/* HarmonyOS NEXT — 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(180,185,210,0.28);
  --text: #e6edf3;
  --text-2: #adbac7;
  --text-3: #768390;
  --accent: #CF0A2C;
  --accent-2: #ff4d5e;
  --accent-glow: rgba(207,10,44,0.18);
  --green: #56d364;
  --blue: #79c0ff;
  --yellow: #e3b341;
  --purple: #d2a8ff;
  --red: #f87171;
  --cyan: #39d4e0;
  --radius: 10px;
  --radius-lg: 14px;
}

*, *::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', 'Noto Sans SC', sans-serif;
  font-size: 16px;
  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(13,17,23,0.94);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}
.nav-back {
  color: var(--accent-2); text-decoration: none;
  font-size: 0.85rem; font-weight: 600; opacity: 0.85;
  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; }
.nav-badge {
  font-size: 0.72rem; font-weight: 700; letter-spacing: 0.08em;
  padding: 0.2rem 0.6rem; border-radius: 5px;
  background: rgba(207,10,44,0.15); color: var(--accent-2);
  border: 1px solid rgba(207,10,44,0.3);
}

/* ── Hero (index page) ───────────────────────────── */
.hero {
  position: relative; overflow: hidden;
  padding: 6rem 2rem 5rem; text-align: center;
  background: radial-gradient(ellipse 80% 60% at 50% 0%, rgba(207,10,44,0.1) 0%, #161b22 40%, #0d1117 100%);
}
.hero::before {
  content: '';
  position: absolute; inset: 0;
  background:
    radial-gradient(circle at 15% 50%, rgba(207,10,44,0.07) 0%, transparent 50%),
    radial-gradient(circle at 85% 20%, rgba(255,77,94,0.05) 0%, transparent 40%);
  pointer-events: none;
}
.hero-icon {
  font-size: 3.5rem; margin-bottom: 1rem;
  display: block; position: relative; z-index: 1;
  filter: drop-shadow(0 0 20px rgba(207,10,44,0.4));
}
.hero-badge {
  display: inline-block; padding: 0.3rem 1rem;
  border: 1px solid rgba(207,10,44,0.4);
  border-radius: 20px; font-size: 0.78rem;
  color: var(--accent-2); letter-spacing: 0.12em;
  text-transform: uppercase; margin-bottom: 1.5rem;
  background: rgba(207,10,44,0.08);
  position: relative;
}
.hero h1 {
  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%, #ffb3bb 100%);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text; position: relative;
}
.hero h1 span {
  background: linear-gradient(135deg, #fff 0%, #ffd0d5 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;
  line-height: 1.8; position: relative;
}
.hero-chips {
  display: flex; flex-wrap: wrap; justify-content: center;
  gap: 0.6rem; margin-bottom: 2.5rem; position: relative;
}
.hero-chip {
  padding: 0.3rem 0.85rem; border-radius: 20px;
  font-size: 0.8rem; font-weight: 500;
  background: rgba(207,10,44,0.1);
  border: 1px solid rgba(207,10,44,0.25);
  color: var(--accent-2);
}
.hero-meta {
  display: flex; justify-content: center; gap: 2rem;
  font-size: 0.85rem; color: var(--text-3); position: relative;
}
.hero-meta span { display: flex; align-items: center; gap: 0.4rem; }

/* ── Container / Section ─────────────────────────── */
.container { max-width: 1100px; margin: 0 auto; padding: 4rem 2rem; }
.section-header { text-align: center; margin-bottom: 3rem; }
.section-header h2 { font-size: 1.8rem; font-weight: 700; color: var(--text); margin-bottom: 0.5rem; }
.section-header p { color: var(--text-3); font-size: 0.95rem; }

/* ── Card Grid (index chapter list) ─────────────── */
.card-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 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;
}
.card:hover {
  background: var(--card-hover); border-color: var(--border-bright);
  transform: translateY(-3px);
  box-shadow: 0 8px 32px rgba(207,10,44,0.18);
}
@keyframes cardIn { to { opacity: 1; transform: translateY(0); } }
.card-num { font-size: 0.75rem; font-weight: 700; letter-spacing: 0.12em; text-transform: uppercase; color: var(--accent); opacity: 0.7; }
.card-title { font-size: 1rem; font-weight: 600; color: var(--text); line-height: 1.4; }
.card-desc { font-size: 0.85rem; color: var(--text-3); line-height: 1.6; flex: 1; }
.card-tags { display: flex; flex-wrap: wrap; gap: 0.4rem; margin-top: 0.25rem; }
.tag {
  font-size: 0.72rem; padding: 0.2rem 0.55rem; border-radius: 6px;
  background: rgba(207,10,44,0.1); color: var(--accent-2);
  border: 1px solid rgba(207,10,44,0.22);
}

/* ── Overview Grid (index tech grid) ────────────── */
.overview-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 1rem; margin-top: 2rem;
}
.overview-item {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 1.25rem;
  text-align: center;
  transition: border-color 0.2s, background 0.2s;
}
.overview-item:hover { border-color: rgba(207,10,44,0.35); background: var(--card); }
.overview-icon { font-size: 1.8rem; margin-bottom: 0.5rem; }
.overview-name { font-size: 0.9rem; font-weight: 600; color: var(--text); margin-bottom: 0.25rem; }
.overview-desc { font-size: 0.78rem; color: var(--text-3); line-height: 1.5; }

/* ── Chapter Hero ────────────────────────────────── */
.chapter-hero {
  padding: 4.5rem 2rem 3.5rem; text-align: center;
  background: radial-gradient(ellipse at top, #161b22 0%, #0d1117 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, rgba(207,10,44,0.4), transparent);
}
.ch-num {
  font-size: 0.75rem; font-weight: 700; letter-spacing: 0.15em;
  text-transform: uppercase; color: var(--accent); opacity: 0.6; 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: 560px; margin: 0 auto; line-height: 1.8; }

/* ── Content (chapter body) ──────────────────────── */
.content { max-width: 860px; margin: 0 auto; padding: 3rem 2rem 5rem; }
.content h2 {
  font-size: 1.45rem; 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: 40px; height: 1px; background: var(--accent);
}
.content h3 { font-size: 1.1rem; font-weight: 600; color: var(--accent-2); margin: 2rem 0 0.75rem; }
.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: 0.4rem; line-height: 1.7; }
.content strong { color: var(--text); }

/* ── Progress ────────────────────────────────────── */
.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); }

/* ── Def List ────────────────────────────────────── */
.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: 0.9rem; font-weight: 700; color: var(--accent-2); margin-bottom: 0.3rem; }
.def-desc { font-size: 0.9rem; color: var(--text-3); line-height: 1.7; }

/* ── Callouts ────────────────────────────────────── */
.callout {
  border-radius: var(--radius); padding: 1rem 1.25rem;
  margin: 1.5rem 0; border-left: 3px solid;
  font-size: 0.92rem; line-height: 1.7;
}
.callout strong { display: block; font-size: 0.8rem; letter-spacing: 0.08em; text-transform: uppercase; margin-bottom: 0.4rem; }
.callout.info  { background: rgba(121,192,255,0.07); border-color: var(--blue);   color: var(--text-2); }
.callout.info  strong { color: var(--blue); }
.callout.tip   { background: rgba(86,211,100,0.07);  border-color: var(--green);  color: var(--text-2); }
.callout.tip   strong { color: var(--green); }
.callout.warning { background: rgba(227,179,65,0.07); border-color: var(--yellow); color: var(--text-2); }
.callout.warning strong { color: var(--yellow); }
.callout.danger  { background: rgba(207,10,44,0.08);  border-color: var(--accent); color: var(--text-2); }
.callout.danger  strong { color: var(--accent-2); }

/* ── Pre / Code ──────────────────────────────────── */
pre {
  background: #090d12; border: 1px solid var(--border);
  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;
}
pre::before {
  content: attr(data-lang); position: absolute;
  top: 0.5rem; right: 0.75rem;
  font-size: 0.7rem; color: var(--text-3);
  letter-spacing: 0.05em; text-transform: uppercase;
}
code { font-family: 'JetBrains Mono', 'Fira Code', 'SF Mono', Consolas, monospace; font-size: 0.875em; }
p code, li code {
  background: rgba(207,10,44,0.12); color: var(--accent-2);
  padding: 0.1em 0.4em; border-radius: 4px; font-size: 0.85em;
}

/* Code highlight spans */
.kw { color: #ff4d5e; font-weight: 600; }   /* keywords, decorators — Huawei red */
.ty { color: #39d4e0; }                       /* types — cyan */
.st { color: #56d364; }                       /* strings — green */
.cm { color: #5c7a6e; font-style: italic; }  /* comments */
.fn { color: #e3b341; }                       /* functions — yellow */
.nu { color: #d2a8ff; }                       /* numbers — purple */
.at { color: #ffa657; }                       /* attributes/annotations — orange */
.pr { color: #79c0ff; }                       /* properties — blue */

/* ── Tables ──────────────────────────────────────── */
.compare-table { width: 100%; border-collapse: collapse; margin: 1.5rem 0; font-size: 0.875rem; }
.compare-table th { background: var(--surface-2); color: var(--accent-2); font-weight: 600; padding: 0.75rem 1rem; text-align: left; border: 1px solid var(--border); }
.compare-table td { padding: 0.65rem 1rem; border: 1px solid var(--border); color: var(--text-2); vertical-align: top; }
.compare-table tr:nth-child(even) td { background: rgba(207,10,44,0.03); }
.compare-table tr:hover td { background: rgba(207,10,44,0.06); }

/* ── Two Col ─────────────────────────────────────── */
.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: 0.9rem; font-weight: 700; color: var(--accent); margin-bottom: 0.75rem; }
.two-col-item ul { font-size: 0.875rem; color: var(--text-3); padding-left: 1.2rem; }
.two-col-item li { margin-bottom: 0.35rem; }

/* ── ASCII / Flow diagrams ───────────────────────── */
.ascii-flow {
  background: #090d12; 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: var(--text-2);
  overflow-x: auto; white-space: pre;
}

/* ── Step List ───────────────────────────────────── */
.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: 1.7;
}
.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 rgba(207,10,44,0.4);
  border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-size: 0.75rem; font-weight: 700; color: var(--accent);
}

/* ── Highlight Box ───────────────────────────────── */
.highlight-box {
  background: linear-gradient(135deg, rgba(207,10,44,0.07), rgba(255,77,94,0.03));
  border: 1px solid rgba(207,10,44,0.25); border-radius: var(--radius-lg);
  padding: 1.5rem; margin: 1.5rem 0;
}

/* ── Chapter Nav ─────────────────────────────────── */
.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); border-color: var(--border-bright); }
.chapter-nav .nav-dir { font-size: 0.72rem; text-transform: uppercase; letter-spacing: 0.1em; color: var(--text-3); }
.chapter-nav .nav-title-text { font-size: 0.9rem; font-weight: 600; color: var(--accent-2); 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; }

/* ── Site Footer ─────────────────────────────────── */
.site-footer { text-align: center; padding: 1.5rem; font-size: 0.82rem; color: var(--text-3); border-top: 1px solid var(--border); }
.site-footer a { color: var(--accent-2); text-decoration: none; opacity: 0.8; }
.site-footer a:hover { opacity: 1; }

/* ── Responsive ──────────────────────────────────── */
@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%; }
  .overview-grid { grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); }
}