@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&display=swap');

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

:root {
  --text: #333;
  --text-secondary: #555;
  --bg: #fff;
  --bg-card: #f5f5f5;
  --accent: #2563eb;
  --muted: #888;
  --border: #e5e5e5;
  --nav-bg: rgba(255, 255, 255, 0.85);
  --max-w: 800px;
}

[data-theme="dark"] {
  --text: #e0e0e0;
  --text-secondary: #aaa;
  --bg: #1a1a2e;
  --bg-card: #16213e;
  --accent: #60a5fa;
  --muted: #888;
  --border: #2a2a4a;
  --nav-bg: rgba(26, 26, 46, 0.9);
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
  font-size: 15px;
  -webkit-font-smoothing: antialiased;
  transition: color 0.3s, background 0.3s;
  overflow-wrap: break-word;
}

body.lang-zh [lang="en"],
body.lang-en [lang="zh"] { display: none; }

/* Navigation */
nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: var(--nav-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  transition: background 0.3s, border-color 0.3s;
}

.nav-inner {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0.6rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.nav-name {
  font-weight: 700;
  font-size: 0.95rem;
  color: var(--text);
  text-decoration: none;
}

.nav-right {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  position: static;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-right: 0.5rem;
}

.nav-links a {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.8rem;
  font-weight: 500;
  transition: color 0.2s;
}

.nav-links a:hover { color: var(--accent); }

.nav-btn {
  background: transparent;
  color: var(--muted);
  border: 1px solid var(--border);
  padding: 0.25rem 0.6rem;
  font-family: inherit;
  font-size: 0.75rem;
  font-weight: 500;
  cursor: pointer;
  border-radius: 5px;
  transition: all 0.2s;
}

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

.hamburger {
  display: none;
  background: transparent;
  border: none;
  color: var(--text);
  font-size: 1.4rem;
  cursor: pointer;
  padding: 0.2rem;
  line-height: 1;
}

.container {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 5rem 2rem 2rem;
}

/* Header with photo */
header {
  margin-bottom: 3.5rem;
  display: flex;
  gap: 2rem;
  align-items: flex-start;
}

.profile-photo {
  width: 140px;
  height: 140px;
  border-radius: 10px;
  object-fit: cover;
  flex-shrink: 0;
  border: 3px solid var(--border);
  transition: border-color 0.3s;
}

.header-info {
  flex: 1;
}

.header-info h1 {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 0.3rem;
}

.header-info .subtitle {
  font-size: 0.9rem;
  color: var(--muted);
  font-weight: 400;
  margin-bottom: 1rem;
}

.header-info .links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.header-info .links a {
  display: inline-block;
  color: var(--accent);
  text-decoration: none;
  font-size: 0.82rem;
  font-weight: 500;
  padding: 0.25rem 0.65rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  transition: all 0.2s;
}

.header-info .links a:hover {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

/* Sections */
section {
  margin-bottom: 3rem;
}

section h2 {
  font-size: 1.1rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  margin-bottom: 1.2rem;
  padding-left: 0.8rem;
  border-left: 3px solid var(--accent);
  transition: border-color 0.3s;
}

/* About */
.about p {
  font-size: 0.92rem;
  line-height: 1.8;
  color: var(--text-secondary);
}

.about p + p { margin-top: 0.5rem; }

/* News */
.scrollable {
  max-height: 400px;
  overflow-y: auto;
  padding-right: 0.3rem;
}

.scrollable::-webkit-scrollbar { width: 4px; }
.scrollable::-webkit-scrollbar-track { background: transparent; }
.scrollable::-webkit-scrollbar-thumb {
  background: var(--border);
  border-radius: 2px;
}
.scrollable::-webkit-scrollbar-thumb:hover { background: var(--muted); }

.news-list { list-style: none; }

.news-list li {
  padding: 0.45rem 0;
  display: flex;
  gap: 1rem;
  font-size: 0.88rem;
}

.news-list .date {
  color: var(--muted);
  flex-shrink: 0;
  min-width: 5rem;
  font-weight: 500;
  font-variant-numeric: tabular-nums;
}

/* Education */
.edu-item {
  margin-bottom: 1rem;
  padding: 0.9rem 1.1rem;
  background: var(--bg-card);
  border-radius: 8px;
  transition: background 0.3s;
}

.edu-item .period {
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 500;
}

.edu-item h3 {
  font-size: 0.92rem;
  font-weight: 600;
  margin: 0.15rem 0;
}

.edu-item p {
  font-size: 0.83rem;
  color: var(--text-secondary);
}

/* Publications */
.pub-note {
  font-size: 0.78rem;
  color: var(--muted);
  margin-bottom: 1rem;
}

.pub-list { list-style: none; }

.pub-list li {
  margin-bottom: 1.1rem;
  padding-bottom: 1.1rem;
  border-bottom: 1px solid var(--border);
  transition: border-color 0.3s;
}

.pub-list li:last-child { border-bottom: none; padding-bottom: 0; }

.pub-list .title {
  font-weight: 600;
  font-size: 0.92rem;
  display: block;
  margin-bottom: 0.15rem;
}

.pub-list .authors {
  font-size: 0.82rem;
  color: var(--text-secondary);
}

.pub-list .venue {
  font-size: 0.82rem;
  color: var(--muted);
  font-style: italic;
}

.pub-list .pub-links {
  margin-top: 0.35rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
}

.pub-list .pub-links a {
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--accent);
  text-decoration: none;
  padding: 0.12rem 0.45rem;
  border: 1px solid var(--accent);
  border-radius: 4px;
  transition: all 0.2s;
}

.pub-list .pub-links a:hover {
  background: var(--accent);
  color: #fff;
}

/* Projects */
.project-item {
  margin-bottom: 1.2rem;
  padding: 0.9rem 1.1rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  transition: border-color 0.3s;
}

.project-item h3 {
  font-size: 0.92rem;
  font-weight: 600;
}

.project-item .period {
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 500;
}

.project-item p {
  font-size: 0.83rem;
  color: var(--text-secondary);
  margin-top: 0.25rem;
}

.project-item .tech {
  font-size: 0.78rem;
  color: var(--accent);
  margin-top: 0.35rem;
  font-weight: 500;
}

/* Awards */
.awards-list { list-style: none; }

.awards-list li {
  padding: 0.35rem 0;
  display: flex;
  gap: 0.8rem;
  font-size: 0.88rem;
}

.awards-list .year {
  color: var(--muted);
  flex-shrink: 0;
  min-width: 2.8rem;
  font-weight: 500;
}

/* Services */
.services h3 {
  font-size: 0.88rem;
  font-weight: 600;
  margin-bottom: 0.3rem;
  margin-top: 0.8rem;
}

.services h3:first-of-type { margin-top: 0; }

.services ul {
  margin-left: 1.2rem;
  font-size: 0.83rem;
  color: var(--text-secondary);
}

.services li { margin-bottom: 0.12rem; }

/* Contact */
.contact p {
  font-size: 0.88rem;
  margin-bottom: 0.3rem;
}

.contact a {
  color: var(--accent);
  text-decoration: none;
}

.contact a:hover { text-decoration: underline; }

/* Map */
.visitor-map {
  text-align: center;
  margin-top: 2rem;
  padding-bottom: 2rem;
  border-bottom: 1px solid var(--border);
}

.visitor-map p {
  font-size: 0.78rem;
  color: var(--muted);
  margin-bottom: 0.8rem;
}

/* Footer */
footer {
  text-align: center;
  color: var(--muted);
  font-size: 0.78rem;
  margin-top: 2rem;
  padding-bottom: 2rem;
}

/* Toast */
.toast {
  position: fixed;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%) translateY(1rem);
  background: var(--text);
  color: var(--bg);
  padding: 0.5rem 1.2rem;
  border-radius: 6px;
  font-size: 0.82rem;
  font-weight: 500;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s, transform 0.3s;
  z-index: 200;
}

.toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* ============ Responsive ============ */

/* Tablet */
@media (max-width: 768px) {
  .nav-inner { padding: 0.5rem 1.2rem; }
  .container { padding: 4.5rem 1.2rem 2rem; }

  header {
    gap: 1.5rem;
  }

  .profile-photo {
    width: 110px;
    height: 110px;
  }

  .header-info h1 { font-size: 1.7rem; }
}

/* Mobile */
@media (max-width: 600px) {
  .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    margin-right: 0;
    background: var(--bg-card);
    flex-direction: column;
    padding: 0.8rem 1.2rem;
    border-bottom: 1px solid var(--border);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.12);
    gap: 0.6rem;
    z-index: 99;
  }

  .nav-links.open { display: flex; }

  .nav-links a { font-size: 0.85rem; }

  .hamburger { display: block; }

  .container { padding: 4rem 1rem 1.5rem; }

  header {
    flex-direction: column;
    align-items: center;
    text-align: center;
    gap: 1rem;
  }

  .profile-photo {
    width: 120px;
    height: 120px;
  }

  .header-info .links { justify-content: center; }
  .header-info h1 { font-size: 1.6rem; }

  section { margin-bottom: 2.5rem; }

  .news-list li { flex-direction: column; gap: 0.1rem; }
  .awards-list li { flex-direction: column; gap: 0.1rem; }
  .edu-item, .project-item { padding: 0.7rem 0.9rem; }
}