/* ===== VS Code + Git Tutorial Styles (Based on MARL Notes) ===== */

/* ---------- Reset & Base ---------- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg: #fafaf9;
  --bg-sidebar: #1e293b;
  --bg-sidebar-hover: #334155;
  --bg-card: #ffffff;
  --text: #1e293b;
  --text-light: #64748b;
  --text-sidebar: #cbd5e1;
  --text-sidebar-active: #f8fafc;
  --accent: #2563eb;
  --accent-light: #dbeafe;
  --accent-dark: #1d4ed8;
  --border: #e2e8f0;
  --green: #16a34a;
  --green-light: #dcfce7;
  --orange: #ea580c;
  --orange-light: #ffedd5;
  --purple: #7c3aed;
  --purple-light: #ede9fe;
  --red: #dc2626;
  --red-light: #fee2e2;
  --radius: 8px;
  --shadow-sm: 0 1px 2px rgba(0,0,0,.05);
  --shadow: 0 1px 3px rgba(0,0,0,.1), 0 1px 2px rgba(0,0,0,.06);
  --shadow-lg: 0 4px 12px rgba(0,0,0,.1);
  --sidebar-w: 280px;
  --progress-h: 3px;
  --font-sans: "Segoe UI", "PingFang SC", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
  --font-mono: "Cascadia Code", "Fira Code", "JetBrains Mono", Consolas, monospace;
}

html { scroll-behavior: smooth; font-size: 16px; }
body {
  font-family: var(--font-sans);
  color: var(--text);
  background: var(--bg);
  line-height: 1.75;
  display: flex;
  min-height: 100vh;
}

/* ---------- Progress Bar (top) ---------- */
#progress-bar {
  position: fixed;
  top: 0; left: 0;
  width: 0%;
  height: var(--progress-h);
  background: linear-gradient(90deg, var(--accent), var(--purple));
  z-index: 1000;
  transition: width .15s ease-out;
}

/* ---------- Sidebar ---------- */
#sidebar {
  position: fixed;
  top: 0; left: 0;
  width: var(--sidebar-w);
  height: 100vh;
  background: var(--bg-sidebar);
  color: var(--text-sidebar);
  display: flex;
  flex-direction: column;
  z-index: 900;
  overflow: hidden;
  transition: transform .3s ease;
}
#sidebar .sidebar-header {
  padding: 20px 18px 12px;
  border-bottom: 1px solid rgba(255,255,255,.08);
}
#sidebar .sidebar-header h2 {
  font-size: .85rem;
  text-transform: uppercase;
  letter-spacing: .08em;
  color: var(--text-sidebar);
  margin-bottom: 10px;
  font-weight: 600;
}
#sidebar .sidebar-header a {
  color: var(--text-sidebar);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: .95rem;
  margin-bottom: 10px;
  opacity: .85;
  transition: opacity .2s;
}
#sidebar .sidebar-header a:hover { opacity: 1; }
#search-box {
  width: 100%;
  padding: 8px 12px;
  border: 1px solid rgba(255,255,255,.15);
  border-radius: 6px;
  background: rgba(255,255,255,.06);
  color: #fff;
  font-size: .85rem;
  outline: none;
  transition: border-color .2s;
}
#search-box::placeholder { color: rgba(255,255,255,.35); }
#search-box:focus { border-color: var(--accent); }

#sidebar nav {
  flex: 1;
  overflow-y: auto;
  padding: 10px 0;
}
#sidebar nav::-webkit-scrollbar { width: 4px; }
#sidebar nav::-webkit-scrollbar-thumb { background: rgba(255,255,255,.12); border-radius: 2px; }

#sidebar nav ul { list-style: none; }
#sidebar nav > ul > li {}
#sidebar nav .nav-section-title {
  display: block;
  padding: 8px 18px 4px;
  font-size: .7rem;
  text-transform: uppercase;
  letter-spacing: .06em;
  color: rgba(255,255,255,.35);
  font-weight: 600;
}
#sidebar nav a {
  display: block;
  padding: 6px 18px 6px 24px;
  color: var(--text-sidebar);
  text-decoration: none;
  font-size: .85rem;
  border-left: 3px solid transparent;
  transition: all .15s;
}
#sidebar nav a:hover {
  background: var(--bg-sidebar-hover);
  color: var(--text-sidebar-active);
}
#sidebar nav a.active {
  background: rgba(37, 99, 235, .15);
  color: var(--text-sidebar-active);
  border-left-color: var(--accent);
  font-weight: 500;
}
#sidebar nav a.sub {
  padding-left: 40px;
  font-size: .8rem;
}
.nav-hidden { display: none !important; }

/* Mobile toggle */
#sidebar-toggle {
  display: none;
  position: fixed;
  top: 10px; left: 10px;
  z-index: 950;
  width: 40px; height: 40px;
  border: none;
  border-radius: 8px;
  background: var(--bg-sidebar);
  color: #fff;
  font-size: 1.2rem;
  cursor: pointer;
}

/* ---------- Main Content ---------- */
#main {
  margin-left: var(--sidebar-w);
  flex: 1;
  min-height: 100vh;
  padding: 40px 48px 80px;
  max-width: 900px;
}

/* ---------- Typography ---------- */
h1 {
  font-size: 1.85rem;
  font-weight: 700;
  margin-bottom: 8px;
  color: var(--text);
  line-height: 1.3;
}
.page-subtitle {
  font-size: 1rem;
  color: var(--text-light);
  margin-bottom: 28px;
  border-bottom: 1px solid var(--border);
  padding-bottom: 16px;
}
h2 {
  font-size: 1.35rem;
  font-weight: 650;
  margin: 36px 0 12px;
  padding-bottom: 6px;
  border-bottom: 2px solid var(--accent-light);
  color: var(--text);
  scroll-margin-top: 80px; /* Offset for sticky navs or just spacing */
}
h3 {
  font-size: 1.1rem;
  font-weight: 600;
  margin: 24px 0 8px;
  color: var(--accent-dark);
  scroll-margin-top: 80px;
}
h4 {
  font-size: 1rem;
  font-weight: 600;
  margin: 18px 0 6px;
  color: var(--text);
}
p { margin: 8px 0; }
a { color: var(--accent); }
a:hover { text-decoration: underline; }
strong { font-weight: 600; }
code {
  background: #f1f5f9;
  padding: 2px 6px;
  border-radius: 4px;
  font-family: var(--font-mono);
  font-size: .85em;
  color: var(--purple);
}
pre {
  background: #1e293b;
  color: #f1f5f9;
  padding: 16px;
  border-radius: var(--radius);
  overflow-x: auto;
  margin: 16px 0;
  font-family: var(--font-mono);
  font-size: .9rem;
  line-height: 1.5;
}
pre code {
  background: transparent;
  padding: 0;
  color: inherit;
  border-radius: 0;
}

ul, ol { margin: 8px 0 8px 24px; }
li { margin: 4px 0; }

/* ---------- Cards / Concept Blocks ---------- */
.concept-block {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px 24px;
  margin: 16px 0;
  box-shadow: var(--shadow-sm);
}
.concept-block summary {
  font-weight: 600;
  font-size: 1.05rem;
  cursor: pointer;
  padding: 4px 0;
  list-style: none;
  display: flex;
  align-items: center;
  gap: 8px;
}
.concept-block summary::before {
  content: "▸";
  font-size: .85rem;
  color: var(--accent);
  transition: transform .2s;
  display: inline-block;
}
.concept-block[open] summary::before {
  transform: rotate(90deg);
}
.concept-block summary::-webkit-details-marker { display: none; }
.concept-block .block-content {
  margin-top: 12px;
  padding-top: 12px;
  border-top: 1px solid var(--border);
}

/* Tag badges */
.tag {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 12px;
  font-size: .7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: .04em;
  margin-right: 4px;
}
.tag-info { background: var(--accent-light); color: var(--accent-dark); }
.tag-analogy { background: var(--green-light); color: var(--green); }
.tag-example { background: var(--orange-light); color: var(--orange); }
.tag-key { background: var(--purple-light); color: var(--purple); }
.tag-warning { background: var(--red-light); color: var(--red); }

/* Analogy & Example boxes */
.analogy-box, .example-box {
  border-radius: var(--radius);
  padding: 14px 18px;
  margin: 12px 0;
  font-size: .92rem;
}
.analogy-box {
  background: var(--green-light);
  border-left: 4px solid var(--green);
}
.analogy-box::before {
  content: "🎮 游戏类比";
  display: block;
  font-weight: 600;
  font-size: .78rem;
  color: var(--green);
  text-transform: uppercase;
  letter-spacing: .04em;
  margin-bottom: 6px;
}
.example-box {
  background: var(--orange-light);
  border-left: 4px solid var(--orange);
}
.example-box::before {
  content: "🌰 举个例子";
  display: block;
  font-weight: 600;
  font-size: .78rem;
  color: var(--orange);
  text-transform: uppercase;
  letter-spacing: .04em;
  margin-bottom: 6px;
}

/* Key insight */
.key-insight {
  background: var(--purple-light);
  border-left: 4px solid var(--purple);
  border-radius: var(--radius);
  padding: 14px 18px;
  margin: 12px 0;
  font-size: .92rem;
}
.key-insight::before {
  content: "💡 核心提示";
  display: block;
  font-weight: 600;
  font-size: .78rem;
  color: var(--purple);
  text-transform: uppercase;
  letter-spacing: .04em;
  margin-bottom: 6px;
}

/* ---------- Search Highlight ---------- */
.search-highlight {
  background: #fef08a;
  padding: 1px 2px;
  border-radius: 2px;
}

/* ---------- Responsive ---------- */
@media (max-width: 860px) {
  #sidebar {
    transform: translateX(-100%);
  }
  #sidebar.open {
    transform: translateX(0);
  }
  #sidebar-toggle {
    display: block;
  }
  #main {
    margin-left: 0;
    padding: 24px 20px 60px;
  }
}
@media (min-width: 1200px) {
  #main {
    padding-left: 64px;
    padding-right: 64px;
  }
}

/* ---------- Print ---------- */
@media print {
  #sidebar, #progress-bar, #sidebar-toggle { display: none; }
  #main { margin-left: 0; max-width: 100%; }
}

/* Table styles */
table {
  width: 100%;
  border-collapse: collapse;
  margin: 16px 0;
  font-size: .9rem;
}
th, td {
  border: 1px solid var(--border);
  padding: 10px 12px;
  text-align: left;
}
th {
  background: #f8fafc;
  font-weight: 600;
  color: var(--text);
}
tr:nth-child(even) {
  background: #fbfcff;
}