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

:root {
  --bg-dark: #0f172a; /* Slate 900 */
  --bg-panel: #1e293b; /* Slate 800 */
  --bg-hover: #334155; /* Slate 700 */
  --accent-sapphire: #2563eb; /* Blue 600 */
  --accent-sapphire-hover: #1d4ed8; /* Blue 700 */
  --text-primary: #f8fafc; /* Slate 50 */
  --text-secondary: #94a3b8; /* Slate 400 */
  --border-color: #334155;
}

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

body {
  font-family: 'Inter', sans-serif;
  font-size: 14px;
  background-color: var(--bg-dark);
  color: var(--text-primary);
  line-height: 1.5;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  overflow-y: auto;
}

/* Search Tab Specific Layout */
.search-container {
  display: flex;
  flex-direction: column;
  gap: 16px;
  max-width: 600px;
  margin: 0 auto;
  background-color: var(--bg-panel);
  padding: 32px;
  border-radius: 12px;
  border: 1px solid var(--border-color);
}

.search-container h2 {
  font-size: 20px;
  font-weight: 600;
  color: var(--accent-sapphire);
  margin-bottom: 16px;
}

.search-group {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 24px;
}

.search-group label {
  font-size: 12px;
  color: var(--text-secondary);
  font-weight: 500;
}

input[type="text"], select {
  background-color: var(--bg-dark);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  padding: 10px 12px;
  border-radius: 6px;
  font-size: 13px;
  outline: none;
  transition: border-color 0.2s;
}

input[type="text"]:focus, select:focus {
  border-color: var(--accent-sapphire);
}

button.primary-btn {
  background-color: var(--accent-sapphire);
  color: white;
  border: none;
  padding: 10px 16px;
  border-radius: 6px;
  font-weight: 500;
  cursor: pointer;
  transition: background-color 0.2s;
  font-size: 13px;
}

button.primary-btn:hover {
  background-color: var(--accent-sapphire-hover);
}

/* Main Content */
.main-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  max-width: 1400px;
  margin: 0 auto;
  width: 100%;
}

.header {
  padding: 24px 32px;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
}

.header h1 {
  font-size: 20px;
  font-weight: 600;
}

.tabs {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.tab-btn {
  background: none;
  border: none;
  color: var(--text-secondary);
  font-size: 14px;
  font-weight: 500;
  cursor: pointer;
  padding: 8px 0;
  border-bottom: 2px solid transparent;
  transition: all 0.2s;
  white-space: nowrap;
  flex-shrink: 0;
}

@keyframes pulse-bg {
  0% { background-color: var(--bg-panel); color: var(--text-primary); border-color: var(--border-color); box-shadow: 0 0 0px rgba(16, 185, 129, 0); }
  50% { background-color: rgba(16, 185, 129, 0.2); color: #10b981; border-color: #10b981; box-shadow: 0 0 8px rgba(16, 185, 129, 0.4); }
  100% { background-color: var(--bg-panel); color: var(--text-primary); border-color: var(--border-color); box-shadow: 0 0 0px rgba(16, 185, 129, 0); }
}

.scroll-btn-active {
  animation: pulse-bg 2s infinite !important;
}

.tab-btn.active {
  color: var(--accent-sapphire);
  border-bottom-color: var(--accent-sapphire);
}

.tab-content {
  display: none;
  flex: 1;
  padding: 32px;
}

.tab-content.active {
  display: flex;
  flex-direction: column;
}

/* Clustering Interface */
.cluster-controls {
  background-color: var(--bg-panel);
  padding: 24px;
  border-radius: 8px;
  margin-bottom: 24px;
  border: 1px solid var(--border-color);
}

.cluster-controls h3 {
  font-size: 16px;
  margin-bottom: 16px;
}

.cluster-input-group {
  display: flex;
  flex-direction: column;
  gap: 16px;
  align-items: flex-start;
}

.cluster-controls-top, .cluster-controls-bottom {
  display: flex;
  gap: 16px;
  align-items: center;
  width: 100%;
  flex-wrap: wrap;
}

.tag-input-container {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
  border: 1px solid var(--border-color);
  background-color: var(--bg-dark);
  padding: 8px;
  border-radius: 6px;
  flex: 1;
}

.tag {
  background-color: var(--bg-hover);
  color: var(--text-primary);
  padding: 4px 10px;
  border-radius: 16px;
  font-size: 13px;
  display: flex;
  align-items: center;
  gap: 6px;
}

.tag .remove-tag {
  cursor: pointer;
  color: var(--text-secondary);
  font-weight: bold;
}

.tag .remove-tag:hover {
  color: #ef4444;
}

#categoryTagInput {
  border: none;
  background: transparent;
  color: var(--text-primary);
  flex: 1;
  min-width: 250px;
  outline: none;
  padding: 4px;
  font-size: 13px;
}

.secondary-btn {
  background: transparent;
  color: var(--text-secondary);
  border: 1px solid var(--border-color);
  padding: 6px 12px;
  border-radius: 6px;
  font-size: 12px;
  cursor: pointer;
  transition: all 0.2s;
}

.secondary-btn:hover {
  color: var(--text-primary);
  border-color: var(--text-secondary);
}

.radio-group {
  display: flex;
  gap: 16px;
}

.radio-group label {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  cursor: pointer;
}

/* Clustering Results Board */
.cluster-board {
  display: flex;
  gap: 24px;
  overflow-x: auto;
  overflow-y: auto;
  max-height: calc(100vh - 200px);
  padding-bottom: 24px;
  flex: 1;
}

.cluster-column {
  min-width: 320px;
  width: 320px;
  background-color: var(--bg-panel);
  border-radius: 8px;
  display: flex;
  flex-direction: column;
  border: 1px solid var(--border-color);
  max-height: 100%;
}

.cluster-header {
  padding: 16px;
  border-bottom: 1px solid var(--border-color);
  font-weight: 600;
  font-size: 14px;
  display: flex;
  justify-content: space-between;
}

.cluster-items {
  padding: 16px;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.item-card {
  background-color: var(--bg-dark);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  padding: 16px;
  cursor: pointer;
  transition: transform 0.2s, border-color 0.2s;
}

.item-card:hover {
  transform: translateY(-2px);
  border-color: var(--accent-sapphire);
}

.item-text {
  font-size: 13px;
  margin-bottom: 12px;
  color: var(--text-primary);
}

.item-meta {
  font-size: 11px;
  color: var(--text-secondary);
  display: flex;
  justify-content: space-between;
}

/* Data Grid (All Papers) */
.data-grid {
  width: 100%;
  border-collapse: collapse;
}

.data-grid th, .data-grid td {
  padding: 12px 16px;
  text-align: left;
  border-bottom: 1px solid var(--border-color);
  font-size: 13px;
}

.data-grid th {
  font-weight: 600;
  color: var(--text-secondary);
  position: sticky;
  top: 0;
  background-color: var(--bg-dark);
}

.data-grid tr {
  cursor: pointer;
  transition: background-color 0.2s;
}

.data-grid tr:hover {
  background-color: var(--bg-hover);
}

/* Modal */
.modal-overlay {
  position: fixed;
  top: 0; left: 0; right: 0; bottom: 0;
  background-color: rgba(0, 0, 0, 0.7);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s;
  backdrop-filter: blur(4px);
}

.modal-overlay.active {
  opacity: 1;
  pointer-events: auto;
}

.modal-content {
  background-color: var(--bg-panel);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  width: 800px;
  max-width: 90vw;
  max-height: 90vh;
  display: flex;
  flex-direction: column;
  transform: translateY(20px);
  transition: transform 0.3s;
}

.modal-overlay.active .modal-content {
  transform: translateY(0);
}

.modal-header {
  padding: 24px;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
}

.modal-title {
  font-size: 18px;
  font-weight: 600;
  color: var(--accent-sapphire);
  margin-bottom: 8px;
}

.modal-authors {
  font-size: 13px;
  color: var(--text-secondary);
}

.close-btn {
  background: none;
  border: none;
  color: var(--text-secondary);
  font-size: 24px;
  cursor: pointer;
}

.close-btn:hover {
  color: var(--text-primary);
}

.modal-body {
  padding: 24px;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.paper-links a {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--accent-sapphire);
  text-decoration: none;
  font-size: 13px;
  font-weight: 500;
  margin-right: 16px;
}

.paper-links a:hover {
  text-decoration: underline;
}

.section-title {
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 12px;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.modal-list {
  list-style-type: none;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.modal-list li {
  background-color: var(--bg-dark);
  padding: 12px;
  border-radius: 6px;
  border-left: 3px solid var(--accent-sapphire);
  font-size: 13px;
}

/* Semantic Search Results */
#searchResults {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-top: 24px;
}

.search-result-card {
  background-color: var(--bg-dark);
  border: 1px solid var(--border-color);
  padding: 12px;
  border-radius: 6px;
  cursor: pointer;
  transition: border-color 0.2s;
}

.search-result-card:hover {
  border-color: var(--accent-sapphire);
}

.search-result-title {
  font-size: 13px;
  font-weight: 600;
  margin-bottom: 6px;
}

.search-result-meta {
  font-size: 11px;
  color: var(--text-secondary);
}

/* Loader */
.loader {
  display: none;
  border: 3px solid var(--border-color);
  border-top: 3px solid var(--accent-sapphire);
  border-radius: 50%;
  width: 24px;
  height: 24px;
  animation: spin 1s linear infinite;
  margin-left: 16px;
}

@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

/* Mobile Hero and General Responsiveness */
.hero-box {
  background-color: var(--bg-panel); 
  padding: 40px; 
  border-radius: 12px; 
  border: 1px solid var(--border-color); 
  text-align: center; 
  margin-bottom: 24px;
}
.hero-title {
  font-size: 2.5rem; 
  margin-bottom: 16px; 
  color: var(--text-primary);
}
.hero-subtitle {
  font-size: 1.25rem; 
  color: var(--text-secondary); 
  max-width: 900px; 
  margin: 0 auto 32px auto; 
  line-height: 1.6;
}
.hero-grid {
  display: grid; 
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); 
  gap: 16px; 
  text-align: left; 
  max-width: 1000px; 
  margin: 0 auto;
}
.hero-card {
  background: var(--bg-dark); 
  padding: 20px; 
  border-radius: 8px; 
  border: 1px solid var(--border-color);
}
.table-responsive {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  width: 100%;
}
.scroll-hint {
  display: none;
  color: var(--text-secondary);
  font-size: 12px;
  text-align: right;
  margin-bottom: 8px;
  font-style: italic;
}

@media (max-width: 768px) {
  .hero-box {
    padding: 20px;
  }
  .hero-title {
    font-size: 1.75rem;
  }
  .hero-subtitle {
    font-size: 1rem;
    margin-bottom: 20px;
  }
  .hero-card {
    padding: 16px;
  }
  .scroll-hint.mobile-only {
    display: block;
  }
}