:root {
  --color-bg: #ffffff;
  --color-text: #24292f;
  --color-text-muted: #656d76;
  --color-border: #d0d7de;
  --color-border-light: #e8ecf0;
  --color-primary: #0969da;
  --color-primary-hover: #0550ae;
  --color-sidebar-bg: #f6f8fa;
  --color-sidebar-active: #0969da;
  --color-code-bg: #f6f8fa;
  --color-header-bg: #24292f;
  --color-header-text: #ffffff;
  --sidebar-width: 260px;
  --content-max: 860px;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans", Helvetica, Arial, sans-serif;
  --font-mono: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --color-bg: #0d1117;
    --color-text: #c9d1d9;
    --color-text-muted: #8b949e;
    --color-border: #30363d;
    --color-border-light: #21262d;
    --color-primary: #58a6ff;
    --color-primary-hover: #79c0ff;
    --color-sidebar-bg: #161b22;
    --color-sidebar-active: #58a6ff;
    --color-code-bg: #161b22;
    --color-header-bg: #161b22;
    --color-header-text: #c9d1d9;
  }
}

[data-theme="dark"] {
  --color-bg: #0d1117;
  --color-text: #c9d1d9;
  --color-text-muted: #8b949e;
  --color-border: #30363d;
  --color-border-light: #21262d;
  --color-primary: #58a6ff;
  --color-primary-hover: #79c0ff;
  --color-sidebar-bg: #161b22;
  --color-sidebar-active: #58a6ff;
  --color-code-bg: #161b22;
  --color-header-bg: #161b22;
  --color-header-text: #c9d1d9;
}

[data-theme="light"] {
  --color-bg: #ffffff;
  --color-text: #24292f;
  --color-text-muted: #656d76;
  --color-border: #d0d7de;
  --color-border-light: #e8ecf0;
  --color-primary: #0969da;
  --color-primary-hover: #0550ae;
  --color-sidebar-bg: #f6f8fa;
  --color-sidebar-active: #0969da;
  --color-code-bg: #f6f8fa;
  --color-header-bg: #24292f;
  --color-header-text: #ffffff;
}

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

body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-text);
  background: var(--color-bg);
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--color-header-bg);
  border-bottom: 1px solid var(--color-border);
}

.header-inner {
  max-width: calc(var(--sidebar-width) + var(--content-max) + 80px);
  margin: 0 auto;
  padding: 0 24px;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.site-logo {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 18px;
  font-weight: 600;
  color: var(--color-header-text);
  text-decoration: none;
}

.site-logo-img {
  width: 28px;
  height: 28px;
  border-radius: 6px;
  flex-shrink: 0;
}

.header-nav {
  display: flex;
  align-items: center;
  gap: 16px;
}

.nav-link {
  color: var(--color-header-text);
  text-decoration: none;
  font-size: 14px;
  opacity: 0.85;
}
.nav-link:hover { opacity: 1; }

.lang-switch {
  display: inline-flex;
  align-items: center;
  padding: 4px 12px;
  border: 1px solid rgba(255,255,255,0.3);
  border-radius: 6px;
  color: var(--color-header-text);
  text-decoration: none;
  font-size: 13px;
  font-weight: 500;
  transition: border-color 0.15s;
}
.lang-switch:hover { border-color: rgba(255,255,255,0.6); }

.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  background: none;
  border: 1px solid rgba(255,255,255,0.3);
  border-radius: 6px;
  color: var(--color-header-text);
  cursor: pointer;
  font-size: 15px;
  line-height: 1;
  transition: border-color 0.15s;
  padding: 0;
}
.theme-toggle:hover { border-color: rgba(255,255,255,0.6); }

.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  color: var(--color-header-text);
  cursor: pointer;
  padding: 4px;
}

/* Layout */
.site-wrapper {
  max-width: calc(var(--sidebar-width) + var(--content-max) + 80px);
  margin: 0 auto;
  display: flex;
  min-height: calc(100vh - 56px - 60px);
}

/* Sidebar */
.sidebar {
  width: var(--sidebar-width);
  flex-shrink: 0;
  padding: 24px 16px 24px 24px;
  border-right: 1px solid var(--color-border-light);
  background: var(--color-sidebar-bg);
}

.sidebar-nav {
  display: flex;
  flex-direction: column;
  gap: 2px;
  position: sticky;
  top: 80px;
}

.sidebar-link {
  display: block;
  padding: 8px 12px;
  border-radius: 6px;
  color: var(--color-text);
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
  transition: background 0.15s;
}
.sidebar-link:hover { background: var(--color-border-light); }
.sidebar-link.active {
  color: var(--color-sidebar-active);
  background: rgba(9, 105, 218, 0.08);
}

/* Content */
.content {
  flex: 1;
  min-width: 0;
  max-width: var(--content-max);
  padding: 32px 40px 64px;
}

.page-content h1 { font-size: 32px; font-weight: 700; margin-bottom: 16px; padding-bottom: 12px; border-bottom: 1px solid var(--color-border-light); }
.home-content h1 { font-size: 32px; font-weight: 700; margin-bottom: 16px; }

h2 { font-size: 24px; font-weight: 600; margin: 32px 0 12px; padding-bottom: 8px; border-bottom: 1px solid var(--color-border-light); }
h3 { font-size: 18px; font-weight: 600; margin: 24px 0 8px; }
h4 { font-size: 16px; font-weight: 600; margin: 20px 0 8px; }

p { margin: 0 0 16px; }

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

ul, ol { margin: 0 0 16px; padding-left: 24px; }
li { margin-bottom: 4px; }

blockquote {
  margin: 0 0 16px;
  padding: 12px 16px;
  border-left: 4px solid var(--color-primary);
  background: var(--color-code-bg);
  color: var(--color-text-muted);
  border-radius: 0 6px 6px 0;
}
blockquote p:last-child { margin-bottom: 0; }

code {
  font-family: var(--font-mono);
  font-size: 85%;
  background: var(--color-code-bg);
  padding: 2px 6px;
  border-radius: 4px;
}

pre {
  margin: 0 0 16px;
  padding: 16px;
  background: var(--color-code-bg);
  border-radius: 8px;
  overflow-x: auto;
  border: 1px solid var(--color-border-light);
}
pre code {
  background: none;
  padding: 0;
  font-size: 13px;
  line-height: 1.5;
}

table {
  width: 100%;
  margin: 0 0 16px;
  border-collapse: collapse;
  font-size: 14px;
}
th, td {
  padding: 8px 12px;
  border: 1px solid var(--color-border);
  text-align: left;
}
th {
  background: var(--color-sidebar-bg);
  font-weight: 600;
}
tr:hover td { background: var(--color-code-bg); }

img { max-width: 100%; height: auto; }

hr { border: none; border-top: 1px solid var(--color-border-light); margin: 32px 0; }

/* Home page hero */
.hero {
  text-align: center;
  padding: 48px 0 32px;
}
.hero-logo {
  width: 96px;
  height: 96px;
  border-radius: 20px;
  margin-bottom: 16px;
  display: block;
  margin-left: auto;
  margin-right: auto;
}
.hero h1 { border-bottom: none; font-size: 40px; margin-bottom: 8px; }
.hero .tagline { font-size: 20px; color: var(--color-text-muted); margin-bottom: 24px; }
.hero-actions {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}
.hero-btn {
  display: inline-flex;
  align-items: center;
  padding: 10px 24px;
  border-radius: 8px;
  font-weight: 600;
  font-size: 15px;
  text-decoration: none;
  transition: all 0.15s;
}
.hero-btn.primary {
  background: var(--color-primary);
  color: #fff;
}
.hero-btn.primary:hover { background: var(--color-primary-hover); text-decoration: none; }
.hero-btn.secondary {
  border: 1px solid var(--color-border);
  color: var(--color-text);
}
.hero-btn.secondary:hover { border-color: var(--color-text-muted); text-decoration: none; }

/* Feature cards */
.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px;
  margin: 24px 0;
}
.feature-card {
  padding: 20px;
  border: 1px solid var(--color-border-light);
  border-radius: 8px;
  background: var(--color-sidebar-bg);
}
.feature-card h3 { margin-top: 0; font-size: 16px; }
.feature-card p { margin-bottom: 0; font-size: 14px; color: var(--color-text-muted); }

/* Footer */
.site-footer {
  border-top: 1px solid var(--color-border-light);
  background: var(--color-sidebar-bg);
}
.footer-inner {
  max-width: calc(var(--sidebar-width) + var(--content-max) + 80px);
  margin: 0 auto;
  padding: 16px 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 13px;
  color: var(--color-text-muted);
}
.footer-inner a { color: var(--color-text-muted); }

/* Mobile overlay */
.sidebar-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.4);
  z-index: 49;
}

/* Responsive */
@media (max-width: 768px) {
  .mobile-menu-btn { display: block; }
  .header-nav { display: none; }

  .sidebar {
    position: fixed;
    top: 56px;
    left: 0;
    bottom: 0;
    z-index: 50;
    transform: translateX(-100%);
    transition: transform 0.2s ease;
    width: 280px;
  }

  body.sidebar-open .sidebar { transform: translateX(0); }
  body.sidebar-open .sidebar-overlay { display: block; }
  body.sidebar-open .header-nav { display: flex; position: absolute; right: 60px; }

  .content { padding: 24px 16px 48px; }
  .hero h1 { font-size: 28px; }
  .hero .tagline { font-size: 16px; }
}