/* Light values are the default */
:root {
  --bg-1: #e8f4ff;
  --bg-2: #d8eaff;
  --radial-1: rgba(2, 132, 199, 0.12);
  --radial-2: rgba(124, 58, 237, 0.10);
  --panel: rgba(255, 255, 255, 0.82);
  --panel-strong: rgba(255, 255, 255, 0.98);
  --text: #0f1f3d;
  --muted: #4a5c7e;
  --accent: #0284c7;
  --accent-2: #7c3aed;
  --border: rgba(30, 60, 120, 0.14);
  --shadow: 0 20px 60px rgba(0, 0, 60, 0.10);
  --max-width: 1160px;
  --header-bg: rgba(232, 244, 255, 0.85);
  --brand-fg: #ffffff;
  color-scheme: light;
}

/* Dark values applied when OS prefers dark (and user hasn't forced light) */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg-1: #081120;
    --bg-2: #0d1830;
    --radial-1: rgba(103, 232, 249, 0.15);
    --radial-2: rgba(139, 92, 246, 0.18);
    --panel: rgba(15, 23, 42, 0.82);
    --panel-strong: rgba(15, 23, 42, 0.96);
    --text: #e5eefc;
    --muted: #9db0d0;
    --accent: #67e8f9;
    --accent-2: #8b5cf6;
    --border: rgba(148, 163, 184, 0.18);
    --shadow: 0 20px 60px rgba(0, 0, 0, 0.35);
    --header-bg: rgba(8, 17, 32, 0.72);
    --brand-fg: #04111f;
    color-scheme: dark;
  }
}

/* Explicit overrides from the toggle button */
:root[data-theme="dark"] {
  --bg-1: #081120;
  --bg-2: #0d1830;
  --radial-1: rgba(103, 232, 249, 0.15);
  --radial-2: rgba(139, 92, 246, 0.18);
  --panel: rgba(15, 23, 42, 0.82);
  --panel-strong: rgba(15, 23, 42, 0.96);
  --text: #e5eefc;
  --muted: #9db0d0;
  --accent: #67e8f9;
  --accent-2: #8b5cf6;
  --border: rgba(148, 163, 184, 0.18);
  --shadow: 0 20px 60px rgba(0, 0, 0, 0.35);
  --header-bg: rgba(8, 17, 32, 0.72);
  --brand-fg: #04111f;
  color-scheme: dark;
}

:root[data-theme="light"] {
  --bg-1: #e8f4ff;
  --bg-2: #d8eaff;
  --radial-1: rgba(2, 132, 199, 0.12);
  --radial-2: rgba(124, 58, 237, 0.10);
  --panel: rgba(255, 255, 255, 0.82);
  --panel-strong: rgba(255, 255, 255, 0.98);
  --text: #0f1f3d;
  --muted: #4a5c7e;
  --accent: #0284c7;
  --accent-2: #7c3aed;
  --border: rgba(30, 60, 120, 0.14);
  --shadow: 0 20px 60px rgba(0, 0, 60, 0.10);
  --header-bg: rgba(232, 244, 255, 0.85);
  --brand-fg: #ffffff;
  color-scheme: light;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: var(--text);
  background:
    radial-gradient(circle at top left, var(--radial-1), transparent 28%),
    radial-gradient(circle at top right, var(--radial-2), transparent 24%),
    linear-gradient(180deg, var(--bg-1) 0%, var(--bg-2) 45%, var(--bg-1) 100%);
  min-height: 100vh;
  line-height: 1.6;
}

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

a:hover {
  text-decoration: underline;
}

.container {
  width: min(calc(100% - 2rem), var(--max-width));
  margin: 0 auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  backdrop-filter: blur(18px);
  background: var(--header-bg);
  border-bottom: 1px solid rgba(148, 163, 184, 0.12);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.95rem 0;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  font-weight: 700;
  color: var(--text);
}

.brand-mark {
  font-family: ui-sans-serif, system-ui, sans-serif;
  font-weight: 700;
  font-size: 1rem;
  letter-spacing: 0.03em;
  color: var(--accent);
}

.nav {
  display: flex;
  gap: 0.25rem;
  flex-wrap: wrap;
  align-items: center;
}

.nav a {
  color: var(--muted);
  font-size: 0.95rem;
  padding: 0.3rem 0.75rem;
  border-radius: 999px;
  transition: background 0.2s, color 0.2s;
}

.nav a:hover {
  color: var(--text);
  text-decoration: none;
  background: color-mix(in srgb, var(--muted) 12%, transparent);
}

.nav a.active {
  color: var(--accent);
  background: color-mix(in srgb, var(--accent) 14%, transparent);
}

.theme-toggle {
  margin-left: 0.5rem;
  background: none;
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 0.28rem 0.6rem;
  cursor: pointer;
  font-size: 1rem;
  line-height: 1;
  color: var(--muted);
  transition: border-color 0.2s, color 0.2s;
}

.theme-toggle:hover {
  color: var(--text);
  border-color: var(--accent);
}

.hero {
  padding: 1.8rem 0 1.2rem;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.35fr 0.95fr;
  gap: 2rem;
  align-items: center;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.45rem 0.8rem;
  border-radius: 999px;
  background: rgba(103, 232, 249, 0.1);
  color: var(--accent);
  font-size: 0.85rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

h1,
h2,
h3 {
  margin: 0 0 0.8rem;
  line-height: 1.12;
}

h1,
h2 {
  font-family: "Cormorant Garamond", Georgia, serif;
}

h1 {
  font-size: clamp(2.8rem, 6vw, 5rem);
  letter-spacing: -0.03em;
  margin-top: 1rem;
}

.hero p {
  max-width: 62ch;
  color: var(--muted);
  font-size: 1.08rem;
}

.hero-actions {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  margin-top: 1.6rem;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.9rem 1.25rem;
  border-radius: 999px;
  border: 1px solid transparent;
  font-weight: 700;
  transition: transform 0.2s ease, border-color 0.2s ease, background 0.2s ease;
}

.button:hover {
  transform: translateY(-1px);
  text-decoration: none;
}

.button-primary {
  background: linear-gradient(135deg, var(--accent), #38bdf8);
  color: #04111f;
  box-shadow: var(--shadow);
}

.button-secondary {
  border-color: var(--border);
  color: var(--text);
  background: rgba(148, 163, 184, 0.08);
}

.hero-card,
.section-card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 28px;
  box-shadow: var(--shadow);
}

.hero-card {
  padding: 1.5rem;
}

.hero-card h2 {
  font-size: 1.25rem;
}

.hero-card p,
.hero-card li,
.section-intro {
  color: var(--muted);
}

.hero-card ul {
  padding-left: 1.2rem;
  margin: 1rem 0 0;
}

main {
  padding-bottom: 4rem;
}

section {
  padding: 1rem 0 0;
}

#people {
  padding-top: 0;
}

.section-heading {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1.25rem;
}

.section-heading h2 {
  font-size: clamp(1.4rem, 2.5vw, 1.9rem);
}

.people-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1rem;
}

.person-card {
  padding: 1.25rem;
  overflow: hidden;
}

.person-top::after {
  content: '';
  display: table;
  clear: both;
}

.person-photo-stack,
img.person-photo {
  width: 5.52rem;
  height: calc(5.52rem * 1.618);
  float: left;
  display: block;
  margin-right: 0.9rem;
  margin-bottom: 0.5rem;
  border-radius: 16px;
  overflow: hidden;
  border: 1px solid var(--border);
  box-shadow: 0 10px 24px rgba(0, 0, 0, 0.18);
}

.person-photo-stack {
  position: relative;
}

img.person-photo {
  object-fit: cover;
  object-position: center top;
  background: color-mix(in srgb, var(--muted) 12%, transparent);
}

.person-photo-stack img.person-photo {
  width: 100%;
  height: 100%;
}

.person-photo-stack .person-photo {
  position: absolute;
  inset: 0;
  transition: opacity 180ms ease;
}

.person-photo-stack .person-photo-hover {
  opacity: 0;
}

.person-card:hover .person-photo-stack.has-hover-photo .person-photo-hover,
.person-card:focus-within .person-photo-stack.has-hover-photo .person-photo-hover {
  opacity: 1;
}

.person-card:hover .person-photo-stack.has-hover-photo .person-photo-default,
.person-card:focus-within .person-photo-stack.has-hover-photo .person-photo-default {
  opacity: 0;
}

.person-card h3 {
  font-size: 1.2rem;
  margin: 0 0 0.15rem 0;
}

.person-card .email-link {
  color: inherit;
  text-decoration: none;
  cursor: pointer;
  transition: color 180ms ease;
}

.person-card .email-link:hover {
  color: var(--accent);
}

.person-card .email-icon {
  font-size: 0.9em;
  color: var(--muted);
  text-decoration: none;
  cursor: pointer;
  transition: color 180ms ease;
  display: inline;
  vertical-align: middle;
  margin-left: 0.3rem;
}

.person-card .email-icon:hover {
  color: var(--accent);
}

.person-card .email {
  font-size: 0.92rem;
  color: var(--muted);
}

.person-role {
  margin-top: 0.2rem;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--accent);
}

.person-card p {
  margin: 0.1rem 0 0;
  color: var(--muted);
}

.publications-list,
.conference-list {
  display: grid;
  gap: 0.85rem;
}

.publication-card,
.conference-card {
  padding: 1.35rem 1.4rem;
}

.publication-card {
  padding: 1rem 1.1rem;
}

.pub-body {
  display: flex;
  gap: 1rem;
  align-items: flex-start;
}

.pub-thumbnail {
  width: 5.5rem;
  height: 5.5rem;
  border-radius: 6px;
  flex: none;
  object-fit: cover;
}

@media (max-width: 480px) {
  .pub-thumbnail { display: none; }
}

.publication-card h3,
.conference-card h3 {
  font-size: 1.18rem;
  margin-bottom: 0.45rem;
}

.publication-card h3 {
  font-size: 1.08rem;
  margin-bottom: 0.3rem;
}

.publication-card p,
.conference-card p {
  margin: 0.45rem 0 0;
}

.journal,
.conference-note {
  color: var(--accent);
  font-weight: 700;
  margin-bottom: 0.55rem;
}

.author-list {
  color: var(--muted);
  font-size: 0.94rem;
  margin-bottom: 0.55rem;
}

.journal a {
  color: var(--accent);
}

.journal-ref {
  color: var(--muted);
  font-size: 0.92rem;
  margin-top: -0.2rem;
}

.conference-card ul {
  margin: 0.7rem 0 0;
  padding-left: 1.15rem;
}

.conference-card li + li {
  margin-top: 0.35rem;
}

.footer {
  padding: 2rem 0 3rem;
  color: var(--muted);
  font-size: 0.95rem;
}

@media (max-width: 1024px) {
  .hero-grid,
  .people-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 760px) {
  .site-header .container,
  .section-heading {
    align-items: flex-start;
    flex-direction: column;
  }

  .hero {
    padding-top: 1.2rem;
  }

  .hero-grid,
  .people-grid {
    grid-template-columns: 1fr;
  }

  .nav {
    gap: 0.75rem;
  }
}

/* ── Alumni list ─────────────────────────────────────────────────── */
.alumni-card {
  padding: 1.25rem 1.5rem;
}

.alumni-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  font-size: 0.97rem;
}

.alumni-list .alumni-name {
  font-weight: 600;
}

.alumni-list .code-authors {
  color: var(--muted);
  font-size: 0.88em;
}

/* ── Thesis list ─────────────────────────────────────────────────── */
.thesis-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 0.55rem;
}

.thesis-list li {
  display: flex;
  align-items: baseline;
  gap: 0.4rem;
  font-size: 0.97rem;
}

.thesis-list a {
  color: var(--fg);
  text-decoration: none;
}

.thesis-list a:hover {
  color: var(--accent);
}

.thesis-list .pdf-icon {
  width: 1.1em;
  height: 1.1em;
  vertical-align: middle;
  display: inline-block;
  flex-shrink: 0;
  margin-left: 0.25rem;
  position: relative;
  top: -0.05em;
}

.thesis-list .thesis-year {
  color: var(--muted);
  font-size: 0.88em;
  white-space: nowrap;
}