* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
  }
  body {
    background: #0a0e27;
    font-family: 'Segoe UI', Arial, sans-serif;
    position: relative;
    overflow-x: hidden;
  }
  #bgCanvas {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 0;
    opacity: 0.6;
  }
  .content-wrapper {
    position: relative;
    z-index: 1;
    min-height: 100vh;
  }
  .container1 {
    max-width: 60%;
    margin: 40px auto;
    background: rgba(255, 255, 255, 0.98);
    border-radius: 16px;
    box-shadow: 0 12px 40px rgba(0,0,0,0.3);
    padding: 34px 22px 22px 22px;
    backdrop-filter: blur(10px);
  }
  h2 {
    color: #23496a;
    font-size: 1.5em;
    text-align: center;
    font-weight: 700;
    margin-top: 0;
    margin-bottom: 18px;
    letter-spacing: 1.2px;
  }
  #dropzone {
    border: 2.5px dashed #69a1e9;
    background: #f7fafd;
    padding: 40px 12px;
    border-radius: 12px;
    margin-bottom: 20px;
    font-size: 1.08em;
    color: #295184;
    text-align: center;
    cursor: pointer;
    font-weight: 500;
    transition: border-color 0.2s, background 0.16s;
  }
  #dropzone.hover { 
    border-color: #3366cc; 
    background: #e9f2fd; 
  }
  #fileList {
    display: flex;
    flex-direction: row;
    overflow-x: auto;
    padding: 12px 0;
    gap: 14px;
    margin-bottom: 18px;
    list-style: none;
    scrollbar-width: thin;
    scrollbar-color: #bed7f3 #f4f8fc;
  }
  #fileList::-webkit-scrollbar {
    height: 8px;
  }
  #fileList::-webkit-scrollbar-track {
    background: #f4f8fc;
    border-radius: 4px;
  }
  #fileList::-webkit-scrollbar-thumb {
    background: #bed7f3;
    border-radius: 4px;
  }
  #fileList li {
    display: flex;
    flex-direction: column;
    align-items: center;
    background: #f2f8fd;
    border-radius: 8px;
    border: 1.2px solid #dde6f2;
    box-shadow: 0 0.5px 3px #cde3fa4a;
    min-width: 110px;
    max-width: 130px;
    padding: 12px 8px 9px 8px;
    cursor: grab;
    transition: transform 0.2s, box-shadow 0.2s;
  }
  #fileList li:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px #c2d4ef66;
  }
  #fileList li img {
    width: 64px;
    height: 64px;
    border-radius: 6px;
    object-fit: cover;
    background: #fff;
    margin-bottom: 8px;
    box-shadow: 0 1px 5px #b9c6dd38;
  }
  #fileList li .pdf-icon {
    width: 64px;
    height: 64px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: #e15252;
    color: #fff;
    font-size: 22px;
    font-weight: 800;
    letter-spacing: 1px;
    border-radius: 6px;
    margin-bottom: 8px;
    user-select: none;
    box-shadow: 0 1px 5px #e1525266;
  }
  #fileList li span {
    text-align: center;
    font-size: 0.92em;
    color: #395175;
    margin-bottom: 7px;
    width: 100%;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    padding: 0 3px;
    font-weight: 500;
  }
  .file-actions {
    display: flex;
    gap: 5px;
    margin-top: 5px;
  }
  .download-btn-small {
    background: #4caf50;
    color: white;
    border: none;
    padding: 4px 8px;
    border-radius: 4px;
    font-size: 11px;
    cursor: pointer;
    font-weight: 600;
    transition: background 0.2s, transform 0.1s;
  }
  .download-btn-small:hover {
    background: #45a049;
    transform: scale(1.05);
  }
  .remove-btn-small {
    background: none;
    color: #d7263d;
    border: none;
    font-size: 18px;
    cursor: pointer;
    padding: 0 5px;
    line-height: 1;
    transition: transform 0.1s;
  }
  .remove-btn-small:hover {
    transform: scale(1.2);
  }
  .flex-row {
    display: flex;
    align-items: center;
    gap: 14px;
    margin-bottom: 16px;
  }
  #filenameInput {
    flex: 1;
    padding: 9px 13px;
    border-radius: 6px;
    border: 1.2px solid #bed7f3;
    font-size: 1.06em;
    color: #23496a;
    background: #f8fbfe;
    outline: none;
    transition: border 0.13s;
  }
  #filenameInput:focus { 
    border-color: #69a1e9; 
  }
  #controls { 
    text-align: right;
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    justify-content: flex-end;
    align-items: center;
  }
  .btn {
    padding: 10px 18px;
    border-radius: 7px;
    background: linear-gradient(90deg, #398afc 65%, #296eca);
    color: #fff;
    border: none;
    font-size: 1.07em;
    font-weight: 600;
    letter-spacing: 0.1px;
    transition: background 0.13s, transform 0.1s;
    cursor: pointer;
  }
  .btn:hover {
    transform: translateY(-1px);
    background: linear-gradient(90deg, #2a7eef 65%, #1f5eb8);
  }
  .btn:disabled { 
    background: #b1cbe4 !important; 
    color: #eee; 
    cursor: default;
    transform: none;
  }
  .btn-secondary {
    background: #ebf3f9;
    color: #3366cc;
    font-weight: 700;
    border: 1.2px solid #bfd8eb;
  }
  .btn-secondary:hover {
    background: #ddeaf5;
  }
  .btn-success {
    background: linear-gradient(90deg, #4caf50 65%, #388e3c);
    color: #fff;
  }
  .btn-success:hover {
    background: linear-gradient(90deg, #45a049 65%, #2e7d32);
  }
  .btn-success:disabled {
    background: #a5d6a7 !important;
  }
  
  /* Tutorial Section */
  .tutorial-section {
    max-width: 800px;
    margin: 60px auto 40px;
    background: rgba(255, 255, 255, 0.98);
    border-radius: 16px;
    padding: 40px 32px;
    box-shadow: 0 12px 40px rgba(0,0,0,0.3);
    backdrop-filter: blur(10px);
  }
  .tutorial-section h3 {
    color: #23496a;
    font-size: 1.8em;
    margin-bottom: 20px;
    text-align: center;
    font-weight: 700;
  }
  .tutorial-section h4 {
    color: #398afc;
    font-size: 1.3em;
    margin: 30px 0 15px;
    font-weight: 600;
  }
  .tutorial-section p {
    color: #3d5166;
    line-height: 1.8;
    margin-bottom: 16px;
    font-size: 1.05em;
  }
  .tutorial-section ul {
    margin: 15px 0 20px 25px;
    color: #3d5166;
    line-height: 1.9;
  }
  .tutorial-section ul li {
    margin-bottom: 10px;
    font-size: 1.04em;
  }
  .tutorial-section strong {
    color: #23496a;
    font-weight: 600;
  }
  .feature-box {
    background: #f0f7ff;
    border-left: 4px solid #398afc;
    padding: 15px 20px;
    margin: 20px 0;
    border-radius: 6px;
  }
  
  @media (max-width: 600px) {
    .container {
      max-width: 95vw;
      padding: 8vw 4vw 4vw 4vw;
      margin: 20px auto;
    }
    h2 {
      font-size: 1.3em;
    }
    #dropzone {
      padding: 30px 10px;
      font-size: 1em;
    }
    #fileList li {
      min-width: 95px;
      max-width: 110px;
    }
    .flex-row {
      flex-direction: column;
      align-items: stretch;
    }
    #filenameInput {
      font-size: 1em;
    }
    .btn {
      font-size: 0.95em;
      padding: 9px 12px;
    }
    #controls {
      justify-content: center;
    }
    .tutorial-section {
      max-width: 95vw;
      padding: 30px 20px;
      margin: 40px auto 20px;
    }
    .tutorial-section h3 {
      font-size: 1.5em;
    }
    .tutorial-section h4 {
      font-size: 1.2em;
    }
    .tutorial-section p, .tutorial-section ul li {
      font-size: 1em;
    }
  }
/* File Statistics Display */
.file-stats {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: #e8f4f8;
    border: 1px solid #a3d5ea;
    border-radius: 8px;
    padding: 12px 18px;
    margin-bottom: 18px;
    font-size: 0.98em;
    color: #2c5a7a;
    font-weight: 600;
}

.file-stats span {
    display: flex;
    align-items: center;
    gap: 6px;
}

.file-stats span::before {
    content: "📊";
    font-size: 1.1em;
}

/* Compression Option Styles */
.compression-option {
    background: #f0f7ff;
    border: 1.5px solid #b3d9ff;
    border-radius: 8px;
    padding: 14px 18px;
    margin-bottom: 18px;
}

.checkbox-container {
    display: flex;
    align-items: center;
    cursor: pointer;
    user-select: none;
    margin-bottom: 10px;
}

.checkbox-container input[type="checkbox"] {
    margin-right: 10px;
    width: 18px;
    height: 18px;
    cursor: pointer;
}

.checkbox-label {
    color: #23496a;
    font-weight: 500;
    font-size: 1.02em;
}

.compression-select {
    width: 100%;
    padding: 8px 12px;
    border-radius: 6px;
    border: 1.2px solid #bed7f3;
    background: #fff;
    font-size: 0.98em;
    color: #23496a;
    cursor: pointer;
    transition: border 0.2s;
}

.compression-select:disabled {
    background: #f0f0f0;
    cursor: not-allowed;
    opacity: 0.6;
}

.compression-select:enabled:hover {
    border-color: #69a1e9;
}

@media (max-width: 600px) {
    .file-stats {
        flex-direction: column;
        align-items: flex-start;
        gap: 8px;
        font-size: 0.9em;
    }
    
    .compression-option {
        padding: 12px 14px;
    }
    
    .checkbox-label {
        font-size: 0.95em;
    }
    
    .compression-select {
        font-size: 0.9em;
    }
}