:root {
      --clr1: #09203F;
      --clr2: #537895;
      --clr3: #09203F;
      --clr4: #537895;
      --btn-bg: rgba(255, 255, 255, 0.85);
      --btn-shadow: rgba(0, 0, 0, 0.15);
      --input-bg: rgba(255, 255, 255, 0.7);
      --input-shadow: rgba(0, 0, 0, 0.05);
      --radius: 6px;
      --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      --btn-gap: 0.75rem;
    }

    html, body { height: 100%; margin: 0; padding: 0; }
    
    body {
      font-family: var(--font);
      min-height: 100vh;
      background: linear-gradient(45deg, var(--clr1), var(--clr2), var(--clr3), var(--clr4));
      background-size: 400% 400%;
      animation: gradientBG 15s ease infinite;
      display: flex;
      flex-direction: column;
      align-items: center;
      color: #2b2b2b;
      overflow-y: auto;
    }

    @keyframes gradientBG {
      0% { background-position: 0% 50%; }
      50% { background-position: 100% 50%; }
      100% { background-position: 0% 50%; }
    }

    .header, .container {
      width: min(1200px, 94vw);
      background: rgba(255, 255, 255, 0.311);
      border-radius: var(--radius);
      backdrop-filter: blur(15px);
      box-shadow: 0 8px 32px rgba(0,0,0,0.08);
      padding: 1.5rem;
      margin: 1rem;
      text-align: center;
    }

    .header h1 { 
      margin: 0 0 .35rem 0; 
      color: #000;
      font-size: 2rem;
    }
    
    .header h2 { 
      margin: 0; 
      font-weight: 500; 
      opacity: .9; 
      color: #000;
      font-size: 1.2rem;
    }

    button {
      background: var(--btn-bg);
      border: none;
      border-radius: var(--radius);
      padding: 0.6rem 1.2rem;
      font-size: 1rem;
      color: #333;
      cursor: pointer;
      transition: transform .2s ease, box-shadow .2s ease, background .2s ease;
      box-shadow: 4px 4px 8px var(--btn-shadow), -4px -4px 8px #fff;
    }

    button:hover {
      transform: translateY(-2px);
      background: rgba(255,255,255,1);
      box-shadow: 6px 6px 12px var(--btn-shadow), -6px -6px 12px #fff;
    }

    button:disabled {
      opacity: 0.5;
      cursor: not-allowed;
      transform: none;
    }

    #drop-zone {
      border: 2px dashed rgba(255,255,255,0.9);
      border-radius: var(--radius);
      padding: 4rem 2rem;
      text-align: center;
      color: #fff;
      font-size: 1.1rem;
      transition: background .3s, border-color .3s;
      background: rgba(255,255,255,0.1);
      margin: 1.25rem auto;
      cursor: pointer;
    }

    #drop-zone.dragover {
      background: rgba(255,255,255,0.2);
      border-color: #fff;
    }

    .controls {
      display: flex;
      flex-wrap: wrap;
      gap: var(--btn-gap);
      justify-content: center;
      margin: 1.5rem 0;
    }

    .page-grid {
      display: grid;
      grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
      gap: 1.5rem;
      margin: 2rem 0;
      padding: 1rem;
      background: rgba(255,255,255,0.5);
      border-radius: var(--radius);
      min-height: 200px;
    }

    .page-card {
      background: white;
      border-radius: var(--radius);
      padding: 1rem;
      box-shadow: 0 4px 12px rgba(0,0,0,0.1);
      cursor: move;
      transition: transform 0.2s, box-shadow 0.2s;
      position: relative;
      user-select: none;
    }

    .page-card:hover {
      transform: translateY(-4px);
      box-shadow: 0 8px 20px rgba(0,0,0,0.15);
    }

    .page-card.dragging {
      opacity: 0.5;
      transform: scale(0.95);
    }

    .page-card.drag-over {
      border: 2px dashed #667eea;
      background: rgba(102, 126, 234, 0.1);
    }

    .page-preview {
      width: 100%;
      aspect-ratio: 0.707;
      background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
      border-radius: 4px;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 3rem;
      color: rgba(0,0,0,0.3);
      margin-bottom: 0.5rem;
    }

    .page-number {
      text-align: center;
      font-weight: bold;
      color: #333;
      font-size: 0.9rem;
      margin-bottom: 0.5rem;
    }

    .page-actions {
      display: flex;
      gap: 0.5rem;
      justify-content: center;
    }

    .btn-small {
      padding: 0.3rem 0.6rem;
      font-size: 0.85rem;
    }

    .btn-danger {
      background: linear-gradient(135deg, #ff416c, #ff4b2b);
      color: white;
    }

    .btn-rotate {
      background: linear-gradient(135deg, #667eea, #764ba2);
      color: white;
    }

    .select-checkbox {
      position: absolute;
      top: 0.5rem;
      left: 0.5rem;
      width: 20px;
      height: 20px;
      cursor: pointer;
      z-index: 10;
    }

    .empty-state {
      text-align: center;
      color: rgba(255,255,255,0.8);
      padding: 3rem;
      font-size: 1.1rem;
    }

    .contact {
      position: fixed;
      bottom: 1rem;
      left: 90%;
      transform: translateX(-50%);
      background: var(--btn-bg);
      padding: 0.75rem 1.5rem;
      border-radius: var(--radius);
      text-decoration: none;
      color: #333;
      font-weight: bold;
      opacity: 0;
      animation: slideUpFadeIn 0.8s ease-out forwards;
      transition: transform 0.3s ease, background 0.3s ease;
    }

    @keyframes slideUpFadeIn {
      from { opacity: 0; transform: translateX(-50%) translateY(20px); }
      to { opacity: 1; transform: translateX(-50%) translateY(0); }
    }

    .contact:hover {
      transform: translateX(-50%) translateY(-3px);
      background: rgba(255, 255, 255, 1);
    }

    .toast {
      position: fixed;
      bottom: 2rem;
      right: 2rem;
      background: rgba(0,0,0,0.9);
      color: white;
      padding: 1rem 1.5rem;
      border-radius: var(--radius);
      box-shadow: 0 8px 24px rgba(0,0,0,0.3);
      opacity: 0;
      transform: translateY(20px);
      transition: all 0.3s ease;
      z-index: 1000;
    }

    .toast.show {
      opacity: 1;
      transform: translateY(0);
    }

    @media (max-width: 768px) {
      .page-grid {
        grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
        gap: 1rem;
      }
    }