frontend/src/index.css

/* ── Design Tokens ──────────────────────────────────────────────────────── */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&family=JetBrains+Mono:wght@400;500&display=swap');

:root {
  --bg-base:        #080b14;
  --bg-surface:     #0d1120;
  --bg-card:        #111827;
  --bg-glass:       rgba(17, 24, 39, 0.72);
  --bg-input:       #161f32;
  --border:         rgba(99, 130, 255, 0.18);
  --border-hover:   rgba(99, 130, 255, 0.45);

  --accent:         #6366f1;          /* indigo */
  --accent-glow:    rgba(99, 102, 241, 0.35);
  --accent-2:       #8b5cf6;          /* violet */
  --accent-3:       #06b6d4;          /* cyan */
  --gold:           #f59e0b;

  --text-primary:   #f0f4ff;
  --text-secondary: #8b9ec7;
  --text-muted:     #4b5a7a;

  --heat-0:  #0d1120;
  --heat-100: #f59e0b;

  --radius-sm:  6px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-xl: 28px;

  --shadow-card: 0 4px 32px rgba(0,0,0,0.45), 0 1px 3px rgba(0,0,0,0.3);
  --shadow-glow: 0 0 24px var(--accent-glow);

  --transition: 0.22s cubic-bezier(0.4,0,0.2,1);
}

/* ── Reset ────────────────────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }

body {
  font-family: 'Inter', system-ui, sans-serif;
  background: var(--bg-base);
  color: var(--text-primary);
  min-height: 100vh;
  overflow-x: hidden;
  /* subtle grid pattern */
  background-image:
    linear-gradient(rgba(99,102,241,0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(99,102,241,0.03) 1px, transparent 1px);
  background-size: 32px 32px;
}

/* ── Scrollbar ────────────────────────────────────────────────────────────── */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 99px; }
::-webkit-scrollbar-thumb:hover { background: var(--border-hover); }

/* ── Layout ───────────────────────────────────────────────────────────────── */
#root { min-height: 100vh; display: flex; flex-direction: column; }

.app-shell {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  max-width: 1440px;
  margin: 0 auto;
  width: 100%;
  padding: 0 24px 48px;
}

/* ── Header ───────────────────────────────────────────────────────────────── */
.app-header {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 28px 0 20px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 28px;
}

.app-logo {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  box-shadow: var(--shadow-glow);
  flex-shrink: 0;
}

.app-title {
  font-size: 22px;
  font-weight: 700;
  background: linear-gradient(135deg, #fff 40%, var(--accent-3));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.app-subtitle {
  font-size: 13px;
  color: var(--text-secondary);
  margin-top: 2px;
  font-weight: 400;
}

.header-badge {
  margin-left: auto;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent-3);
  background: rgba(6,182,212,0.12);
  border: 1px solid rgba(6,182,212,0.25);
  padding: 4px 12px;
  border-radius: 99px;
}

/* ── Main Grid ────────────────────────────────────────────────────────────── */
.main-grid {
  display: grid;
  grid-template-columns: 340px 1fr;
  gap: 20px;
  flex: 1;
}

@media (max-width: 900px) {
  .main-grid { grid-template-columns: 1fr; }
}

/* ── Cards / Glass ────────────────────────────────────────────────────────── */
.card {
  background: var(--bg-glass);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 24px;
  box-shadow: var(--shadow-card);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
}

.card-title {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-secondary);
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.card-title::before {
  content: '';
  display: inline-block;
  width: 3px;
  height: 14px;
  border-radius: 2px;
  background: linear-gradient(var(--accent), var(--accent-2));
}

/* ── Left Panel ───────────────────────────────────────────────────────────── */
.left-panel {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

/* ── Text Input ───────────────────────────────────────────────────────────── */
.text-input-wrap textarea {
  width: 100%;
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-family: 'Inter', sans-serif;
  font-size: 14px;
  line-height: 1.7;
  padding: 14px 16px;
  resize: vertical;
  min-height: 120px;
  outline: none;
  transition: border-color var(--transition), box-shadow var(--transition);
}

.text-input-wrap textarea:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-glow);
}

.text-input-wrap textarea::placeholder { color: var(--text-muted); }

.char-count {
  text-align: right;
  font-size: 11px;
  color: var(--text-muted);
  margin-top: 6px;
  font-variant-numeric: tabular-nums;
}

/* ── Analyze Button ───────────────────────────────────────────────────────── */
.btn-analyze {
  width: 100%;
  padding: 13px;
  border: none;
  border-radius: var(--radius-md);
  font-family: 'Inter', sans-serif;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  background: linear-gradient(135deg, var(--accent) 0%, var(--accent-2) 100%);
  color: #fff;
  letter-spacing: 0.02em;
  transition: opacity var(--transition), transform var(--transition), box-shadow var(--transition);
  box-shadow: 0 4px 16px var(--accent-glow);
  position: relative;
  overflow: hidden;
}

.btn-analyze::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(rgba(255,255,255,0.1), transparent);
  opacity: 0;
  transition: opacity var(--transition);
}

.btn-analyze:hover:not(:disabled)::after { opacity: 1; }
.btn-analyze:hover:not(:disabled) { transform: translateY(-1px); box-shadow: 0 6px 24px var(--accent-glow); }
.btn-analyze:active:not(:disabled) { transform: translateY(0); }
.btn-analyze:disabled { opacity: 0.5; cursor: not-allowed; }

/* ── Model Selector ───────────────────────────────────────────────────────── */
.model-cards {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.model-card {
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 12px 14px;
  cursor: pointer;
  transition: border-color var(--transition), background var(--transition), transform var(--transition);
  background: var(--bg-input);
  position: relative;
  overflow: hidden;
}

.model-card.selected {
  border-color: var(--accent);
  background: rgba(99,102,241,0.08);
  box-shadow: 0 0 0 1px var(--accent);
}

.model-card:hover:not(.selected) { border-color: var(--border-hover); transform: translateX(2px); }

.model-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 4px;
}

.model-card-label {
  font-size: 13px;
  font-weight: 600;
  color: var(--text-primary);
}

.model-type-badge {
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  padding: 2px 8px;
  border-radius: 99px;
}

.model-type-badge.encoder {
  background: rgba(99,102,241,0.15);
  color: #818cf8;
  border: 1px solid rgba(99,102,241,0.3);
}

.model-type-badge.decoder {
  background: rgba(6,182,212,0.12);
  color: #22d3ee;
  border: 1px solid rgba(6,182,212,0.25);
}

.model-card-desc {
  font-size: 11px;
  color: var(--text-muted);
}

.model-card.selected .model-card-label { color: #a5b4fc; }

/* ── Layer/Head Controls ──────────────────────────────────────────────────── */
.lhc-sliders { display: flex; flex-direction: column; gap: 18px; }

.slider-group label {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 12px;
  color: var(--text-secondary);
  margin-bottom: 10px;
}

.slider-group label span {
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  color: var(--accent-3);
  background: rgba(6,182,212,0.1);
  padding: 1px 8px;
  border-radius: 4px;
}

input[type=range] {
  -webkit-appearance: none;
  width: 100%;
  height: 4px;
  border-radius: 99px;
  background: var(--bg-input);
  outline: none;
  cursor: pointer;
}

input[type=range]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  box-shadow: 0 0 8px var(--accent-glow);
  cursor: pointer;
  transition: transform var(--transition);
}

input[type=range]::-webkit-slider-thumb:hover { transform: scale(1.2); }

.head-grid {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 6px;
  margin-top: 8px;
}

.head-btn {
  aspect-ratio: 1;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--bg-input);
  color: var(--text-secondary);
  font-size: 11px;
  font-family: 'JetBrains Mono', monospace;
  cursor: pointer;
  transition: all var(--transition);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0;
}

.head-btn:hover { border-color: var(--border-hover); color: var(--text-primary); }
.head-btn.active {
  border-color: var(--accent);
  background: rgba(99,102,241,0.2);
  color: #a5b4fc;
  box-shadow: 0 0 8px var(--accent-glow);
}

.avg-toggle {
  width: 100%;
  padding: 9px;
  margin-top: 10px;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  background: transparent;
  color: var(--text-secondary);
  font-family: 'Inter', sans-serif;
  font-size: 12px;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition);
}

.avg-toggle:hover { border-color: var(--accent-3); color: var(--accent-3); }
.avg-toggle.active {
  background: rgba(6,182,212,0.1);
  border-color: var(--accent-3);
  color: var(--accent-3);
}

/* ── Right Panel ──────────────────────────────────────────────────────────── */
.right-panel {
  display: flex;
  flex-direction: column;
  gap: 16px;
  min-width: 0;
}

/* ── Token Row ────────────────────────────────────────────────────────────── */
.token-row-wrap {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  align-items: center;
  min-height: 40px;
}

.token-chip {
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  padding: 5px 10px;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  cursor: pointer;
  transition: all var(--transition);
  white-space: nowrap;
  user-select: none;
  position: relative;
}

.token-chip:hover { transform: translateY(-2px); }
.token-chip.selected { border-color: var(--accent); box-shadow: 0 0 8px var(--accent-glow); }

/* ── Heatmap Panel ────────────────────────────────────────────────────────── */
.heatmap-container {
  flex: 1;
  min-height: 420px;
  position: relative;
}

.heatmap-container .plotly-container {
  width: 100% !important;
  height: 100% !important;
  min-height: 420px;
}

/* ── Info Panel ───────────────────────────────────────────────────────────── */
.info-panel {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 10px;
}

.info-stat {
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 12px 16px;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.info-stat-label {
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-muted);
}

.info-stat-value {
  font-family: 'JetBrains Mono', monospace;
  font-size: 18px;
  font-weight: 700;
  color: var(--text-primary);
}

.info-stat-value.accent { color: var(--accent-3); }

/* ── Loading State ────────────────────────────────────────────────────────── */
.loading-overlay {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 16px;
  padding: 60px 20px;
  color: var(--text-secondary);
  font-size: 14px;
}

.spinner {
  width: 40px;
  height: 40px;
  border: 3px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

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

.loading-model-name {
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  color: var(--accent-3);
}

/* ── Empty State ──────────────────────────────────────────────────────────── */
.empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 12px;
  padding: 60px 20px;
  color: var(--text-muted);
  text-align: center;
}

.empty-icon {
  font-size: 48px;
  opacity: 0.4;
  animation: float 3s ease-in-out infinite;
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50%       { transform: translateY(-6px); }
}

.empty-state h3 { font-size: 16px; color: var(--text-secondary); font-weight: 600; }
.empty-state p  { font-size: 13px; line-height: 1.6; max-width: 280px; }

/* ── Error ────────────────────────────────────────────────────────────────── */
.error-banner {
  background: rgba(239,68,68,0.1);
  border: 1px solid rgba(239,68,68,0.3);
  border-radius: var(--radius-md);
  padding: 12px 16px;
  font-size: 13px;
  color: #fca5a5;
  display: flex;
  align-items: flex-start;
  gap: 8px;
}

/* ── Subtle animations ─────────────────────────────────────────────────────── */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to   { opacity: 1; transform: translateY(0); }
}

.fade-in { animation: fadeIn 0.35s ease forwards; }

/* ── Plotly dark overrides ─────────────────────────────────────────────────── */
.js-plotly-plot .plotly .modebar { background: transparent !important; }
.js-plotly-plot .plotly .modebar-btn path { fill: var(--text-muted) !important; }
.js-plotly-plot .plotly .modebar-btn:hover path { fill: var(--text-primary) !important; }