/* ===== Typography & base ===== */
:root {
  --bg: #f8f8fb;
  --bg-elevated: #ffffff;
  --bg-soft: #f1f1f7;
  --text: #1e1e1e;
  --text-muted: #666666;
  --accent: #a51c30; /* Harvard crimson-like */
  --accent-soft: #fbeaed;
  --border: #dedee5;
  --shadow-soft: 0 12px 30px rgba(0, 0, 0, 0.06);

  --radius-lg: 14px;
  --radius-pill: 999px;
  --max-width: 980px;
  --transition-fast: 0.18s ease;
}

html[data-theme="dark"] {
  --bg: #0f172a;
  --bg-elevated: #020617;
  --bg-soft: #020617;
  --text: #e5e7eb;
  --text-muted: #9ca3af;
  --accent: #f97373;
  --accent-soft: rgba(248, 113, 113, 0.12);
  --border: #1f2937;
  --shadow-soft: 0 16px 40px rgba(0, 0, 0, 0.7);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

body {
  margin: 0;
  padding: 0;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI",
    sans-serif;
  background: radial-gradient(circle at top, #fdfdfd 0, var(--bg) 55%);
  color: var(--text);
  line-height: 1.6;
}

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

/* layout */
.page {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}
.container {
  max-width: var(--max-width);
  padding: 0 1rem;
  margin: 0 auto;
}

/* ===== Nav bar ===== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: blur(12px);
  background: color-mix(in srgb, var(--bg) 80%, transparent 20%);
  border-bottom: 1px solid rgba(0, 0, 0, 0.04);
}
html[data-theme="dark"] .site-header {
  border-bottom-color: rgba(148, 163, 184, 0.2);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.7rem 1rem;
  max-width: var(--max-width);
  margin: 0 auto;
}
.nav-left {
  display: flex;
  align-items: baseline;
  gap: 0.4rem;
}
.nav-name {
  font-family: "Georgia", "Times New Roman", serif;
  font-size: 1.05rem;
  font-weight: 600;
  letter-spacing: 0.04em;
}
.nav-title {
  font-size: 0.85rem;
  color: var(--text-muted);
}
.nav-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  font-size: 0.88rem;
}
.nav-links a {
  padding: 0.35rem 0.7rem;
  border-radius: var(--radius-pill);
  border: 1px solid transparent;
}
.nav-links a:hover {
  background: var(--accent-soft);
  text-decoration: none;
}
.nav-links a.is-active {
  border-color: var(--accent);
  background: var(--accent-soft);
}

/* Dark mode toggle */
.theme-toggle {
  display: flex;
  align-items: center;
  gap: 0.3rem;
  font-size: 0.8rem;
  color: var(--text-muted);
}
.theme-toggle button {
  border-radius: var(--radius-pill);
  border: 1px solid var(--border);
  background: var(--bg-elevated);
  cursor: pointer;
  padding: 0.25rem 0.6rem;
  font-size: 0.8rem;
  display: inline-flex;
  gap: 0.25rem;
  align-items: center;
}
.theme-toggle button:hover {
  background: var(--accent-soft);
}

/* ===== Hero on home ===== */
.hero {
  padding: 2.3rem 0 2rem 0;
}
.hero-inner {
  display: grid;
  grid-template-columns: minmax(0, 1.7fr) minmax(0, 1.1fr);
  gap: 2.2rem;
  align-items: center;
}
@media (max-width: 840px) {
  .hero-inner {
    grid-template-columns: minmax(0, 1fr);
  }
}
.hero-title {
  font-family: "Georgia", "Times New Roman", serif;
  font-size: 2.1rem;
  margin: 0 0 0.3rem 0;
}
.hero-subtitle {
  font-size: 1rem;
  color: var(--text-muted);
  margin-bottom: 0.7rem;
}
.hero-tagline {
  font-size: 1rem;
  padding: 0.8rem 1rem;
  border-radius: var(--radius-lg);
  background: var(--accent-soft);
  border: 1px solid rgba(0, 0, 0, 0.04);
  margin-bottom: 1rem;
}
.hero-meta {
  font-size: 0.94rem;
  color: var(--text-muted);
}
.hero-meta strong {
  color: var(--text);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  margin-top: 1rem;
}

/* buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-pill);
  padding: 0.45rem 0.95rem;
  font-size: 0.88rem;
  border: 1px solid transparent;
  cursor: pointer;
  text-decoration: none;
  transition: transform var(--transition-fast), box-shadow var(--transition-fast),
    background var(--transition-fast), border-color var(--transition-fast);
}
.btn-primary {
  background: var(--accent);
  color: #ffffff;
  box-shadow: var(--shadow-soft);
}
.btn-primary:hover {
  text-decoration: none;
  transform: translateY(-1px);
  box-shadow: 0 18px 40px rgba(0, 0, 0, 0.35);
}
.btn-ghost {
  background: transparent;
  border-color: var(--border);
}
.btn-ghost:hover {
  background: var(--bg-soft);
  text-decoration: none;
}
.btn-soft {
  background: var(--accent-soft);
  color: var(--accent);
  border-color: transparent;
}
.btn-soft:hover {
  background: var(--accent);
  color: white;
}

/* headshot */
.hero-headshot-wrap {
  display: flex;
  justify-content: center;
}
.hero-headshot {
  width: 260px;
  height: 260px;
  border-radius: 50%;
  object-fit: cover;
  object-position: 50% 30%;
  transform: scale(1.22);
  box-shadow: var(--shadow-soft);
  border: 3px solid #ffffff;
}

/* shared section layout */
.main {
  flex: 1;
}
.section {
  padding: 1.8rem 0;
}
.section-heading {
  font-family: "Georgia", "Times New Roman", serif;
  font-size: 1.35rem;
  margin-bottom: 0.3rem;
}
.section-subtitle {
  font-size: 0.95rem;
  color: var(--text-muted);
  margin-bottom: 1rem;
}

/* cards, lists */
.card {
  background: var(--bg-elevated);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  padding: 1rem 1.2rem;
  box-shadow: var(--shadow-soft);
  margin-bottom: 1rem;
}
.card h3 {
  margin-top: 0;
  margin-bottom: 0.35rem;
  font-size: 1.02rem;
  font-family: "Georgia", "Times New Roman", serif;
}
.muted {
  color: var(--text-muted);
  font-size: 0.9rem;
}

/* lists */
.simple-list,
.pub-list,
.teaching-list {
  list-style: none;
  padding: 0;
  margin: 0;
}
.simple-list li,
.pub-list li,
.teaching-list li {
  margin-bottom: 0.7rem;
  font-size: 0.95rem;
}

/* publications */
.pub-title {
  font-weight: 600;
}
.pub-venue {
  font-style: italic;
}
.pub-meta {
  font-size: 0.85rem;
  color: var(--text-muted);
}
.badge {
  display: inline-flex;
  align-items: center;
  border-radius: var(--radius-pill);
  padding: 0.1rem 0.5rem;
  font-size: 0.75rem;
  background: #e5e7eb;
  color: #374151;
}
html[data-theme="dark"] .badge {
  background: #1f2937;
  color: #e5e7eb;
}

/* pills */
.pill-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}
.pill {
  font-size: 0.78rem;
  padding: 0.18rem 0.55rem;
  border-radius: var(--radius-pill);
  background: #e5e7f5;
  color: #27303f;
}
html[data-theme="dark"] .pill {
  background: #111827;
  color: #e5e7eb;
}

/* footer */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 1.2rem 0 2rem 0;
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* small tweaks */
@media (max-width: 640px) {
  .nav {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.5rem;
  }
}

/* page-specific helpers */
.home-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(0, 1.1fr);
  gap: 1.1rem;
}
@media (max-width: 840px) {
  .home-grid {
    grid-template-columns: minmax(0, 1fr);
  }
}

/* research image grid */
.image-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
  margin-top: 0.5rem;
}

.image-card {
  background: var(--bg-elevated);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  padding: 0.6rem 0.6rem 0.9rem 0.6rem;
  box-shadow: var(--shadow-soft);
}

.image-card img {
  width: 100%;
  height: 180px;
  object-fit: contain;
  display: block;
  margin-bottom: 0.4rem;
}

.image-card-title {
  font-size: 0.9rem;
  font-weight: 600;
}

.image-card-caption {
  font-size: 0.8rem;
  color: var(--text-muted);
}