/* ===== 设计变量：改这里就能整体换配色 ===== */
:root {
  --bg: #0b0f19;
  --bg-soft: #111827;
  --text: #e5e7eb;
  --text-dim: #9ca3af;
  --line: rgba(255, 255, 255, 0.08);
  --accent: #6366f1;
  --accent-2: #22d3ee;
  --radius: 16px;
  --maxw: 880px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", Roboto, Helvetica, Arial, sans-serif;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

/* 背景光晕 */
.bg-glow {
  position: fixed;
  inset: -20% -10% auto -10%;
  height: 70vh;
  background:
    radial-gradient(45% 45% at 30% 20%, rgba(99, 102, 241, 0.28), transparent 70%),
    radial-gradient(40% 40% at 75% 10%, rgba(34, 211, 238, 0.18), transparent 70%);
  filter: blur(30px);
  pointer-events: none;
  z-index: 0;
}

a { color: inherit; }

/* ===== 顶部导航 ===== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 1rem 1.25rem;
  backdrop-filter: blur(12px);
  background: rgba(11, 15, 25, 0.6);
  border-bottom: 1px solid var(--line);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 700;
  text-decoration: none;
  letter-spacing: 0.02em;
}

.brand-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  box-shadow: 0 0 12px rgba(99, 102, 241, 0.8);
}

.nav { display: flex; gap: 1.25rem; font-size: 0.9rem; }

.nav a {
  color: var(--text-dim);
  text-decoration: none;
  transition: color 0.2s ease;
}

.nav a:hover { color: var(--text); }

/* ===== 布局容器 ===== */
main {
  position: relative;
  z-index: 1;
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 1.25rem 4rem;
}

/* ===== HERO ===== */
.hero { padding: 5rem 0 4rem; text-align: left; }

.eyebrow {
  margin: 0 0 0.75rem;
  font-size: 0.95rem;
  color: var(--text-dim);
}

.hero-title {
  margin: 0;
  font-size: clamp(2.5rem, 8vw, 4.25rem);
  line-height: 1.1;
  letter-spacing: -0.03em;
  background: linear-gradient(120deg, #fff 20%, var(--accent-2) 60%, var(--accent) 90%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.hero-sub {
  margin: 1.25rem 0 0;
  max-width: 34rem;
  font-size: clamp(1rem, 2.2vw, 1.15rem);
  color: var(--text-dim);
}

.hero-sub em { color: var(--text); font-style: normal; font-weight: 600; }

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 2rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.7rem 1.35rem;
  border-radius: 999px;
  font-size: 0.95rem;
  font-weight: 600;
  text-decoration: none;
  transition: transform 0.15s ease, box-shadow 0.2s ease, background 0.2s ease;
}

.btn:active { transform: translateY(1px); }

.btn-primary {
  color: #0b0f19;
  background: linear-gradient(135deg, var(--accent-2), #a5b4fc);
  box-shadow: 0 8px 24px rgba(34, 211, 238, 0.22);
}

.btn-primary:hover { box-shadow: 0 10px 30px rgba(34, 211, 238, 0.34); }

.btn-ghost {
  color: var(--text);
  border: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.03);
}

.btn-ghost:hover { background: rgba(255, 255, 255, 0.07); }

.hero-note {
  margin-top: 2rem;
  font-size: 0.82rem;
  color: rgba(156, 163, 175, 0.7);
}

/* ===== 区块 ===== */
.section { padding: 2.5rem 0; }

.section-title {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  margin: 0 0 1.25rem;
  font-size: 1.05rem;
  font-weight: 600;
  letter-spacing: 0.02em;
}

.num {
  font-size: 0.75rem;
  font-variant-numeric: tabular-nums;
  color: var(--accent-2);
  border: 1px solid rgba(34, 211, 238, 0.3);
  border-radius: 6px;
  padding: 0.1rem 0.4rem;
}

/* ===== 卡片 ===== */
.card {
  padding: 1.25rem 1.4rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.045), rgba(255, 255, 255, 0.015));
}

.card p { margin: 0; color: var(--text-dim); }
.card p + p { margin-top: 0.75rem; }

.card code {
  font-size: 0.85em;
  padding: 0.1em 0.35em;
  border-radius: 4px;
  background: rgba(255, 255, 255, 0.08);
  color: var(--text);
}

.card-link {
  display: block;
  text-decoration: none;
  transition: transform 0.18s ease, border-color 0.18s ease, background 0.18s ease;
}

.card-link:hover {
  transform: translateY(-3px);
  border-color: rgba(99, 102, 241, 0.5);
  background: linear-gradient(180deg, rgba(99, 102, 241, 0.12), rgba(255, 255, 255, 0.02));
}

.card-link h3 { margin: 0 0 0.4rem; font-size: 1rem; }

.card-meta {
  display: inline-block;
  margin-top: 0.85rem;
  font-size: 0.85rem;
  color: var(--accent-2);
}

.grid {
  display: grid;
  gap: 1rem;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

/* ===== 标签 ===== */
.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  list-style: none;
  padding: 0;
  margin: 1rem 0 0;
}

.tags li {
  font-size: 0.82rem;
  color: var(--text-dim);
  padding: 0.3rem 0.7rem;
  border: 1px solid var(--line);
  border-radius: 999px;
}

/* ===== 链接列表 ===== */
.links {
  list-style: none;
  padding: 0;
  margin: 1rem 0 0;
  display: grid;
  gap: 0.5rem;
}

.links a {
  text-decoration: none;
  color: var(--text);
  font-size: 0.95rem;
  transition: color 0.2s ease;
}

.links a:hover { color: var(--accent-2); }

/* ===== 页脚 ===== */
.site-footer {
  position: relative;
  z-index: 1;
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 2rem 1.25rem 3rem;
  border-top: 1px solid var(--line);
  font-size: 0.82rem;
  color: rgba(156, 163, 175, 0.65);
}

.site-footer p { margin: 0; }

/* ===== 移动端 ===== */
@media (max-width: 560px) {
  .hero { padding: 3.5rem 0 2.5rem; }
  .nav { gap: 0.9rem; font-size: 0.85rem; }
}

/* 尊重用户的减少动效设置 */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { transition: none !important; animation: none !important; }
}