:root {
  --bg: #0f1115;
  --bg-alt: #161922;
  --surface: #1b1f2a;
  --border: #2a2f3d;
  --text: #e7e9ee;
  --text-dim: #9aa3b2;
  --accent: #6ea8fe;
  --accent-2: #b692ff;
  --radius: 14px;
  --maxw: 960px;
  --shadow: 0 8px 30px rgba(0, 0, 0, .35);
}

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

html { scroll-behavior: smooth; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }

.container { max-width: var(--maxw); margin: 0 auto; padding: 0 20px; }

/* Header */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: rgba(15, 17, 21, .8);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}
.header-inner { display: flex; align-items: center; justify-content: space-between; height: 62px; }
.brand { font-weight: 800; font-size: 20px; letter-spacing: .5px; }
.brand-mark { color: var(--accent); }
.brand-domain { color: var(--accent-2); }
.nav { display: flex; gap: 26px; }
.nav a { color: var(--text-dim); font-size: 15px; transition: color .2s; position: relative; }
.nav a:hover { color: var(--text); }
.nav a.active { color: var(--text); }
.nav a.active::after {
  content: ""; position: absolute; left: 0; right: 0; bottom: -20px; height: 2px;
  background: linear-gradient(90deg, var(--accent), var(--accent-2)); border-radius: 2px;
}

/* Hero */
.hero { padding: 96px 0 72px; text-align: center;
  background: radial-gradient(1200px 400px at 50% -10%, rgba(110,168,254,.18), transparent 70%); }
.hero-greeting { color: var(--text-dim); font-size: 16px; }
.hero-title {
  font-size: clamp(40px, 8vw, 72px); font-weight: 900; margin: 6px 0 14px;
  background: linear-gradient(120deg, var(--accent), var(--accent-2));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.hero-sub { color: var(--text-dim); font-size: 17px; max-width: 560px; margin: 0 auto 30px; }
.hero-actions { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }

.btn { display: inline-block; padding: 11px 22px; border-radius: 999px; font-size: 15px; font-weight: 600; transition: transform .15s, box-shadow .2s, opacity .2s; }
.btn:hover { transform: translateY(-2px); }
.btn-primary { background: linear-gradient(120deg, var(--accent), var(--accent-2)); color: #0b0d12; box-shadow: 0 8px 24px rgba(110,168,254,.35); }
.btn-ghost { border: 1px solid var(--border); color: var(--text); }
.btn-ghost:hover { border-color: var(--accent); }

/* Sections */
.section { padding: 64px 0; }
.section-alt { background: var(--bg-alt); border-top: 1px solid var(--border); border-bottom: 1px solid var(--border); }
.section-head { display: flex; align-items: baseline; justify-content: space-between; margin-bottom: 28px; }
.section-head h2 { font-size: 26px; font-weight: 800; }
.link-more { color: var(--accent); font-size: 14px; }
.link-more:hover { text-decoration: underline; }

/* Post cards */
.post-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 20px; }
.post-card {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 22px; transition: transform .18s, border-color .2s, box-shadow .2s;
  display: flex; flex-direction: column; gap: 10px;
}
.post-card:hover { transform: translateY(-4px); border-color: var(--accent); box-shadow: var(--shadow); }
.post-card .tag { align-self: flex-start; font-size: 12px; color: var(--accent); background: rgba(110,168,254,.12); padding: 3px 10px; border-radius: 999px; }
.post-card h3 { font-size: 19px; font-weight: 700; }
.post-card p { color: var(--text-dim); font-size: 14.5px; flex: 1; }
.post-card .meta { color: var(--text-dim); font-size: 13px; }

.post-list { display: flex; flex-direction: column; gap: 16px; }
.post-row {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 20px 24px; display: flex; align-items: center; justify-content: space-between; gap: 18px;
  transition: transform .15s, border-color .2s;
}
.post-row:hover { transform: translateX(4px); border-color: var(--accent); }
.post-row .info { min-width: 0; }
.post-row h3 { font-size: 18px; font-weight: 700; margin-bottom: 4px; }
.post-row .desc { color: var(--text-dim); font-size: 14px; }
.post-row .date { color: var(--text-dim); font-size: 13px; white-space: nowrap; }

/* Topics */
.topic-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); gap: 18px; }
.topic-card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 22px; }
.topic-card .topic-ico { font-size: 28px; margin-bottom: 8px; }
.topic-card h3 { font-size: 17px; margin-bottom: 6px; }
.topic-card p { color: var(--text-dim); font-size: 14px; }

/* About */
.about { max-width: 680px; }
.avatar {
  width: 84px; height: 84px; border-radius: 50%; display: grid; place-items: center;
  font-size: 38px; font-weight: 900; color: #0b0d12;
  background: linear-gradient(120deg, var(--accent), var(--accent-2)); margin-bottom: 18px;
}
.about h1 { font-size: 30px; margin-bottom: 16px; }
.about .lead { font-size: 18px; margin-bottom: 14px; }
.about p { color: var(--text-dim); margin-bottom: 14px; }
.about h3 { font-size: 19px; margin: 22px 0 10px; }
.about-list { list-style: none; display: grid; gap: 8px; }
.about-list li { color: var(--text-dim); }

/* Footer（备案号居中悬挂，工信部链接在其下方） */
.site-footer { border-top: 1px solid var(--border); padding: 26px 0 30px; }
.footer-inner { display: flex; flex-direction: column; align-items: center; text-align: center; color: var(--text-dim); font-size: 14px; gap: 10px; }
.footer-beian { display: flex; flex-direction: column; align-items: center; gap: 4px; }
.beian-no { font-size: 14px; color: var(--text-dim); letter-spacing: .3px; }
.beian-no:hover { color: var(--accent); text-decoration: underline; }
.footer-copy { font-size: 13px; }
.footer-inner a:hover { color: var(--accent); }

@media (max-width: 600px) {
  .nav { gap: 16px; }
  .hero { padding: 64px 0 48px; }
  .post-row { flex-direction: column; align-items: flex-start; }
  .post-row .date { align-self: flex-end; }
}