/* ==========================================================================
   Tharaka D. Fonseka — personal academic website
   Modern light theme with Princeton-orange accent
   ========================================================================== */

:root {
  --accent: #1565c0;          /* deep blue */
  --accent-dark: #0d47a1;
  --accent-soft: #e8f1fb;
  --ink: #1f2430;
  --ink-soft: #4b5263;
  --ink-faint: #8890a0;
  --bg: #ffffff;
  --bg-alt: #f7f8fa;
  --card: #ffffff;
  --line: #e6e8ee;
  --radius: 14px;
  --shadow: 0 1px 3px rgba(20, 24, 35, 0.06), 0 8px 24px rgba(20, 24, 35, 0.06);
  --font-body: "Inter", system-ui, -apple-system, sans-serif;
  --font-head: "Source Serif 4", Georgia, serif;
}

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

html { scroll-behavior: smooth; scroll-padding-top: 76px; }

body {
  font-family: var(--font-body);
  color: var(--ink);
  background: var(--bg);
  line-height: 1.65;
  font-size: 16.5px;
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: 1040px;
  margin: 0 auto;
  padding: 0 24px;
}

h1, h2, h3 { font-family: var(--font-head); line-height: 1.25; }

a { color: var(--accent-dark); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ---------- Navigation (fixed left sidebar on desktop) ---------- */

.site-nav {
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  width: 230px;
  z-index: 100;
  background: #fff;
  border-right: 1px solid var(--line);
  overflow-y: auto;
}

.nav-inner {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 30px;
  padding: 32px 20px;
}

.nav-name {
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 0.92rem;
  line-height: 1.35;
  color: var(--ink);
  padding-left: 12px;
  white-space: nowrap;
}
.nav-name:hover { text-decoration: none; color: var(--accent-dark); }

.nav-links {
  display: flex;
  flex-direction: column;
  gap: 4px;
  width: 100%;
}

.nav-links a {
  color: var(--ink-soft);
  font-size: 0.94rem;
  font-weight: 500;
  padding: 8px 12px;
  border-left: 3px solid transparent;
  border-radius: 0 8px 8px 0;
}
.nav-links a:hover,
.nav-links a.active {
  color: var(--accent-dark);
  text-decoration: none;
  border-left-color: var(--accent);
  background: var(--accent-soft);
}

main,
.site-footer { margin-left: 230px; }

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px;
}
.nav-toggle span {
  width: 22px;
  height: 2px;
  background: var(--ink);
  border-radius: 2px;
  transition: transform 0.2s ease, opacity 0.2s ease;
}

/* ---------- Hero ---------- */

.hero {
  padding: 32px 0 20px;
  background:
    radial-gradient(1200px 500px at 85% -10%, var(--accent-soft), transparent 60%),
    var(--bg);
}

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 220px;
  gap: 32px;
  align-items: center;
}

.hero h1 { font-size: 2.15rem; margin-bottom: 4px; }

.hero-sub {
  color: var(--ink-soft);
  font-size: 0.95rem;
  font-weight: 500;
  margin-bottom: 16px;
}

.hero-bio { color: var(--ink-soft); margin-bottom: 10px; font-size: 0.86rem; line-height: 1.55; }
.hero-bio strong { color: var(--ink); }

.hero-list { margin: -2px 0 10px; font-size: 0.86rem; }
.hero-list li { font-size: 0.86rem; padding: 3px 0 3px 18px; }

.hero-links { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 16px; }

.hero-photo { display: flex; justify-content: flex-end; }

.hero-photo img {
  width: 200px;
  height: 200px;
  object-fit: cover;
  border-radius: 50%;
  border: 6px solid #fff;
  box-shadow: var(--shadow);
  background: var(--bg-alt);
}

/* ---------- Buttons ---------- */

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 9px 18px;
  border-radius: 999px;
  border: 1.5px solid var(--line);
  color: var(--ink-soft);
  font-size: 0.9rem;
  font-weight: 550;
  background: #fff;
  transition: all 0.15s ease;
}
.btn:hover {
  border-color: var(--accent);
  color: var(--accent-dark);
  text-decoration: none;
  transform: translateY(-1px);
}

.btn-primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}
.btn-primary:hover { background: var(--accent-dark); border-color: var(--accent-dark); color: #fff; }

.btn-lg { padding: 13px 28px; font-size: 1.02rem; }

/* Inline SVG icons in buttons and links */
.icon {
  width: 1em;
  height: 1em;
  flex-shrink: 0;
  fill: currentColor;
  vertical-align: -0.125em;
}
.btn-lg .icon { width: 1.1em; height: 1.1em; }

/* ---------- Sections ---------- */

.section { padding: 32px 0; }
.section-alt { background: var(--bg-alt); }

.section h2 {
  font-size: 1.9rem;
  margin-bottom: 18px;
  position: relative;
  padding-bottom: 10px;
}
.section h2::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 52px;
  height: 3px;
  border-radius: 2px;
  background: var(--accent);
}

.section-note { color: var(--ink-faint); font-size: 0.86rem; margin: -16px 0 24px; }

/* ---------- News ---------- */

.news-list { list-style: none; }

.news-list li {
  display: grid;
  grid-template-columns: 110px 1fr;
  gap: 18px;
  padding: 13px 0;
  border-bottom: 1px solid var(--line);
  color: var(--ink-soft);
  font-size: 0.86rem;
}
.news-list li:last-child { border-bottom: none; }
.news-list strong, .news-list em { color: var(--ink); }

.news-date {
  color: var(--accent-dark);
  font-weight: 600;
  font-size: 0.88rem;
  white-space: nowrap;
  padding-top: 2px;
}

.news-list a { text-decoration: underline; }
.news-list a.no-underline { text-decoration: none; }

.flag-us {
  display: inline-block;
  width: 1.15em;
  height: 0.61em;
  vertical-align: 0.08em;
  margin: 0 0.12em;
  border-radius: 1px;
  box-shadow: 0 0 0 0.5px rgba(0, 0, 0, 0.18);
}

/* ---------- Cards ---------- */

.card-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 22px;
}
.card-grid.two-col { grid-template-columns: repeat(2, 1fr); }

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 24px 26px;
  box-shadow: var(--shadow);
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}
.card:hover {
  transform: translateY(-3px);
  box-shadow: 0 4px 10px rgba(20, 24, 35, 0.08), 0 14px 34px rgba(20, 24, 35, 0.1);
}

.card h3 { font-size: 1.12rem; margin-bottom: 10px; }
.card p { color: var(--ink-soft); font-size: 0.86rem; }

.card-links { margin-top: 12px; font-size: 0.86rem; }

.plain-list { list-style: none; }
.plain-list li {
  color: var(--ink-soft);
  font-size: 0.86rem;
  padding: 6px 0 6px 18px;
  position: relative;
}
.plain-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 15px;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
}

.hero-list.plain-list li {
  font-size: 0.86rem;
  padding: 3px 0 3px 18px;
}
.hero-list.plain-list li::before {
  top: 11px;
}

/* ---------- Publications ---------- */

.pub-group {
  font-size: 1.2rem;
  margin: 30px 0 14px;
  color: var(--ink);
}

.pub-list { list-style: none; counter-reset: pub; }

.pub-list li {
  padding: 16px 18px;
  margin-bottom: 12px;
  background: var(--bg-alt);
  border-left: 3px solid var(--accent);
  border-radius: 0 var(--radius) var(--radius) 0;
  color: var(--ink-soft);
  font-size: 0.86rem;
}

.pub-title { font-weight: 600; color: var(--ink); font-size: 0.86rem; }
.pub-venue { font-style: italic; color: var(--ink-faint); }
.pub-links { font-size: 0.86rem; }

.badge {
  display: inline-block;
  margin-left: 8px;
  padding: 2px 10px;
  border-radius: 999px;
  background: var(--accent);
  color: #fff;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.03em;
  vertical-align: middle;
}

/* ---------- Timeline (experience / education) ---------- */

.timeline { position: relative; }

.timeline-item {
  display: grid;
  grid-template-columns: 160px 1fr;
  gap: 24px;
  padding: 20px 0;
  border-bottom: 1px solid var(--line);
}
.timeline-item:last-child { border-bottom: none; }

.timeline-when {
  color: var(--accent-dark);
  font-weight: 600;
  font-size: 0.9rem;
  padding-top: 3px;
  white-space: nowrap;
}

.timeline-body h3 { font-size: 1.12rem; margin-bottom: 2px; }

.edu-logo {
  float: right;
  width: 52px;
  height: 52px;
  object-fit: contain;
  margin: 0 0 8px 14px;
}

.timeline-where {
  color: var(--ink-faint);
  font-size: 0.86rem;
  font-style: italic;
  margin-bottom: 8px;
}

.timeline-body p { color: var(--ink-soft); font-size: 0.86rem; }

/* ---------- Awards ---------- */

.award-list { list-style: none; }

.award-list li {
  padding: 11px 0;
  border-bottom: 1px solid var(--line);
  color: var(--ink-soft);
  font-size: 0.86rem;
}
.award-list li:last-child { border-bottom: none; }
.award-list strong { color: var(--ink); }

.award-year {
  display: inline-block;
  min-width: 52px;
  color: var(--accent-dark);
  font-weight: 600;
  font-size: 0.88rem;
}

/* ---------- Contact ---------- */

.section-contact {
  background:
    radial-gradient(900px 400px at 15% 110%, var(--accent-soft), transparent 60%),
    var(--bg);
  text-align: center;
}

.contact-inner h2 { display: inline-block; }
.contact-inner h2::after { left: 50%; transform: translateX(-50%); }

.contact-inner p { color: var(--ink-soft); margin: 6px 0 24px; font-size: 0.86rem; }

.contact-links {
  margin-top: 26px;
  display: flex;
  justify-content: center;
  gap: 26px;
  flex-wrap: wrap;
  font-weight: 500;
}
.contact-links a {
  display: inline-flex;
  align-items: center;
  gap: 7px;
}

/* ---------- Footer ---------- */

.site-footer {
  border-top: 1px solid var(--line);
  padding: 22px 0;
  text-align: center;
  color: var(--ink-faint);
  font-size: 0.87rem;
}

/* ---------- Scroll reveal ---------- */

.reveal {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}
.reveal.visible { opacity: 1; transform: none; }

/* ---------- Responsive ---------- */

@media (max-width: 860px) {
  .hero-grid { grid-template-columns: 1fr; gap: 32px; }
  .hero-photo { order: -1; }
  .hero-photo img { width: 180px; height: 180px; }
  .hero h1 { font-size: 1.85rem; }
  .card-grid, .card-grid.two-col { grid-template-columns: 1fr; }
  .timeline-item { grid-template-columns: 1fr; gap: 4px; }
  .news-list li { grid-template-columns: 84px 1fr; gap: 12px; }

  /* Sidebar collapses back into a sticky top bar with a hamburger menu */
  .site-nav {
    position: sticky;
    left: auto;
    bottom: auto;
    width: auto;
    border-right: none;
    border-bottom: 1px solid var(--line);
    overflow-y: visible;
  }
  .nav-inner {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    padding: 14px 24px;
  }
  .nav-name { padding-left: 0; font-size: 1.05rem; }
  main, .site-footer { margin-left: 0; }

  .nav-toggle { display: flex; }
  .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    gap: 0;
    background: #fff;
    border-bottom: 1px solid var(--line);
    padding: 8px 24px 16px;
    box-shadow: var(--shadow);
  }
  .nav-links.open { display: flex; }
  .nav-links a {
    padding: 10px 0;
    border-left: none;
    border-radius: 0;
  }
  .nav-links a:hover,
  .nav-links a.active { background: none; }
}