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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    background: white;
    border-radius: 12px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.2);
    overflow: hidden;
}

header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 30px;
    text-align: center;
}

header h1 {
    font-size: 2.5em;
    font-weight: 600;
}

.tabs {
    display: flex;
    background: #f5f5f5;
    border-bottom: 2px solid #e0e0e0;
}

.tab-btn {
    flex: 1;
    padding: 15px 20px;
    background: none;
    border: none;
    cursor: pointer;
    font-size: 16px;
    font-weight: 500;
    color: #666;
    transition: all 0.3s;
}

.tab-btn:hover {
    background: #e8e8e8;
    color: #333;
}

.tab-btn.active {
    background: white;
    color: #667eea;
    border-bottom: 3px solid #667eea;
}

.tab-content {
    display: none;
    padding: 30px;
}

.tab-content.active {
    display: block;
}

.upload-section, .list-section, .compare-section {
    max-width: 800px;
    margin: 0 auto;
}

h2 {
    margin-bottom: 20px;
    color: #333;
    font-size: 1.8em;
}

.upload-area {
    border: 3px dashed #667eea;
    border-radius: 8px;
    padding: 40px;
    text-align: center;
    background: #f9f9f9;
    transition: all 0.3s;
    cursor: pointer;
}

.upload-area:hover {
    border-color: #764ba2;
    background: #f0f0f0;
}

.upload-placeholder p {
    margin-bottom: 20px;
    color: #666;
    font-size: 16px;
}

.btn {
    padding: 12px 24px;
    border: none;
    border-radius: 6px;
    font-size: 16px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s;
}

.btn-primary {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.4);
}

.btn-secondary {
    background: #6c757d;
    color: white;
    margin-bottom: 20px;
}

.btn-secondary:hover {
    background: #5a6268;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.upload-progress {
    margin-top: 20px;
}

.progress-bar {
    width: 100%;
    height: 30px;
    background: #e0e0e0;
    border-radius: 15px;
    overflow: hidden;
    margin-bottom: 10px;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, #667eea 0%, #764ba2 100%);
    width: 0%;
    transition: width 0.3s;
    border-radius: 15px;
}

.result-message {
    margin-top: 20px;
    padding: 15px;
    border-radius: 6px;
    display: none;
}

.result-message.success {
    background: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
    display: block;
}

.result-message.error {
    background: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
    display: block;
}

.video-list {
    margin-top: 20px;
}

.video-item {
    background: #f8f9fa;
    border: 1px solid #e0e0e0;
    border-radius: 8px;
    padding: 20px;
    margin-bottom: 15px;
    transition: all 0.3s;
}

.video-item:hover {
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    transform: translateY(-2px);
}

.video-item-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 10px;
}

.video-item-title {
    font-size: 18px;
    font-weight: 600;
    color: #333;
}

.video-item-meta {
    color: #666;
    font-size: 14px;
    margin-bottom: 10px;
}

.video-item-actions {
    display: flex;
    gap: 10px;
    margin-top: 15px;
}

.btn-small {
    padding: 8px 16px;
    font-size: 14px;
}

.btn-info {
    background: #17a2b8;
    color: white;
}

.btn-info:hover {
    background: #138496;
}

.btn-success {
    background: #28a745;
    color: white;
}

.btn-success:hover {
    background: #218838;
}

.loading {
    text-align: center;
    padding: 40px;
    color: #666;
}

.compare-controls {
    margin-bottom: 30px;
}

.video-selector {
    margin-bottom: 20px;
}

.video-selector label {
    display: block;
    margin-bottom: 10px;
    font-weight: 500;
    color: #333;
}

.video-checkboxes {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 10px;
    max-height: 300px;
    overflow-y: auto;
    padding: 15px;
    background: #f8f9fa;
    border-radius: 6px;
}

.video-checkbox-item {
    display: flex;
    align-items: center;
    padding: 10px;
    background: white;
    border-radius: 4px;
    border: 1px solid #e0e0e0;
}

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

.compare-result-content {
    background: #f8f9fa;
    padding: 20px;
    border-radius: 6px;
    margin-top: 20px;
    white-space: pre-wrap;
    line-height: 1.6;
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    overflow: auto;
}

.modal-content {
    background-color: white;
    margin: 5% auto;
    padding: 30px;
    border-radius: 12px;
    width: 90%;
    max-width: 800px;
    max-height: 80vh;
    overflow-y: auto;
    position: relative;
}

.close {
    color: #aaa;
    float: right;
    font-size: 28px;
    font-weight: bold;
    cursor: pointer;
    position: absolute;
    right: 20px;
    top: 20px;
}

.close:hover {
    color: #000;
}

.modal-body {
    margin-top: 20px;
}

.detail-section {
    margin-bottom: 20px;
}

.detail-section h3 {
    color: #667eea;
    margin-bottom: 10px;
}

.detail-section p {
    color: #666;
    line-height: 1.6;
}

@media (max-width: 768px) {
    header h1 {
        font-size: 1.8em;
    }
    
    .tab-btn {
        font-size: 14px;
        padding: 12px 10px;
    }
    
    .upload-area {
        padding: 20px;
    }
    
    .video-item-header {
        flex-direction: column;
        align-items: flex-start;
    }
}