/* === Base Reset & Variables === */
:root {
  --bg: #1a1a2e;
  --surface: #16213e;
  --text: #e0e0e0;
  --heading: #fff;
  --link: #64b5f6;
  --link-hover: #90caf9;
  --sidebar-width: 220px;
  --border: #2a2a4a;
  --code-bg: #0f1629;
  --accent: #64b5f6;
}

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

html, body {
  height: 100%;
  font-family: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  font-size: 16px;
  line-height: 1.7;
  color: var(--text);
  background: var(--bg);
}

/* === Sidebar === */
.sidebar {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--sidebar-width);
  height: 100vh;
  background: var(--surface);
  border-right: 1px solid var(--border);
  overflow-y: auto;
  z-index: 100;
  padding: 20px 0;
}

.sidebar-header {
  padding: 0 16px 16px;
  font-size: 15px;
  font-weight: 700;
  color: var(--heading);
  border-bottom: 1px solid var(--border);
  margin-bottom: 12px;
}

.sidebar nav ul {
  list-style: none;
}

.sidebar nav > ul > li {
  margin-bottom: 2px;
}

.sidebar nav a {
  display: block;
  padding: 6px 16px;
  color: var(--text);
  text-decoration: none;
  font-size: 14px;
  border-left: 3px solid transparent;
  transition: background 0.15s, border-color 0.15s;
}

.sidebar nav a:hover {
  background: rgba(100, 181, 246, 0.08);
}

.sidebar nav a.active {
  color: var(--link);
  border-left-color: var(--link);
  background: rgba(100, 181, 246, 0.12);
}

.sidebar .group-label {
  display: block;
  padding: 10px 16px 4px;
  font-size: 13px;
  font-weight: 700;
  color: #aaa;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.sidebar .children a {
  padding-left: 28px;
  font-size: 13px;
}

/* === Main Content === */
.main {
  margin-left: var(--sidebar-width);
  padding: 40px 48px;
  max-width: 900px;
  min-height: 100vh;
}

.main .content {
  max-width: 760px;
}

/* === Typography === */
.content h1, .content h2, .content h3,
.content h4, .content h5, .content h6 {
  color: var(--heading);
  margin-top: 1.6em;
  margin-bottom: 0.6em;
  line-height: 1.3;
}

.content h1 { font-size: 2em; margin-top: 0; }
.content h2 { font-size: 1.5em; border-bottom: 1px solid var(--border); padding-bottom: 0.3em; }
.content h3 { font-size: 1.25em; }
.content h4 { font-size: 1.1em; }

.content p {
  margin-bottom: 1em;
}

.content a {
  color: var(--link);
  text-decoration: none;
}

.content a:hover {
  color: var(--link-hover);
  text-decoration: underline;
}

.content ul, .content ol {
  margin-bottom: 1em;
  padding-left: 1.8em;
}

.content li {
  margin-bottom: 0.3em;
}

.content img {
  max-width: 100%;
  border-radius: 4px;
  margin: 1em 0;
}

/* === Code === */
.content code {
  background: var(--code-bg);
  padding: 2px 6px;
  border-radius: 3px;
  font-size: 0.9em;
  font-family: "JetBrains Mono", "Fira Code", Consolas, monospace;
}

.content pre {
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 16px;
  overflow-x: auto;
  margin-bottom: 1.2em;
}

.content pre code {
  background: none;
  padding: 0;
  font-size: 0.85em;
  line-height: 1.5;
}

/* === Blockquote === */
.content blockquote {
  border-left: 4px solid var(--accent);
  padding: 12px 16px;
  margin: 1em 0;
  background: rgba(100, 181, 246, 0.05);
  border-radius: 0 4px 4px 0;
}

.content blockquote p {
  margin-bottom: 0.4em;
}

/* === Tables === */
.content table {
  width: 100%;
  border-collapse: collapse;
  margin: 1em 0;
  font-size: 0.9em;
}

.content th, .content td {
  border: 1px solid var(--border);
  padding: 10px 12px;
  text-align: left;
}

.content th {
  background: var(--surface);
  color: var(--heading);
  font-weight: 600;
}

.content tr:nth-child(even) {
  background: rgba(22, 33, 62, 0.5);
}

/* === Horizontal Rule === */
.content hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 2em 0;
}

/* === 404 === */
.not-found {
  text-align: center;
  padding: 80px 20px;
}

.not-found h1 {
  font-size: 3em;
  color: var(--heading);
}

.not-found p {
  color: #888;
  margin-top: 12px;
}

/* === Mobile hamburger === */
.menu-toggle {
  display: none;
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 200;
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text);
  font-size: 20px;
  padding: 6px 10px;
  border-radius: 4px;
  cursor: pointer;
}

/* === Responsive === */
@media (max-width: 768px) {
  .sidebar {
    transform: translateX(-100%);
    transition: transform 0.25s ease;
  }

  .sidebar.open {
    transform: translateX(0);
  }

  .main {
    margin-left: 0;
    padding: 60px 20px 40px;
  }

  .menu-toggle {
    display: block;
  }
}

/* === Scrollbar === */
.sidebar::-webkit-scrollbar {
  width: 4px;
}

.sidebar::-webkit-scrollbar-thumb {
  background: var(--border);
  border-radius: 2px;
}

.content::-webkit-scrollbar {
  width: 6px;
}

.content::-webkit-scrollbar-thumb {
  background: var(--border);
  border-radius: 3px;
}