:root {
      --bg-dark: #0a0a0a;
      --bg-darker: #050505;
      --bg-surface: #141414;
      --bg-panel: #ffffff;
      --border-subtle: #222222;
      --border-light: #333333;
      --text-primary: #e8e8e8;
      --text-secondary: #aaaaaa;
      --text-muted: #666666;
      --accent-red: #e63946;
      --accent-red-dim: rgba(230, 57, 70, 0.25);
      --accent-green: #2ecc71;
      --accent-orange: #f39c12;
      --pin-color: #c8c8c8;
      --pin-stroke: #b0b0b0;
      --shape-color: #000000;
      --radius: 6px;
      --font: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Helvetica Neue', Arial, sans-serif;
      --font-mono: 'SF Mono', 'Fira Code', 'Consolas', monospace;
    }

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

    html, body {
      height: 100%;
      overflow: hidden;
    }

    body {
      font-family: var(--font);
      background: var(--bg-dark);
      color: var(--text-primary);
      display: grid;
      grid-template-areas:
        "header header"
        "sidebar main"
        "footer footer";
      grid-template-columns: 220px 1fr;
      grid-template-rows: auto 1fr auto;
      overscroll-behavior-y: none;
    }

    #app-header {
      grid-area: header;
      background: var(--bg-darker);
      border-bottom: 1px solid var(--border-subtle);
      display: flex;
      align-items: center;
      justify-content: space-between;
      padding: 12px 24px;
      gap: 16px;
      flex-wrap: wrap;
    }

    .header-left {
      display: flex;
      align-items: center;
      gap: 12px;
      flex-shrink: 0;
    }

    .header-left h1 {
      font-size: 18px;
      font-weight: 700;
      letter-spacing: -0.02em;
      color: var(--text-primary);
    }

    .header-left .subtitle {
      font-size: 12px;
      font-weight: 400;
      color: var(--text-muted);
      letter-spacing: 0.04em;
      text-transform: uppercase;
    }

    .header-actions {
      display: flex;
      gap: 8px;
    }

    .header-actions button {
      display: inline-flex;
      align-items: center;
      gap: 6px;
      font-family: var(--font);
      font-size: 12px;
      font-weight: 600;
      padding: 7px 14px;
      border: 1px solid var(--border-light);
      border-radius: 4px;
      background: transparent;
      color: var(--text-secondary);
      cursor: pointer;
      transition: all 0.15s ease;
      letter-spacing: 0.01em;
    }

    .header-actions button svg {
      width: 14px;
      height: 14px;
      stroke: currentColor;
      fill: none;
      stroke-width: 2;
      stroke-linecap: round;
      stroke-linejoin: round;
      flex-shrink: 0;
    }

    .header-actions button:hover {
      background: var(--accent-red);
      border-color: var(--accent-red);
      color: #fff;
    }

    .header-actions button:active {
      transform: scale(0.97);
    }

    #sidebar {
      grid-area: sidebar;
      background: var(--bg-surface);
      border-right: 1px solid var(--border-subtle);
      padding: 24px 20px;
      display: flex;
      flex-direction: column;
      gap: 24px;
      overflow-y: auto;
    }

    .sidebar-section h3 {
      font-size: 10px;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: 0.1em;
      color: var(--text-muted);
      margin-bottom: 12px;
    }

    .input-group {
      display: flex;
      align-items: center;
      justify-content: space-between;
      margin-bottom: 8px;
    }

    .input-group label {
      font-size: 13px;
      color: var(--text-secondary);
    }

    .input-group input[type="number"] {
      width: 60px;
      padding: 5px 8px;
      font-family: var(--font-mono);
      font-size: 13px;
      background: var(--bg-dark);
      border: 1px solid var(--border-light);
      border-radius: 3px;
      color: var(--text-primary);
      text-align: center;
      outline: none;
      transition: border-color 0.15s ease;
    }

    .input-group input[type="number"]:focus {
      border-color: var(--accent-red);
    }

    .input-group input[type="number"]::-webkit-inner-spin-button,
    .input-group input[type="number"]::-webkit-outer-spin-button {
      -webkit-appearance: none;
      margin: 0;
    }
    .input-group input[type="number"] { -moz-appearance: textfield; }

    #status {
      font-size: 13px;
      font-weight: 600;
      padding: 8px 12px;
      border-radius: 4px;
      text-align: center;
      transition: all 0.25s ease;
    }

    #status.status-idle {
      background: rgba(255,255,255,0.04);
      color: var(--text-muted);
    }

    #status.status-drawing {
      background: rgba(243, 156, 18, 0.12);
      color: var(--accent-orange);
    }

    #status.status-closed {
      background: rgba(46, 204, 113, 0.12);
      color: var(--accent-green);
    }

    #pin-counter {
      font-size: 12px;
      color: var(--text-muted);
      font-family: var(--font-mono);
      margin-top: 4px;
      text-align: center;
    }

    #area-display {
      font-size: 12px;
      color: var(--text-muted);
      font-family: var(--font-mono);
      margin-top: 2px;
      text-align: center;
      min-height: 16px;
    }

    .sidebar-help {
      margin-top: auto;
    }

    .sidebar-help p {
      font-size: 11px;
      line-height: 1.6;
      color: var(--text-muted);
    }

    .sidebar-help kbd {
      font-family: var(--font-mono);
      font-size: 10px;
      background: var(--bg-dark);
      border: 1px solid var(--border-light);
      border-radius: 3px;
      padding: 1px 5px;
      color: var(--text-secondary);
    }

    #panels {
      grid-area: main;
      display: flex;
      gap: 20px;
      padding: 20px;
      overflow: hidden;
    }

    .panel {
      flex: 1;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      min-width: 0;
    }

    .panel h2 {
      font-size: 10px;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: 0.1em;
      color: var(--text-muted);
      margin-bottom: 10px;
      flex-shrink: 0;
    }

    .canvas-wrap {
      flex: 0 0 auto;
      background: var(--bg-panel);
      border-radius: var(--radius);
      overflow: hidden;
      position: relative;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    .canvas-wrap canvas {
      display: block;
      width: 100%;
      height: 100%;
    }

    #wrap-op, #canvas-op { cursor: crosshair; }
    #canvas-res { 
      cursor: default; 
      touch-action: auto; 
    }

    .canvas-wrap.success-flash {
      box-shadow: 0 0 20px rgba(46, 204, 113, 0.3);
      transition: box-shadow 0.3s ease;
    }

    @media (max-width: 960px) {
      body {
        grid-template-areas:
          "header"
          "sidebar"
          "main"
          "footer";
        grid-template-columns: 1fr;
        grid-template-rows: auto auto 1fr auto;
        overflow-y: auto;
      }

      #sidebar {
        flex-direction: row;
        flex-wrap: wrap;
        align-items: center;
        gap: 12px;
        padding: 12px 20px;
        border-right: none;
        border-bottom: 1px solid var(--border-subtle);
      }

      .sidebar-section { margin-bottom: 0; }
      .sidebar-section:nth-child(2) {
        margin-left: auto;
        display: flex;
        flex-direction: column;
        align-items: flex-end;
        text-align: right;
      }
      .sidebar-section h3 { margin-bottom: 4px; }
      .sidebar-help { display: none; }

      .input-group { gap: 6px; margin-bottom: 0; }

      #panels {
        flex-direction: column;
        overflow-y: auto;
      }
      .panel {
        flex: 0 0 auto;
        width: 100%;
      }
    }

    @media (max-width: 600px) {
      #app-header { 
        padding: 10px 16px; 
        flex-wrap: wrap; 
        height: auto; 
        gap: 12px;
      }
      .header-left h1 { font-size: 16px; }
      .header-actions button { 
        padding: 8px 12px; 
        font-size: 13px; 
      }
      #sidebar {
        padding: 12px 16px;
      }
      .input-group input[type="number"] {
        font-size: 16px; /* Prevents iOS zoom */
        padding: 6px 10px;
        width: 70px;
      }
      #panels { 
        padding: 16px 16px 40px 16px;
        gap: 32px;
      }
      .panel h2 {
        padding: 6px 0;
        font-size: 12px;
        text-align: left;
      }
    }

    canvas {
      -webkit-touch-callout: none;
      -webkit-user-select: none;
      user-select: none;
      touch-action: none;
    }

    #app-footer {
      grid-area: footer;
      background: var(--bg-darker);
      border-top: 1px solid var(--border-subtle);
      padding: 12px 24px;
      display: grid;
      grid-template-columns: 1fr auto 1fr;
      align-items: center;
      font-size: 12px;
      color: var(--text-muted);
      z-index: 10;
    }

    .footer-center {
      grid-column: 2;
      text-align: center;
    }

    .footer-right {
      grid-column: 3;
      justify-self: end;
      display: flex;
    }

    #app-footer a {
      color: var(--text-secondary);
      text-decoration: none;
      transition: color 0.15s ease;
    }

    #app-footer a:hover {
      color: var(--accent-red);
    }