:root {
      --bg-deep:      #f8fafc;
      --bg-panel:     #ffffff;
      --bg-card:      #ffffff;
      --border:       #e2e8f0;
      --border-glow:  #cbd5e1;
      --accent:       #ef4444;
      --accent-dim:   #fee2e2;
      --amber:        #f59e0b;
      --green:        #10b981;
      --cyan:         #0ea5e9;
      --text-primary: #0f172a;
      --text-muted:   #475569;
      --text-dim:     #94a3b8;
      --font-display: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
      --font-mono:    var(--font-ui);
      --font-ui:      -apple-system, BlinkMacSystemFont, "SF Pro Text", "SF Pro", "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    }

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

    html, body {
      height: 100%;
      background: var(--bg-deep);
      color: var(--text-primary);
      font-family: var(--font-ui);
      overflow-x: hidden;
    }

    /* Scanline overlay */
    body::before {
      content: '';
      position: fixed;
      inset: 0;
      background: repeating-linear-gradient(
        0deg,
        transparent,
        transparent 2px,
        rgba(0,0,0,0.02) 2px,
        rgba(0,0,0,0.02) 4px
      );
      pointer-events: none;
      z-index: 1000;
    }

    /* ───── LAYOUT ───── */
    .app-shell {
      min-height: 100dvh;
      display: flex;
      flex-direction: column;
      max-width: 480px;
      margin: 0 auto;
      padding: 0 0 env(safe-area-inset-bottom);
    }

    /* ───── HEADER ───── */
    header {
      padding: 14px 20px 10px;
      border-bottom: 1px solid var(--border);
      background: var(--bg-panel);
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 12px;
      flex-shrink: 0;
    }

    .logo-group {
      display: flex;
      align-items: center;
      gap: 10px;
    }

    .logo-icon {
      width: 36px;
      height: 36px;
      background: linear-gradient(135deg, var(--accent-dim), var(--accent));
      border-radius: 6px;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 18px;
      flex-shrink: 0;
      box-shadow: 0 0 12px rgba(239,68,68,0.2);
    }

    .logo-text {
      display: flex;
      flex-direction: column;
      line-height: 1.1;
    }

    .logo-title {
      font-family: var(--font-display);
      font-weight: 800;
      font-size: 15px;
      letter-spacing: 0.04em;
      color: var(--text-primary);
    }

    .logo-sub {
      font-family: var(--font-mono);
      font-size: 9px;
      color: var(--text-muted);
      letter-spacing: 0.1em;
    }

    .status-badge {
      font-family: var(--font-mono);
      font-size: 10px;
      padding: 3px 8px;
      border-radius: 6px;
      border: 1px solid;
      letter-spacing: 0.08em;
      text-transform: uppercase;
      display: flex;
      align-items: center;
      gap: 5px;
    }

    .status-badge.ready {
      color: var(--green);
      border-color: var(--green);
      background: rgba(34,197,94,0.08);
    }

    .status-badge.loading {
      color: var(--amber);
      border-color: var(--amber);
      background: rgba(245,158,11,0.08);
    }

    .status-badge.idle {
      color: var(--text-muted);
      border-color: var(--border);
      background: transparent;
    }

    .status-dot {
      width: 6px;
      height: 6px;
      border-radius: 50%;
      background: currentColor;
    }

    .status-badge.ready .status-dot {
      animation: pulse-dot 1.4s ease-in-out infinite;
    }

    @keyframes pulse-dot {
      0%, 100% { opacity: 1; }
      50% { opacity: 0.3; }
    }

    /* ───── MAIN CONTENT ───── */
    main {
      flex: 1;
      display: flex;
      flex-direction: column;
      padding: 16px;
      gap: 14px;
      overflow-y: auto;
    }

    /* ───── INSTRUCTION STRIP ───── */
    .instruction-strip {
      background: rgba(6, 182, 212, 0.06);
      border: 1px solid rgba(6,182,212,0.2);
      border-left: 3px solid var(--cyan);
      border-radius: 12px;
      padding: 8px 12px;
      font-size: 12px;
      color: var(--cyan);
      font-family: var(--font-mono);
      letter-spacing: 0.02em;
      text-align: center;
      line-height: 1.4;
    }

    /* ───── CAMERA CONTAINER ───── */
    .camera-container {
      position: relative;
      width: 100%;
      aspect-ratio: 1 / 1;
      background: #000;
      border-radius: 20px;
      overflow: hidden;
      border: 1px solid var(--border);
      box-shadow: 0 0 0 1px var(--border-glow), 0 8px 32px rgba(0,0,0,0.1);
    }

    #videoFeed {
      width: 100%;
      height: 100%;
      object-fit: cover;
      display: block;
    }

    /* Corner decorations */
    .cam-corner {
      position: absolute;
      width: 24px;
      height: 24px;
      border-color: var(--cyan);
      border-style: solid;
      opacity: 0.7;
      z-index: 2;
    }
    .cam-corner.tl { top: 12px; left: 12px; border-width: 2px 0 0 2px; border-top-left-radius: 16px; }
    .cam-corner.tr { top: 12px; right: 12px; border-width: 2px 2px 0 0; border-top-right-radius: 16px; }
    .cam-corner.bl { bottom: 12px; left: 12px; border-width: 0 0 2px 2px; border-bottom-left-radius: 16px; }
    .cam-corner.br { bottom: 12px; right: 12px; border-width: 0 2px 2px 0; border-bottom-right-radius: 16px; }

    /* Viewfinder */
    .viewfinder {
      position: absolute;
      top: 50%;
      left: 50%;
      transform: translate(-50%, -50%);
      width: 45%;
      aspect-ratio: 1 / 1;
      border: 2px solid var(--accent);
      border-radius: 16px;
      box-shadow: 0 0 0 1px rgba(232,64,64,0.3), 0 0 16px rgba(232,64,64,0.4), inset 0 0 16px rgba(232,64,64,0.05);
      z-index: 3;
      pointer-events: none;
      animation: vf-breathe 3s ease-in-out infinite;
    }

    @keyframes vf-breathe {
      0%, 100% { box-shadow: 0 0 0 1px rgba(232,64,64,0.3), 0 0 16px rgba(232,64,64,0.4), inset 0 0 16px rgba(232,64,64,0.05); }
      50% { box-shadow: 0 0 0 1px rgba(232,64,64,0.5), 0 0 28px rgba(232,64,64,0.6), inset 0 0 24px rgba(232,64,64,0.1); }
    }

    .viewfinder::before, .viewfinder::after {
      content: '';
      position: absolute;
      background: var(--accent);
      opacity: 0.7;
    }
    .viewfinder::before { /* horizontal crosshair */
      width: 14px; height: 1px;
      top: 50%; left: 50%;
      transform: translate(-50%, -50%);
    }
    .viewfinder::after { /* vertical crosshair */
      width: 1px; height: 14px;
      top: 50%; left: 50%;
      transform: translate(-50%, -50%);
    }

    /* VF corner ticks */
    .vf-tick {
      position: absolute;
      width: 16px;
      height: 16px;
      border-color: var(--accent);
      border-style: solid;
    }
    .vf-tick.tl { top: -2px; left: -2px; border-width: 2px 0 0 2px; border-top-left-radius: 16px; }
    .vf-tick.tr { top: -2px; right: -2px; border-width: 2px 2px 0 0; border-top-right-radius: 16px; }
    .vf-tick.bl { bottom: -2px; left: -2px; border-width: 0 0 2px 2px; border-bottom-left-radius: 16px; }
    .vf-tick.br { bottom: -2px; right: -2px; border-width: 0 2px 2px 0; border-bottom-right-radius: 16px; }

    /* Scan line animation over viewfinder */
    .vf-scan {
      position: absolute;
      top: 50%;
      left: 50%;
      transform: translate(-50%, -50%);
      width: 45%;
      aspect-ratio: 1/1;
      z-index: 4;
      pointer-events: none;
      overflow: hidden;
      border-radius: 16px;
    }

    .vf-scan::after {
      content: '';
      position: absolute;
      top: 0; left: 0; right: 0;
      height: 2px;
      background: linear-gradient(90deg, transparent, rgba(232,64,64,0.8), transparent);
      animation: scan-line 2.5s linear infinite;
    }

    @keyframes scan-line {
      0% { top: 0; }
      100% { top: 100%; }
    }

    /* HUD overlays */
    .cam-hud {
      position: absolute;
      bottom: 24px;
      left: 20px;
      right: 20px;
      display: flex;
      justify-content: space-between;
      align-items: flex-end;
      z-index: 5;
      pointer-events: none;
    }

    .hud-tag {
      font-family: var(--font-mono);
      font-size: 9px;
      color: rgba(255,255,255,0.45);
      letter-spacing: 0.06em;
      line-height: 1.6;
    }

    /* ───── ZOOM CONTROL ───── */
    .zoom-control-container {
      display: flex;
      flex-direction: column;
      gap: 10px;
      background: var(--bg-card);
      padding: 12px 16px;
      border-radius: 16px;
      border: 1px solid var(--border);
    }
    .zoom-label {
      font-family: var(--font-mono);
      font-size: 11px;
      color: var(--text-muted);
      letter-spacing: 0.1em;
      text-transform: uppercase;
      display: flex;
      justify-content: space-between;
    }
    #zoomValOut {
      color: var(--cyan);
      font-weight: bold;
    }
    input[type=range] {
      -webkit-appearance: none;
      appearance: none;
      width: 100%;
      background: transparent;
    }
    input[type=range]::-webkit-slider-thumb {
      -webkit-appearance: none;
      appearance: none;
      height: 18px;
      width: 18px;
      border-radius: 50%;
      background: var(--cyan);
      cursor: pointer;
      margin-top: -7px;
      box-shadow: 0 0 10px rgba(6,182,212,0.4);
    }
    input[type=range]::-webkit-slider-runnable-track {
      width: 100%;
      height: 4px;
      cursor: pointer;
      background: var(--border-glow);
      border-radius: 2px;
    }

    /* ───── RESULT VIEW ───── */
    .result-container {
      display: none;
      flex-direction: column;
      gap: 14px;
    }

    .visual-comparison {
      position: relative;
      width: 100%;
      margin: 16px 0;
      border-radius: 12px;
      overflow: hidden;
      display: flex;
      justify-content: center;
      align-items: center;
      background: #fff;
      border: 1px solid var(--border);
    }
    
    .chart-img {
      width: 100%;
      height: auto;
      display: block;
      position: relative;
      z-index: 2;
      pointer-events: none;
    }
    
    #captureCanvas {
      position: absolute;
      top: 50%;
      left: 50%;
      transform: translate(-50%, -50%);
      width: 50%;
      aspect-ratio: 1/1;
      object-fit: cover;
      z-index: 1;
    }

    .result-stamp {
      position: absolute;
      top: 16px;
      right: 16px;
      font-family: var(--font-mono);
      font-size: 9px;
      color: var(--text-muted);
      letter-spacing: 0.06em;
    }

    /* ───── RESULT CARD ───── */
    .result-card {
      background: var(--bg-card);
      border: 1px solid var(--border);
      border-radius: 20px;
      padding: 16px;
      position: relative;
      overflow: hidden;
    }

    .result-card::before {
      content: '';
      position: absolute;
      top: 0; left: 0; right: 0;
      height: 3px;
      background: var(--result-accent, var(--text-muted));
    }

    .result-label {
      font-family: var(--font-mono);
      font-size: 10px;
      color: var(--text-muted);
      letter-spacing: 0.12em;
      text-transform: uppercase;
      margin-bottom: 8px;
    }

    .result-scale {
      font-family: var(--font-display);
      font-weight: 800;
      font-size: 32px;
      line-height: 1;
      color: var(--result-accent, var(--text-primary));
      margin-bottom: 4px;
      letter-spacing: -0.02em;
    }

    .result-desc {
      font-family: var(--font-ui);
      font-size: 16px;
      font-weight: 600;
      color: var(--text-primary);
      margin-bottom: 12px;
    }

    .result-meta-row {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 8px;
      margin-top: 10px;
    }

    .meta-cell {
      background: rgba(0,0,0,0.02);
      border: 1px solid var(--border);
      border-radius: 10px;
      padding: 8px 10px;
    }

    .meta-cell-label {
      font-family: var(--font-mono);
      font-size: 9px;
      color: var(--text-muted);
      letter-spacing: 0.1em;
      text-transform: uppercase;
      margin-bottom: 3px;
    }

    .meta-cell-value {
      font-family: var(--font-mono);
      font-size: 13px;
      color: var(--text-primary);
    }

    .color-swatch {
      display: inline-block;
      width: 12px; height: 12px;
      border-radius: 4px;
      vertical-align: middle;
      margin-right: 5px;
      border: 1px solid rgba(0,0,0,0.1);
    }

    /* ───── RINGELMANN SCALE LEGEND ───── */
    .scale-legend {
      background: var(--bg-card);
      border: 1px solid var(--border);
      border-radius: 16px;
      padding: 12px 14px;
    }

    .legend-title {
      font-family: var(--font-mono);
      font-size: 10px;
      color: var(--text-muted);
      letter-spacing: 0.12em;
      text-transform: uppercase;
      margin-bottom: 10px;
    }

    .scale-bars {
      display: flex;
      flex-direction: column;
      gap: 5px;
    }

    .scale-bar-row {
      display: flex;
      align-items: center;
      gap: 8px;
      cursor: default;
      transition: opacity 0.2s;
    }

    .scale-bar-row.dimmed { opacity: 0.3; }
    .scale-bar-row.highlighted { opacity: 1; }

    .scale-bar-num {
      font-family: var(--font-mono);
      font-size: 11px;
      color: var(--text-muted);
      width: 12px;
      flex-shrink: 0;
    }

    .scale-bar-swatch {
      width: 18px; height: 18px;
      border-radius: 6px;
      flex-shrink: 0;
      border: 1px solid rgba(0,0,0,0.1);
    }

    .scale-bar-fill {
      height: 8px;
      border-radius: 4px;
      flex: 1;
    }

    .scale-bar-info {
      font-family: var(--font-ui);
      font-size: 11px;
      font-weight: 600;
      flex-shrink: 0;
      min-width: 95px;
      text-align: right;
    }

    /* ───── BUTTONS ───── */
    .btn-capture {
      width: 100%;
      padding: 16px;
      background: linear-gradient(135deg, #c92a2a, var(--accent));
      border: none;
      border-radius: 18px;
      color: #fff;
      font-family: var(--font-display);
      font-weight: 800;
      font-size: 17px;
      letter-spacing: 0.05em;
      text-transform: uppercase;
      cursor: pointer;
      position: relative;
      overflow: hidden;
      box-shadow: 0 4px 20px rgba(239,68,68,0.2), 0 2px 4px rgba(0,0,0,0.1);
      transition: transform 0.12s, box-shadow 0.12s;
    }

    .btn-capture::after {
      content: '';
      position: absolute;
      top: 0; left: -100%;
      width: 60%;
      height: 100%;
      background: linear-gradient(90deg, transparent, rgba(255,255,255,0.12), transparent);
      transform: skewX(-20deg);
      animation: btn-shimmer 3s ease-in-out infinite 1s;
    }

    @keyframes btn-shimmer {
      0% { left: -100%; }
      40%, 100% { left: 150%; }
    }

    .btn-capture:active {
      transform: scale(0.97);
      box-shadow: 0 2px 10px rgba(232,64,64,0.3);
    }

    .btn-retry {
      width: 100%;
      padding: 14px;
      background: transparent;
      border: 1px solid var(--border-glow);
      border-radius: 16px;
      color: var(--cyan);
      font-family: var(--font-display);
      font-weight: 700;
      font-size: 15px;
      letter-spacing: 0.06em;
      text-transform: uppercase;
      cursor: pointer;
      transition: background 0.2s, border-color 0.2s, box-shadow 0.2s;
    }

    .btn-retry:hover {
      background: rgba(6,182,212,0.08);
      border-color: var(--cyan);
      box-shadow: 0 0 16px rgba(6,182,212,0.15);
    }

    /* ───── PERMISSION ERROR ───── */
    .perm-error {
      display: none;
      background: var(--bg-card);
      border: 1px solid var(--accent-dim);
      border-radius: 16px;
      padding: 20px;
      text-align: center;
      gap: 10px;
      flex-direction: column;
    }

    .perm-error.visible { display: flex; }

    .perm-icon { font-size: 32px; }
    .perm-title { font-family: var(--font-display); font-weight: 700; font-size: 16px; color: var(--accent); }
    .perm-msg { font-size: 13px; color: var(--text-muted); line-height: 1.5; }

    /* ───── LOADING OVERLAY ───── */
    .processing-overlay {
      display: none;
      position: fixed;
      inset: 0;
      background: rgba(255,255,255,0.85);
      z-index: 500;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 16px;
      backdrop-filter: blur(4px);
    }

    .processing-overlay.visible { display: flex; }

    .proc-spinner {
      width: 48px;
      height: 48px;
      border: 2px solid var(--border);
      border-top-color: var(--accent);
      border-radius: 50%;
      animation: spin 0.7s linear infinite;
    }

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

    .proc-label {
      font-family: var(--font-mono);
      font-size: 12px;
      color: var(--text-muted);
      letter-spacing: 0.12em;
      text-transform: uppercase;
    }

    /* ───── FOOTER ───── */
    footer {
      padding: 8px 16px 12px;
      text-align: center;
      font-family: var(--font-mono);
      font-size: 9px;
      color: var(--text-dim);
      letter-spacing: 0.08em;
      border-top: 1px solid var(--border);
      flex-shrink: 0;
    }

    /* Hidden canvas */
    #hiddenCanvas { display: none; }

    /* ─────────── INFO BOX ─────────── */
    .info-box {
      background: var(--bg-card);
      border: 1px solid var(--border);
      border-radius: 16px;
      padding: 16px 16px;
      margin-top: 4px;
    }

    .info-box-title {
      font-family: var(--font-display);
      font-size: 14px;
      font-weight: 800;
      color: var(--cyan);
      margin-bottom: 12px;
      display: flex;
      align-items: center;
      gap: 6px;
      text-transform: uppercase;
      letter-spacing: 0.05em;
    }

    .info-section {
      margin-bottom: 16px;
    }

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

    .info-subtitle {
      font-family: var(--font-display);
      font-size: 11px;
      font-weight: 700;
      color: var(--text-primary);
      text-transform: uppercase;
      letter-spacing: 0.05em;
      margin-bottom: 6px;
      border-bottom: 1px solid var(--border);
      padding-bottom: 4px;
    }

    .info-box-text {
      font-family: var(--font-ui);
      font-size: 13px;
      color: var(--text-muted);
      line-height: 1.5;
    }
    
    .info-box-text strong {
      color: var(--text-primary);
      font-weight: 600;
    }

    .info-list {
      padding-left: 20px;
      margin-top: 4px;
      display: flex;
      flex-direction: column;
      gap: 6px;
    }

    /* ─────────── RINGELMANN ILLUS ─────────── */
    .rc-illus {
      display: flex;
      justify-content: space-between;
      margin-top: 16px;
      gap: 6px;
    }
    
    .rc-item {
      flex: 1;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 6px;
    }
    
    .rc-box {
      width: 100%;
      aspect-ratio: 1/1;
      border-radius: 8px;
      border: 1px solid rgba(0,0,0,0.15);
      box-shadow: 0 2px 8px rgba(0,0,0,0.1);
    }
    
    .rc-label {
      font-family: var(--font-mono);
      font-size: 11px;
      color: var(--text-muted);
      font-weight: bold;
    }

    .rc-box[data-scale="0"] { background: #ffffff; }
    .rc-box[data-scale="1"] { 
      background-color: #ffffff;
      background-image: 
        linear-gradient(#222 1px, transparent 1px), 
        linear-gradient(90deg, #222 1px, transparent 1px);
      background-size: 9px 9px;
    }
    .rc-box[data-scale="2"] { 
      background-color: #ffffff;
      background-image: 
        linear-gradient(#222 2px, transparent 2px), 
        linear-gradient(90deg, #222 2px, transparent 2px);
      background-size: 9px 9px;
    }
    .rc-box[data-scale="3"] { 
      background-color: #ffffff;
      background-image: 
        linear-gradient(#222 3px, transparent 3px), 
        linear-gradient(90deg, #222 3px, transparent 3px);
      background-size: 8px 8px;
    }
    .rc-box[data-scale="4"] { 
      background-color: #ffffff;
      background-image: 
        linear-gradient(#222 4px, transparent 4px), 
        linear-gradient(90deg, #222 4px, transparent 4px);
      background-size: 7px 7px;
    }
    .rc-box[data-scale="5"] { background: #111111; }

    /* ───── RESPONSIVE ───── */
    @media (min-height: 800px) {
      .camera-container { max-width: 380px; margin: 0 auto; }
    }

    #cameraView {
      display: flex;
      flex-direction: column;
      gap: 14px;
    }