/* Vue 3 / Nuxt 教程 — common.css */
:root {
  --bg: #0d1117;
  --surface: #161b22;
  --surface-2: #21262d;
  --card: #1c2128;
  --card-hover: #262c36;
  --border: rgba(180,185,210,0.12);
  --border-bright: rgba(180,185,210,0.26);
  --text: #e6edf3;
  --text-2: #adbac7;
  --text-3: #768390;
  --accent: #58a6e6;
  --accent-2: #3b6ea0;
  --accent-light: #8ec6f5;
  --accent-glow: rgba(88,166,230,0.2);
  --yellow: #f0c060;
  --orange: #e8855a;
  --red: #f07070;
  --blue: #58a6e6;
  --purple: #b48af5;
  --radius: 10px;
  --radius-lg: 14px;
}

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

html { font-size: 16px; scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
  line-height: 1.7;
  min-height: 100vh;
}

/* ── NAV ── */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 0 2rem;
  height: 56px;
  background: rgba(13,17,23,0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}

.nav-back {
  color: var(--accent);
  text-decoration: none;
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  opacity: 0.85;
  transition: opacity 0.2s;
}
.nav-back:hover { opacity: 1; }
.nav-back::before { content: '← '; }

.nav-title {
  color: var(--text-2);
  font-size: 0.9rem;
  margin-left: auto;
}

/* ── INDEX HERO ── */
.hero {
  position: relative;
  overflow: hidden;
  padding: 5rem 2rem 4rem;
  text-align: center;
  background: radial-gradient(ellipse 80% 60% at 50% 0%, rgba(66,184,131,0.08) 0%, #161b22 50%, #0d1117 100%);
}
.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 60% 50% at 20% 40%, rgba(88,166,230,0.08) 0%, transparent 60%),
    radial-gradient(ellipse 50% 40% at 80% 60%, rgba(59,110,160,0.08) 0%, transparent 60%);
  pointer-events: none;
}
.hero-badge {
  display: inline-block;
  padding: 0.3rem 1rem;
  border: 1px solid var(--border-bright);
  border-radius: 999px;
  font-size: 0.78rem;
  color: var(--accent);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin-bottom: 1.5rem;
  background: rgba(88,166,230,0.08);
}
.hero h1 {
  font-size: clamp(2rem, 5vw, 3.2rem);
  font-weight: 800;
  line-height: 1.15;
  margin-bottom: 1rem;
  background: linear-gradient(135deg, #e6edf5 30%, var(--accent) 70%, var(--accent-light) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero p {
  font-size: 1.1rem;
  color: var(--text-2);
  max-width: 600px;
  margin: 0 auto 2.5rem;
}
.hero-meta {
  display: flex;
  justify-content: center;
  gap: 2rem;
  flex-wrap: wrap;
  color: var(--text-3);
  font-size: 0.85rem;
}
.hero-meta span { color: var(--accent); font-weight: 600; }

/* ── INDEX CONTAINER / CHAPTERS GRID ── */
.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 3rem 2rem;
}

.section-title {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 0.5rem;
}
.section-sub {
  color: var(--text-2);
  font-size: 0.9rem;
  margin-bottom: 2rem;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.25rem;
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  text-decoration: none;
  color: var(--text);
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
  transition: background 0.2s, border-color 0.2s, transform 0.2s, box-shadow 0.2s;
  position: relative;
  overflow: hidden;
}
.card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--accent), var(--accent-light));
  opacity: 0;
  transition: opacity 0.2s;
}
.card:hover {
  background: var(--card-hover);
  border-color: var(--border-bright);
  transform: translateY(-2px);
  box-shadow: 0 8px 30px rgba(88,166,230,0.12);
}
.card:hover::before { opacity: 1; }

.card-num {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--accent);
  opacity: 0.7;
}
.card-title {
  font-size: 1rem;
  font-weight: 700;
  line-height: 1.35;
}
.card-desc {
  font-size: 0.82rem;
  color: var(--text-2);
  line-height: 1.55;
}
.card-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-top: auto;
  padding-top: 0.5rem;
}
.tag {
  font-size: 0.7rem;
  padding: 0.2rem 0.55rem;
  border-radius: 999px;
  background: rgba(88,166,230,0.1);
  color: var(--accent);
  border: 1px solid var(--border);
}

/* ── CHAPTER HERO ── */
.chapter-hero {
  padding: 3.5rem 2rem 2.5rem;
  background: radial-gradient(ellipse at top, #161b22 0%, #0d1117 70%);
  border-bottom: 1px solid var(--border);
  position: relative;
  overflow: hidden;
}
.chapter-hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 50% 80% at 10% 50%, rgba(88,166,230,0.07) 0%, transparent 60%),
    radial-gradient(ellipse 40% 60% at 90% 30%, rgba(59,110,160,0.07) 0%, transparent 60%);
  pointer-events: none;
}
.ch-num {
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent);
  opacity: 0.7;
  margin-bottom: 0.75rem;
}
.chapter-hero h1 {
  font-size: clamp(1.6rem, 4vw, 2.4rem);
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: 0.75rem;
  background: linear-gradient(135deg, #e6edf5 40%, var(--accent-light));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  max-width: 800px;
}
.chapter-hero p {
  color: var(--text-2);
  font-size: 1rem;
  max-width: 680px;
}

/* ── CONTENT ── */
.content {
  max-width: 860px;
  margin: 0 auto;
  padding: 2.5rem 2rem 4rem;
}

/* Progress */
.progress {
  height: 4px;
  background: var(--surface-2);
  border-radius: 999px;
  margin-bottom: 2.5rem;
  overflow: hidden;
}
.progress-bar {
  height: 100%;
  border-radius: 999px;
  background: linear-gradient(90deg, var(--accent), var(--accent-light));
  transition: width 0.4s ease;
}

/* Typography */
.content h2 {
  font-size: 1.45rem;
  font-weight: 700;
  color: var(--text);
  margin: 2.5rem 0 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border);
}
.content h3 {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--accent-light);
  margin: 2rem 0 0.75rem;
}
.content p { margin-bottom: 1rem; color: var(--text); }
.content ul, .content ol {
  padding-left: 1.5rem;
  margin-bottom: 1rem;
  color: var(--text);
}
.content li { margin-bottom: 0.35rem; }
.content strong { color: var(--accent-light); font-weight: 600; }
.content a { color: var(--accent); text-decoration: none; }
.content a:hover { text-decoration: underline; }

/* Code */
pre {
  background: #090d12;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem 1.5rem;
  overflow-x: auto;
  margin: 1.25rem 0;
  font-size: 0.88rem;
  line-height: 1.65;
  position: relative;
}
pre::before {
  content: attr(data-lang);
  position: absolute;
  top: 0.5rem; right: 0.75rem;
  font-size: 0.65rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-3);
  font-family: inherit;
}
code {
  font-family: 'Fira Code', 'Cascadia Code', 'JetBrains Mono', monospace;
  font-size: 0.87em;
}
p code, li code {
  background: rgba(88,166,230,0.1);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 0.1em 0.4em;
  color: var(--accent-light);
}

/* Syntax highlight */
.kw { color: #79b8ff; font-weight: 600; }
.fn { color: #b392f0; }
.st { color: #f0c060; }
.cm { color: #5c8a9a; font-style: italic; }
.ty { color: #56d4dd; }
.nu { color: #d4a8ff; }
.at { color: #e8855a; }
.pr { color: #8ec6f5; }

/* Callouts */
.callout {
  border-radius: var(--radius);
  padding: 1rem 1.25rem;
  margin: 1.5rem 0;
  border-left: 3px solid;
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}
.callout-title {
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}
.callout p { margin: 0; font-size: 0.92rem; }
.callout.info {
  background: rgba(88,166,230,0.07);
  border-color: var(--accent);
}
.callout.info .callout-title { color: var(--accent); }
.callout.tip {
  background: rgba(142,198,245,0.07);
  border-color: var(--accent-light);
}
.callout.tip .callout-title { color: var(--accent-light); }
.callout.warning {
  background: rgba(251,191,36,0.07);
  border-color: var(--yellow);
}
.callout.warning .callout-title { color: var(--yellow); }
.callout.danger {
  background: rgba(248,113,113,0.07);
  border-color: var(--red);
}
.callout.danger .callout-title { color: var(--red); }

/* Def list */
.def-list { display: flex; flex-direction: column; gap: 0.75rem; margin: 1.25rem 0; }
.def-item { display: grid; grid-template-columns: 160px 1fr; gap: 1rem; align-items: start; }
.def-term {
  font-weight: 600;
  font-size: 0.88rem;
  color: var(--accent-light);
  padding-top: 0.1rem;
}
.def-desc { font-size: 0.88rem; color: var(--text-2); }

/* Table */
.content table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.25rem 0;
  font-size: 0.88rem;
}
.content th {
  background: var(--surface-2);
  color: var(--accent);
  font-weight: 600;
  padding: 0.65rem 1rem;
  text-align: left;
  border: 1px solid var(--border);
}
.content td {
  padding: 0.6rem 1rem;
  border: 1px solid var(--border);
  color: var(--text-2);
  vertical-align: top;
}
.content tr:hover td { background: rgba(88,166,230,0.04); }

/* Two-col */
.two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.25rem;
  margin: 1.25rem 0;
}
@media (max-width: 640px) { .two-col { grid-template-columns: 1fr; } }

/* chapter-nav */
.chapter-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 3.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
  gap: 1rem;
}
.chapter-nav a {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.65rem 1.25rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  color: var(--text-2);
  text-decoration: none;
  font-size: 0.88rem;
  font-weight: 500;
  transition: border-color 0.2s, color 0.2s, background 0.2s;
  background: var(--surface);
}
.chapter-nav a:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: rgba(88,166,230,0.07);
}
.chapter-nav .prev::before { content: '← '; }
.chapter-nav .next::after { content: ' →'; }

/* site-footer */
.site-footer {
  text-align: center;
  padding: 2rem;
  border-top: 1px solid var(--border);
  color: var(--text-3);
  font-size: 0.82rem;
}
.site-footer a {
  color: var(--accent);
  text-decoration: none;
}
.site-footer a:hover { text-decoration: underline; }

/* Animations */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(16px); }
  to   { opacity: 1; transform: translateY(0); }
}
.fade-up { animation: fadeUp 0.5s ease both; }
.delay-1 { animation-delay: 0.1s; }
.delay-2 { animation-delay: 0.2s; }
.delay-3 { animation-delay: 0.3s; }

/* Responsive */
@media (max-width: 768px) {
  .nav { padding: 0 1rem; }
  .content { padding: 1.5rem 1rem 3rem; }
  .chapter-hero { padding: 2.5rem 1rem 2rem; }
  .hero { padding: 3rem 1rem 2.5rem; }
  .container { padding: 2rem 1rem; }
  .def-item { grid-template-columns: 1fr; gap: 0.25rem; }
}