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

:root {
  --bg-primary: #0a0a0f;
  --bg-secondary: #12121a;
  --bg-card: #1a1a2e;
  --bg-card-hover: #222240;
  --border: #2a2a4a;
  --text-primary: #e8e8f0;
  --text-secondary: #9090b0;
  --text-muted: #606080;
  --accent: #6c63ff;
  --accent-glow: rgba(108, 99, 255, 0.3);
  --green: #4ade80;
  --orange: #fb923c;
  --blue: #60a5fa;
  --pink: #f472b6;
  --radius: 12px;
  --radius-sm: 8px;
  --transition: 0.2s ease;
}

html { font-size: 16px; scroll-behavior: smooth; }

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
}

a { color: var(--accent); text-decoration: none; transition: color var(--transition); }
a:hover { color: #8b83ff; }

/* ===== Header ===== */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(10, 10, 15, 0.85);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border);
  padding: 0 2rem;
}

.header-inner {
  max-width: 1400px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--text-primary);
}

.logo-icon {
  width: 32px;
  height: 32px;
  background: linear-gradient(135deg, var(--accent), #a78bfa);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
}

/* Navigation */
.nav { display: flex; gap: 0.25rem; }

.nav-btn {
  background: none;
  border: none;
  color: var(--text-secondary);
  padding: 0.5rem 1rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 0.875rem;
  font-weight: 500;
  transition: all var(--transition);
}

.nav-btn:hover { color: var(--text-primary); background: var(--bg-card); }
.nav-btn.active { color: var(--accent); background: rgba(108, 99, 255, 0.1); }

/* Search */
.search-box {
  position: relative;
  width: 240px;
}

.search-box input {
  width: 100%;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.5rem 0.75rem 0.5rem 2.2rem;
  color: var(--text-primary);
  font-size: 0.875rem;
  outline: none;
  transition: border-color var(--transition);
}

.search-box input::placeholder { color: var(--text-muted); }
.search-box input:focus { border-color: var(--accent); }

.search-box::before {
  content: '🔍';
  position: absolute;
  left: 0.6rem;
  top: 50%;
  transform: translateY(-50%);
  font-size: 0.8rem;
  pointer-events: none;
}

/* ===== Main Layout ===== */
.main {
  max-width: 1400px;
  margin: 0 auto;
  padding: 1.5rem 2rem;
}

/* Section views */
.section { display: none; }
.section.active { display: block; }

/* ===== Dashboard Grid ===== */
.dashboard-grid {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 1.5rem;
}

/* ===== Section Headers ===== */
.section-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1rem;
}

.section-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.section-count {
  font-size: 0.75rem;
  color: var(--text-muted);
  background: var(--bg-card);
  padding: 0.2rem 0.6rem;
  border-radius: 999px;
}

/* ===== Cards ===== */
.card-list {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  max-height: calc(100vh - 200px);
  overflow-y: auto;
  padding-right: 0.25rem;
}

.card-list::-webkit-scrollbar { width: 4px; }
.card-list::-webkit-scrollbar-track { background: transparent; }
.card-list::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }

.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem;
  transition: all var(--transition);
  cursor: pointer;
}

.card:hover {
  background: var(--bg-card-hover);
  border-color: var(--accent);
  box-shadow: 0 0 20px var(--accent-glow);
  transform: translateY(-1px);
}

.card-source {
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
  margin-bottom: 0.4rem;
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.card-title {
  font-size: 0.9rem;
  font-weight: 600;
  line-height: 1.4;
  margin-bottom: 0.4rem;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.card-excerpt {
  font-size: 0.8rem;
  color: var(--text-secondary);
  line-height: 1.5;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
  margin-bottom: 0.5rem;
}

.card-meta {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 0.7rem;
  color: var(--text-muted);
}

.card-tag {
  background: rgba(108, 99, 255, 0.15);
  color: var(--accent);
  padding: 0.15rem 0.5rem;
  border-radius: 999px;
  font-size: 0.65rem;
  font-weight: 500;
}

/* ===== Tools Grid ===== */
.tools-section { margin-top: 2rem; }

.tools-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1rem;
}

.tool-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
  transition: all var(--transition);
}

.tool-card:hover {
  background: var(--bg-card-hover);
  border-color: var(--accent);
  box-shadow: 0 0 20px var(--accent-glow);
  transform: translateY(-2px);
}

.tool-name {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 0.35rem;
}

.tool-desc {
  font-size: 0.8rem;
  color: var(--text-secondary);
  line-height: 1.5;
  margin-bottom: 0.75rem;
}

.tool-tags { display: flex; flex-wrap: wrap; gap: 0.35rem; }

.tool-tags .card-tag { font-size: 0.6rem; }

.tool-category {
  font-size: 0.65rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--green);
  margin-bottom: 0.5rem;
}

/* Filter bar */
.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1.25rem;
}

.filter-btn {
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--text-secondary);
  padding: 0.35rem 0.85rem;
  border-radius: 999px;
  cursor: pointer;
  font-size: 0.75rem;
  font-weight: 500;
  transition: all var(--transition);
}

.filter-btn:hover { border-color: var(--accent); color: var(--text-primary); }
.filter-btn.active { background: var(--accent); border-color: var(--accent); color: #fff; }

/* ===== Skeleton Loading ===== */
.skeleton {
  background: linear-gradient(90deg, var(--bg-card) 25%, var(--bg-card-hover) 50%, var(--bg-card) 75%);
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite;
  border-radius: var(--radius-sm);
}

.skeleton-card {
  height: 120px;
  border-radius: var(--radius);
  margin-bottom: 0.75rem;
}

@keyframes shimmer {
  0% { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}

/* ===== Error State ===== */
.error-msg {
  text-align: center;
  padding: 2rem;
  color: var(--text-muted);
  font-size: 0.85rem;
}

.error-msg span { font-size: 1.5rem; display: block; margin-bottom: 0.5rem; }

/* ===== Footer ===== */
.footer {
  max-width: 1400px;
  margin: 3rem auto 0;
  padding: 1.5rem 2rem;
  border-top: 1px solid var(--border);
  text-align: center;
  font-size: 0.75rem;
  color: var(--text-muted);
}

.footer a { color: var(--text-secondary); }

/* ===== Responsive ===== */
@media (max-width: 1024px) {
  .dashboard-grid {
    grid-template-columns: 1fr 1fr;
  }
  .dashboard-grid > :nth-child(3) {
    grid-column: span 2;
  }
}

@media (max-width: 768px) {
  .header { padding: 0 1rem; }
  .header-inner { flex-wrap: wrap; height: auto; padding: 0.75rem 0; gap: 0.5rem; }
  .search-box { width: 100%; order: 3; }
  .nav { order: 2; }
  .main { padding: 1rem; }
  .dashboard-grid { grid-template-columns: 1fr; }
  .dashboard-grid > :nth-child(3) { grid-column: span 1; }
  .card-list { max-height: 50vh; }
  .tools-grid { grid-template-columns: 1fr; }
}

/* ===== Paper-specific styles ===== */
.paper-authors {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-bottom: 0.3rem;
  display: -webkit-box;
  -webkit-line-clamp: 1;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.paper-categories { display: flex; gap: 0.3rem; flex-wrap: wrap; }