/* ─────────────────────────────────────────────────────────────
   CSS Custom Properties
──────────────────────────────────────────────────────────────── */
:root {
  --color-bg:        #ffffff;
  --color-bg-alt:    #f8fafc;
  --color-text:      #111827;
  --color-muted:     #6b7280;
  --color-border:    #e5e7eb;
  --color-accent:    #2563eb;
  --color-accent-h:  #1d4ed8;
  --color-accent-bg: #eff6ff;

  --color-conf:      #2563eb;
  --color-conf-bg:   #eff6ff;
  --color-jour:      #059669;
  --color-jour-bg:   #ecfdf5;
  --color-work:      #d97706;
  --color-work-bg:   #fffbeb;
  --color-book:      #7c3aed;
  --color-book-bg:   #f5f3ff;

  --nav-height:      64px;
  --max-width:       1100px;
  --radius:          8px;
  --shadow-sm:       0 1px 3px rgba(0,0,0,.08), 0 1px 2px rgba(0,0,0,.05);
  --shadow:          0 4px 6px -1px rgba(0,0,0,.08), 0 2px 4px -2px rgba(0,0,0,.05);

  --font-sans: 'Inter', system-ui, -apple-system, sans-serif;
}

/* ─────────────────────────────────────────────────────────────
   Dark Mode Overrides
──────────────────────────────────────────────────────────────── */
[data-theme="dark"] {
  --color-bg:        #1c1c1e;
  --color-bg-alt:    #2c2c2e;
  --color-text:      #f1f5f9;
  --color-muted:     #94a3b8;
  --color-border:    #334155;
  --color-accent:    #60a5fa;
  --color-accent-h:  #93c5fd;
  --color-accent-bg: #1e3a5f;

  --color-conf:      #60a5fa;
  --color-conf-bg:   #1e3a5f;
  --color-jour:      #34d399;
  --color-jour-bg:   #064e3b;
  --color-work:      #fbbf24;
  --color-work-bg:   #451a03;
  --color-book:      #a78bfa;
  --color-book-bg:   #2e1065;

  --shadow-sm: 0 1px 3px rgba(0,0,0,.3);
  --shadow:    0 4px 6px -1px rgba(0,0,0,.4);
}

[data-theme="dark"] .site-header {
  background: rgba(28,28,30,.92);
}

[data-theme="dark"] .note-callout {
  background: #422006;
  border-left-color: #fbbf24;
}

[data-theme="dark"] .pub-item,
[data-theme="dark"] .timeline-body,
[data-theme="dark"] .dataset-card,
[data-theme="dark"] .contact-note {
  background: #2c2c2e;
}

[data-theme="dark"] .bio-section {
  background: var(--color-bg-alt);
}

[data-theme="dark"] .pub-content a { text-decoration-color: #3b82f6; }

/* ─────────────────────────────────────────────────────────────
   Reset & Base
──────────────────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--nav-height) + 16px);
}

body {
  font-family: var(--font-sans);
  font-size: 15px;
  line-height: 1.7;
  color: var(--color-text);
  background: var(--color-bg);
}

img { max-width: 100%; display: block; }

a {
  color: var(--color-accent);
  text-decoration: none;
  transition: color .15s;
}
a:hover { color: var(--color-accent-h); text-decoration: underline; }

/* ─────────────────────────────────────────────────────────────
   Layout helpers
──────────────────────────────────────────────────────────────── */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

.section {
  padding: 3rem 0;
}

/* ─────────────────────────────────────────────────────────────
   Navigation
──────────────────────────────────────────────────────────────── */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--nav-height);
  background: rgba(255,255,255,.92);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--color-border);
}

.nav-container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  font-weight: 700;
  font-size: 1rem;
  color: var(--color-text);
  letter-spacing: -.01em;
  text-decoration: none;
}
.nav-logo:hover { color: var(--color-accent); text-decoration: none; }

.nav-links {
  display: flex;
  list-style: none;
  gap: 2rem;
}

.nav-links a {
  font-size: .875rem;
  font-weight: 500;
  color: var(--color-muted);
  text-decoration: none;
  transition: color .15s;
}
.nav-links a:hover { color: var(--color-accent); }

.nav-right {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 34px;
  height: 34px;
  background: var(--color-bg-alt);
  border: 1px solid var(--color-border);
  border-radius: 50%;
  cursor: pointer;
  font-size: 1rem;
  transition: background .2s, border-color .2s, transform .15s;
  flex-shrink: 0;
}
.theme-toggle:hover {
  background: var(--color-accent-bg);
  border-color: var(--color-accent);
  transform: rotate(20deg);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}
.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: all .2s;
}

/* ─────────────────────────────────────────────────────────────
   Hero Section
──────────────────────────────────────────────────────────────── */
.hero-section {
  background: var(--color-bg);
  padding-top: 2.5rem;
  padding-bottom: 2rem;
}

.hero-grid {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 2.5rem;
  align-items: center;
}

.hero-photo img {
  width: 175px;
  height: 175px;
  border-radius: 50%;
  object-fit: cover;
  object-position: center center;
  box-shadow: 0 0 0 3px var(--color-border), var(--shadow);
}

.hero-greeting {
  font-size: .85rem;
  font-weight: 500;
  color: var(--color-accent);
  text-transform: uppercase;
  letter-spacing: .08em;
  margin-bottom: .25rem;
}

.hero-name {
  font-size: 1.75rem;
  font-weight: 700;
  letter-spacing: -.025em;
  line-height: 1.2;
  margin-bottom: .4rem;
}

.hero-title {
  font-size: 1rem;
  font-weight: 500;
  color: var(--color-text);
  margin-bottom: .15rem;
}

.hero-org {
  font-size: .9rem;
  color: var(--color-muted);
  margin-bottom: .1rem;
}

.hero-affil {
  font-size: .875rem;
  color: var(--color-muted);
  margin-bottom: 1.25rem;
}

.hero-interests {
  display: flex;
  flex-wrap: wrap;
  gap: .5rem;
  margin-bottom: 1.25rem;
}

.tag {
  display: inline-block;
  padding: .25rem .75rem;
  background: var(--color-accent-bg);
  color: var(--color-accent);
  font-size: .78rem;
  font-weight: 500;
  border-radius: 999px;
  border: 1px solid #bfdbfe;
}

.hero-social {
  display: flex;
  gap: .75rem;
}

.social-btn {
  display: inline-block;
  padding: .45rem 1.1rem;
  background: var(--color-accent);
  color: #fff !important;
  font-size: .825rem;
  font-weight: 600;
  border-radius: var(--radius);
  text-decoration: none !important;
  transition: background .15s, transform .1s;
}
.social-btn:hover {
  background: var(--color-accent-h);
  transform: translateY(-1px);
}

/* ─────────────────────────────────────────────────────────────
   Bio / About Section
──────────────────────────────────────────────────────────────── */
.bio-section {
  background: var(--color-bg-alt);
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}

.bio-main p {
  margin-bottom: 1rem;
  color: var(--color-text);
  text-align: justify;
}

.note-callout {
  padding: .75rem 1rem;
  background: #fef3c7;
  border-left: 3px solid #f59e0b;
  border-radius: 0 var(--radius) var(--radius) 0;
  font-size: .875rem;
}

/* ─────────────────────────────────────────────────────────────
   Section Headings
──────────────────────────────────────────────────────────────── */
.section-title {
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: -.02em;
  margin-bottom: 1.5rem;
  padding-bottom: .6rem;
  border-bottom: 2px solid var(--color-accent);
  display: inline-block;
}

.subsection-title {
  font-size: .9rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .06em;
  color: var(--color-muted);
  margin-bottom: 1rem;
}

.section-lead {
  color: var(--color-muted);
  margin-bottom: 1.5rem;
}

/* ─────────────────────────────────────────────────────────────
   Publications
──────────────────────────────────────────────────────────────── */
.pub-section { background: var(--color-bg); }

.pub-disclaimer {
  font-size: .8rem;
  color: var(--color-muted);
  font-style: italic;
  margin-bottom: 1.5rem;
  padding: .75rem 1rem;
  background: var(--color-bg-alt);
  border-radius: var(--radius);
  border: 1px solid var(--color-border);
}

/* Filter buttons */
.pub-filter {
  display: flex;
  flex-wrap: wrap;
  gap: .5rem;
  margin-bottom: 2rem;
}

.filter-btn {
  padding: .35rem .9rem;
  font-family: var(--font-sans);
  font-size: .8rem;
  font-weight: 500;
  border: 1px solid var(--color-border);
  border-radius: 999px;
  background: var(--color-bg);
  color: var(--color-muted);
  cursor: pointer;
  transition: all .15s;
}
.filter-btn:hover,
.filter-btn.active {
  background: var(--color-accent);
  color: #fff;
  border-color: var(--color-accent);
}

/* Year groups */
.pub-year-group {
  margin-bottom: 2rem;
}

.pub-year-header {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--color-muted);
  letter-spacing: .02em;
  margin-bottom: .75rem;
  position: relative;
  padding-left: .85rem;
}
.pub-year-header::before {
  content: '';
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 3px;
  height: 1em;
  background: var(--color-accent);
  border-radius: 2px;
}

/* Publication list */
.pub-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: .75rem;
}

.pub-item {
  display: flex;
  align-items: flex-start;
  gap: .75rem;
  padding: .85rem 1rem;
  background: var(--color-bg-alt);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  transition: box-shadow .15s, border-color .15s;
}
.pub-item:hover {
  box-shadow: var(--shadow);
  border-color: #d1d5db;
}

.pub-id {
  flex-shrink: 0;
  font-size: .72rem;
  font-weight: 700;
  font-family: ui-monospace, 'SF Mono', monospace;
  color: var(--color-muted);
  width: 2.5rem;
  padding-top: .1rem;
}

.pub-badge {
  flex-shrink: 0;
  width: 6rem;
  text-align: center;
  font-size: .68rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: .04em;
  padding: .15rem .55rem;
  border-radius: 999px;
  white-space: nowrap;
  margin-top: .1rem;
}

.badge-conf { background: var(--color-conf-bg); color: var(--color-conf); }
.badge-jour { background: var(--color-jour-bg); color: var(--color-jour); }
.badge-work { background: var(--color-work-bg); color: var(--color-work); }
.badge-book { background: var(--color-book-bg); color: var(--color-book); }

.pub-content {
  flex: 1;
  font-size: .875rem;
  line-height: 1.6;
  color: var(--color-text);
  text-align: justify;
}

.pub-content a {
  font-weight: 600;
  text-decoration: underline;
  text-underline-offset: 2px;
  text-decoration-color: #93c5fd;
}
.pub-content a:hover {
  text-decoration-color: var(--color-accent);
}

.pub-content > em::before {
  content: '\A';
  white-space: pre;
}

.pub-authors {
  display: block;
  margin-top: .25rem;
  font-size: .8rem;
  color: var(--color-muted);
  font-style: normal;
}

.award {
  display: inline-block;
  margin-left: .5rem;
  font-size: .72rem;
  font-weight: 700;
  color: #d97706;
  background: #fef3c7;
  padding: .1rem .45rem;
  border-radius: 999px;
  border: 1px solid #fde68a;
  white-space: nowrap;
}


/* hidden by filter */
.pub-item.hidden { display: none; }
.pub-year-group.hidden { display: none; }

/* ─────────────────────────────────────────────────────────────
   Experience / Timeline
──────────────────────────────────────────────────────────────── */
.exp-section { background: var(--color-bg-alt); }

.timeline {
  position: relative;
  padding-left: 2rem;
}
.timeline::before {
  content: '';
  position: absolute;
  left: 7px;
  top: 6px;
  bottom: 0;
  width: 2px;
  background: var(--color-border);
}

.timeline-item {
  position: relative;
  margin-bottom: 2rem;
}
.timeline-item:last-child { margin-bottom: 0; }

.timeline-dot {
  position: absolute;
  left: -2rem;
  top: 6px;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--color-accent);
  border: 2px solid var(--color-bg-alt);
  box-shadow: 0 0 0 2px var(--color-accent);
}

.timeline-body {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.1rem 1.25rem;
  transition: box-shadow .15s;
}
.timeline-body:hover { box-shadow: var(--shadow); }

.timeline-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 1rem;
  margin-bottom: .4rem;
}

.timeline-org {
  font-weight: 700;
  font-size: .95rem;
}

.timeline-role {
  font-size: .85rem;
  color: var(--color-muted);
  font-weight: 500;
}

.timeline-date {
  font-size: .78rem;
  font-weight: 500;
  color: var(--color-accent);
  white-space: nowrap;
  background: var(--color-accent-bg);
  padding: .2rem .65rem;
  border-radius: 999px;
  flex-shrink: 0;
}

.timeline-desc {
  font-size: .85rem;
  color: var(--color-muted);
  margin-top: .3rem;
}

/* ─────────────────────────────────────────────────────────────
   Datasets
──────────────────────────────────────────────────────────────── */
.dataset-section { background: var(--color-bg); }

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

.dataset-card {
  display: flex;
  flex-direction: column;
  gap: .35rem;
  padding: 1.25rem;
  background: var(--color-bg-alt);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  text-decoration: none;
  color: var(--color-text);
  transition: box-shadow .15s, border-color .15s, transform .15s;
}
.dataset-card:hover {
  box-shadow: var(--shadow);
  border-color: var(--color-accent);
  transform: translateY(-2px);
  text-decoration: none;
  color: var(--color-text);
}

.dataset-icon { font-size: 1.5rem; }

.dataset-title {
  font-weight: 600;
  font-size: .9rem;
  color: var(--color-accent);
}

.dataset-meta {
  font-size: .75rem;
  font-weight: 500;
  color: var(--color-muted);
  text-transform: uppercase;
  letter-spacing: .05em;
}

.dataset-desc {
  font-size: .82rem;
  color: #6b7280;
  line-height: 1.5;
}

/* ─────────────────────────────────────────────────────────────
   Tutorials
──────────────────────────────────────────────────────────────── */
.tutorial-card {
  background: var(--color-bg-alt);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.75rem 2rem;
}

.tutorial-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: .75rem;
}

.tutorial-desc {
  color: var(--color-text);
  line-height: 1.7;
  margin-bottom: 1rem;
  text-align: justify;
}

.tutorial-slides,
.tutorial-meta-grid > div {
  margin-top: 1.25rem;
}

.tutorial-slides h4,
.tutorial-meta-grid h4 {
  font-size: .8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .06em;
  color: var(--color-muted);
  margin-bottom: .5rem;
}

.tutorial-slides ul,
.tutorial-meta-grid ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: .3rem;
}

.tutorial-slides li,
.tutorial-meta-grid li {
  font-size: .9rem;
  color: var(--color-text);
}

.tutorial-meta-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
  margin-top: 1.25rem;
  border-top: 1px solid var(--color-border);
  padding-top: 1.25rem;
}

[data-theme="dark"] .tutorial-card { background: #2c2c2e; }

/* ─────────────────────────────────────────────────────────────
   Contact
──────────────────────────────────────────────────────────────── */
.contact-section { background: var(--color-bg-alt); }

.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: start;
}

.contact-item {
  display: flex;
  gap: 1rem;
  margin-bottom: 1.25rem;
  align-items: flex-start;
}

.contact-label {
  font-size: .75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .06em;
  color: var(--color-muted);
  min-width: 60px;
  padding-top: .1rem;
}

.contact-value {
  font-size: .9rem;
  color: var(--color-text);
  line-height: 1.6;
}

.contact-note {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.5rem;
  font-size: .9rem;
  color: #4b5563;
  display: flex;
  align-items: center;
}

/* ─────────────────────────────────────────────────────────────
   Footer
──────────────────────────────────────────────────────────────── */
.site-footer {
  background: var(--color-text);
  color: #9ca3af;
  padding: 1.5rem 0;
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: .8rem;
}

.back-to-top {
  color: #9ca3af;
  text-decoration: none;
  transition: color .15s;
}
.back-to-top:hover { color: #fff; }

/* ─────────────────────────────────────────────────────────────
   Responsive
──────────────────────────────────────────────────────────────── */
@media (max-width: 768px) {
  /* Mobile nav */
  .nav-toggle { display: flex; }
  .nav-links {
    display: none;
    position: absolute;
    top: var(--nav-height);
    left: 0; right: 0;
    background: #fff;
    border-bottom: 1px solid var(--color-border);
    flex-direction: column;
    padding: 1rem 1.5rem;
    gap: 1rem;
  }
  .nav-links.open { display: flex; }

  /* Hero */
  .hero-grid {
    grid-template-columns: 1fr;
    text-align: center;
    gap: 1.5rem;
  }
  .hero-photo { justify-self: center; }
  .hero-interests, .hero-social { justify-content: center; }
  .hero-name { font-size: 1.6rem; }

  /* Timeline */
  .timeline-header { flex-direction: column; gap: .4rem; }
  .timeline-date { align-self: flex-start; }

  /* Contact */
  .contact-grid { grid-template-columns: 1fr; gap: 1.5rem; }

  /* Footer */
  .footer-inner { flex-direction: column; gap: .5rem; text-align: center; }
}

@media (max-width: 480px) {
  .pub-item { flex-wrap: wrap; }
  .pub-id { width: auto; }
}