/* ============================================================
   Thang Ha — personal site
   Design tokens
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=Newsreader:ital,opsz,wght@0,6..72,400;0,6..72,500;0,6..72,600;1,6..72,400&family=Inter:wght@400;500;600&family=IBM+Plex+Mono:wght@400;500&display=swap');

:root {
  --ink: #16233A;       /* primary text, headings */
  --ink-soft: #2C3E52;  /* body text */
  --slate: #5B6B7C;     /* secondary / meta text */
  --paper: #FAF9F5;     /* page background */
  --paper-raised: #F2EFE6; /* card / panel background */
  --gold: #97731E;      /* accent — links, marks */
  --gold-soft: #B8912F; /* accent, lighter (motif lines) */
  --line: #DDD8CC;      /* hairline rules */

  --font-display: 'Newsreader', Georgia, serif;
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'IBM Plex Mono', 'Courier New', monospace;

  --measure: 640px;
  --nav-height: 72px;
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink-soft);
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--gold);
  text-decoration: none;
  border-bottom: 1px solid rgba(151, 115, 30, 0.35);
  transition: border-color 0.15s ease, color 0.15s ease;
}

a:hover,
a:focus-visible {
  border-bottom-color: var(--gold);
}

a:focus-visible,
button:focus-visible {
  outline: 2px solid var(--gold);
  outline-offset: 3px;
}

h1, h2, h3 {
  font-family: var(--font-display);
  color: var(--ink);
  font-weight: 500;
  line-height: 1.15;
  margin: 0 0 0.5em;
}

h1 { font-size: clamp(2.8rem, 5.5vw, 4.4rem); font-weight: 600; letter-spacing: -0.01em; }
h2 { font-size: 1.5rem; margin-top: 2.2em; }
h3 { font-size: 1.15rem; margin-top: 1.6em; }

p { margin: 0 0 1.2em; }

.eyebrow {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.11em;
  text-transform: uppercase;
  color: var(--slate);
}

.meta {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--slate);
}

/* ---------- layout shell ---------- */

.wrap {
  max-width: var(--measure);
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------- nav ---------- */

.site-nav {
  border-bottom: 1px solid var(--line);
  background: var(--paper);
  position: sticky;
  top: 0;
  z-index: 10;
}

.site-nav .wrap {
  max-width: 1080px;
  height: 92px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.site-nav .brand {
  font-family: var(--font-display);
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--ink);
  border-bottom: none;
}

.site-nav ul {
  list-style: none;
  display: flex;
  gap: 34px;
  margin: 0;
  padding: 0;
}

.site-nav a {
  font-family: var(--font-mono);
  font-size: 0.95rem;
  letter-spacing: 0.03em;
  text-transform: uppercase;
  color: var(--ink-soft);
  border-bottom: 1px solid transparent;
}

.site-nav a:hover,
.site-nav a.active {
  color: var(--gold);
  border-bottom-color: var(--gold);
}

.nav-toggle { display: none; }

/* ---------- hero / header motif ---------- */

.hero {
  position: relative;
  padding: 56px 0 60px;
}

.hero .wrap {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 24px;
}

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 380px;
  gap: 64px;
  align-items: start;
}

.bio-text .lede { font-size: 1.05rem; }

.headshot {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 4 / 5;
  object-fit: cover;
  background: var(--paper-raised);
}

.headshot.placeholder {
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--slate);
  text-align: center;
  padding: 8px;
  border: 1px solid var(--line);
}

.signoff {
  font-family: var(--font-display);
  font-size: 1.1rem;
  color: var(--ink);
  line-height: 1.5;
  margin: 20px 0 0;
}

.signoff a {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--slate);
  border-bottom-color: rgba(91,107,124,0.3);
}

/* ---------- main content ---------- */

main {
  max-width: 760px;
  margin: 0 auto;
  padding: 0 0 100px;
}

main .wrap { padding: 0 24px; }

.lede {
  font-size: 1.05rem;
  color: var(--ink-soft);
}

/* ---------- research entries ---------- */

.entry {
  border-top: 1px solid var(--line);
  padding: 28px 0;
}

.entry:first-of-type { border-top: none; padding-top: 0; }

.entry h3 { margin-top: 0; }

.entry .meta { margin-bottom: 10px; }

.entry .status {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--gold);
  border: 1px solid rgba(151, 115, 30, 0.4);
  border-radius: 3px;
  padding: 2px 7px;
  margin-bottom: 10px;
}

/* ---------- teaching table ---------- */

.course-list {
  border-top: 1px solid var(--line);
}

.course {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  padding: 16px 0;
  border-bottom: 1px solid var(--line);
}

.course .role { color: var(--ink); font-weight: 500; }
.course .where { color: var(--slate); font-size: 0.92rem; }
.course .when {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--slate);
  white-space: nowrap;
}

/* ---------- contact ---------- */

.contact-list {
  list-style: none;
  padding: 0;
  margin: 24px 0;
  border-top: 1px solid var(--line);
}

.contact-list li {
  border-bottom: 1px solid var(--line);
  padding: 14px 0;
  display: flex;
  gap: 12px;
  align-items: baseline;
}

.contact-list .label {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--slate);
  width: 90px;
  flex-shrink: 0;
}

/* ---------- cv page ---------- */

.cv-embed {
  border: 1px solid var(--line);
  height: 80vh;
  margin-top: 20px;
}

.download-btn {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--ink);
  border: 1px solid var(--ink);
  padding: 9px 16px;
  border-bottom: 1px solid var(--ink);
  border-radius: 3px;
  margin-top: 8px;
}

.download-btn:hover {
  background: var(--ink);
  color: var(--paper);
}

/* ---------- footer ---------- */

footer {
  border-top: 1px solid var(--line);
  margin-top: 40px;
  padding: 28px 0 60px;
}

footer .wrap {
  max-width: 760px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 10px;
}

footer .meta a { color: var(--slate); border-bottom-color: rgba(91,107,124,0.3); }

/* ---------- responsive ---------- */

@media (max-width: 620px) {
  .site-nav ul { gap: 16px; }
  .site-nav a { font-size: 0.72rem; }
  .hero-grid { grid-template-columns: 1fr; gap: 32px; }
  .bio-photo { max-width: 320px; }
  .course { flex-direction: column; gap: 4px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { transition: none !important; }
}