:root {
  --teal: #0b7a83;
  --teal-dark: #075b63;
  --teal-deep: #0a4f5a;
  --teal-mist: #e6f2f3;
  --seafoam: #9fd8d3;
  --ink: #202124;
  --muted: #5f6368;
  --line: #d8e6e8;
  --bg: #ffffff;
  --max: 1120px;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif; font-size: 17px; color: var(--ink); background: var(--bg); line-height: 1.65; }
a { color: var(--teal-dark); text-decoration: none; }
a:hover { text-decoration: underline; }

/* Header: ocean band */
.site-header { background: linear-gradient(90deg, var(--teal-deep), var(--teal)); border-bottom: 4px solid var(--seafoam); }
.header-inner { max-width: var(--max); margin: 0 auto; padding: 22px 28px 0; display: flex; align-items: flex-end; justify-content: space-between; gap: 28px; }
.site-name { font-size: 26px; font-weight: 600; letter-spacing: .01em; color: #fff; white-space: nowrap; padding-bottom: 16px; }
.site-name:hover { text-decoration: none; color: var(--seafoam); }
.nav { display: flex; gap: 6px; font-size: 15.5px; }
.nav a { color: rgba(255,255,255,.82); padding: 8px 14px 14px; border-bottom: 3px solid transparent; font-weight: 500; }
.nav a:hover { color: #fff; text-decoration: none; background: rgba(255,255,255,.08); }
.nav a.active { color: #fff; border-bottom-color: var(--seafoam); }

main { max-width: var(--max); margin: 0 auto; padding: 52px 28px 80px; }

/* Home: sidebar + bio */
.hero { display: grid; grid-template-columns: 240px 1fr; gap: 60px; align-items: start; }
.sidebar { position: sticky; top: 24px; }
.profile-photo { width: 240px; aspect-ratio: 1; object-fit: cover; border-radius: 50%; background: var(--teal-mist); box-shadow: 0 0 0 4px var(--teal-mist), 0 0 0 6px var(--seafoam); margin: 6px 0 22px; display: block; }
.sidebar-name { font-size: 21px; font-weight: 600; margin: 0 0 4px; }
.sidebar-role { color: var(--muted); font-size: 15px; margin: 0 0 18px; line-height: 1.45; }
.contact { list-style: none; padding: 0; margin: 0; font-size: 15px; }
.contact li { display: flex; align-items: center; gap: 9px; padding: 6px 0; border-top: 1px solid var(--line); }
.contact li:first-child { border-top: 0; }
.contact svg { width: 17px; height: 17px; flex: none; fill: var(--teal); }
.contact a { color: var(--teal-dark); font-weight: 500; }
.contact span.label { color: var(--muted); }

.hero-copy { max-width: 680px; padding-top: 6px; }
h1 { margin: 0 0 22px; font-size: 30px; font-weight: 600; color: var(--teal-deep); }
h2 { margin: 44px 0 20px; font-size: 23px; font-weight: 600; color: var(--teal-deep); padding-bottom: 8px; border-bottom: 2px solid var(--teal-mist); max-width: 850px; }
h3 { margin: 0 0 5px; font-size: 18px; font-weight: 600; }
p { margin: 0 0 17px; }

.section-intro { max-width: 760px; margin-bottom: 42px; color: var(--muted); }
.paper, .course { max-width: 850px; margin-bottom: 34px; }
.paper-title { font-size: 18px; font-weight: 600; }
.meta { color: var(--muted); margin: 4px 0 8px; font-size: 16px; }
.paper-links { margin: 7px 0 10px; }
.paper-links a { font-weight: 500; }
.paper-links a + a::before { content: " · "; color: var(--muted); }
details { margin-top: 8px; }
summary { color: var(--teal-dark); cursor: pointer; font-weight: 500; }
details p { margin-top: 10px; max-width: 820px; }
.divider { height: 1px; background: var(--line); margin: 38px 0; max-width: 850px; }
.footer { max-width: var(--max); margin: 0 auto; padding: 0 28px 40px; color: var(--muted); font-size: 13px; }

@media (max-width: 720px) {
  .header-inner { align-items: flex-start; flex-direction: column; gap: 4px; }
  .site-name { padding-bottom: 6px; }
  .nav { gap: 2px; flex-wrap: wrap; }
  .nav a { padding: 6px 10px 12px; }
  main { padding-top: 36px; }
  .hero { grid-template-columns: 1fr; gap: 32px; }
  .sidebar { position: static; }
  .profile-photo { width: 200px; }
}