/* ── Theme tokens ── */
:root {
  --sidebar-bg: #1a1a2e;
  --sidebar-text: #e0e0e0;
  --sidebar-accent: #81aff0;
  --bg: #ffffff;
  --text: #333333;
  --muted: #6b7280;
  --line: #e5e7eb;
  --accent: #81aff0;
  --card-bg: #f9fafb;
  --sidebar-w: 280px;
}

[data-theme="dark"] {
  --bg: #111827;
  --text: #e5e7eb;
  --muted: #9ca3af;
  --line: #374151;
  --card-bg: #1f2937;
}

/* ── Reset ── */
*, *::before, *::after { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: 'IBM Plex Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  line-height: 1.75;
  transition: background .3s, color .3s;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color .2s, border-color .2s;
}
a:hover {
  color: #5b8fd8;
  border-bottom: 1px solid currentColor;
}

/* ── Sidebar ── */
.sidebar {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--sidebar-w);
  height: 100vh;
  background: var(--sidebar-bg);
  color: var(--sidebar-text);
  display: flex;
  flex-direction: column;
  z-index: 100;
  overflow-y: auto;
}

.sidebar-content {
  display: flex;
  flex-direction: column;
  min-height: 100%;
  padding: 2rem 1.5rem;
}

.sidebar-top {
  text-align: center;
  margin-bottom: 1.5rem;
}

.avatar-wrapper {
  margin-bottom: 1rem;
}

.avatar {
  width: 140px;
  height: 140px;
  border-radius: 50%;
  object-fit: cover;
  border: 3px solid rgba(255,255,255,0.15);
}

.sidebar-name {
  margin: 0;
  font-family: 'Source Sans 3', 'IBM Plex Sans', sans-serif;
  font-size: 1.4rem;
  font-weight: 700;
  color: #fff;
}

.sidebar-name-alt {
  margin: 0.2rem 0 0;
  font-size: 1.05rem;
  color: rgba(255,255,255,0.6);
}

.sidebar-title {
  margin: 0.8rem 0 0;
  font-size: 0.92rem;
  color: var(--sidebar-accent);
}

.sidebar-affiliation {
  margin: 0.15rem 0 0;
  font-size: 0.88rem;
  color: rgba(255,255,255,0.5);
}

/* Sidebar nav */
.sidebar-nav {
  display: flex;
  flex-direction: column;
  gap: 0.1rem;
  margin-bottom: 1.5rem;
}

.sidebar-nav a {
  color: var(--sidebar-text);
  padding: 0.45rem 0.75rem;
  border-radius: 6px;
  font-size: 0.92rem;
  transition: background .2s, color .2s;
  border-bottom: none;
}
.sidebar-nav a:hover {
  background: rgba(255,255,255,0.08);
  color: #fff;
  border-bottom: none;
}

/* Sidebar social icons */
.sidebar-social {
  display: flex;
  justify-content: center;
  gap: 0.9rem;
  margin-bottom: 1.5rem;
}

.sidebar-social a {
  color: rgba(255,255,255,0.55);
  transition: color .2s;
  border-bottom: none;
  display: flex;
  align-items: center;
}
.sidebar-social a:hover {
  color: #fff;
  border-bottom: none;
}

/* Sidebar bottom */
.sidebar-bottom {
  margin-top: auto;
  display: flex;
  justify-content: center;
  gap: 0.75rem;
  padding-top: 1rem;
}

.icon-btn {
  background: none;
  border: 1px solid rgba(255,255,255,0.2);
  color: var(--sidebar-text);
  border-radius: 50%;
  width: 34px;
  height: 34px;
  font-size: 1.1rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background .2s, border-color .2s;
}
.icon-btn:hover {
  background: rgba(255,255,255,0.1);
  border-color: rgba(255,255,255,0.4);
}

.lang-btn {
  border: 1px solid rgba(255,255,255,0.2);
  background: transparent;
  color: var(--sidebar-text);
  border-radius: 999px;
  padding: 0.2rem 0.75rem;
  font-size: 0.85rem;
  cursor: pointer;
  transition: background .2s, border-color .2s;
}
.lang-btn:hover {
  background: rgba(255,255,255,0.1);
  border-color: rgba(255,255,255,0.4);
}

/* ── Mobile header ── */
.mobile-header {
  display: none;
  position: sticky;
  top: 0;
  z-index: 90;
  background: var(--sidebar-bg);
  color: #fff;
  padding: 0.5rem 1rem;
  align-items: center;
  justify-content: space-between;
}

.menu-btn {
  background: none;
  border: none;
  color: #fff;
  font-size: 1.4rem;
  cursor: pointer;
  padding: 0.25rem;
}

.mobile-brand {
  font-weight: 600;
  font-size: 1.05rem;
}

.mobile-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.mobile-actions .icon-btn,
.mobile-actions .lang-btn {
  font-size: 0.9rem;
  width: 30px;
  height: 30px;
}
.mobile-actions .lang-btn {
  width: auto;
  padding: 0.15rem 0.6rem;
}

/* Sidebar overlay */
.sidebar-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.5);
  z-index: 99;
}
.sidebar-overlay.active {
  display: block;
}

/* ── Main content ── */
.content {
  margin-left: var(--sidebar-w);
  min-height: 100vh;
  padding: 3rem 3rem 2rem;
  overflow-x: hidden;
  transition: background .3s;
}

/* ── Sections ── */
.section {
  margin-bottom: 2.5rem;
}

h2 {
  font-family: 'Source Sans 3', 'IBM Plex Sans', sans-serif;
  font-size: 1.25rem;
  font-weight: 700;
  margin: 0 0 0.75rem;
  padding-bottom: 0.4rem;
  border-bottom: 2px solid var(--accent);
  display: inline-block;
}

p, li {
  font-size: 0.97rem;
}

/* Tag list */
.tag-list, .paper-list, .plain-list {
  margin: 0;
  padding: 0;
  list-style: none;
}

.tag-list li {
  display: inline-block;
  margin: 0 0.5rem 0.5rem 0;
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0.2rem 0.85rem;
  font-size: 0.88rem;
  background: var(--card-bg);
  transition: background .3s, border-color .3s;
}

.paper-list li {
  margin-bottom: 1rem;
  padding: 0.8rem 1rem;
  background: var(--card-bg);
  border-radius: 8px;
  border-left: 3px solid var(--accent);
  transition: background .3s, transform .15s;
}
.paper-list li:hover {
  transform: translateX(4px);
}

.paper-list .paper-title {
  font-weight: 500;
}

.paper-list .paper-meta {
  color: var(--muted);
  font-size: 0.9rem;
}

.paper-list .paper-links a {
  font-size: 0.85rem;
  margin-right: 0.5rem;
}

.plain-list li {
  margin-bottom: 0.5rem;
}

/* CV button */
.cv-btn {
  display: inline-block;
  padding: 0.5rem 1.5rem;
  border: 1px solid var(--accent);
  border-radius: 6px;
  font-weight: 500;
  transition: background .2s, color .2s;
}
.cv-btn:hover {
  background: var(--accent);
  color: #fff;
  border-bottom: 1px solid var(--accent);
}

/* ── Footer ── */
.site-footer {
  margin-top: 3rem;
  border-top: 1px solid var(--line);
  padding: 1.5rem 0;
  color: var(--muted);
  font-size: 0.85rem;
  text-align: center;
}

/* ── Fade-in animation ── */
.fade-in {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity .5s ease-out, transform .5s ease-out;
}
.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ── Responsive ── */
@media (max-width: 768px) {
  .sidebar {
    transform: translateX(-100%);
    transition: transform .3s ease;
  }
  .sidebar.open {
    transform: translateX(0);
  }

  .mobile-header {
    display: flex;
  }

  .content {
    margin-left: 0;
    padding: 1.5rem 1.25rem;
  }
}

@media (min-width: 769px) {
  .mobile-header {
    display: none;
  }
}