:root {
  --bg: #ffffff;
  --fg: #0f172a;
  --muted: #64748b;
  --accent: #2563eb;
  --card: #f8fafc;
  --border: #e2e8f0;
  --chip: #eef2ff;
}

html[data-theme="dark"] {
  --bg: #0b1220;
  --fg: #e5e7eb;
  --muted: #9aa3b2;
  --accent: #60a5fa;
  --card: #111827;
  --border: #1f2937;
  --chip: #111827;
}

* { box-sizing: border-box; }

html, body { height: 100%; }

body {
  margin: 0;
  font-family: Inter, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, "Apple Color Emoji", "Segoe UI Emoji";
  color: var(--fg);
  background: var(--bg);
  line-height: 1.6;
}

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

.container {
  width: 100%;
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 16px;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--bg);
  border-bottom: 1px solid var(--border);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}
.brand { font-weight: 700; font-size: 20px; color: var(--fg); text-decoration: none; }

.nav-toggle { display: none; }
.nav-list { display: flex; list-style: none; gap: 20px; margin: 0; padding: 0; }
.nav-list a { color: var(--fg); text-decoration: none; opacity: 0.9; }
.nav-list a:hover { color: var(--accent); }

.btn { border: 1px solid var(--border); background: transparent; color: var(--fg); padding: 10px 14px; border-radius: 10px; text-decoration: none; display: inline-flex; align-items: center; gap: 8px; }
.btn:hover { border-color: var(--accent); }
.btn-primary { background: var(--accent); color: white; border-color: var(--accent); }
.btn-ghost { background: transparent; border-color: transparent; }
.btn-sm { padding: 6px 10px; border-radius: 8px; font-size: 14px; }

.hero { padding: 64px 0; }
.hero-inner { display: grid; grid-template-columns: 1.5fr 1fr; gap: 32px; align-items: center; }
.hero h1 { font-size: 42px; margin: 0 0 12px; }
.lead { font-size: 18px; opacity: 0.9; }
.accent { color: var(--accent); }
.meta { margin-top: 10px; color: var(--muted); font-size: 14px; }

.avatar { height: 140px; width: 140px; border-radius: 50%; background: linear-gradient(135deg, var(--accent), #9333ea); color: white; display: grid; place-items: center; font-weight: 700; font-size: 40px; margin: 0 0 0 auto; }

.section { padding: 56px 0; border-top: 1px solid var(--border); }
.section h2 { margin: 0 0 16px; font-size: 28px; }

.highlights { margin: 10px 0 0; padding-left: 20px; }

.chips { display: flex; flex-wrap: wrap; gap: 10px; }
.chip { background: var(--chip); border: 1px solid var(--border); color: var(--fg); padding: 8px 10px; border-radius: 999px; font-size: 14px; }

.grid { display: grid; gap: 16px; }
.projects-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }

.card { background: var(--card); border: 1px solid var(--border); border-radius: 14px; overflow: hidden; }
.card-body { padding: 16px; display: grid; gap: 8px; }
.tags { display: flex; flex-wrap: wrap; gap: 8px; padding: 0; margin: 0; list-style: none; }
.tags li { background: var(--chip); border: 1px solid var(--border); padding: 4px 8px; border-radius: 999px; font-size: 12px; }
.card-actions { display: flex; gap: 8px; margin-top: 4px; }

.timeline { display: grid; gap: 16px; border-left: none; padding-left: 0; }
.timeline-item { position: relative; background: var(--card); border: 1px solid var(--border); border-radius: 12px; padding: 12px; }
.timeline-dot { display: none; }
.timeline-content h3 { margin: 0 0 6px; font-size: 16px; display: flex; flex-wrap: wrap; gap: 8px; align-items: baseline; }
.timeline-content .muted { display: block; margin-bottom: 8px; }
.card summary.btn { background: transparent; border-color: var(--border); color: var(--fg); }
.card summary.btn:hover { background: transparent; border-color: var(--accent); }

.edu-list { list-style: none; padding: 0; margin: 0; display: grid; gap: 10px; }

.site-footer { padding: 24px 0 40px; border-top: 1px solid var(--border); color: var(--muted); font-size: 14px; }

.cta-group { display: flex; gap: 12px; flex-wrap: wrap; }

.skills-groups { display: grid; gap: 20px; }
.skill-group h3 { margin: 0 0 8px; font-size: 16px; color: var(--muted); }

.scroll-container { overflow-x: auto; scroll-behavior: smooth; }
.skills-scroll { display: grid; grid-template-columns: auto 1fr auto; align-items: center; gap: 8px; }
.scroll-arrow { border: 1px solid var(--border); background: var(--card); color: var(--fg); height: 36px; width: 36px; border-radius: 8px; }
.scroll-arrow:hover { border-color: var(--accent); }

.card details { margin-top: 6px; }
.card details[open] summary { color: var(--accent); }
.card summary { cursor: pointer; list-style: none; }
.card summary::-webkit-details-marker { display: none; }

[data-reveal] { opacity: 0; transform: translateY(12px); transition: opacity .5s ease, transform .5s ease; }
[data-reveal].visible { opacity: 1; transform: translateY(0); }

.fab { position: fixed; right: 18px; bottom: 18px; height: 52px; width: 52px; display: grid; place-items: center; border-radius: 999px; background: var(--accent); color: #fff; text-decoration: none; box-shadow: 0 6px 20px rgba(0,0,0,.2); z-index: 60; }

.back-to-top { position: fixed; right: 18px; bottom: 80px; height: 40px; width: 40px; border-radius: 10px; background: var(--card); color: var(--fg); border: 1px solid var(--border); display: none; z-index: 60; }
.back-to-top.show { display: inline-grid; place-items: center; }

@media (max-width: 900px) {
  .hero-inner { grid-template-columns: 1fr; }
  .avatar { margin: 0; }
  .projects-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 640px) {
  .nav-toggle { display: inline-flex; align-items: center; justify-content: center; height: 38px; width: 38px; border: 1px solid var(--border); background: transparent; border-radius: 10px; }
  .nav-list { display: none; position: absolute; right: 16px; top: 64px; background: var(--bg); border: 1px solid var(--border); border-radius: 12px; padding: 10px; flex-direction: column; gap: 10px; }
  .nav-list.open { display: flex; }
  .projects-grid { grid-template-columns: 1fr; }
}