/* LlamaIndex 数据框架实战 — common.css
 * 深浅双主题(data-theme="dark" | "light")
 * Accent: #E8A33D (LlamaIndex 琥珀金) + #0B2A5B (深海蓝)
 * 对比度: WCAG AAA (正文 ≥ 7:1)
 */

/* ── DARK THEME (default) ── */
:root,
:root[data-theme="dark"] {
  --bg:            #0a0f1f;
  --surface:       #101731;
  --surface-2:     #172040;
  --card:          #131a36;
  --card-hover:    #1b2449;
  --border:        rgba(232,163,61,0.13);
  --border-bright: rgba(232,163,61,0.32);
  --text:          #f1ead8;
  --text-2:        #d6cbae;
  --text-3:        #a99a76;
  --accent:        #f4b860;
  --accent-2:      #e8a33d;
  --accent-soft:   #ffd591;
  --accent-glow:   rgba(232,163,61,0.28);
  --accent-tint:   rgba(232,163,61,0.10);
  --accent-tint-2: rgba(232,163,61,0.05);
  --navy:          #3b6bc9;
  --navy-soft:     rgba(59,107,201,0.22);
  --green:         #68d391;
  --blue:          #63b3ed;
  --red:           #fc8181;
  --yellow:        #f6ad55;
  --cyan:          #4fd1c5;
  --code-bg:       #05080f;
  --inline-code-bg: rgba(232,163,61,0.16);
  --inline-code-color: #ffd591;
  --radius:    10px;
  --radius-lg: 14px;
  color-scheme: dark;
}

/* ── LIGHT THEME ── */
:root[data-theme="light"] {
  --bg:            #fbf7ee;
  --surface:       #ffffff;
  --surface-2:     #f5ead1;
  --card:          #ffffff;
  --card-hover:    #fbf0d7;
  --border:        rgba(120,80,10,0.16);
  --border-bright: rgba(120,80,10,0.30);
  --text:          #1a1408;
  --text-2:        #3a2e12;
  --text-3:        #6b5626;
  --accent:        #8a5a0a;
  --accent-2:      #6b4408;
  --accent-soft:   #b47b15;
  --accent-glow:   rgba(138,90,10,0.20);
  --accent-tint:   rgba(138,90,10,0.08);
  --accent-tint-2: rgba(138,90,10,0.04);
  --navy:          #0B2A5B;
  --navy-soft:     rgba(11,42,91,0.10);
  --green:         #15803d;
  --blue:          #1d4ed8;
  --red:           #b91c1c;
  --yellow:        #a16207;
  --cyan:          #0e7490;
  --code-bg:       #1a1408;
  --inline-code-bg: rgba(138,90,10,0.10);
  --inline-code-color: #6b4408;
  color-scheme: light;
}

@media (prefers-color-scheme: light) {
  :root:not([data-theme]) {
    --bg:            #fbf7ee;
    --surface:       #ffffff;
    --surface-2:     #f5ead1;
    --card:          #ffffff;
    --card-hover:    #fbf0d7;
    --border:        rgba(120,80,10,0.16);
    --border-bright: rgba(120,80,10,0.30);
    --text:          #1a1408;
    --text-2:        #3a2e12;
    --text-3:        #6b5626;
    --accent:        #8a5a0a;
    --accent-2:      #6b4408;
    --accent-soft:   #b47b15;
    --accent-glow:   rgba(138,90,10,0.20);
    --accent-tint:   rgba(138,90,10,0.08);
    --accent-tint-2: rgba(138,90,10,0.04);
    --navy:          #0B2A5B;
    --navy-soft:     rgba(11,42,91,0.10);
    --green:         #15803d;
    --blue:          #1d4ed8;
    --red:           #b91c1c;
    --yellow:        #a16207;
    --cyan:          #0e7490;
    --code-bg:       #1a1408;
    --inline-code-bg: rgba(138,90,10,0.10);
    --inline-code-color: #6b4408;
    color-scheme: light;
  }
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: 'SF Pro Text', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', sans-serif;
  font-size: 16px;
  line-height: 1.75;
  min-height: 100vh;
  transition: background-color 0.25s ease, color 0.25s ease;
}

.nav {
  position: sticky; top: 0; z-index: 100;
  display: flex; align-items: center; gap: 1rem;
  padding: 0 2rem; height: 56px;
  background: color-mix(in srgb, var(--bg) 92%, transparent);
  backdrop-filter: blur(12px);
  -webkit-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: 0.03em;
  opacity: 0.9; transition: opacity 0.2s;
  display: flex; align-items: center; gap: 0.4rem;
}
.nav-back::before { content: '←'; font-size: 1rem; }
.nav-back:hover { opacity: 1; }
.nav-title { flex: 1; text-align: center; font-size: 0.9rem; color: var(--text-2); font-weight: 500; }

.theme-toggle {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: 999px; width: 36px; height: 36px;
  display: inline-flex; align-items: center; justify-content: center;
  cursor: pointer; color: var(--text-2);
  transition: background 0.2s, border-color 0.2s, color 0.2s, transform 0.2s;
  padding: 0;
}
.theme-toggle:hover {
  background: var(--card-hover); border-color: var(--border-bright);
  color: var(--accent); transform: translateY(-1px);
}
.theme-toggle svg { width: 18px; height: 18px; }
.theme-toggle .icon-moon { display: none; }
.theme-toggle .icon-sun { display: block; }
:root[data-theme="dark"] .theme-toggle .icon-sun { display: none; }
:root[data-theme="dark"] .theme-toggle .icon-moon { display: block; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) .theme-toggle .icon-sun { display: none; }
  :root:not([data-theme]) .theme-toggle .icon-moon { display: block; }
}

/* ── HERO ── */
.hero {
  position: relative; overflow: hidden;
  padding: 6rem 2rem 5rem; text-align: center;
  background: radial-gradient(ellipse 80% 60% at 50% 0%, var(--accent-tint) 0%, var(--surface) 45%, var(--bg) 100%);
}
.hero::before {
  content: ''; position: absolute; inset: 0;
  background:
    radial-gradient(circle at 15% 50%, var(--accent-tint) 0%, transparent 45%),
    radial-gradient(circle at 85% 20%, var(--navy-soft) 0%, transparent 40%),
    radial-gradient(circle at 55% 85%, var(--accent-tint-2) 0%, transparent 40%);
  pointer-events: none;
}

.hero-badge {
  display: inline-block; padding: 0.35rem 1rem;
  border: 1px solid var(--border-bright); border-radius: 20px;
  font-size: 0.78rem; color: var(--accent);
  letter-spacing: 0.1em; text-transform: uppercase;
  margin-bottom: 1.5rem; background: var(--accent-tint); font-weight: 600;
  position: relative;
}
.hero h1, .hero-title {
  font-size: clamp(2rem, 5vw, 3.2rem); font-weight: 700;
  letter-spacing: -0.02em; line-height: 1.2; margin-bottom: 1.2rem;
  background: linear-gradient(135deg, var(--accent) 0%, var(--accent-2) 50%, var(--accent-soft) 100%);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text;
  position: relative;
}
.hero p, .hero-subtitle {
  font-size: 1.1rem; color: var(--text-2); max-width: 640px;
  margin: 0 auto 2rem; line-height: 1.85; position: relative;
}
.hero-meta { display: flex; justify-content: center; gap: 2rem; font-size: 0.85rem; color: var(--text-3); position: relative; flex-wrap: wrap; }
.hero-meta span { display: flex; align-items: center; gap: 0.4rem; }

.container { max-width: 1100px; margin: 0 auto; padding: 4rem 2rem; }

.intro-box { background: var(--surface); border: 1px solid var(--border); border-left: 4px solid var(--accent); border-radius: var(--radius-lg); padding: 1.75rem 2rem; margin-bottom: 3rem; }
.intro-box h2 { font-size: 1.2rem; font-weight: 700; color: var(--accent); margin-bottom: 0.8rem; }
.intro-box p { color: var(--text-2); font-size: 0.95rem; line-height: 1.85; margin-bottom: 0.75rem; }
.intro-box p:last-child { margin-bottom: 0; }

.card-list { 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);
  transition: background 0.2s, border-color 0.2s, transform 0.2s, box-shadow 0.2s;
  display: flex; flex-direction: column; gap: 0.75rem;
  opacity: 0; transform: translateY(20px);
  animation: cardIn 0.5s ease forwards;
  box-shadow: 0 1px 2px rgba(0,0,0,0.04);
}
.card:hover {
  background: var(--card-hover); border-color: var(--border-bright);
  transform: translateY(-3px); box-shadow: 0 10px 32px var(--accent-glow);
}
@keyframes cardIn { to { opacity: 1; transform: translateY(0); } }
.card-head { display: flex; align-items: center; justify-content: space-between; }
.card-num { font-size: 0.75rem; font-weight: 700; letter-spacing: 0.12em; text-transform: uppercase; color: var(--accent); opacity: 0.85; }
.card-dot { width: 8px; height: 8px; border-radius: 50%; background: var(--accent); box-shadow: 0 0 6px var(--accent-glow); }
.card h3 { font-size: 1rem; font-weight: 600; color: var(--text); line-height: 1.4; }
.card p { font-size: 0.875rem; color: var(--text-3); line-height: 1.65; flex: 1; }
.card-tags { display: flex; flex-wrap: wrap; gap: 0.4rem; margin-top: 0.25rem; }
.card-tags span { font-size: 0.72rem; padding: 0.2rem 0.55rem; border-radius: 6px; background: var(--accent-tint); color: var(--accent); border: 1px solid var(--accent-glow); font-weight: 600; }

.chapter-hero {
  padding: 4.5rem 2rem 3.5rem; text-align: center;
  background: radial-gradient(ellipse at top, var(--surface) 0%, var(--bg) 70%);
  border-bottom: 1px solid var(--border);
  position: relative; overflow: hidden;
}
.chapter-hero::after {
  content: ''; position: absolute; bottom: 0; left: 50%;
  transform: translateX(-50%);
  width: 200px; height: 1px;
  background: linear-gradient(90deg, transparent, var(--accent-glow), transparent);
}
.ch-num { font-size: 0.75rem; font-weight: 700; letter-spacing: 0.15em; text-transform: uppercase; color: var(--accent); opacity: 0.85; margin-bottom: 1rem; }
.chapter-hero h1 {
  font-size: clamp(1.6rem, 4vw, 2.4rem); font-weight: 700;
  letter-spacing: -0.02em; margin-bottom: 1rem;
  background: linear-gradient(135deg, var(--accent-2), var(--text));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text;
}
.chapter-hero p { font-size: 1rem; color: var(--text-2); max-width: 600px; margin: 0 auto; line-height: 1.85; }

.content { max-width: 860px; margin: 0 auto; padding: 3rem 2rem 5rem; }
.content h2 {
  font-size: 1.5rem; font-weight: 700; color: var(--text);
  margin: 3rem 0 1rem; padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border); position: relative;
}
.content h2::before {
  content: ''; position: absolute; bottom: -1px; left: 0;
  width: 48px; height: 2px; background: var(--accent); border-radius: 1px;
}
.content h3 { font-size: 1.15rem; font-weight: 600; color: var(--accent-2); margin: 2rem 0 0.75rem; }
.content h4 { font-size: 1rem; font-weight: 600; color: var(--text); margin: 1.5rem 0 0.5rem; }
.content p { color: var(--text-2); margin-bottom: 1.2rem; line-height: 1.85; }
.content ul, .content ol { color: var(--text-2); padding-left: 1.5rem; margin-bottom: 1.2rem; }
.content li { margin-bottom: 0.45rem; line-height: 1.75; }
.content strong { color: var(--text); font-weight: 700; }
.content a { color: var(--accent); text-decoration: none; border-bottom: 1px dashed var(--accent-glow); transition: color 0.15s, border-color 0.15s; }
.content a:hover { color: var(--accent-2); border-bottom-color: var(--accent); }

.progress { width: 100%; height: 4px; background: var(--surface-2); border-radius: 2px; margin-bottom: 3rem; overflow: hidden; }
.progress-bar { height: 100%; background: linear-gradient(90deg, var(--accent), var(--accent-2)); border-radius: 2px; box-shadow: 0 0 8px var(--accent-glow); transition: width 0.6s ease; }

.def-list { display: flex; flex-direction: column; gap: 0.75rem; margin: 1.5rem 0; }
.def-item { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 1rem 1.25rem; border-left: 3px solid var(--accent); }
.def-term { font-size: 0.92rem; font-weight: 700; color: var(--accent-2); margin-bottom: 0.3rem; letter-spacing: 0.02em; }
.def-desc { font-size: 0.92rem; color: var(--text-2); line-height: 1.75; }

.callout { border-radius: var(--radius); padding: 1rem 1.25rem; margin: 1.5rem 0; border-left: 3px solid; font-size: 0.92rem; line-height: 1.75; background: var(--surface); }
.callout strong { display: block; font-size: 0.78rem; letter-spacing: 0.08em; text-transform: uppercase; margin-bottom: 0.4rem; }
.callout.info    { border-color: var(--accent); color: var(--text-2); }
.callout.info strong { color: var(--accent); }
.callout.tip     { border-color: var(--green); color: var(--text-2); }
.callout.tip strong { color: var(--green); }
.callout.warning { border-color: var(--yellow); color: var(--text-2); }
.callout.warning strong { color: var(--yellow); }
.callout.danger  { border-color: var(--red); color: var(--text-2); }
.callout.danger strong { color: var(--red); }

pre {
  background: var(--code-bg); border: 1px solid var(--border);
  border-top: 2px solid var(--accent); border-radius: var(--radius);
  padding: 1.25rem 1.5rem; overflow-x: auto; margin: 1.5rem 0;
  font-size: 0.875rem; line-height: 1.75; position: relative; color: #e6edf3;
}
pre::before { content: attr(data-lang); position: absolute; top: 0.5rem; right: 0.75rem; font-size: 0.7rem; color: #9b8a5d; font-family: inherit; letter-spacing: 0.05em; text-transform: uppercase; }
code { font-family: 'JetBrains Mono', 'Fira Code', 'Cascadia Code', 'SF Mono', Consolas, monospace; font-size: 0.875em; }
p code, li code, td code { background: var(--inline-code-bg); color: var(--inline-code-color); padding: 0.12em 0.42em; border-radius: 4px; font-size: 0.86em; border: 1px solid var(--accent-glow); }

.kw { color: #f4b860; font-weight: 600; }
.fn { color: #7cc4ff; }
.st { color: #9fe59f; }
.cm { color: #8e7c57; font-style: italic; }
.ty { color: #5ee6dc; }
.nu { color: #ffd591; }
.at { color: #ffa39e; }
.pr { color: #9ec5fe; }

.two-col { display: grid; grid-template-columns: 1fr 1fr; gap: 1.25rem; margin: 1.5rem 0; }
@media (max-width: 640px) { .two-col { grid-template-columns: 1fr; } }
.two-col-item { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 1.25rem; }
.two-col-item h4 { font-size: 0.92rem; font-weight: 700; color: var(--accent); margin-bottom: 0.75rem; }
.two-col-item ul { font-size: 0.88rem; color: var(--text-2); padding-left: 1.2rem; margin-bottom: 0; }
.two-col-item li { margin-bottom: 0.4rem; }

.ascii-flow { background: var(--code-bg); border: 1px solid var(--border); border-radius: var(--radius); padding: 1.5rem 2rem; margin: 1.5rem 0; font-family: 'JetBrains Mono', 'Fira Code', monospace; font-size: 0.82rem; line-height: 1.9; color: #d6cbae; overflow-x: auto; white-space: pre; }

.compare-table { width: 100%; border-collapse: collapse; margin: 1.5rem 0; font-size: 0.885rem; }
.compare-table th { background: var(--surface-2); color: var(--accent); font-weight: 700; padding: 0.75rem 1rem; text-align: left; border: 1px solid var(--border); }
.compare-table td { padding: 0.7rem 1rem; border: 1px solid var(--border); color: var(--text-2); vertical-align: top; }
.compare-table tr:nth-child(even) td { background: var(--accent-tint-2); }
.compare-table tr:hover td { background: var(--accent-tint); }

.chapter-nav { display: flex; justify-content: space-between; gap: 1rem; margin-top: 4rem; padding-top: 2rem; border-top: 1px solid var(--border); }
.chapter-nav a { display: flex; flex-direction: column; gap: 0.25rem; padding: 0.875rem 1.25rem; background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); text-decoration: none; color: var(--text); transition: background 0.2s, border-color 0.2s; min-width: 0; max-width: 48%; }
.chapter-nav a:hover { background: var(--card-hover); border-color: var(--border-bright); }
.chapter-nav .label { font-size: 0.72rem; text-transform: uppercase; letter-spacing: 0.1em; color: var(--text-3); }
.chapter-nav .title { font-size: 0.9rem; font-weight: 600; color: var(--accent); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.chapter-nav .prev { align-items: flex-start; }
.chapter-nav .next { align-items: flex-end; margin-left: auto; }

.pagefoot, .site-footer { text-align: center; padding: 1.5rem; font-size: 0.82rem; color: var(--text-3); border-top: 1px solid var(--border); }
.pagefoot a, .site-footer a { color: var(--accent); text-decoration: none; opacity: 0.9; }
.pagefoot a:hover, .site-footer a:hover { opacity: 1; }

.highlight-box { background: linear-gradient(135deg, var(--accent-tint), var(--accent-tint-2)); border: 1px solid var(--border-bright); border-radius: var(--radius-lg); padding: 1.5rem; margin: 1.5rem 0; }

.step-list { counter-reset: step; list-style: none; padding: 0; margin: 1.5rem 0; }
.step-list li { counter-increment: step; padding: 0.75rem 0.75rem 0.75rem 3.5rem; position: relative; border-left: 1px solid var(--border); margin-left: 1.5rem; margin-bottom: 0.5rem; color: var(--text-2); font-size: 0.92rem; line-height: 1.75; }
.step-list li::before { content: counter(step); position: absolute; left: -1.5rem; top: 0.65rem; width: 2rem; height: 2rem; background: var(--card); border: 1px solid var(--border-bright); border-radius: 50%; display: flex; align-items: center; justify-content: center; font-size: 0.75rem; font-weight: 700; color: var(--accent); }

@media (max-width: 768px) {
  .nav { padding: 0 1rem; }
  .content { padding: 2rem 1.25rem 4rem; }
  .chapter-hero { padding: 3rem 1.25rem 2.5rem; }
  .container { padding: 3rem 1.25rem; }
  .ascii-flow { font-size: 0.72rem; padding: 1rem; }
  .compare-table { font-size: 0.8rem; }
  .chapter-nav { flex-direction: column; }
  .chapter-nav a { max-width: 100%; }
  .hero-meta { gap: 1rem; }
}

/* ── COSMETIC PATCH ── */
.hero-inner {
  position: relative; z-index: 2;
  max-width: 980px; margin: 0 auto;
}