:root {
    --fv-bg-dark: #0a0f1a;
    --fv-bg-card: #0f1629;
    --fv-bg-elevated: #141d32;
    --fv-border: rgba(56, 189, 248, 0.15);
    --fv-border-active: rgba(52, 211, 153, 0.6);
    --fv-accent-primary: #34d399;
    --fv-accent-secondary: #38bdf8;
    --fv-accent-warning: #fbbf24;
    --fv-accent-danger: #f87171;
    --fv-text-primary: #f1f5f9;
    --fv-text-secondary: #94a3b8;
    --fv-text-muted: #64748b;
    --fv-glow-green: 0 0 40px rgba(52, 211, 153, 0.15);
    --fv-glow-blue: 0 0 60px rgba(56, 189, 248, 0.1);
    --fv-chlorophyll: #00FF9D;
    --font-display: 'Playfair Display', Georgia, serif;
    --font-body: 'DM Sans', system-ui, sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
  }

  /* LIGHT THEME OVERRIDES */
  :root[data-theme="light"] {
    --fv-bg-dark: #f3f4f6;
    --fv-bg-card: rgba(255, 255, 255, 0.88);
    --fv-bg-elevated: rgba(255, 255, 255, 0.96);
    --fv-border: rgba(148, 163, 184, 0.5);
    --fv-border-active: rgba(59, 130, 246, 0.8);
    --fv-text-primary: #020617;
    --fv-text-secondary: #4b5563;
    --fv-text-muted: #6b7280;
    --fv-glow-green: 0 0 30px rgba(34, 197, 94, 0.22);
    --fv-glow-blue: 0 0 40px rgba(37, 99, 235, 0.18);
    --fv-chlorophyll: #059669;
  }

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

  body {
    font-family: var(--font-body);
    background: var(--fv-bg-dark);
    color: var(--fv-text-primary);
    line-height: 1.6;
    min-height: 100vh;
    transition: background 0.35s ease, color 0.35s ease;
  }

  /* ATMOSPHERIC BACKGROUND */
  .fv-atmosphere {
    position: fixed;
    inset: 0;
    pointer-events: none;
    z-index: 0;
    overflow: hidden;
  }

  .fv-atmosphere::before {
    content: "";
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background:
      radial-gradient(ellipse 80% 50% at 20% 0%, rgba(52, 211, 153, 0.08) 0%, transparent 50%),
      radial-gradient(ellipse 60% 40% at 80% 20%, rgba(56, 189, 248, 0.06) 0%, transparent 45%),
      radial-gradient(ellipse 50% 30% at 50% 100%, rgba(139, 92, 246, 0.04) 0%, transparent 40%);
    animation: atmosphereShift 30s ease-in-out infinite alternate;
    opacity: 0.9;
  }

  :root[data-theme="light"] .fv-atmosphere::before {
    background:
      radial-gradient(ellipse 80% 50% at 20% 0%, rgba(74, 222, 128, 0.16) 0%, transparent 50%),
      radial-gradient(ellipse 60% 40% at 80% 20%, rgba(59, 130, 246, 0.12) 0%, transparent 45%),
      radial-gradient(ellipse 50% 30% at 50% 100%, rgba(129, 140, 248, 0.09) 0%, transparent 40%);
  }

  @keyframes atmosphereShift {
    0% { transform: translate(0, 0) rotate(0deg); }
    100% { transform: translate(-2%, 2%) rotate(1deg); }
  }

  /* MAIN WRAPPER
     Note: top padding is reduced because the hero is now in a collapsible intro
     above the wrapper; the workspace nav + tool header provide visual framing. */
  .fv-wrapper {
    position: relative;
    z-index: 1;
    padding: 1.5rem 1.5rem 3rem;
    max-width: 1440px;
    margin: 0 auto;
  }

  /* THEME TOGGLE */
  .fv-theme-toggle {
    display: flex;
    justify-content: flex-end;
    margin-bottom: 1rem;
  }

  .fv-theme-toggle-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    padding: 0.35rem 0.9rem;
    border-radius: 999px;
    border: 1px solid var(--fv-border);
    background: rgba(15, 23, 42, 0.9);
    color: var(--fv-text-secondary);
    font-family: var(--font-mono);
    font-size: 0.72rem;
    cursor: pointer;
    backdrop-filter: blur(12px);
    transition: background 0.2s ease, border-color 0.2s ease, transform 0.15s ease;
  }

  :root[data-theme="light"] .fv-theme-toggle-btn {
    background: rgba(255, 255, 255, 0.9);
    color: var(--fv-text-secondary);
  }

  .fv-theme-toggle-btn:hover {
    border-color: var(--fv-accent-primary);
    transform: translateY(-1px);
  }

  .fv-theme-toggle-icon {
    font-size: 0.85rem;
  }

  /* HERO SECTION */
  .fv-hero {
    text-align: center;
    margin-bottom: 4rem;
    animation: fadeInUp 0.8s ease-out;
  }

  @keyframes fadeInUp {
    from { opacity: 0; transform: translateY(20px); }
    to   { opacity: 1; transform: translateY(0); }
  }

  .fv-hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.4rem 1rem;
    background: linear-gradient(135deg, rgba(52, 211, 153, 0.1), rgba(56, 189, 248, 0.08));
    border: 1px solid var(--fv-border);
    border-radius: 50px;
    font-family: var(--font-mono);
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--fv-accent-primary);
    letter-spacing: 0.05em;
    text-transform: uppercase;
    margin-bottom: 1.5rem;
  }

  :root[data-theme="light"] .fv-hero-badge {
    background: linear-gradient(135deg, rgba(34, 197, 94, 0.12), rgba(59, 130, 246, 0.12));
  }

  .fv-hero-badge i { font-size: 0.85rem; }

  .fv-hero-title {
    font-family: var(--font-display);
    font-size: clamp(2rem, 5vw, 3.2rem);
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 1rem;
    background: linear-gradient(135deg, var(--fv-text-primary) 0%, var(--fv-accent-primary) 50%, var(--fv-accent-secondary) 100%);
    background-size: 200% auto;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    animation: gradientShift 8s ease infinite;
  }

  @keyframes gradientShift {
    0%, 100% { background-position: 0% center; }
    50%       { background-position: 100% center; }
  }

  .fv-hero-subtitle {
    max-width: 720px;
    margin: 0 auto;
    font-size: 1.05rem;
    color: var(--fv-text-secondary);
    line-height: 1.8;
  }

  .fv-hero-subtitle strong { color: var(--fv-accent-primary); font-weight: 600; }

  /* DIFFERENTIATORS */
  .fv-diff-section { margin-bottom: 3rem; }

  .fv-diff-header {
    text-align: center;
    margin-bottom: 2rem;
  }

  .fv-diff-title {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
  }

  .fv-diff-subtitle {
    font-size: 0.95rem;
    color: var(--fv-text-muted);
  }

  .fv-diff-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.25rem;
  }

  .fv-diff-card {
    position: relative;
    background: var(--fv-bg-card);
    border: 1px solid var(--fv-border);
    border-radius: 1rem;
    padding: 1.25rem;
    transition: all 0.3s ease;
    overflow: hidden;
  }

  .fv-diff-card::before {
    content: "";
    position: absolute;
    top: 0; left: 0; right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--fv-accent-primary), var(--fv-accent-secondary));
    opacity: 0;
    transition: opacity 0.3s ease;
  }

  .fv-diff-card:hover {
    border-color: var(--fv-border-active);
    transform: translateY(-2px);
    box-shadow: var(--fv-glow-green);
  }

  .fv-diff-card:hover::before { opacity: 1; }

  .fv-diff-card-num {
    position: absolute;
    top: 1rem; right: 1rem;
    font-family: var(--font-mono);
    font-size: 0.7rem;
    color: var(--fv-accent-secondary);
    opacity: 0.7;
  }

  .fv-diff-card-icon {
    width: 40px; height: 40px;
    display: flex; align-items: center; justify-content: center;
    background: linear-gradient(135deg, rgba(52, 211, 153, 0.15), rgba(56, 189, 248, 0.1));
    border-radius: 10px;
    margin-bottom: 0.9rem;
    color: var(--fv-accent-primary);
    font-size: 1.1rem;
  }

  .fv-diff-card-title { font-weight: 600; font-size: 0.95rem; margin-bottom: 0.4rem; }
  .fv-diff-card-text  { font-size: 0.85rem; color: var(--fv-text-secondary); line-height: 1.65; }

  /* ══════════════════════════════════════════════════
     INTERACTIVE PLAYGROUND — THREE COLUMN LAYOUT
     ══════════════════════════════════════════════════ */

  .fv-playground {
    background: var(--fv-bg-card);
    border: 1px solid var(--fv-border);
    border-radius: 1.5rem;
    overflow: hidden;
    box-shadow: var(--fv-glow-blue);
    animation: fadeInUp 0.8s ease-out 0.3s backwards;
  }

  .fv-playground-header {
    padding: 1.25rem 1.75rem;
    border-bottom: 1px solid var(--fv-border);
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    align-items: center;
    gap: 1rem;
    background: linear-gradient(180deg, var(--fv-bg-elevated) 0%, var(--fv-bg-card) 100%);
  }

  .fv-playground-title-group h2 {
    font-family: var(--font-display);
    font-size: 1.35rem;
    font-weight: 600;
    margin-bottom: 0.25rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
  }

  .fv-playground-title-group p { font-size: 0.88rem; color: var(--fv-text-muted); }

  .fv-playground-badges { display: flex; flex-wrap: wrap; gap: 0.5rem; }

  .fv-badge {
    font-family: var(--font-mono);
    font-size: 0.72rem;
    padding: 0.3rem 0.7rem;
    border-radius: 50px;
    border: 1px solid var(--fv-border);
    background: rgba(15, 22, 41, 0.8);
    color: var(--fv-text-secondary);
  }

  :root[data-theme="light"] .fv-badge { background: rgba(255, 255, 255, 0.9); }

  .fv-badge.green {
    border-color: rgba(52, 211, 153, 0.4);
    background: rgba(52, 211, 153, 0.1);
    color: var(--fv-accent-primary);
  }

  /* THREE COLUMN SHELL
     Breakpoints:
       desktop  ≥ 1024px  → three columns
       tablet   640–1023px → two columns (upload | image+knowledge stacked)
       mobile   < 640px   → single column, scrollable
  */
  .fv-playground-shell {
    display: grid;
    grid-template-columns: 340px 1fr 380px;
    min-height: 600px;
    max-height: 820px;
  }

  @media (max-width: 1280px) {
    .fv-playground-shell {
      grid-template-columns: 300px 1fr 320px;
    }
  }

  @media (max-width: 1023px) {
    .fv-playground-shell {
      grid-template-columns: 1fr;
      max-height: none;
    }
  }

  /* ─── COLUMN 1: UPLOAD PANEL ──────────────────────── */

  .upload-panel {
    background: var(--fv-bg-elevated);
    border-right: 1px solid var(--fv-border);
    display: flex;
    flex-direction: column;
    padding: 2rem 1.5rem;
    overflow-y: auto;
    overflow-x: hidden;
    max-height: 820px;
  }

  @media (max-width: 1023px) {
    .upload-panel {
      border-right: none;
      border-bottom: 1px solid var(--fv-border);
      max-height: none;
    }
  }

  .fv-flash-stack {
    position: fixed;
    top: 20px; right: 20px;
    z-index: 9999;
    max-width: 400px;
  }

  .selection-area { display: flex; flex-direction: column; gap: 1.5rem; }

  .welcome-content { text-align: center; padding: 1.5rem 1rem; }

  .welcome-icon {
    font-size: 3rem;
    color: var(--fv-accent-primary);
    margin-bottom: 1rem;
    opacity: 0.85;
  }

  .welcome-content p {
    font-size: 0.9rem;
    color: var(--fv-text-secondary);
    margin-bottom: 0.4rem;
    line-height: 1.7;
  }

  /* Plant Selector
     ─────────────────────────────────────────────────────
     FIX: No country-gate in this flow. The selector is
     always accessible. The disabled state (opacity+pointer-
     events) is kept only as a JS-controlled fallback via
     the :not(.enabled) guard — but the HTML ships with
     .enabled already applied, so it is always interactive.
  */
  .plant-selector {
    background: linear-gradient(135deg, rgba(52, 211, 153, 0.08), rgba(56, 189, 248, 0.05));
    border: 1px solid var(--fv-border);
    border-radius: 0.75rem;
    padding: 1rem;
    /* Default: accessible. JS can still remove .enabled to lock it if needed. */
    opacity: 1;
    pointer-events: all;
    transition: all 0.3s ease;
  }

  /* Keep .enabled rule so JS toggling still works */
  .plant-selector.enabled {
    opacity: 1;
    pointer-events: all;
  }

  .plant-selector-label {
    font-size: 0.88rem;
    font-weight: 600;
    color: var(--fv-accent-primary);
    margin-bottom: 0.75rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
  }

  .plant-options {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 0.65rem;
  }

  .plant-option {
    background: var(--fv-bg-elevated);
    border: 2px solid var(--fv-border);
    padding: 0.75rem;
    border-radius: 0.65rem;
    text-align: center;
    cursor: pointer;
    transition: all 0.2s ease;
    font-size: 0.85rem;
    color: var(--fv-text-secondary);
  }

  .plant-option:hover {
    border-color: var(--fv-accent-primary);
    background: var(--fv-bg-card);
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(52, 211, 153, 0.15);
  }

  .plant-option.selected {
    background: linear-gradient(135deg, var(--fv-accent-primary), #10b981);
    color: #022c22;
    border-color: var(--fv-accent-primary);
    font-weight: 600;
  }

  .plant-option-tag {
    display: inline-block;
    font-size: 0.65rem;
    padding: 1px 5px;
    border-radius: 3px;
    margin-left: 4px;
    vertical-align: middle;
  }

  /* Upload Button */
  .upload-button-container {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
  }

  .upload-btn {
    width: 100%;
    padding: 1rem 1.5rem;
    background: linear-gradient(135deg, var(--fv-accent-primary), #10b981);
    color: #022c22;
    border: none;
    border-radius: 0.75rem;
    font-family: var(--font-body);
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.65rem;
    box-shadow: 0 4px 15px rgba(52, 211, 153, 0.3);
    opacity: 0.5;
    pointer-events: none;
  }

  .upload-btn.enabled {
    opacity: 1;
    pointer-events: all;
  }

  .upload-btn.enabled:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(52, 211, 153, 0.4);
  }

  .upload-btn i { font-size: 1.2rem; }

  /* Camera capture button — ghost teal, mobile-only (hidden ≥1024px) */
  .upload-btn--camera {
    background: transparent;
    color: var(--fv-accent-secondary);
    border: 1.5px solid rgba(56, 189, 248, 0.45);
    box-shadow: 0 4px 15px rgba(56, 189, 248, 0.08);
  }

  .upload-btn--camera.enabled:hover {
    background: rgba(56, 189, 248, 0.08);
    border-color: rgba(56, 189, 248, 0.7);
    box-shadow: 0 6px 20px rgba(56, 189, 248, 0.2);
    transform: translateY(-2px);
  }

  /* Hide camera button on desktop — capture="environment" is a mobile UX */
  @media (min-width: 1024px) {
    .upload-btn--camera { display: none; }
  }

  /* Status Message */
  .status-message {
    padding: 0.85rem 1rem;
    background: rgba(56, 189, 248, 0.08);
    border: 1px solid rgba(56, 189, 248, 0.3);
    border-radius: 0.65rem;
    font-size: 0.82rem;
    color: var(--fv-text-secondary);
    text-align: center;
    min-height: 3rem;
    display: none;
    align-items: center;
    justify-content: center;
  }

  .status-message.active { display: flex; }

  /* ─── COLUMN 2: IMAGE PANEL ───────────────────────── */

  .image-panel {
    display: flex;
    flex-direction: column;
    background: var(--fv-bg-dark);
    border-right: 1px solid var(--fv-border);
    max-height: 820px;
    overflow: hidden;
  }

  @media (max-width: 1023px) {
    .image-panel {
      border-right: none;
      border-bottom: 1px solid var(--fv-border);
      max-height: none;
    }
  }

  .image-display {
    flex: 1;
    background: linear-gradient(135deg, var(--fv-bg-dark), var(--fv-bg-elevated));
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 2rem;
    position: relative;
    min-height: 400px;
    overflow: hidden;
  }

  .image-placeholder {
    text-align: center;
    color: var(--fv-text-muted);
    opacity: 0.7;
  }

  .image-placeholder i {
    font-size: 4rem;
    margin-bottom: 1rem;
    display: block;
    color: var(--fv-accent-secondary);
    opacity: 0.5;
  }

  .uploaded-image {
    max-width: 100%;
    max-height: 100%;
    border-radius: 0.75rem;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
    object-fit: contain;
  }

  /* Grad-CAM Tabs */
  .fv-demo-tabs {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    padding: 1rem 1.5rem;
    border-top: 1px solid var(--fv-border);
    background: var(--fv-bg-card);
  }

  .fv-demo-tab {
    position: relative;
    padding: 0.5rem 0.9rem;
    background: var(--fv-bg-dark);
    border: 1px solid var(--fv-border);
    border-radius: 0.5rem;
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--fv-text-secondary);
    cursor: pointer;
    transition: all 0.25s ease;
    display: flex;
    align-items: center;
    gap: 0.5rem;
  }

  .fv-demo-tab:hover {
    border-color: var(--fv-accent-primary);
    color: var(--fv-text-primary);
  }

  .fv-demo-tab.active {
    background: linear-gradient(135deg, rgba(52, 211, 153, 0.15), rgba(56, 189, 248, 0.1));
    border-color: var(--fv-accent-primary);
    color: var(--fv-text-primary);
  }

  .fv-demo-tab-rank {
    width: 20px; height: 20px;
    display: flex; align-items: center; justify-content: center;
    background: rgba(52, 211, 153, 0.2);
    border-radius: 4px;
    font-weight: 600;
    font-size: 0.7rem;
    color: var(--fv-accent-primary);
  }

  .fv-demo-tab.active .fv-demo-tab-rank {
    background: var(--fv-accent-primary);
    color: var(--fv-bg-dark);
  }

  .fv-demo-tab-conf { color: var(--fv-accent-primary); font-weight: 500; }

  /* Heatmap Controls */
  .fv-heatmap-controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem 1.5rem;
    background: var(--fv-bg-elevated);
    border-top: 1px solid var(--fv-border);
  }

  .fv-toggle-label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.82rem;
    color: var(--fv-text-secondary);
    cursor: pointer;
  }

  .fv-toggle-label input { accent-color: var(--fv-accent-primary); }

  .fv-band-indicator {
    font-family: var(--font-mono);
    font-size: 0.72rem;
    padding: 0.25rem 0.6rem;
    border-radius: 50px;
  }

  .fv-band-indicator.high {
    background: rgba(52, 211, 153, 0.15);
    border: 1px solid rgba(52, 211, 153, 0.4);
    color: var(--fv-accent-primary);
  }

  .fv-band-indicator.medium {
    background: rgba(251, 191, 36, 0.15);
    border: 1px solid rgba(251, 191, 36, 0.4);
    color: var(--fv-accent-warning);
  }

  .fv-band-indicator.low {
    background: rgba(248, 113, 113, 0.15);
    border: 1px solid rgba(248, 113, 113, 0.4);
    color: var(--fv-accent-danger);
  }

  /* ─── COLUMN 3: KNOWLEDGE PANEL ──────────────────── */

  .knowledge-panel {
    background: var(--fv-bg-card);
    display: flex;
    flex-direction: column;
    overflow: hidden;
    height: 100%;
    max-height: 820px;
  }

  .knowledge-header {
    padding: 1.25rem 1.5rem;
    border-bottom: 1px solid var(--fv-border);
    background: linear-gradient(135deg, var(--fv-bg-elevated), var(--fv-bg-card));
    flex-shrink: 0;
  }

  .knowledge-header h3 {
    font-family: var(--font-display);
    font-size: 1.15rem;
    font-weight: 600;
    color: var(--fv-accent-primary);
    margin-bottom: 0.25rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
  }

  .knowledge-header p { font-size: 0.8rem; color: var(--fv-text-muted); }

  .knowledge-content {
    flex: 1;
    min-height: 0;       /* critical — lets flex child shrink below content size */
    padding: 1.5rem;
    overflow-y: auto;
    overflow-x: hidden;
    background: var(--fv-bg-elevated);
  }

  .knowledge-content::-webkit-scrollbar { width: 6px; }
  .knowledge-content::-webkit-scrollbar-track { background: transparent; }
  .knowledge-content::-webkit-scrollbar-thumb {
    background: var(--fv-accent-primary);
    border-radius: 10px;
  }
  .knowledge-content::-webkit-scrollbar-thumb:hover { background: var(--fv-accent-secondary); }

  /* KB Sections */
  .kb-section {
    padding: 1rem;
    background: rgba(10, 15, 26, 0.5);
    border-radius: 10px;
    border-left: 3px solid var(--fv-accent-primary);
    margin-bottom: 1rem;
  }

  :root[data-theme="light"] .kb-section { background: rgba(248, 250, 252, 0.95); }

  .kb-section.warning {
    border-left-color: var(--fv-accent-warning);
    background: rgba(251, 191, 36, 0.05);
  }

  :root[data-theme="light"] .kb-section.warning { background: rgba(254, 243, 199, 0.55); }

  .kb-section.info   { border-left-color: var(--fv-accent-secondary); }

  /* Sources section — evidence citations at bottom of knowledge panel */
  .kb-section.sources {
    border-left-color: var(--fv-text-muted);
    background: rgba(15, 23, 42, 0.3);
  }

  :root[data-theme="light"] .kb-section.sources { background: rgba(241, 245, 249, 0.9); }

  .kb-section.sources .kb-section-title i { color: var(--fv-text-muted); }

  .kb-section.sources ol {
    padding-left: 1.25rem;
    margin: 0;
  }

  .kb-section.sources ol li {
    margin-bottom: 0.6rem;
    font-size: 0.82rem;
    line-height: 1.5;
    color: var(--fv-text-secondary);
  }

  .kb-section.sources ol li a {
    color: var(--fv-text-primary);
    font-weight: 500;
    text-decoration: none;
    border-bottom: 1px solid transparent;
    transition: border-color 0.2s ease;
  }

  .kb-section.sources ol li a:hover {
    border-bottom-color: var(--fv-accent-secondary);
    color: var(--fv-accent-secondary);
  }

  .kb-section:last-child { margin-bottom: 0; }

  .kb-section-title {
    font-weight: 600;
    font-size: 0.88rem;
    margin-bottom: 0.5rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
  }

  .kb-section-title i { font-size: 0.85rem; color: var(--fv-accent-primary); }
  .kb-section.warning .kb-section-title i { color: var(--fv-accent-warning); }
  .kb-section.info    .kb-section-title i { color: var(--fv-accent-secondary); }

  .kb-section-content {
    font-size: 0.82rem;
    color: var(--fv-text-secondary);
    line-height: 1.75;
  }

  .kb-section-content ul {
    margin: 0;
    padding: 0 0 0 1.25rem;
  }

  .kb-section-content li { margin-bottom: 0.2rem; }
  .kb-section-content p  { margin-bottom: 0.5rem; }
  .kb-section-content p:last-child { margin-bottom: 0; }

  /* Footer Note */
  .fv-footer-note {
    padding: 1.25rem 1.75rem;
    border-top: 1px dashed var(--fv-border);
    font-size: 0.78rem;
    color: var(--fv-text-muted);
    line-height: 1.7;
    background: var(--fv-bg-card);
  }

  .fv-footer-note strong { color: var(--fv-accent-primary); }

  /* Language Selector */
  .language-selector {
    background: linear-gradient(135deg, rgba(56, 189, 248, 0.08), rgba(139, 92, 246, 0.05));
    border: 1px solid var(--fv-border);
    border-radius: 0.75rem;
    padding: 1rem;
    margin-bottom: 1.5rem;
  }

  :root[data-theme="light"] .language-selector {
    background: linear-gradient(135deg, rgba(59, 130, 246, 0.12), rgba(129, 140, 248, 0.09));
  }

  .language-selector-label {
    font-size: 0.88rem;
    font-weight: 600;
    color: var(--fv-accent-secondary);
    margin-bottom: 0.75rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
  }

  .language-dropdown-wrapper { position: relative; width: 100%; }

  .language-dropdown {
    width: 100%;
    padding: 0.75rem 2.5rem 0.75rem 1rem;
    background: var(--fv-bg-elevated);
    border: 2px solid var(--fv-border);
    border-radius: 0.65rem;
    color: var(--fv-text-primary);
    font-family: var(--font-body);
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    appearance: none;
    -webkit-appearance: none;
    transition: all 0.2s ease;
  }

  .language-dropdown:hover {
    border-color: var(--fv-accent-secondary);
    background: var(--fv-bg-card);
    box-shadow: 0 4px 15px rgba(56, 189, 248, 0.15);
  }

  .language-dropdown:focus {
    outline: none;
    border-color: var(--fv-accent-secondary);
    box-shadow: 0 0 0 3px rgba(56, 189, 248, 0.1);
  }

  .language-dropdown option {
    background: var(--fv-bg-elevated);
    color: var(--fv-text-primary);
  }

  .language-dropdown-icon {
    position: absolute;
    right: 1rem; top: 50%;
    transform: translateY(-50%);
    color: var(--fv-accent-secondary);
    font-size: 0.75rem;
    pointer-events: none;
    transition: transform 0.2s ease;
  }

  .language-dropdown:focus + .language-dropdown-icon {
    transform: translateY(-50%) rotate(180deg);
  }

  /* Responsive */
  @media (max-width: 768px) {
    .fv-wrapper { padding: 2rem 1rem 3rem; }

    .fv-playground-header { padding: 1.25rem; }

    .upload-panel { padding: 1.5rem 1.25rem; }

    .plant-options { grid-template-columns: 1fr; }

    .image-display {
      min-height: 300px;
      padding: 1.5rem;
    }

    .knowledge-content { padding: 1.25rem; }
  }
/* ═══════════════════════════════════════════════════════════════════════════
   MOBILE-FIRST RESPONSIVE ADDITIONS  (< 640px)
   ═══════════════════════════════════════════════════════════════════════════ */

@media (max-width: 639px) {

  /* Wrapper */
  .fv-wrapper {
    padding: 0.75rem 0.75rem 5rem; /* extra bottom for mobile thumb zone */
  }

  /* Hero (when revealed via About toggle) */
  .fv-hero { margin-bottom: 1.5rem; }
  .fv-hero-subtitle { font-size: 0.9rem; }

  /* Playground container */
  .fv-playground {
    border-radius: 0.75rem;
  }

  .fv-playground-header {
    padding: 1rem;
    flex-direction: column;
    align-items: flex-start;
  }

  /* Upload panel mobile sizing */
  .upload-panel {
    padding: 1.25rem 1rem;
  }

  /* Plant selector: keep 2×2 but smaller */
  .plant-options {
    grid-template-columns: repeat(2, 1fr);
    gap: 0.5rem;
  }

  .plant-option {
    padding: 0.65rem 0.5rem;
    font-size: 0.82rem;
    min-height: 44px; /* WCAG touch target */
  }

  /* Upload + camera buttons: side-by-side on mobile */
  .upload-button-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.6rem;
  }

  .upload-btn {
    width: 100%;
    padding: 0.85rem 0.75rem;
    font-size: 0.85rem;
    min-height: 48px;
  }

  /* Image panel */
  .image-display {
    padding: 1rem;
    min-height: 200px;
  }

  /* Knowledge panel */
  .knowledge-panel {
    max-height: none;
  }

  .knowledge-header {
    padding: 1rem;
  }

  .knowledge-content {
    padding: 1rem;
  }

  /* Gradcam tabs — scrollable */
  .fv-demo-tabs {
    overflow-x: auto;
    scrollbar-width: none;
    white-space: nowrap;
    padding: 0.5rem 1rem;
  }

  .fv-demo-tabs::-webkit-scrollbar { display: none; }

  /* Footer note */
  .fv-footer-note {
    font-size: 0.78rem;
    padding: 0.75rem 1rem;
  }

  /* Diff cards (in collapsible intro) */
  .fv-diff-grid {
    grid-template-columns: 1fr;
    gap: 0.75rem;
  }

  .fv-diff-card { padding: 1rem; }
}

/* ── TABLET  640–1023px ──────────────────────────────────────────────────── */
@media (min-width: 640px) and (max-width: 1023px) {

  .fv-wrapper { padding: 1rem 1.25rem 3rem; }

  /* Two column: upload + image side-by-side, knowledge below */
  .fv-playground-shell {
    grid-template-columns: 280px 1fr;
    grid-template-rows: auto auto;
    max-height: none;
  }

  .knowledge-panel {
    grid-column: 1 / -1; /* full width on tablet */
    border-top: 1px solid var(--fv-border);
    border-left: none;
    max-height: 400px;
    overflow-y: auto;
  }

  .image-panel {
    border-right: none;
    border-bottom: none;
    max-height: none;
  }

  .upload-panel {
    border-bottom: none;
    max-height: none;
  }
}

/* ══════════════════════════════════════════════════════════════════════════
   QUOTA BANNER
   ══════════════════════════════════════════════════════════════════════════ */

.fv-quota-banner {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 9999;
  background: linear-gradient(135deg, rgba(245, 158, 11, 0.97), rgba(180, 110, 6, 0.97));
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
  padding: .85rem 1.5rem;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
  animation: fvQuotaSlideDown 0.3s ease-out;
}
@keyframes fvQuotaSlideDown {
  from { transform: translateY(-100%); opacity: 0; }
  to   { transform: translateY(0);    opacity: 1; }
}
.fv-quota-banner.active { display: flex; align-items: center; justify-content: center; }
.fv-quota-banner-inner {
  display: flex; align-items: center; gap: .75rem;
  max-width: 1280px; width: 100%;
}
.fv-quota-banner-icon { font-size: 1.4rem; flex-shrink: 0; }
.fv-quota-banner-text { flex: 1; }
.fv-quota-banner-title {
  font-family: 'IBM Plex Sans', sans-serif;
  font-size: .95rem; font-weight: 700; color: #fff; margin-bottom: .2rem;
}
.fv-quota-banner-message {
  font-family: 'IBM Plex Sans', sans-serif;
  font-size: .85rem; color: rgba(255,255,255,.9); line-height: 1.5;
}
.fv-quota-banner-meta {
  font-size: .75rem; color: rgba(255,255,255,.75); margin-top: .25rem;
}
.fv-quota-banner-cta {
  display: inline-flex; align-items: center;
  padding: .4rem .9rem;
  background: rgba(255,255,255,.2);
  border: 1px solid rgba(255,255,255,.35);
  border-radius: 20px;
  color: #fff; font-size: .75rem; font-weight: 600;
  font-family: 'IBM Plex Mono', monospace; letter-spacing: .04em;
  text-decoration: none; white-space: nowrap; flex-shrink: 0;
  transition: background .2s ease;
}
.fv-quota-banner-cta:hover { background: rgba(255,255,255,.3); color: #fff; }
.fv-quota-banner-close {
  background: rgba(255,255,255,.15); border: 1px solid rgba(255,255,255,.2);
  border-radius: 50%; width: 30px; height: 30px;
  display: flex; align-items: center; justify-content: center;
  cursor: pointer; color: #fff; font-size: 1.2rem;
  transition: all .2s ease; flex-shrink: 0;
}
.fv-quota-banner-close:hover { background: rgba(255,255,255,.25); transform: scale(1.05); }