/* =========================================================
   Design tokens
   ========================================================= */
:root {
  --bg: #fafafa;
  --bg-elevated: #ffffff;
  --text: #16181d;
  --text-muted: #5b6270;
  --border: #e4e6eb;
  --accent: #3b5bfd;
  --accent-text: #ffffff;
  --shadow: 0 1px 2px rgba(16, 20, 30, 0.04), 0 8px 24px rgba(16, 20, 30, 0.06);
  --radius: 12px;
  --max-width: 1080px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
}

[data-theme="dark"] {
  --bg: #0f1115;
  --bg-elevated: #171a21;
  --text: #eef0f4;
  --text-muted: #9aa1af;
  --border: #262a33;
  --accent: #6b86ff;
  --accent-text: #0f1115;
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.3), 0 8px 24px rgba(0, 0, 0, 0.35);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
  transition: background 0.15s ease, color 0.15s ease;
}

a {
  color: inherit;
  text-decoration: none;
}

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

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

/* =========================================================
   Header
   ========================================================= */
.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}

.site-header .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 16px;
  padding-bottom: 16px;
}

.brand {
  font-weight: 700;
  font-size: 18px;
  letter-spacing: -0.01em;
}

.brand span { color: var(--accent); }

.header-actions {
  display: flex;
  align-items: center;
  gap: 16px;
}

.header-actions nav {
  display: flex;
  gap: 20px;
}

.header-actions nav a {
  font-size: 14px;
  font-weight: 500;
  color: var(--text-muted);
}

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

.theme-toggle {
  border: 1px solid var(--border);
  background: var(--bg-elevated);
  color: var(--text);
  width: 34px;
  height: 34px;
  border-radius: 999px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  font-size: 15px;
}

.theme-toggle:hover { border-color: var(--accent); }

/* =========================================================
   Hero
   ========================================================= */
.hero {
  padding: 72px 0 48px;
}

.hero h1 {
  font-size: clamp(32px, 5vw, 48px);
  line-height: 1.1;
  letter-spacing: -0.02em;
  margin: 0 0 16px;
}

.hero .accent { color: var(--accent); }

.hero p {
  font-size: 18px;
  color: var(--text-muted);
  max-width: 620px;
  margin: 0 0 28px;
}

.hero-actions {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 18px;
  border-radius: 999px;
  font-size: 14px;
  font-weight: 600;
  border: 1px solid var(--border);
  background: var(--bg-elevated);
  cursor: pointer;
}

.btn:hover { border-color: var(--accent); }

.btn-primary {
  background: var(--accent);
  color: var(--accent-text);
  border-color: var(--accent);
}

.btn-primary:hover { opacity: 0.92; }

/* =========================================================
   Section headings
   ========================================================= */
.section {
  padding: 40px 0;
}

.section-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
  margin-bottom: 24px;
}

.section-head h2 {
  font-size: 22px;
  margin: 0;
  letter-spacing: -0.01em;
}

/* =========================================================
   Filters
   ========================================================= */
.filters {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.filter-btn {
  border: 1px solid var(--border);
  background: var(--bg-elevated);
  color: var(--text-muted);
  padding: 6px 14px;
  border-radius: 999px;
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
}

.filter-btn:hover { color: var(--text); }

.filter-btn.active {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--accent-text);
}

/* =========================================================
   Project grid / cards
   ========================================================= */
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 20px;
}

.card {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow);
}

.card-thumb {
  aspect-ratio: 16 / 9;
  background: var(--border);
  overflow: hidden;
}

.card-thumb img { width: 100%; height: 100%; object-fit: cover; }

.card-body {
  padding: 18px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  flex: 1;
}

.card-tag {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--accent);
}

.card-title {
  font-size: 17px;
  font-weight: 700;
  margin: 0;
  letter-spacing: -0.01em;
}

.card-tagline {
  font-size: 14px;
  color: var(--text-muted);
  margin: 0;
  flex: 1;
}

.card-tech {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
  margin-top: 4px;
}

.chip {
  font-size: 11px;
  font-family: var(--font-mono);
  color: var(--text-muted);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 3px 7px;
}

.empty-state {
  color: var(--text-muted);
  font-size: 14px;
  padding: 32px 0;
}

/* =========================================================
   About
   ========================================================= */
.about p {
  color: var(--text-muted);
  max-width: 640px;
}

/* =========================================================
   Footer
   ========================================================= */
.site-footer {
  border-top: 1px solid var(--border);
  margin-top: 40px;
  padding: 28px 0 48px;
}

.site-footer .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}

.footer-links {
  display: flex;
  gap: 18px;
}

.footer-links a { color: var(--text-muted); font-size: 14px; }
.footer-links a:hover { color: var(--text); }

.footer-note { color: var(--text-muted); font-size: 13px; }

/* =========================================================
   Project detail page
   ========================================================= */
.back-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--text-muted);
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 20px;
}

.back-link:hover { color: var(--text); }

.project-header { padding: 24px 0 8px; }

.project-header .card-tag { display: block; margin-bottom: 10px; }

.project-header h1 {
  font-size: clamp(28px, 4vw, 38px);
  margin: 0 0 10px;
  letter-spacing: -0.02em;
}

.project-header .card-tagline { font-size: 17px; margin-bottom: 18px; }

.project-hero-thumb {
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--border);
  margin: 24px 0;
}

.project-links {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  margin: 20px 0 8px;
}

.project-body p {
  color: var(--text);
  white-space: pre-line;
}

.project-meta {
  display: flex;
  gap: 24px;
  flex-wrap: wrap;
  margin: 24px 0;
  padding: 16px 0;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.meta-item { font-size: 13px; }

.meta-item .label {
  display: block;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  font-size: 11px;
  margin-bottom: 4px;
}

@media (max-width: 640px) {
  .header-actions nav { display: none; }
  .hero { padding: 48px 0 32px; }
}