:root {
  --bg: #ffffff;
  --surface: #f8fafc;
  --text: #1e293b;
  --text-muted: #64748b;
  --accent: #2563eb;
  --accent-soft: rgba(37, 99, 235, 0.1);
  --border: #e2e8f0;
  --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1);
  --sidebar-w: 280px;
  --container-max: 960px;
  --font-serif: "Lora", Georgia, serif;
  --font-sans: "Inter", -apple-system, sans-serif;
}

[data-theme="dark"] {
  --bg: #0f172a;
  --surface: #1e293b;
  --text: #f1f5f9;
  --text-muted: #94a3b8;
  --accent: #60a5fa;
  --accent-soft: rgba(96, 165, 250, 0.1);
  --border: #334155;
  --shadow: 0 10px 15px -3px rgb(0 0 0 / 0.4);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  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(--accent);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

/* Layout */
.app-container {
  display: flex;
  min-height: 100vh;
}

.sidebar {
  width: var(--sidebar-w);
  background: var(--surface);
  border-right: 1px solid var(--border);
  padding: 40px 30px;
  position: fixed;
  height: 100vh;
  overflow-y: auto;
  z-index: 100;
}

.content {
  flex: 1;
  margin-left: var(--sidebar-w);
  padding: 60px 80px;
  max-width: var(--container-max);
}

/* Profile Card */
.profile-card {
  text-align: center;
}

.avatar {
  width: 160px;
  height: 160px;
  border-radius: 50%;
  object-fit: cover;
  border: 4px solid var(--bg);
  box-shadow: var(--shadow);
  margin-bottom: 24px;
}

.name {
  font-family: var(--font-serif);
  font-size: 28px;
  margin: 0;
  color: var(--text);
}

.title {
  margin: 8px 0 4px;
  font-weight: 500;
  color: var(--text-muted);
  font-size: 14px;
  line-height: 1.3;
}

.affiliation {
  margin: 0 0 24px;
  font-size: 13px;
  color: var(--text-muted);
}

.side-nav {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin: 32px 0;
  text-align: left;
}

.side-nav a {
  font-weight: 500;
  color: var(--text);
  font-size: 15px;
  padding: 8px 12px;
  border-radius: 8px;
  transition: background 0.2s;
}

.side-nav a:hover {
  background: var(--accent-soft);
  color: var(--accent);
  text-decoration: none;
}

.social-links {
  display: flex;
  justify-content: center;
  gap: 16px;
  margin: 24px 0;
}

.social-links svg {
  width: 20px;
  height: 20px;
  fill: var(--text-muted);
  transition: fill 0.2s, transform 0.2s;
}

.social-links a:hover svg {
  fill: var(--accent);
  transform: translateY(-2px);
}

/* Sections */
section {
  margin-bottom: 80px;
}

h2 {
  font-family: var(--font-serif);
  font-size: 32px;
  margin: 0 0 32px;
  padding-bottom: 12px;
  border-bottom: 2px solid var(--border);
}

.bio-text p {
  font-size: 18px;
  color: var(--text);
  margin-bottom: 20px;
}

/* News */
.news-list {
  list-style: none;
  padding: 0;
}

.news-list li {
  margin-bottom: 16px;
  font-size: 15px;
}

.date {
  display: inline-block;
  min-width: 90px;
  font-weight: 700;
  font-size: 13px;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

/* Publications */
.section-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: 32px;
  flex-wrap: wrap;
  gap: 16px;
  border-bottom: 2px solid var(--border);
  padding-bottom: 12px;
}

.section-header h2 {
  margin: 0;
  border: none;
  padding: 0;
}

.pub-filters {
  display: flex;
  gap: 8px;
}

.pub-filters input,
.pub-filters select {
  padding: 6px 12px;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  font-size: 14px;
}

.pub-list {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.pub {
  padding: 0;
}

.pub-title {
  font-size: 19px;
  font-weight: 600;
  margin: 0 0 6px;
  line-height: 1.4;
  font-family: var(--font-sans);
}

.pub-meta {
  font-size: 15px;
  color: var(--text-muted);
  margin: 0 0 12px;
}

.pub-links {
  display: flex;
  gap: 12px;
}

.pill {
  font-size: 12px;
  font-weight: 600;
  padding: 4px 12px;
  border-radius: 20px;
  background: var(--accent-soft);
  color: var(--accent);
  border: 1px solid transparent;
  transition: all 0.2s;
}

.pill:hover {
  background: var(--accent);
  color: white;
  text-decoration: none;
}

/* Education */
.edu-item {
  margin-bottom: 24px;
}

.edu-header {
  display: flex;
  justify-content: space-between;
  font-size: 17px;
}

.edu-item p {
  margin: 4px 0;
  color: var(--text-muted);
}

/* Theme Toggle */
.theme-toggle {
  position: fixed;
  bottom: 24px;
  right: 24px;
  background: var(--surface);
  border: 1px solid var(--border);
  padding: 10px;
  border-radius: 50%;
  cursor: pointer;
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  box-shadow: var(--shadow);
  transition: transform 0.2s;
}

.theme-toggle:hover {
  transform: scale(1.1);
}

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

.main-footer {
  margin-top: 100px;
  padding: 40px 0;
  border-top: 1px solid var(--border);
  text-align: center;
  color: var(--text-muted);
  font-size: 13px;
}

/* Responsive */
@media (max-width: 1024px) {
  .content {
    padding: 60px 40px;
  }
}

@media (max-width: 768px) {
  .app-container {
    flex-direction: column;
  }
  .sidebar {
    position: relative;
    width: 100%;
    height: auto;
    border-right: none;
    border-bottom: 1px solid var(--border);
    padding: 40px 20px;
  }
  .content {
    margin-left: 0;
    padding: 40px 20px;
  }
  .side-nav {
    flex-direction: row;
    justify-content: center;
    flex-wrap: wrap;
  }
}