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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, 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: 15px;
    padding: 30px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.2);
}

header {
    text-align: center;
    margin-bottom: 30px;
    padding-bottom: 20px;
    border-bottom: 2px solid #667eea;
}

header h1 {
    color: #667eea;
    font-size: 2.5em;
    margin-bottom: 10px;
}

header p {
    color: #666;
    font-size: 1.1em;
}

.user-section {
    margin-bottom: 30px;
    padding: 20px;
    background: #f8f9fa;
    border-radius: 10px;
}

.requirement-box {
    margin-top: 15px;
    padding: 15px;
    background: white;
    border-left: 4px solid #667eea;
    border-radius: 5px;
}

.requirement-box p {
    margin-top: 10px;
    color: #333;
    font-size: 1.05em;
}

.tabs {
    display: flex;
    gap: 10px;
    margin-bottom: 30px;
    border-bottom: 2px solid #e0e0e0;
}

.tab-btn {
    padding: 12px 30px;
    background: transparent;
    border: none;
    border-bottom: 3px solid transparent;
    cursor: pointer;
    font-size: 1.1em;
    color: #666;
    transition: all 0.3s;
}

.tab-btn:hover {
    color: #667eea;
}

.tab-btn.active {
    color: #667eea;
    border-bottom-color: #667eea;
    font-weight: bold;
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
    animation: fadeIn 0.3s;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: #333;
}

.form-control {
    width: 100%;
    padding: 12px;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    font-size: 1em;
    transition: border-color 0.3s;
}

.form-control:focus {
    outline: none;
    border-color: #667eea;
}

.form-group small {
    display: block;
    margin-top: 5px;
    color: #999;
    font-size: 0.9em;
}

.tags-container {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.tag-item {
    display: flex;
    align-items: center;
    gap: 5px;
}

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

.tag-item label {
    margin: 0;
    cursor: pointer;
    color: #333;
}

.video-url-item {
    display: flex;
    gap: 10px;
    margin-bottom: 10px;
}

.video-url-item .form-control {
    flex: 1;
}

.btn {
    padding: 12px 25px;
    border: none;
    border-radius: 8px;
    font-size: 1em;
    cursor: pointer;
    transition: all 0.3s;
    font-weight: 600;
}

.btn-primary {
    background: #667eea;
    color: white;
}

.btn-primary:hover {
    background: #5568d3;
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.3);
}

.btn-secondary {
    background: #6c757d;
    color: white;
    margin-top: 10px;
}

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

.btn-preview {
    padding: 8px 15px;
    background: #17a2b8;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
}

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

.btn-remove {
    padding: 8px 15px;
    background: #dc3545;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
}

.btn-remove:hover {
    background: #c82333;
}

.alert {
    padding: 15px 20px;
    border-radius: 8px;
    margin: 20px 0;
    animation: slideDown 0.3s;
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.alert-info {
    background: #d1ecf1;
    color: #0c5460;
    border-left: 4px solid #17a2b8;
}

.alert-success {
    background: #d4edda;
    color: #155724;
    border-left: 4px solid #28a745;
}

.alert-error {
    background: #f8d7da;
    color: #721c24;
    border-left: 4px solid #dc3545;
}

.alert-warning {
    background: #fff3cd;
    color: #856404;
    border-left: 4px solid #ffc107;
}

.videos-preview {
    margin: 20px 0;
    padding: 20px;
    background: #f8f9fa;
    border-radius: 10px;
}

.videos-preview h3 {
    margin-bottom: 15px;
    color: #667eea;
}

.video-preview-item {
    padding: 10px;
    background: white;
    border-radius: 5px;
    margin-bottom: 10px;
    border-left: 3px solid #667eea;
}

.video-preview-item h4 {
    font-size: 1em;
    color: #333;
    margin-bottom: 5px;
}

.video-preview-item p {
    font-size: 0.9em;
    color: #666;
    margin: 3px 0;
}

.total-duration {
    margin-top: 15px;
    padding: 15px;
    background: white;
    border-radius: 5px;
    font-size: 1.1em;
    text-align: center;
}

.filters {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 15px;
    margin-bottom: 30px;
    padding: 20px;
    background: #f8f9fa;
    border-radius: 10px;
}

.stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.stat-card {
    padding: 20px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border-radius: 10px;
    text-align: center;
}

.stat-card h3 {
    font-size: 2.5em;
    margin-bottom: 10px;
}

.stat-card p {
    font-size: 1.1em;
}

.data-table {
    overflow-x: auto;
    margin-bottom: 30px;
}

.data-table table {
    width: 100%;
    border-collapse: collapse;
    background: white;
    border-radius: 10px;
    overflow: hidden;
}

.data-table th {
    background: #667eea;
    color: white;
    padding: 15px;
    text-align: left;
    font-weight: 600;
}

.data-table td {
    padding: 12px 15px;
    border-bottom: 1px solid #e0e0e0;
}

.data-table tr:hover {
    background: #f8f9fa;
}

.data-table a {
    color: #667eea;
    text-decoration: none;
}

.data-table a:hover {
    text-decoration: underline;
}

.tag-badge {
    display: inline-block;
    padding: 5px 10px;
    background: #667eea;
    color: white;
    border-radius: 15px;
    font-size: 0.85em;
    margin-right: 5px;
    margin-bottom: 5px;
}

.empty-message {
    text-align: center;
    padding: 40px;
    color: #999;
    font-size: 1.1em;
}

#alertBox {
    position: fixed;
    top: 20px;
    right: 20px;
    max-width: 400px;
    z-index: 1000;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.2);
}

@media (max-width: 768px) {
    .container {
        padding: 15px;
    }

    header h1 {
        font-size: 1.8em;
    }

    .tabs {
        flex-direction: column;
    }

    .video-url-item {
        flex-direction: column;
    }

    .filters {
        grid-template-columns: 1fr;
    }
}