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

:root {
  --bg: #f6f7fb;
  --card: #ffffff;
  --ink: #1d1d1f;
  --muted: #6e6e73;
  --accent: #2563eb;
  --accent-soft: #eff4ff;
  --border: #e5e7eb;
  --radius: 14px;
}

html { scroll-behavior: smooth; }

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

/* ===== Nav ===== */
.nav {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}
.nav-inner {
  max-width: 960px;
  margin: 0 auto;
  padding: 0.9rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.nav-brand { font-weight: 700; font-size: 1.15rem; letter-spacing: .5px; }
.nav-brand .dot { color: var(--accent); }
.nav-links a {
  color: var(--muted);
  text-decoration: none;
  font-size: .92rem;
  margin-left: 1.4rem;
  transition: color .2s;
}
.nav-links a:hover { color: var(--accent); }

/* ===== Hero ===== */
.hero {
  background: linear-gradient(160deg, #1e3a8a 0%, #2563eb 55%, #3b82f6 100%);
  color: #fff;
  text-align: center;
  padding: 4.5rem 1.5rem 4rem;
}
.hero h1 { font-size: 3rem; letter-spacing: 2px; margin-bottom: .6rem; }
.hero-sub { font-size: 1.05rem; opacity: .92; }
.hero-tag { margin-top: .5rem; font-size: .95rem; opacity: .85; }
.hero-contact {
  margin-top: 1.6rem;
  display: flex;
  gap: 1.8rem;
  justify-content: center;
  font-size: .95rem;
  flex-wrap: wrap;
}

/* ===== Layout ===== */
main { max-width: 960px; margin: 0 auto; padding: 2.5rem 1.5rem 3rem; }

.section { margin-bottom: 3rem; }
.section h2 {
  font-size: 1.5rem;
  margin-bottom: 1.2rem;
  padding-left: .8rem;
  border-left: 4px solid var(--accent);
}

/* ===== Cards ===== */
.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 1.1rem; }
.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.3rem 1.4rem;
  transition: transform .2s, box-shadow .2s;
}
.card:hover { transform: translateY(-3px); box-shadow: 0 8px 24px rgba(37, 99, 235, .10); }
.card h3 { font-size: 1.02rem; margin-bottom: .5rem; }
.card p { color: var(--muted); font-size: .92rem; }
.card ul { margin: .5rem 0 0 1.2rem; color: var(--muted); font-size: .92rem; }
.card ul li { margin-bottom: .35rem; }
.card-head { display: flex; justify-content: space-between; align-items: flex-start; gap: 1rem; flex-wrap: wrap; }
.card-head h3 { margin-bottom: .25rem; }
.awards { font-size: .85rem !important; color: var(--accent) !important; font-weight: 600; margin-bottom: .4rem; }

.badge {
  background: var(--accent-soft);
  color: var(--accent);
  font-size: .78rem;
  font-weight: 600;
  padding: .2rem .6rem;
  border-radius: 999px;
  white-space: nowrap;
}

/* ===== Timeline ===== */
.timeline .item,
#education .item {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem 1.6rem;
  margin-bottom: 1.2rem;
}
.item-head { display: flex; align-items: baseline; gap: 1rem; flex-wrap: wrap; margin-bottom: .5rem; }
.item-head h3 { font-size: 1.08rem; }
.role { color: var(--accent); font-weight: 600; font-size: .9rem; }
.date { color: var(--muted); font-size: .85rem; margin-left: auto; }
.item-desc { color: var(--muted); font-size: .93rem; margin-bottom: .6rem; }
.item ul { margin: 0 0 .6rem 1.2rem; color: var(--ink); font-size: .93rem; }
.item ul li { margin-bottom: .4rem; }
.tech {
  font-size: .85rem;
  color: var(--accent);
  background: var(--accent-soft);
  padding: .45rem .8rem;
  border-radius: 8px;
  display: inline-block;
}

/* ===== Skills ===== */
.skill-groups { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 1rem; }
.skill-group {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.1rem 1.3rem;
}
.skill-group h3 { font-size: .95rem; color: var(--accent); margin-bottom: .3rem; }
.skill-group p { font-size: .9rem; color: var(--muted); }

/* ===== Footer ===== */
.footer {
  text-align: center;
  color: var(--muted);
  font-size: .85rem;
  padding: 2rem 1rem 2.5rem;
  border-top: 1px solid var(--border);
}

@media (max-width: 640px) {
  .hero h1 { font-size: 2.2rem; }
  .nav-links a { margin-left: .8rem; font-size: .85rem; }
  .date { margin-left: 0; width: 100%; }
}

/* ===== Reveal animation ===== */
.reveal { opacity: 0; transform: translateY(14px); transition: opacity .5s ease, transform .5s ease; }
.reveal.visible { opacity: 1; transform: translateY(0); }