/* Variables */
:root {
  --bg: #ffffff;
  --text: #1a1a1a;
  --text-muted: #666666;
  --border: #e5e5e5;
  --link: #0066cc;
  --font-serif: 'Playfair Display', Georgia, serif;
  --font-sans: 'Inter', -apple-system, sans-serif;
  --font-mono: 'JetBrains Mono', 'SF Mono', Monaco, monospace;
  --term-bg: #1a1a1a;
  --term-text: #e0e0e0;
}

[data-theme="dark"] {
  --bg: #111111;
  --text: #f0f0f0;
  --text-muted: #999999;
  --border: #333333;
  --link: #66b3ff;
  --term-bg: #0a0a0a;
}

/* Reset */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

/* Base */
body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  color: var(--text);
  background: var(--bg);
  transition: background 0.3s, color 0.3s;
}

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

/* Skip link */
.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--text);
  color: var(--bg);
  padding: 8px 16px;
  z-index: 100;
}
.skip-link:focus { top: 0; }

/* Container */
.container {
  max-width: 720px;
  margin: 0 auto;
  padding: 0 24px;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Header */
.header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 32px 0;
  border-bottom: 1px solid var(--border);
  gap: 24px;
}

.logo {
  font-family: var(--font-serif);
  font-size: 2.5rem;
  font-weight: 600;
  color: var(--text);
  text-decoration: none;
  letter-spacing: -0.02em;
}
.logo:hover { text-decoration: none; opacity: 0.8; }

/* Navigation */
.nav { flex: 1; }

.nav-list {
  display: flex;
  gap: 24px;
  list-style: none;
  justify-content: center;
}

.nav-link {
  color: var(--text-muted);
  font-size: 0.9rem;
  padding: 4px 0;
  border-bottom: 1px solid transparent;
  transition: color 0.2s, border-color 0.2s;
}
.nav-link:hover, .nav-link.active {
  color: var(--text);
  text-decoration: none;
  border-bottom-color: var(--text);
}
.nav-link:focus { outline: 2px solid var(--link); outline-offset: 2px; }

.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
  flex-direction: column;
  gap: 5px;
}
.nav-toggle span {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--text);
  transition: transform 0.2s;
}
.nav-toggle[aria-expanded="true"] span:first-child { transform: translateY(3.5px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:last-child { transform: translateY(-3.5px) rotate(-45deg); }

/* Theme toggle */
.theme-toggle {
  background: none;
  border: 1px solid var(--border);
  border-radius: 50%;
  width: 40px;
  height: 40px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text);
  transition: border-color 0.2s;
  flex-shrink: 0;
}
.theme-toggle:hover { border-color: var(--text); }
.theme-toggle:focus { outline: 2px solid var(--link); outline-offset: 2px; }

.icon-moon { display: none; }
[data-theme="dark"] .icon-sun { display: none; }
[data-theme="dark"] .icon-moon { display: block; }

/* Main content */
main { flex: 1; padding: 48px 0; }

.section { display: none; animation: fadeIn 0.3s ease; }
.section.active { display: block; }
@keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }

.section-title {
  font-family: var(--font-serif);
  font-size: 1.75rem;
  font-weight: 400;
  margin-bottom: 24px;
  letter-spacing: -0.01em;
}

.section-content p { margin-bottom: 16px; }
.section-intro { color: var(--text-muted); margin-bottom: 24px; }

/* Highlights */
.highlights {
  list-style: none;
  margin: 24px 0;
}
.highlights li {
  padding-left: 20px;
  position: relative;
  margin-bottom: 8px;
}
.highlights li::before {
  content: "·";
  position: absolute;
  left: 0;
  color: var(--text-muted);
}

/* Contact Links */
.contact-links {
  margin: 24px 0;
  display: flex;
  gap: 16px;
}
.contact-links a {
  color: var(--text-muted);
  font-size: 0.9rem;
}
.contact-links a:hover { color: var(--link); }

/* Mini Terminal */
.terminal {
  margin-top: 32px;
  background: var(--term-bg);
  border-radius: 8px;
  overflow: hidden;
  font-family: var(--font-mono);
  font-size: 0.85rem;
}

.term-header {
  background: #2d2d2d;
  padding: 8px 12px;
  display: flex;
  align-items: center;
  gap: 6px;
}

.term-dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: #ff5f56;
}
.term-dot:nth-child(2) { background: #ffbd2e; }
.term-dot:nth-child(3) { background: #27ca40; }

.term-title {
  color: #888;
  font-size: 0.75rem;
  margin-left: 8px;
}

.term-output {
  padding: 12px;
  min-height: 60px;
  max-height: 200px;
  overflow-y: auto;
  color: var(--term-text);
  line-height: 1.5;
}

.term-input-row {
  display: flex;
  align-items: center;
  padding: 0 12px 12px;
  gap: 8px;
}

.term-prompt { color: #27ca40; }

.term-input {
  flex: 1;
  background: transparent;
  border: none;
  color: var(--term-text);
  font-family: inherit;
  font-size: inherit;
  outline: none;
}
.term-input::placeholder { color: #555; }

.term-line { margin-bottom: 4px; }
.term-result { margin-bottom: 12px; white-space: pre-wrap; }
.term-cmd { color: #27ca40; }
.term-highlight { color: #66b3ff; }
.term-muted { color: #666; }

/* Publications */
.pub-item {
  margin-bottom: 24px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--border);
}
.pub-item:last-child { border-bottom: none; }
.pub-title { font-weight: 500; margin-bottom: 4px; }
.pub-authors { color: var(--text-muted); font-size: 0.9rem; margin-bottom: 4px; }
.author-highlight { color: var(--text); font-weight: 600; }
.pub-venue { font-style: italic; color: var(--text-muted); font-size: 0.9rem; }
.pub-links { margin-top: 8px; font-size: 0.85rem; }
.pub-links a { margin-right: 12px; }

/* Projects */
.project-item {
  margin-bottom: 24px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--border);
}
.project-item:last-child { border-bottom: none; }
.project-title { font-weight: 500; margin-bottom: 4px; }
.project-desc { color: var(--text-muted); font-size: 0.95rem; margin-bottom: 8px; }
.project-tags { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 8px; }
.tag {
  font-size: 0.75rem;
  padding: 2px 8px;
  background: var(--border);
  border-radius: 3px;
  color: var(--text-muted);
}
.project-links { font-size: 0.85rem; }
.project-links a { margin-right: 12px; }

/* Blog */
.post-item {
  display: block;
  padding: 16px 0;
  border-bottom: 1px solid var(--border);
  color: var(--text);
  cursor: pointer;
}
.post-item:hover { text-decoration: none; }
.post-item:hover .post-title { color: var(--link); }
.post-item:focus { outline: 2px solid var(--link); outline-offset: 4px; }
.post-title { font-weight: 500; margin-bottom: 4px; transition: color 0.2s; }
.post-date { font-size: 0.85rem; color: var(--text-muted); }
.post-summary { font-size: 0.9rem; color: var(--text-muted); margin-top: 4px; }

.back-btn {
  background: none;
  border: none;
  color: var(--link);
  cursor: pointer;
  font-size: 0.9rem;
  padding: 0;
  margin-bottom: 24px;
}
.back-btn:hover { text-decoration: underline; }
.back-btn:focus { outline: 2px solid var(--link); outline-offset: 2px; }

#blog-post-content h1 { font-family: var(--font-serif); font-size: 1.75rem; margin-bottom: 8px; font-weight: 400; }
#blog-post-content h2 { font-size: 1.25rem; margin: 32px 0 16px; font-weight: 500; }
#blog-post-content p { margin-bottom: 16px; }
#blog-post-content ul, #blog-post-content ol { margin: 16px 0; padding-left: 24px; }
#blog-post-content li { margin-bottom: 8px; }
#blog-post-content code {
  font-family: var(--font-mono);
  background: var(--border);
  padding: 2px 6px;
  border-radius: 3px;
  font-size: 0.9em;
}
#blog-post-content pre {
  background: var(--border);
  padding: 16px;
  border-radius: 4px;
  overflow-x: auto;
  margin: 16px 0;
}
#blog-post-content pre code { background: none; padding: 0; }
#blog-post-content blockquote {
  border-left: 2px solid var(--border);
  padding-left: 16px;
  color: var(--text-muted);
  margin: 16px 0;
}

/* Readings */
.reading-item {
  padding: 16px 0;
  border-bottom: 1px solid var(--border);
}
.reading-item:last-child { border-bottom: none; }
a.reading-title { font-weight: 500; text-decoration: none; color: var(--text); }
a.reading-title:hover { color: var(--accent); }
.reading-tags { margin-top: 8px; display: flex; flex-wrap: wrap; gap: 6px; }
.reading-tags .tag { cursor: pointer; transition: background-color 0.2s, color 0.2s; }
.reading-tags .tag:hover { background-color: var(--accent); color: var(--bg); }
.reading-tags .tag.active { background-color: var(--accent); color: var(--bg); }
.reading-filter { margin-bottom: 16px; display: flex; align-items: center; gap: 8px; font-size: 0.9rem; color: var(--text-muted); }
.reading-filter .tag { cursor: default; }
.clear-filter { background: none; border: 1px solid var(--border); color: var(--text-muted); padding: 4px 10px; border-radius: 4px; cursor: pointer; font-size: 0.8rem; }
.clear-filter:hover { border-color: var(--accent); color: var(--accent); }
.reading-meta { font-size: 0.9rem; color: var(--text-muted); margin-top: 2px; }
.reading-note { font-size: 0.9rem; color: var(--text); margin-top: 8px; line-height: 1.5; }
.reading-added { font-size: 0.75rem; color: var(--text-muted); margin-top: 8px; opacity: 0.7; }

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

/* Loading & Muted */
.loading { color: var(--text-muted); font-style: italic; }
.muted { color: var(--text-muted); }
.error { color: #cc0000; }

/* Mobile */
@media (max-width: 600px) {
  .header { flex-wrap: wrap; padding: 24px 0; }
  .logo { font-size: 2rem; }

  .nav-toggle { display: flex; }
  .nav {
    position: fixed;
    top: 0;
    right: -100%;
    width: 200px;
    height: 100vh;
    background: var(--bg);
    border-left: 1px solid var(--border);
    padding: 80px 24px 24px;
    transition: right 0.3s;
    z-index: 50;
  }
  .nav.open { right: 0; }
  .nav-list { flex-direction: column; gap: 16px; }

  .theme-toggle { order: -1; }

  .terminal { font-size: 0.8rem; }
}

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}