/* === DESIGN TOKENS === */
:root {
  /* Type Scale */
  --text-xs:   clamp(0.75rem,  0.7rem  + 0.25vw, 0.875rem);
  --text-sm:   clamp(0.875rem, 0.8rem  + 0.35vw, 1rem);
  --text-base: clamp(1rem,     0.95rem + 0.25vw, 1.125rem);
  --text-lg:   clamp(1.125rem, 1rem    + 0.75vw, 1.5rem);
  --text-xl:   clamp(1.5rem,   1.2rem  + 1.25vw, 2.25rem);
  --text-2xl:  clamp(2rem,     1.2rem  + 2.5vw,  3.5rem);

  /* Spacing */
  --space-1:  0.25rem;
  --space-2:  0.5rem;
  --space-3:  0.75rem;
  --space-4:  1rem;
  --space-5:  1.25rem;
  --space-6:  1.5rem;
  --space-8:  2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;
  --space-32: 8rem;

  /* Fonts */
  --font-display: 'General Sans', 'Helvetica Neue', sans-serif;
  --font-body: 'Satoshi', 'Inter', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  /* Radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-full: 9999px;

  /* Transitions */
  --transition-interactive: 180ms cubic-bezier(0.16, 1, 0.3, 1);

  /* Content widths */
  --content-narrow: 640px;
  --content-default: 960px;
  --content-wide: 1200px;
}

/* === LIGHT MODE (Research-focused: cool slate + teal accent) === */
:root, [data-theme="light"] {
  --color-bg:             #f5f7fa;
  --color-surface:        #ffffff;
  --color-surface-2:      #f9fafb;
  --color-surface-offset: #eef1f5;
  --color-surface-dynamic: #e2e7ed;
  --color-divider:        #d5dbe3;
  --color-border:         #c8d0da;

  --color-text:           #1a1f2e;
  --color-text-muted:     #64748b;
  --color-text-faint:     #94a3b8;
  --color-text-inverse:   #f8fafc;

  /* Teal accent — academic/data feel */
  --color-primary:        #0f766e;
  --color-primary-hover:  #0d6963;
  --color-primary-active: #085f56;
  --color-primary-light:  #ccfbf1;
  --color-primary-highlight: #d1e7e5;

  --color-success:        #16a34a;
  --color-warning:        #ca8a04;
  --color-error:          #dc2626;

  --shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.05);
  --shadow-md: 0 4px 12px rgba(15, 23, 42, 0.08);
  --shadow-lg: 0 12px 32px rgba(15, 23, 42, 0.12);
}

/* === DARK MODE === */
[data-theme="dark"] {
  --color-bg:             #0f1117;
  --color-surface:        #1a1d27;
  --color-surface-2:      #1f2231;
  --color-surface-offset: #161925;
  --color-surface-dynamic: #252937;
  --color-divider:        #2a2e3d;
  --color-border:         #353a4d;

  --color-text:           #e2e8f0;
  --color-text-muted:     #94a3b8;
  --color-text-faint:     #64748b;
  --color-text-inverse:   #1a1f2e;

  --color-primary:        #5eead4;
  --color-primary-hover:  #2dd4bf;
  --color-primary-active: #14b8a6;
  --color-primary-light:  rgba(94, 234, 212, 0.1);
  --color-primary-highlight: #1a3a36;

  --color-success:        #4ade80;
  --color-warning:        #fbbf24;
  --color-error:          #f87171;

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 12px 32px rgba(0, 0, 0, 0.5);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) {
    --color-bg:             #0f1117;
    --color-surface:        #1a1d27;
    --color-surface-2:      #1f2231;
    --color-surface-offset: #161925;
    --color-surface-dynamic: #252937;
    --color-divider:        #2a2e3d;
    --color-border:         #353a4d;
    --color-text:           #e2e8f0;
    --color-text-muted:     #94a3b8;
    --color-text-faint:     #64748b;
    --color-text-inverse:   #1a1f2e;
    --color-primary:        #5eead4;
    --color-primary-hover:  #2dd4bf;
    --color-primary-active: #14b8a6;
    --color-primary-light:  rgba(94, 234, 212, 0.1);
    --color-primary-highlight: #1a3a36;
    --color-success:        #4ade80;
    --color-warning:        #fbbf24;
    --color-error:          #f87171;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 12px 32px rgba(0, 0, 0, 0.5);
  }
}

/* === LAYOUT === */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: color-mix(in srgb, var(--color-bg) 90%, transparent);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-divider);
  padding: var(--space-4) var(--space-6);
}

.header-inner {
  max-width: var(--content-wide);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  text-decoration: none;
  color: var(--color-text);
}

.logo svg {
  width: 32px;
  height: 32px;
  flex-shrink: 0;
}

.logo-text {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: var(--text-sm);
  letter-spacing: -0.01em;
  line-height: 1.2;
}

.logo-text span {
  display: block;
  font-size: var(--text-xs);
  font-weight: 400;
  color: var(--color-text-muted);
  font-family: var(--font-body);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-md);
  color: var(--color-text-muted);
}
.theme-toggle:hover {
  background: var(--color-surface-offset);
  color: var(--color-text);
}

.gh-link {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  text-decoration: none;
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
}
.gh-link:hover {
  background: var(--color-surface-offset);
  color: var(--color-text);
  border-color: var(--color-text-faint);
}
.gh-link svg { width: 16px; height: 16px; }

/* === HERO === */
.hero {
  padding: clamp(var(--space-12), 6vw, var(--space-20)) var(--space-6);
  text-align: center;
}

.hero-inner {
  max-width: var(--content-default);
  margin: 0 auto;
}

.hero h1 {
  font-family: var(--font-display);
  font-size: var(--text-2xl);
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--color-text);
  margin-bottom: var(--space-4);
}

.hero-subtitle {
  font-size: var(--text-base);
  color: var(--color-text-muted);
  max-width: 56ch;
  margin: 0 auto var(--space-8);
}

.hero-stats {
  display: flex;
  justify-content: center;
  gap: var(--space-8);
  flex-wrap: wrap;
}

.stat {
  text-align: center;
}

.stat-value {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: 700;
  color: var(--color-primary);
  font-variant-numeric: tabular-nums;
}

.stat-label {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* === FILTERS === */
.filters-section {
  padding: 0 var(--space-6) var(--space-8);
}

.filters-inner {
  max-width: var(--content-wide);
  margin: 0 auto;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  box-shadow: var(--shadow-sm);
}

.filters-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-5);
  flex-wrap: wrap;
  gap: var(--space-3);
}

.filters-header h2 {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: 600;
}

.filter-reset {
  font-size: var(--text-xs);
  color: var(--color-primary);
  cursor: pointer;
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-sm);
}
.filter-reset:hover {
  background: var(--color-primary-light);
}

.filter-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-5);
}

@media (max-width: 640px) {
  .filter-grid {
    grid-template-columns: 1fr;
  }
}

.filter-group label {
  display: block;
  font-size: var(--text-xs);
  font-weight: 500;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-2);
}

.filter-group select,
.filter-group input[type="text"] {
  width: 100%;
  padding: var(--space-3) var(--space-4);
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  font-size: var(--text-sm);
  color: var(--color-text);
  appearance: none;
  -webkit-appearance: none;
}

.filter-group select {
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='%2364748b' stroke-width='2'%3E%3Cpath d='M6 9l6 6 6-6'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right var(--space-3) center;
  padding-right: var(--space-10);
}

.filter-group input:focus,
.filter-group select:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px var(--color-primary-light);
}

.filter-group input::placeholder {
  color: var(--color-text-faint);
}

.hashtag-suggestions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1);
  margin-top: var(--space-2);
}

.hashtag-chip {
  font-size: var(--text-xs);
  padding: 2px var(--space-2);
  border-radius: var(--radius-full);
  background: var(--color-surface-offset);
  color: var(--color-text-muted);
  cursor: pointer;
  border: 1px solid transparent;
}
.hashtag-chip:hover {
  background: var(--color-primary-light);
  color: var(--color-primary);
  border-color: var(--color-primary);
}
.hashtag-chip.active {
  background: var(--color-primary);
  color: var(--color-text-inverse);
}

/* === RESULTS === */
.results-section {
  padding: 0 var(--space-6) var(--space-12);
}

.results-inner {
  max-width: var(--content-wide);
  margin: 0 auto;
}

.results-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-4);
  flex-wrap: wrap;
  gap: var(--space-3);
}

.results-count {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}
.results-count strong {
  color: var(--color-text);
  font-variant-numeric: tabular-nums;
}

.results-export {
  font-size: var(--text-xs);
  color: var(--color-primary);
  padding: var(--space-2) var(--space-4);
  border: 1px solid var(--color-primary);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  gap: var(--space-2);
}
.results-export:hover {
  background: var(--color-primary);
  color: var(--color-text-inverse);
}
.results-export svg { width: 14px; height: 14px; }

/* Table */
.table-wrap {
  overflow-x: auto;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  background: var(--color-surface);
  box-shadow: var(--shadow-sm);
}

.data-table {
  width: 100%;
  font-size: var(--text-sm);
}

.data-table thead {
  background: var(--color-surface-offset);
  position: sticky;
  top: 0;
  z-index: 2;
}

.data-table th {
  text-align: left;
  padding: var(--space-3) var(--space-4);
  font-size: var(--text-xs);
  font-weight: 600;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  border-bottom: 1px solid var(--color-divider);
  white-space: nowrap;
  cursor: pointer;
  user-select: none;
}
.data-table th:hover {
  color: var(--color-text);
}
.data-table th .sort-icon {
  display: inline-block;
  margin-left: var(--space-1);
  opacity: 0.4;
}
.data-table th.sorted .sort-icon {
  opacity: 1;
  color: var(--color-primary);
}

.data-table td {
  padding: var(--space-3) var(--space-4);
  border-bottom: 1px solid var(--color-divider);
  vertical-align: top;
}

.data-table tbody tr:hover {
  background: var(--color-surface-offset);
}

.data-table tbody tr:last-child td {
  border-bottom: none;
}

.cell-id {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  white-space: nowrap;
}

.cell-date {
  white-space: nowrap;
  font-variant-numeric: tabular-nums;
  color: var(--color-text-muted);
  font-size: var(--text-xs);
}

.cell-desc {
  max-width: 360px;
  line-height: 1.5;
  color: var(--color-text);
}

.cell-hashtags {
  max-width: 280px;
}

.cell-hashtags .tag {
  display: inline-block;
  font-size: 11px;
  padding: 1px var(--space-2);
  border-radius: var(--radius-full);
  background: var(--color-surface-offset);
  color: var(--color-text-muted);
  margin: 1px;
  white-space: nowrap;
}
.cell-hashtags .tag.highlight {
  background: var(--color-primary-light);
  color: var(--color-primary);
  font-weight: 500;
}

/* Pagination */
.pagination {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  margin-top: var(--space-6);
}

.page-btn {
  min-width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  font-variant-numeric: tabular-nums;
  border: 1px solid transparent;
}
.page-btn:hover {
  background: var(--color-surface-offset);
  color: var(--color-text);
}
.page-btn.active {
  background: var(--color-primary);
  color: var(--color-text-inverse);
  font-weight: 600;
}
.page-btn:disabled {
  opacity: 0.3;
  cursor: default;
}
.page-btn svg { width: 16px; height: 16px; }

.page-info {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  padding: 0 var(--space-3);
}

/* === EMPTY / LOADING STATES === */
@keyframes shimmer { 0%{background-position:-200% 0} 100%{background-position:200% 0} }

.loading-state {
  padding: var(--space-16) var(--space-8);
  text-align: center;
}

.loading-spinner {
  width: 32px;
  height: 32px;
  border: 3px solid var(--color-border);
  border-top-color: var(--color-primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  margin: 0 auto var(--space-4);
}

@keyframes spin { to { transform: rotate(360deg); } }

.loading-state p {
  color: var(--color-text-muted);
  font-size: var(--text-sm);
}

.empty-state {
  padding: var(--space-16) var(--space-8);
  text-align: center;
}

.empty-state svg {
  width: 48px;
  height: 48px;
  color: var(--color-text-faint);
  margin: 0 auto var(--space-4);
}

.empty-state h3 {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: 600;
  margin-bottom: var(--space-2);
}

.empty-state p {
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  max-width: 36ch;
  margin: 0 auto;
}

/* === FOOTER === */
.site-footer {
  border-top: 1px solid var(--color-divider);
  padding: var(--space-8) var(--space-6);
  text-align: center;
}

.footer-inner {
  max-width: var(--content-wide);
  margin: 0 auto;
}

.footer-inner p {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  margin: 0 auto;
  max-width: none;
}

.footer-inner a {
  color: var(--color-text-muted);
  text-decoration: none;
}
.footer-inner a:hover {
  color: var(--color-primary);
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: var(--space-6);
  margin-bottom: var(--space-3);
  flex-wrap: wrap;
}

/* === ABOUT SECTION === */
.about-section {
  padding: 0 var(--space-6) var(--space-12);
}

.about-inner {
  max-width: var(--content-wide);
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-6);
}

@media (max-width: 768px) {
  .about-inner {
    grid-template-columns: 1fr;
  }
}

.about-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
}

.about-card h3 {
  font-family: var(--font-display);
  font-size: var(--text-base);
  font-weight: 600;
  margin-bottom: var(--space-3);
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.about-card h3 svg {
  width: 18px;
  height: 18px;
  color: var(--color-primary);
}

.about-card p,
.about-card ul {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  line-height: 1.7;
}

.about-card ul {
  list-style: none;
  padding: 0;
}

.about-card li {
  padding: var(--space-1) 0;
}

.about-card li::before {
  content: '→ ';
  color: var(--color-primary);
}

/* === CHART SECTION === */
.chart-section {
  padding: 0 var(--space-6) var(--space-10);
}

.chart-inner {
  max-width: var(--content-wide);
  margin: 0 auto;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  box-shadow: var(--shadow-sm);
}

.chart-header {
  margin-bottom: var(--space-4);
}

.chart-header h2 {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: 600;
}

.chart-header p {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  margin-top: var(--space-1);
}

#timeline-chart {
  width: 100%;
}

.chart-container {
  position: relative;
  height: 220px;
  width: 100%;
}

/* === RESPONSIVE === */
@media (max-width: 480px) {
  .site-header { padding: var(--space-3) var(--space-4); }
  .hero { padding: var(--space-8) var(--space-4); }
  .filters-section,
  .results-section,
  .about-section,
  .chart-section { padding-left: var(--space-4); padding-right: var(--space-4); }
  .filters-inner { padding: var(--space-4); }
  .hero-stats { gap: var(--space-6); }
  .data-table th,
  .data-table td { padding: var(--space-2) var(--space-3); }
  .logo-text { font-size: var(--text-xs); }
}