/* ===== CSS Variables — Light & Dark ===== */
:root {
  --bg: #fafafa;
  --bg-secondary: #f4f4f5;
  --bg-card: #ffffff;
  --text: #18181b;
  --text-secondary: #71717a;
  --text-muted: #a1a1aa;
  --border: #e4e4e7;
  --accent: #4f46e5;
  --accent-hover: #4338ca;
  --accent-light: #eef2ff;
  --success: #22c55e;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
  --radius: 8px;
  --radius-lg: 12px;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow: 0 1px 3px rgba(0,0,0,0.1), 0 1px 2px rgba(0,0,0,0.06);
  --shadow-lg: 0 4px 6px rgba(0,0,0,0.07), 0 2px 4px rgba(0,0,0,0.06);
  --max-width: 1100px;
  --header-height: 64px;
}

html.dark {
  --bg: #09090b;
  --bg-secondary: #18181b;
  --bg-card: #1c1c1f;
  --text: #fafafa;
  --text-secondary: #a1a1aa;
  --text-muted: #71717a;
  --border: #27272a;
  --accent: #818cf8;
  --accent-hover: #6366f1;
  --accent-light: #1e1b4b;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.3);
  --shadow: 0 1px 3px rgba(0,0,0,0.4);
  --shadow-lg: 0 4px 6px rgba(0,0,0,0.4);
}

/* ===== Reset ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--accent); text-decoration: none; transition: color 0.2s; }
a:hover { color: var(--accent-hover); }
img { max-width: 100%; display: block; }
code, pre { font-family: var(--font-mono); }

/* ===== Layout ===== */
.container { max-width: var(--max-width); margin: 0 auto; padding: 0 24px; }
.main-content { min-height: calc(100vh - var(--header-height) - 120px); padding: 48px 24px; max-width: var(--max-width); margin: 0 auto; }

/* ===== Header ===== */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: var(--bg);
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(12px);
  height: var(--header-height);
}
.header-inner {
  display: flex; align-items: center; justify-content: space-between;
  height: 100%;
}
.site-logo {
  font-size: 1.2rem; font-weight: 700; color: var(--text);
  letter-spacing: -0.02em;
  display: flex; align-items: center; gap: 10px;
}
.logo-icon {
  border-radius: 8px;
  transition: transform 0.3s ease;
}
.site-logo:hover .logo-icon {
  transform: rotate(-8deg) scale(1.08);
}
.logo-text {
  display: flex; align-items: center;
}
.logo-dot { color: var(--accent); }
.site-nav { display: flex; gap: 8px; }
.nav-link {
  padding: 6px 14px; border-radius: var(--radius);
  font-size: 0.875rem; font-weight: 500; color: var(--text-secondary);
  transition: all 0.2s;
}
.nav-link:hover { color: var(--text); background: var(--bg-secondary); }
.theme-toggle {
  background: none; border: 1px solid var(--border); border-radius: var(--radius);
  padding: 8px; cursor: pointer; color: var(--text-secondary);
  display: flex; align-items: center; transition: all 0.2s;
}
.theme-toggle:hover { color: var(--text); border-color: var(--text-muted); }
html.dark .icon-sun { display: inline; }
html.dark .icon-moon { display: none; }
html:not(.dark) .icon-sun { display: none; }
html:not(.dark) .icon-moon { display: inline; }
.mobile-menu-btn { display: none; background: none; border: none; color: var(--text); cursor: pointer; padding: 4px; z-index: 101; }
.mobile-menu {
  display: none; position: absolute; top: var(--header-height); left: 0; right: 0;
  background: var(--bg); border-bottom: 1px solid var(--border);
  flex-direction: column; padding: 16px 24px; gap: 8px;
  z-index: 100;
}
.mobile-menu.active { display: flex; }
.mobile-nav-link {
  padding: 10px 8px; font-size: 0.95rem; color: var(--text-secondary);
  transition: all 0.2s; border-radius: var(--radius);
}
.mobile-nav-link:hover { color: var(--text); background: var(--bg-secondary); }

/* ===== Hero ===== */
.hero {
  text-align: center; padding: 80px 0 60px;
}
.hero h1 {
  font-size: 3rem; font-weight: 700; letter-spacing: -0.03em;
  line-height: 1.1; margin-bottom: 16px;
}
.hero .subtitle {
  font-size: 1.25rem; color: var(--text-secondary); max-width: 560px;
  margin: 0 auto 32px; line-height: 1.6;
}
.hero-buttons { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }

/* ===== Buttons ===== */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 10px 20px; border-radius: var(--radius);
  font-size: 0.875rem; font-weight: 500; cursor: pointer;
  border: 1px solid transparent; transition: all 0.2s;
}
.btn-primary {
  background: var(--accent); color: #fff; border-color: var(--accent);
}
.btn-primary:hover { background: var(--accent-hover); color: #fff; }
.btn-secondary {
  background: var(--bg-card); color: var(--text); border-color: var(--border);
}
.btn-secondary:hover { border-color: var(--text-muted); }

/* ===== Section Headings ===== */
.section { padding: 48px 0; }
.section-title {
  font-size: 1.5rem; font-weight: 600; letter-spacing: -0.02em;
  margin-bottom: 24px;
}
.section-subtitle { color: var(--text-secondary); margin-bottom: 32px; }

/* ===== Skills Matrix ===== */
.skills-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 24px; }
.skill-group {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 24px;
}
.skill-group h3 {
  font-size: 0.8rem; font-weight: 600; text-transform: uppercase;
  letter-spacing: 0.05em; color: var(--text-muted); margin-bottom: 12px;
}
.skill-tags { display: flex; flex-wrap: wrap; gap: 8px; }
.skill-tag {
  background: var(--bg-secondary); color: var(--text-secondary);
  padding: 4px 12px; border-radius: 20px; font-size: 0.8rem; font-weight: 500;
}

/* ===== Cards (Projects & Posts) ===== */
.card-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr)); gap: 20px; }
.card {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 24px;
  transition: box-shadow 0.2s, border-color 0.2s;
}
.card:hover { box-shadow: var(--shadow-lg); border-color: var(--text-muted); }
.card h3 { font-size: 1.1rem; font-weight: 600; margin-bottom: 8px; }
.card h3 a { color: var(--text); }
.card h3 a:hover { color: var(--accent); }
.card p { color: var(--text-secondary); font-size: 0.9rem; margin-bottom: 12px; }
.card-meta {
  font-size: 0.8rem; color: var(--text-muted);
  display: flex; gap: 12px; align-items: center; margin-bottom: 12px;
}
.tag-list { display: flex; flex-wrap: wrap; gap: 6px; }
.tag {
  background: var(--accent-light); color: var(--accent);
  padding: 2px 10px; border-radius: 20px; font-size: 0.75rem; font-weight: 500;
}

/* ===== Status Badge ===== */
.status-badge {
  display: inline-block; padding: 2px 10px; border-radius: 20px;
  font-size: 0.75rem; font-weight: 600; text-transform: capitalize;
}
.status-active { background: #dcfce7; color: #166534; }
html.dark .status-active { background: #14532d; color: #86efac; }
.status-archived { background: var(--bg-secondary); color: var(--text-muted); }

/* ===== Filter Bar ===== */
.filter-bar { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 32px; }
.filter-btn {
  background: var(--bg-card); border: 1px solid var(--border);
  padding: 6px 16px; border-radius: 20px; font-size: 0.8rem;
  font-weight: 500; color: var(--text-secondary); cursor: pointer;
  transition: all 0.2s;
}
.filter-btn:hover, .filter-btn.active {
  background: var(--accent); color: #fff; border-color: var(--accent);
}

/* ===== Post / Project Layout ===== */
.post-layout, .project-layout { max-width: 720px; margin: 0 auto; }
.post-header, .project-header { margin-bottom: 48px; }
.post-header h1, .project-header h1 {
  font-size: 2.25rem; font-weight: 700; letter-spacing: -0.03em;
  line-height: 1.2; margin-bottom: 16px;
}
.post-description, .project-description {
  font-size: 1.1rem; color: var(--text-secondary); line-height: 1.6;
}
.post-meta, .project-meta {
  font-size: 0.85rem; color: var(--text-muted);
  display: flex; gap: 12px; align-items: center; margin-bottom: 16px;
}
.separator { color: var(--border); }
.project-links { display: flex; gap: 12px; margin-top: 20px; }

/* ===== Prose (article content) ===== */
.prose h2 { font-size: 1.5rem; font-weight: 600; margin: 40px 0 16px; letter-spacing: -0.02em; }
.prose h3 { font-size: 1.2rem; font-weight: 600; margin: 32px 0 12px; }
.prose p { margin-bottom: 16px; color: var(--text-secondary); }
.prose ul, .prose ol { margin-bottom: 16px; padding-left: 24px; color: var(--text-secondary); }
.prose li { margin-bottom: 8px; }
.prose pre {
  background: var(--bg-secondary); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 20px; overflow-x: auto;
  margin-bottom: 24px; font-size: 0.875rem;
}
.prose code {
  background: var(--bg-secondary); padding: 2px 6px; border-radius: 4px;
  font-size: 0.85em;
}
.prose pre code { background: none; padding: 0; }
.prose blockquote {
  border-left: 3px solid var(--accent);
  padding-left: 16px; color: var(--text-secondary);
  margin-bottom: 16px; font-style: italic;
}
.prose img { border-radius: var(--radius); margin: 24px 0; }

/* ===== About Page ===== */
.about-hero { display: flex; gap: 48px; align-items: flex-start; margin-bottom: 48px; }
.about-photo {
  width: 180px; height: 180px; border-radius: 50%;
  background: var(--bg-secondary); border: 3px solid var(--border);
  flex-shrink: 0; display: flex; align-items: center; justify-content: center;
  font-size: 3rem; color: var(--text-muted);
  overflow: hidden;
}
.profile-img {
  width: 100%; height: 100%;
  object-fit: cover;
  display: block;
  border-radius: 50%;
}
.about-bio h1 { font-size: 2rem; font-weight: 700; margin-bottom: 8px; }
.about-bio p { color: var(--text-secondary); font-size: 1rem; }
.timeline { margin-top: 32px; }
.timeline-item {
  display: flex; gap: 16px; margin-bottom: 24px;
  padding-left: 24px; border-left: 2px solid var(--border);
}
.timeline-year {
  font-size: 0.8rem; font-weight: 600; color: var(--accent);
  min-width: 48px; padding-top: 2px;
}
.timeline-content h3 { font-size: 1rem; font-weight: 600; margin-bottom: 4px; }
.timeline-content p { font-size: 0.875rem; color: var(--text-secondary); }

/* ===== Contact Page ===== */
.contact-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 48px; }
.contact-form { display: flex; flex-direction: column; gap: 16px; }
.form-group label {
  display: block; font-size: 0.85rem; font-weight: 500;
  margin-bottom: 6px; color: var(--text-secondary);
}
.form-group input, .form-group textarea {
  width: 100%; padding: 10px 14px; border: 1px solid var(--border);
  border-radius: var(--radius); background: var(--bg-card);
  color: var(--text); font-family: var(--font-sans); font-size: 0.9rem;
  transition: border-color 0.2s;
}
.form-group input:focus, .form-group textarea:focus {
  outline: none; border-color: var(--accent);
}
.form-group textarea { resize: vertical; min-height: 140px; }
.contact-info h3 { font-size: 1rem; font-weight: 600; margin-bottom: 16px; }
.contact-info p { color: var(--text-secondary); font-size: 0.9rem; margin-bottom: 12px; }
.availability-badge {
  display: inline-flex; align-items: center; gap: 8px;
  background: #dcfce7; color: #166534; padding: 8px 16px;
  border-radius: 20px; font-size: 0.85rem; font-weight: 500;
  margin-bottom: 24px;
}
html.dark .availability-badge { background: #14532d; color: #86efac; }
.availability-dot {
  width: 8px; height: 8px; border-radius: 50%;
  background: #22c55e; animation: pulse 2s infinite;
}
@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.5; }
}

/* ===== Footer ===== */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 32px 24px; margin-top: 64px;
}
.footer-inner {
  display: flex; justify-content: space-between; align-items: center;
  max-width: var(--max-width); margin: 0 auto;
}
.footer-brand { font-weight: 600; font-size: 0.95rem; color: var(--text); margin-bottom: 4px; }
.footer-copy { font-size: 0.8rem; color: var(--text-muted); }
.footer-links { display: flex; gap: 20px; }
.footer-links a { font-size: 0.85rem; color: var(--text-secondary); }
.footer-links a:hover { color: var(--text); }

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .hero h1 { font-size: 2rem; }
  .site-nav { display: none; }
  .mobile-menu { display: none; }
  .mobile-menu.active { display: flex; }
  .mobile-menu-btn { display: block; }
  .about-hero { flex-direction: column; align-items: center; text-align: center; }
  .contact-grid { grid-template-columns: 1fr; }
  .card-grid { grid-template-columns: 1fr; }
  .footer-inner { flex-direction: column; gap: 16px; text-align: center; }
}