon { width: 32px; height: 32px; border-radius: var(--radius-sm); background: var(--color-primary-light); color: var(--color-primary); display: flex; align-items: center; justify-content: center; font-size: 16px; flex-shrink: 0; }
.section-header-title { font-size: 24px; font-weight: 700; color: var(--color-text); margin: 0; }

.category-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }

.category-card {
  background: var(--color-bg-secondary); border: 1px solid var(--color-border); border-radius: var(--radius-md);
  padding: 24px; transition: var(--transition); display: flex; flex-direction: column; gap: 16px;
}
.category-card:hover { border-color: var(--color-primary); transform: translateY(-2px); box-shadow: var(--shadow-md); }
.category-header { display: flex; align-items: center; gap: 12px; }
.category-icon {
  width: 40px; height: 40px; border-radius: var(--radius-sm); background: var(--color-primary-light); color: var(--color-primary);
  display: flex; align-items: center; justify-content: center; font-size: 18px; flex-shrink: 0;
}
.category-title { font-size: 16px; font-weight: 700; color: var(--color-text); }
.category-desc { font-size: 13px; color: var(--color-text-secondary); line-height: 1.5; margin-top: -10px; }
.category-docs { list-style: none; padding: 0; margin: 0; display: flex; flex-direction: column; gap: 8px; }
.category-docs li { margin: 0; }
.doc-link {
  display: flex; align-items: center; justify-content: space-between; gap: 8px;
  padding: 10px 12px; border-radius: var(--radius-sm); background: var(--color-bg); border: 1px solid var(--color-border);
  font-size: 14px; color: var(--color-text); text-decoration: none; transition: var(--transition);
}
.doc-link:hover { border-color: var(--color-primary); background: var(--color-bg-tertiary); text-decoration: none; color: var(--color-text); }
.doc-link-arrow { color: var(--color-text-muted); width: 14px; height: 14px; transition: var(--transition); }
.doc-link:hover .doc-link-arrow { color: var(--color-primary); transform: translateX(2px); }
.doc-tag {
  font-size: 11px; font-weight: 600; text-transform: uppercase; letter-spacing: 0.03em;
  padding: 2px 8px; border-radius: 999px; background: rgba(16,185,129,0.1); color: var(--color-success);
}
.doc-tag-new { background: rgba(16,185,129,0.1); color: var(--color-success); }
.doc-tag-wip { background: rgba(245,158,11,0.1); color: var(--color-warning); }
.doc-tag-popular { background: rgba(37,99,235,0.1); color: var(--color-primary); }

.doc-more-link {
  display: flex; align-items: center; justify-content: center;
  padding: 10px 12px; border-radius: var(--radius-sm);
  background: transparent; border: 1px dashed var(--color-border);
  font-size: 13px; color: var(--color-text-muted);
  text-decoration: none; transition: var(--transition);
}
.doc-more-link:hover { border-color: var(--color-primary); color: var(--color-primary); text-decoration: none; }

/* Footer */
.footer {
  border-top: 1px solid var(--color-border); padding: 32px 24px; text-align: center; font-size: 13px; color: var(--color-text-muted);
}
.footer-links { display: flex; justify-content: center; gap: 20px; margin-top: 12px; flex-wrap: wrap; }

/* Search modal */
.search-modal {
  position: fixed; inset: 0; background: rgba(0,0,0,0.5); z-index: 2000;
  display: none; align-items: flex-start; justify-content: center; padding-top: 120px;
}
.search-modal.active { display: flex; }
.search-modal-content {
  background: var(--color-bg); border-radius: var(--radius-lg); width: 100%; max-width: 600px; max-height: 60vh;
  box-shadow: var(--shadow-lg); overflow: hidden; border: 1px solid var(--color-border);
}
.search-modal-input { width: 100%; padding: 16px 20px; border: none; background: transparent; color: var(--color-text); font-size: 16px; outline: none; border-bottom: 1px solid var(--color-border); }
.search-results { max-height: calc(60vh - 60px); overflow-y: auto; padding: 8px; }
.search-result-item { padding: 12px 16px; border-radius: var(--radius-sm); cursor: pointer; transition: var(--transition); }
.search-result-item:hover { background: var(--color-bg-secondary); }
.search-result-title { font-weight: 500; font-size: 14px; margin-bottom: 2px; }
.search-result-desc { font-size: 13px; color: var(--color-text-muted); }
.search-empty { padding: 24px; text-align: center; color: var(--color-text-muted); font-size: 14px; }

/* Responsive */
@media (max-width: 1024px) {
  .category-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 640px) {
  .header { padding: 0 16px; }
  .hero { padding: 64px 16px 40px; }
  .hero-title { font-size: 34px; }
  .hero-desc { font-size: 16px; }
  .section { padding: 16px 16px 48px; }
  .category-grid { grid-template-columns: 1fr; }
  .header-btn span { display: none; }
  .header-btn { padding: 8px; }
}

::selection { background: var(--color-primary-light); color: var(--color-text); }
[data-theme="dark"] ::selection { background: rgba(59, 130, 246, 0.3); color: #f1f5f9; }