/* ============================================================
   郑奕恺 · 个人主页 · 研究者风格
   Less is more. 1 列布局, 紧凑.
============================================================ */

:root {
  --bg-0: #ffffff;
  --bg-1: #f7f8fa;
  --bg-2: #eef0f4;
  --ink-0: #0f172a;
  --ink-1: #334155;
  --ink-2: #64748b;
  --ink-3: #94a3b8;
  --accent: #0f4c81;
  --line: #e2e8f0;
  --line-2: #cbd5e1;
  --maxw: 760px;          /* 比 920 还窄, 接近研究论文的版心 */
  --radius: 4px;
}

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

body {
  background: var(--bg-0);
  color: var(--ink-0);
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei",
               "Segoe UI", Roboto, Inter, Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  line-height: 1.7;
  font-size: 15.5px;
  overflow-x: hidden;
}

.container {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 28px;
}

/* ====== 导航（极简，研究者主页范式）====== */
.nav {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255, 255, 255, 0.92);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
}
.nav-inner {
  display: flex; align-items: center; justify-content: space-between;
  height: 52px;
}
.brand {
  font-weight: 600; font-size: 14px; letter-spacing: .3px;
  color: var(--ink-0);
}
.brand .mark { color: var(--accent); margin-right: 6px; font-weight: 700; }
.nav-links { display: flex; gap: 2px; }
.nav-links a {
  color: var(--ink-1); text-decoration: none; font-size: 13.5px;
  padding: 6px 12px; border-radius: var(--radius);
  transition: color .15s ease;
}
.nav-links a:hover { color: var(--accent); }
@media (max-width: 720px) { .nav-links { display: none; } }

/* ====== Hero（研究者主页范式：bio 一段 + contact 一行）====== */
.hero {
  padding: 56px 0 40px;
  border-bottom: 1px solid var(--line);
}
.hero-inner {
  display: flex; align-items: flex-start; gap: 32px;
}
.avatar {
  flex: 0 0 auto; width: 132px; height: 176px;
  object-fit: cover; border-radius: 10px;
  border: 1px solid var(--line); box-shadow: 0 4px 14px rgba(15,23,42,.06);
}
.hero-text { flex: 1 1 auto; min-width: 0; }

.eyebrow {
  display: block; font-size: 12px; letter-spacing: 1.5px;
  text-transform: uppercase; color: var(--accent);
  font-weight: 600; margin: 0 0 14px;
}
h1.name {
  font-size: clamp(28px, 4vw, 38px);
  margin: 0 0 18px; line-height: 1.15; letter-spacing: -.5px;
  font-weight: 700;
}
.bio {
  color: var(--ink-0); font-size: 17px; margin: 0 0 18px; line-height: 1.5;
  font-weight: 500;
  max-width: 64ch;
}
.bio b { color: var(--ink-0); font-weight: 600; }
.bio-sub {
  color: var(--ink-1); font-size: 14px; margin: 0 0 22px; line-height: 1.7;
  max-width: 64ch;
}
.bio-sub, ul.langs { color: var(--ink-2); }

.meta-chips {
  list-style: none; padding: 0; margin: 0 0 20px;
  display: grid; grid-template-columns: repeat(2, 1fr); gap: 8px 18px;
  max-width: 64ch;
}
@media (max-width: 600px) {
  .meta-chips { grid-template-columns: 1fr; }
  .hero-inner { flex-direction: column; align-items: center; text-align: center; }
  .avatar { width: 120px; height: 160px; }
}
.meta-chips li {
  display: flex; align-items: baseline; gap: 8px;
  padding: 4px 0;
  border-bottom: 1px solid var(--line);
  font-size: 14px;
}
.meta-chips .chip-k {
  color: var(--ink-2); min-width: 60px;
  letter-spacing: .3px;
}
.meta-chips .chip-v {
  color: var(--ink-0); font-weight: 500;
}

ul.langs {
  list-style: none; padding: 0; margin: 0 0 20px;
  display: flex; flex-wrap: wrap; gap: 6px;
}
ul.langs li {
  font-size: 12.5px; color: var(--ink-2);
  padding: 2px 10px; border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--bg-1);
}
.contact-row { display: flex; flex-wrap: wrap; gap: 4px 16px; }
.contact-item {
  color: var(--ink-1); font-size: 14px;
}
.contact-row a {
  color: var(--accent); text-decoration: none; font-size: 14px;
  font-weight: 500;
}
.contact-row a:hover { text-decoration: underline; }

/* ====== Section（紧凑，1 列）====== */
section { padding: 48px 0; border-bottom: 1px solid var(--line); }
section:last-of-type { border-bottom: none; }

.section-title {
  display: flex; align-items: baseline; justify-content: space-between;
  margin-bottom: 22px; padding-bottom: 10px;
  border-bottom: 1px solid var(--line);
}
.section-title h2 {
  font-size: 18px; font-weight: 700; margin: 0; letter-spacing: -.3px;
}
.section-title .count { font-size: 12px; color: var(--ink-2); }
.section-note { color: var(--ink-2); font-size: 13.5px; margin: -10px 0 22px; }


/* ====== Projects（1 列紧凑，无视觉装饰）====== */
.proj-grid { display: block; }
.proj {
  padding: 18px 0;
  border-bottom: 1px solid var(--line);
}
.proj:last-child { border-bottom: none; }
.proj.featured { padding-left: 12px; border-left: 2px solid var(--accent); }
.proj-head {
  display: flex; justify-content: space-between; align-items: baseline;
  gap: 12px; flex-wrap: wrap; margin-bottom: 8px;
}
.proj h3 {
  margin: 0; font-size: 16px; font-weight: 600; color: var(--ink-0); line-height: 1.4;
}
.proj .hl { color: var(--accent); font-weight: 700; }
.proj .when { font-size: 12.5px; color: var(--ink-2); white-space: nowrap; font-variant-numeric: tabular-nums; }
.proj ul { padding-left: 18px; margin: 6px 0 0; }
.proj li { color: var(--ink-1); font-size: 14px; line-height: 1.7; margin-bottom: 3px; }
.proj b { color: var(--ink-0); font-weight: 600; }
.proj i { color: var(--ink-2); }

/* ====== 项目内嵌视频（极简）====== */
.proj-video {
  position: relative; aspect-ratio: 16 / 9;
  background: var(--bg-2); border: 1px solid var(--line);
  border-radius: var(--radius); margin: 10px 0 0;
  cursor: pointer; overflow: hidden;
  display: grid; place-items: center;
}
.proj-video::before {
  content: "▶"; font-size: 28px; color: var(--ink-3);
  transition: color .15s ease;
}
.proj-video:hover::before { color: var(--accent); }
.proj-video video {
  display: none; width: 100%; height: 100%; background: #000;
}
.proj-video.playing::before { display: none; }
.proj-video.playing video { display: block; }
.proj-video .badge {
  position: absolute; top: 8px; left: 8px;
  font-size: 10.5px; padding: 3px 8px;
  background: #fff; color: var(--ink-1);
  border: 1px solid var(--line-2); border-radius: 2px;
  letter-spacing: .5px; text-transform: uppercase;
}
.proj-video .duration {
  position: absolute; bottom: 8px; right: 8px;
  font-size: 11px; padding: 2px 6px;
  background: rgba(255,255,255,.9); color: var(--ink-1);
  border: 1px solid var(--line); border-radius: 2px;
  font-variant-numeric: tabular-nums;
}

/* ====== Publications ====== */
.pub {
  padding: 14px 0 14px 12px;
  border-left: 2px solid var(--accent);
}
.pub .venue {
  display: inline-block; font-size: 11px; padding: 2px 8px;
  background: var(--bg-2); color: var(--accent);
  border: 1px solid var(--line); border-radius: 2px;
  letter-spacing: .5px; text-transform: uppercase; margin-bottom: 6px;
}
.pub h3 { margin: 0 0 6px; font-size: 15px; line-height: 1.45; color: var(--ink-0); font-weight: 600; }
.pub .authors { margin: 0 0 8px; color: var(--ink-2); font-size: 13.5px; }
.pub .links { display: flex; gap: 14px; flex-wrap: wrap; margin-top: 8px; }
.pub .links a { font-size: 13px; color: var(--accent); text-decoration: none; }
.pub .links a:hover { text-decoration: underline; }

/* ====== Footer（极简一行）====== */
footer {
  padding: 28px 0; border-top: 1px solid var(--line);
}
.footer-inner {
  display: flex; justify-content: space-between; align-items: baseline;
  gap: 16px; flex-wrap: wrap;
  font-size: 12.5px; color: var(--ink-2);
}
.footer-links { display: flex; gap: 18px; }
.footer-links a { color: var(--ink-1); text-decoration: none; }
.footer-links a:hover { color: var(--accent); }

/* ====== 动画入场（保留）====== */
.reveal { opacity: 0; transform: translateY(8px); transition: opacity .5s ease, transform .5s ease; }
.reveal.in { opacity: 1; transform: none; }