/* ---------- Design tokens ---------- */
:root {
  --bg: #0b0e14;
  --bg-elevated: #11151f;
  --bg-card: #141926;
  --border: #232a3a;
  --text: #e8ebf3;
  --text-dim: #9aa4b8;
  --text-faint: #6b7590;
  --accent: #6ee7c7;
  --accent-2: #7aa2ff;
  --accent-soft: rgba(110, 231, 199, 0.12);
  --shadow: 0 20px 50px rgba(0, 0, 0, 0.35);
  --radius: 14px;
  --maxw: 980px;
  color-scheme: dark;
}

:root[data-theme="light"] {
  --bg: #f7f8fb;
  --bg-elevated: #ffffff;
  --bg-card: #ffffff;
  --border: #e4e7ee;
  --text: #171a21;
  --text-dim: #565f75;
  --text-faint: #8890a3;
  --accent: #0d9488;
  --accent-2: #3b5bdb;
  --accent-soft: rgba(13, 148, 136, 0.08);
  --shadow: 0 20px 50px rgba(30, 40, 60, 0.08);
  color-scheme: light;
}

@media (prefers-color-scheme: light) {
  :root:not([data-theme="dark"]) {
    --bg: #f7f8fb;
    --bg-elevated: #ffffff;
    --bg-card: #ffffff;
    --border: #e4e7ee;
    --text: #171a21;
    --text-dim: #565f75;
    --text-faint: #8890a3;
    --accent: #0d9488;
    --accent-2: #3b5bdb;
    --accent-soft: rgba(13, 148, 136, 0.08);
    --shadow: 0 20px 50px rgba(30, 40, 60, 0.08);
    color-scheme: light;
  }
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: "Segoe UI", system-ui, -apple-system, "Inter", Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  transition: background 0.25s ease, color 0.25s ease;
}

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

.bg-decor {
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background:
    radial-gradient(600px circle at 15% -10%, var(--accent-soft), transparent 60%),
    radial-gradient(500px circle at 100% 10%, rgba(122,162,255,0.10), transparent 55%);
}

/* ---------- Topbar ---------- */
.topbar {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: blur(10px);
  background: color-mix(in srgb, var(--bg) 78%, transparent);
  border-bottom: 1px solid var(--border);
}

.topbar-inner {
  display: flex;
  align-items: center;
  gap: 20px;
  height: 64px;
}

.brand {
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--text);
  text-decoration: none;
  font-size: 1.05rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  width: 36px;
  height: 36px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-card);
}

.nav {
  display: flex;
  gap: 22px;
  margin-left: 8px;
  flex: 1;
}

.nav a {
  color: var(--text-dim);
  text-decoration: none;
  font-size: 0.92rem;
  font-weight: 500;
  transition: color 0.2s ease;
}

.nav a:hover { color: var(--text); }

.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--bg-card);
  color: var(--text-dim);
  cursor: pointer;
}
.theme-toggle:hover { color: var(--text); border-color: var(--accent); }
.icon-moon { display: none; }
:root[data-theme="light"] .icon-sun { display: none; }
:root[data-theme="light"] .icon-moon { display: block; }

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 4px;
  width: 36px;
  height: 36px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--bg-card);
  cursor: pointer;
  align-items: center;
  justify-content: center;
}
.nav-toggle span {
  width: 16px;
  height: 2px;
  background: var(--text-dim);
  border-radius: 2px;
}

/* ---------- Hero ---------- */
.hero {
  padding: 96px 24px 72px;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.hero-avatar {
  width: 84px;
  height: 84px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 1.6rem;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: #08131a;
  margin-bottom: 24px;
  box-shadow: var(--shadow);
}

.eyebrow {
  color: var(--accent);
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  font-size: 0.8rem;
  margin: 0 0 8px;
}

.hero h1 {
  font-size: clamp(2.2rem, 5vw, 3.4rem);
  margin: 0 0 12px;
  font-weight: 800;
  letter-spacing: -0.02em;
}

.hero-role {
  color: var(--text-dim);
  font-size: clamp(1.05rem, 2.4vw, 1.3rem);
  font-weight: 600;
  margin: 0 0 20px;
}

.hero-summary {
  max-width: 640px;
  color: var(--text-dim);
  font-size: 1.02rem;
  margin: 0 0 32px;
}

.hero-actions {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
  justify-content: center;
  margin-bottom: 20px;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 22px;
  border-radius: 10px;
  text-decoration: none;
  font-weight: 600;
  font-size: 0.95rem;
  transition: transform 0.15s ease, box-shadow 0.15s ease, border-color 0.15s ease;
}
.btn:hover { transform: translateY(-2px); }

.btn-primary {
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: #08131a;
  box-shadow: 0 10px 24px rgba(110,231,199,0.18);
}

.btn-ghost {
  border: 1px solid var(--border);
  color: var(--text);
  background: var(--bg-card);
}
.btn-ghost:hover { border-color: var(--accent); }

.hero-links {
  color: var(--text-faint);
  font-size: 0.9rem;
}
.hero-links a {
  color: var(--text-dim);
  text-decoration: none;
}
.hero-links a:hover { color: var(--accent); }
.hero-links .dot { margin: 0 8px; }

/* ---------- Sections ---------- */
.section {
  padding: 64px 24px;
  border-top: 1px solid var(--border);
}

.section-title {
  font-size: 1.6rem;
  font-weight: 800;
  margin: 0 0 32px;
  display: flex;
  align-items: baseline;
  gap: 12px;
  letter-spacing: -0.01em;
}

.section-title .num {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--accent);
  font-family: "SFMono-Regular", Consolas, monospace;
}

.sub-title {
  font-size: 1.05rem;
  font-weight: 700;
  margin: 40px 0 16px;
  color: var(--text);
}

/* ---------- About ---------- */
.about-grid {
  display: grid;
  grid-template-columns: 1.6fr 1fr;
  gap: 40px;
  align-items: start;
}

.about-text { color: var(--text-dim); font-size: 1.02rem; margin: 0; }
.about-text strong { color: var(--text); }

.about-stats {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.about-stats li {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px;
  text-align: center;
}

.stat-num {
  display: block;
  font-size: 1.7rem;
  font-weight: 800;
  color: var(--accent);
}

.stat-label {
  display: block;
  font-size: 0.8rem;
  color: var(--text-faint);
  margin-top: 4px;
}

/* ---------- Skills ---------- */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 18px;
}

.skill-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
}

.skill-card h3 {
  margin: 0 0 12px;
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text);
}

.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.tag {
  font-size: 0.8rem;
  padding: 5px 10px;
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--accent);
  border: 1px solid transparent;
  white-space: nowrap;
}

/* ---------- Timeline ---------- */
.timeline {
  position: relative;
  padding-left: 28px;
  border-left: 2px solid var(--border);
}

.timeline-item {
  position: relative;
  margin-bottom: 40px;
}
.timeline-item:last-child { margin-bottom: 0; }

.timeline-marker {
  position: absolute;
  left: -35px;
  top: 4px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 4px var(--accent-soft);
}

.timeline-content {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px 24px;
}

.timeline-head {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 12px;
  flex-wrap: wrap;
}

.timeline-head h3 {
  margin: 0;
  font-size: 1.08rem;
  font-weight: 700;
}

.timeline-date {
  font-size: 0.82rem;
  color: var(--text-faint);
  font-family: "SFMono-Regular", Consolas, monospace;
  white-space: nowrap;
}

.timeline-org {
  margin: 4px 0 14px;
  color: var(--accent);
  font-weight: 600;
  font-size: 0.92rem;
}

.timeline-content ul {
  margin: 0;
  padding-left: 20px;
  color: var(--text-dim);
  font-size: 0.94rem;
}

.timeline-content li { margin-bottom: 7px; }
.timeline-content li:last-child { margin-bottom: 0; }

/* ---------- Projects ---------- */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 20px;
}

.project-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}
.project-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow);
}

.project-date {
  font-size: 0.78rem;
  color: var(--text-faint);
  font-family: "SFMono-Regular", Consolas, monospace;
  margin-bottom: 10px;
}

.project-card h3 {
  margin: 0 0 10px;
  font-size: 1.08rem;
  font-weight: 700;
}

.project-card p {
  color: var(--text-dim);
  font-size: 0.94rem;
  margin: 0 0 16px;
}

/* ---------- Education ---------- */
.edu-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 18px;
  margin-bottom: 8px;
}

.edu-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px;
}

.edu-card h3 { margin: 0 0 8px; font-size: 1.02rem; font-weight: 700; }
.edu-school { margin: 0 0 4px; color: var(--accent); font-size: 0.9rem; font-weight: 600; }
.edu-date { margin: 0; color: var(--text-faint); font-size: 0.82rem; font-family: "SFMono-Regular", Consolas, monospace; }

.cert-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 10px;
}

.cert-list li {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 12px 16px;
}

.cert-list a {
  color: var(--text);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 500;
}
.cert-list a:hover { color: var(--accent); }

/* ---------- Publications ---------- */
.pub-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.pub-list li {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px 22px;
}

.pub-list p {
  margin: 0 0 8px;
  color: var(--text-dim);
  font-size: 0.92rem;
}

.pub-list a {
  color: var(--accent);
  font-size: 0.85rem;
  font-family: "SFMono-Regular", Consolas, monospace;
  text-decoration: none;
}
.pub-list a:hover { text-decoration: underline; }

/* ---------- Contact ---------- */
.contact-section { text-align: center; }
.contact-lead {
  color: var(--text-dim);
  max-width: 520px;
  margin: 0 auto 32px;
}

.contact-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px;
  max-width: 520px;
  margin: 0 auto;
}

.contact-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px;
  text-decoration: none;
  display: flex;
  flex-direction: column;
  gap: 6px;
  transition: transform 0.2s ease, border-color 0.2s ease;
}
.contact-card:hover {
  transform: translateY(-3px);
  border-color: var(--accent);
}

.contact-label {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-faint);
  font-weight: 600;
}

.contact-value {
  color: var(--text);
  font-weight: 600;
  font-size: 0.92rem;
  overflow-wrap: anywhere;
}

/* ---------- Footer ---------- */
.footer {
  border-top: 1px solid var(--border);
  padding: 28px 24px 40px;
  text-align: center;
}
.footer p {
  margin: 0;
  color: var(--text-faint);
  font-size: 0.85rem;
}

/* ---------- Responsive ---------- */
@media (max-width: 760px) {
  .nav { display: none; }
  .nav-toggle { display: flex; }
  .about-grid { grid-template-columns: 1fr; }
  .topbar.open .nav {
    display: flex;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: var(--bg-elevated);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    padding: 16px 24px;
    gap: 14px;
  }
}