:root {
  --bg: #0d1117;
  --bg-alt: #111827;
  --surface: #161b22;
  --surface-2: #1c2330;
  --border: #263041;
  --text: #e6edf3;
  --text-dim: #9aa7b6;
  --accent: #58a6ff;
  --accent-2: #2dd4bf;
  --accent-soft: rgba(88, 166, 255, 0.12);
  --shadow: 0 10px 30px rgba(0, 0, 0, 0.35);
  --radius: 14px;
  --maxw: 1080px;
  --font: "Inter", system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}

[data-theme="light"] {
  --bg: #f7f9fc;
  --bg-alt: #eef2f8;
  --surface: #ffffff;
  --surface-2: #f2f5fa;
  --border: #dde3ec;
  --text: #0f172a;
  --text-dim: #55627a;
  --accent: #2563eb;
  --accent-2: #0d9488;
  --accent-soft: rgba(37, 99, 235, 0.10);
  --shadow: 0 10px 30px rgba(15, 23, 42, 0.08);
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  scroll-padding-top: 84px;
}

body {
  margin: 0;
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  transition: background-color 0.3s ease, color 0.3s ease;
}

.container {
  width: 100%;
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 24px;
}

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

h1, h2, h3 { line-height: 1.2; margin: 0 0 0.5em; }

.skip-link {
  position: absolute;
  left: -999px;
  top: 0;
  background: var(--accent);
  color: #fff;
  padding: 10px 16px;
  border-radius: 0 0 8px 0;
  z-index: 100;
}
.skip-link:focus { left: 0; }

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: saturate(160%) blur(12px);
  border-bottom: 1px solid var(--border);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
  gap: 16px;
}
.brand { display: inline-flex; align-items: center; gap: 12px; color: var(--text); font-weight: 700; }
.brand:hover { text-decoration: none; }
.brand-mark {
  display: grid;
  place-items: center;
  width: 38px; height: 38px;
  border-radius: 10px;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: #06121f;
  font-weight: 800;
  font-size: 0.95rem;
  letter-spacing: 0.5px;
}
.brand-name { font-size: 1.02rem; }

.nav { display: flex; align-items: center; }
.nav-list {
  list-style: none;
  display: flex;
  gap: 26px;
  margin: 0; padding: 0;
}
.nav-list a {
  color: var(--text-dim);
  font-weight: 500;
  font-size: 0.95rem;
  padding: 6px 0;
  position: relative;
}
.nav-list a:hover { color: var(--text); text-decoration: none; }
.nav-list a::after {
  content: "";
  position: absolute;
  left: 0; bottom: 0;
  width: 0; height: 2px;
  background: var(--accent);
  transition: width 0.25s ease;
}
.nav-list a:hover::after { width: 100%; }

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: 0;
  cursor: pointer;
  padding: 8px;
}
.nav-toggle span {
  width: 22px; height: 2px;
  background: var(--text);
  border-radius: 2px;
  transition: transform 0.25s ease, opacity 0.25s ease;
}

.theme-toggle {
  display: grid;
  place-items: center;
  width: 40px; height: 40px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  cursor: pointer;
  transition: background 0.2s ease, border-color 0.2s ease;
}
.theme-toggle:hover { border-color: var(--accent); }
.theme-toggle svg { fill: none; stroke: currentColor; stroke-width: 2; stroke-linecap: round; stroke-linejoin: round; }
.icon-moon { display: none; }
[data-theme="light"] .icon-sun { display: none; }
[data-theme="light"] .icon-moon { display: block; }

/* Hero */
.hero {
  position: relative;
  padding: clamp(64px, 12vw, 140px) 0 clamp(48px, 8vw, 96px);
  overflow: hidden;
}
.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    radial-gradient(60% 60% at 15% 10%, var(--accent-soft), transparent 60%),
    radial-gradient(50% 50% at 90% 0%, color-mix(in srgb, var(--accent-2) 14%, transparent), transparent 60%);
  pointer-events: none;
}
.hero-inner { position: relative; }
.eyebrow {
  font-family: var(--mono);
  color: var(--accent-2);
  font-size: 0.85rem;
  letter-spacing: 1px;
  text-transform: uppercase;
  margin: 0 0 12px;
}
.hero h1 {
  font-size: clamp(2.4rem, 6vw, 4rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: 0.2em;
}
.hero-tagline {
  max-width: 720px;
  font-size: clamp(1.05rem, 2.2vw, 1.35rem);
  color: var(--text-dim);
  margin: 0 0 32px;
}
.hero-tagline strong { color: var(--text); font-weight: 600; }

.hero-actions { display: flex; flex-wrap: wrap; gap: 14px; }
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 22px;
  border-radius: 10px;
  font-weight: 600;
  font-size: 0.98rem;
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.2s ease, background 0.2s ease;
}
.btn:hover { text-decoration: none; transform: translateY(-2px); }
.btn-primary {
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: #06121f;
  box-shadow: var(--shadow);
}
.btn-ghost {
  background: transparent;
  color: var(--text);
  border: 1px solid var(--border);
}
.btn-ghost:hover { border-color: var(--accent); }

.hero-meta {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 28px;
  padding: 0;
  margin: 44px 0 0;
  color: var(--text-dim);
  font-size: 0.95rem;
}
.hero-meta-num {
  display: block;
  font-family: var(--mono);
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--text);
}

/* Sections */
.section { padding: clamp(56px, 9vw, 96px) 0; }
.section-alt { background: var(--bg-alt); }
.section-title {
  font-size: clamp(1.6rem, 4vw, 2.2rem);
  font-weight: 700;
  display: flex;
  align-items: baseline;
  gap: 14px;
  margin-bottom: 36px;
}
.section-index {
  font-family: var(--mono);
  font-size: 1rem;
  color: var(--accent-2);
  font-weight: 500;
}
.section-lead { color: var(--text-dim); max-width: 640px; margin: -20px 0 36px; }

/* About */
.about-grid {
  display: grid;
  grid-template-columns: 1.6fr 1fr;
  gap: 40px;
}
.about-text p { color: var(--text-dim); margin: 0 0 18px; font-size: 1.05rem; }
.about-facts {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--shadow);
}
.about-facts h3 { font-size: 0.85rem; text-transform: uppercase; letter-spacing: 1px; color: var(--text-dim); }
.about-facts dl { margin: 0; }
.about-facts dl > div {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  padding: 12px 0;
  border-top: 1px solid var(--border);
}
.about-facts dt { color: var(--text-dim); }
.about-facts dd { margin: 0; text-align: right; font-weight: 500; }

/* Skills */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 20px;
}
.skill-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px;
  transition: transform 0.2s ease, border-color 0.2s ease;
}
.skill-card:hover { transform: translateY(-3px); border-color: var(--accent); }
.skill-card h3 { font-size: 1.05rem; margin-bottom: 14px; }
.chips { list-style: none; display: flex; flex-wrap: wrap; gap: 8px; padding: 0; margin: 0; }
.chips li {
  font-family: var(--mono);
  font-size: 0.82rem;
  padding: 5px 11px;
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--accent);
  border: 1px solid color-mix(in srgb, var(--accent) 24%, transparent);
}

/* Timeline */
.timeline { list-style: none; margin: 0; padding: 0; position: relative; }
.timeline::before {
  content: "";
  position: absolute;
  left: 8px; top: 6px; bottom: 6px;
  width: 2px;
  background: var(--border);
}
.timeline-item { position: relative; padding: 0 0 34px 40px; }
.timeline-item::before {
  content: "";
  position: absolute;
  left: 1px; top: 6px;
  width: 16px; height: 16px;
  border-radius: 50%;
  background: var(--accent);
  border: 3px solid var(--bg);
}
.timeline-head { display: flex; flex-wrap: wrap; align-items: baseline; gap: 6px 14px; margin-bottom: 10px; }
.timeline-head h3 { margin: 0; font-size: 1.15rem; }
.timeline-org { color: var(--accent); font-weight: 500; }
.timeline-date { font-family: var(--mono); font-size: 0.82rem; color: var(--text-dim); margin-left: auto; }
.timeline-points { margin: 0; padding-left: 18px; color: var(--text-dim); }
.timeline-points li { margin-bottom: 8px; }

/* Education */
.edu-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 20px; }
.edu-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
}
.edu-card h3 { font-size: 1.1rem; }
.edu-org { color: var(--accent); margin: 0 0 4px; font-weight: 500; }
.edu-meta { font-family: var(--mono); font-size: 0.85rem; color: var(--text-dim); margin: 0; }
.edu-list { margin: 8px 0 0; padding-left: 18px; color: var(--text-dim); }
.edu-list li { margin-bottom: 6px; }

/* Projects */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 22px;
}
.project-card {
  display: flex;
  flex-direction: column;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  transition: transform 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
}
.project-card:hover { transform: translateY(-4px); border-color: var(--accent); box-shadow: var(--shadow); }
.project-card h3 { font-size: 1.2rem; margin-bottom: 8px; }
.project-date { font-family: var(--mono); font-size: 0.78rem; color: var(--text-dim); margin: 0 0 12px; }
.project-desc { color: var(--text-dim); margin: 0 0 18px; flex: 1; }
.project-tags { list-style: none; display: flex; flex-wrap: wrap; gap: 7px; padding: 0; margin: 0 0 16px; }
.project-tags li {
  font-family: var(--mono);
  font-size: 0.75rem;
  padding: 3px 9px;
  border-radius: 6px;
  background: var(--surface-2);
  color: var(--text-dim);
  border: 1px solid var(--border);
}
.project-links { display: flex; gap: 16px; margin-top: auto; }
.project-links a { font-weight: 600; font-size: 0.9rem; }
.projects-empty { color: var(--text-dim); font-style: italic; }

/* Contact */
.contact-links { display: flex; flex-wrap: wrap; gap: 18px; }
.contact-link {
  display: flex;
  flex-direction: column;
  gap: 4px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px 26px;
  color: var(--text);
  min-width: 240px;
  transition: transform 0.2s ease, border-color 0.2s ease;
}
.contact-link:hover { transform: translateY(-3px); border-color: var(--accent); text-decoration: none; }
.contact-label { font-size: 0.78rem; text-transform: uppercase; letter-spacing: 1px; color: var(--text-dim); }
.contact-value { font-weight: 600; font-size: 1.05rem; }

/* Footer */
.site-footer { border-top: 1px solid var(--border); padding: 30px 0; }
.footer-inner { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 12px; color: var(--text-dim); font-size: 0.9rem; }
.footer-inner p { margin: 0; }
.footer-note { font-family: var(--mono); font-size: 0.8rem; }
.to-top { font-weight: 600; }

/* Reveal on scroll */
.reveal { opacity: 0; transform: translateY(18px); transition: opacity 0.6s ease, transform 0.6s ease; }
.reveal.is-visible { opacity: 1; transform: none; }

/* Responsive */
@media (max-width: 760px) {
  .about-grid { grid-template-columns: 1fr; }
  .timeline-date { margin-left: 0; }

  .nav-toggle { display: flex; }
  .nav-list {
    position: absolute;
    top: 68px; left: 0; right: 0;
    flex-direction: column;
    gap: 0;
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    padding: 8px 24px 16px;
    transform: translateY(-140%);
    transition: transform 0.3s ease;
    box-shadow: var(--shadow);
  }
  .nav-list.open { transform: translateY(0); }
  .nav-list li { border-top: 1px solid var(--border); }
  .nav-list li:first-child { border-top: 0; }
  .nav-list a { display: block; padding: 14px 0; }
}

@media (prefers-reduced-motion: reduce) {
  * { scroll-behavior: auto !important; }
  .reveal { opacity: 1; transform: none; transition: none; }
}