/* Reset and Base Styles */
* {
    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;
    color: #333;
}

/* Navigation */
.navbar {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: 0 2px 20px rgba(0, 0, 0, 0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.5rem;
    font-weight: bold;
    color: #667eea;
}

.nav-logo i {
    font-size: 1.8rem;
}

.nav-menu {
    display: flex;
    gap: 2rem;
}

.nav-link {
    text-decoration: none;
    color: #666;
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: 8px;
    transition: all 0.3s ease;
}

.nav-link:hover,
.nav-link.active {
    color: #667eea;
    background: rgba(102, 126, 234, 0.1);
}

/* Main Content */
.main-content {
    min-height: calc(100vh - 80px);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
}

.page {
    display: none;
}

.page.active {
    display: block;
}

/* Hero Section */
.hero {
    text-align: center;
    margin-bottom: 3rem;
    color: white;
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
}

.hero p {
    font-size: 1.2rem;
    opacity: 0.9;
}

/* Upload Section */
.upload-section {
    background: white;
    border-radius: 20px;
    padding: 2rem;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
}

.upload-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    margin-bottom: 2rem;
}

.upload-card {
    background: #f8f9fa;
    border-radius: 15px;
    padding: 1.5rem;
    border: 2px dashed #dee2e6;
    transition: all 0.3s ease;
}

.upload-card:hover {
    border-color: #667eea;
    background: #f0f2ff;
}

.upload-card h3 {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 1rem;
    color: #495057;
}

.upload-area {
    text-align: center;
    padding: 2rem;
    cursor: pointer;
    border-radius: 10px;
    transition: all 0.3s ease;
    position: relative;
}

.upload-area:hover {
    background: rgba(102, 126, 234, 0.1);
}

.upload-area.drag-over {
    background: rgba(102, 126, 234, 0.2);
    border-color: #667eea;
    transform: scale(1.02);
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.3);
}

.upload-area.drag-over::before {
    content: "Drop file here";
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background: rgba(102, 126, 234, 0.9);
    color: white;
    padding: 1rem 2rem;
    border-radius: 8px;
    font-weight: 600;
    z-index: 10;
    pointer-events: none;
}

.upload-area i {
    font-size: 3rem;
    color: #667eea;
    margin-bottom: 1rem;
}

.upload-area p {
    color: #6c757d;
    font-weight: 500;
    margin-bottom: 0.5rem;
}

.upload-area small {
    color: #adb5bd;
    font-size: 0.85rem;
    display: block;
}

.preview-container {
    position: relative;
    border-radius: 10px;
    overflow: hidden;
    max-height: 300px;
}

.preview-container img,
.preview-container video {
    width: 100%;
    height: auto;
    max-height: 300px;
    object-fit: cover;
    border-radius: 10px;
}

.remove-btn {
    position: absolute;
    top: 10px;
    right: 10px;
    background: rgba(220, 53, 69, 0.9);
    color: white;
    border: none;
    border-radius: 50%;
    width: 30px;
    height: 30px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s ease;
}

.remove-btn:hover {
    background: #dc3545;
    transform: scale(1.1);
}

/* Examples Section */
.examples-section {
    margin: 2rem 0;
    padding: 1.5rem;
    background: #f8f9fa;
    border-radius: 15px;
}

.examples-section h3 {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 1rem;
    color: #495057;
}

.examples-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 1rem;
}

.example-item {
    cursor: pointer;
    border-radius: 10px;
    overflow: hidden;
    transition: all 0.3s ease;
    border: 2px solid transparent;
}

.example-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
    border-color: #667eea;
}

.example-item.selected {
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.3);
}

.example-item img,
.example-item video {
    width: 100%;
    height: 120px;
    object-fit: cover;
}

.example-item span {
    display: block;
    padding: 0.5rem;
    text-align: center;
    background: white;
    font-weight: 500;
    color: #495057;
}

/* Action Section */
.action-section {
    text-align: center;
    margin: 2rem 0;
}

.swap-button {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    padding: 1rem 2rem;
    font-size: 1.1rem;
    font-weight: 600;
    border-radius: 50px;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin: 0 auto;
}

.swap-button:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.4);
}

.swap-button:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

/* Progress Section */
.progress-section {
    text-align: center;
    margin: 2rem 0;
}

.progress-bar {
    width: 100%;
    height: 8px;
    background: #e9ecef;
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: 1rem;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, #667eea, #764ba2);
    width: 0%;
    transition: width 0.3s ease;
    border-radius: 4px;
}

#progress-text {
    color: #6c757d;
    font-weight: 500;
}

/* Result Section */
.result-section {
    text-align: center;
    margin: 2rem 0;
    padding: 2rem;
    background: #f8f9fa;
    border-radius: 15px;
}

.result-section h3 {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
    color: #28a745;
}

.result-preview {
    margin-bottom: 2rem;
    border-radius: 10px;
    overflow: hidden;
    max-width: 500px;
    margin-left: auto;
    margin-right: auto;
}

.result-preview img,
.result-preview video {
    width: 100%;
    height: auto;
    border-radius: 10px;
}

.result-actions {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

.download-button {
    background: #28a745;
    color: white;
    border: none;
    padding: 0.8rem 1.5rem;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 500;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.download-button:hover {
    background: #218838;
    transform: translateY(-2px);
}

.secondary-button {
    background: #6c757d;
    color: white;
    border: none;
    padding: 0.8rem 1.5rem;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 500;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.secondary-button:hover {
    background: #5a6268;
    transform: translateY(-2px);
}

/* History Page */
.page-header {
    text-align: center;
    margin-bottom: 3rem;
    color: white;
}

.page-header h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
}

.page-header p {
    font-size: 1.1rem;
    opacity: 0.9;
}

.empty-state {
    text-align: center;
    padding: 4rem 2rem;
    color: white;
}

.empty-state i {
    font-size: 4rem;
    margin-bottom: 1rem;
    opacity: 0.5;
}

.empty-state h3 {
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
}

.empty-state p {
    opacity: 0.8;
}

.history-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 2rem;
}

.history-item {
    background: white;
    border-radius: 15px;
    overflow: hidden;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
}

.history-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
}

.history-preview {
    position: relative;
    height: 200px;
    overflow: hidden;
}

.history-preview img,
.history-preview video {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.history-info {
    padding: 1rem;
}

.history-info h4 {
    margin-bottom: 0.5rem;
    color: #495057;
}

.history-date {
    color: #6c757d;
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

.history-actions {
    display: flex;
    gap: 0.5rem;
}

.history-actions button {
    flex: 1;
    padding: 0.5rem;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: all 0.3s ease;
}

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

.preview-btn:hover {
    background: #5a6fd8;
}

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

.download-history-btn:hover {
    background: #218838;
}

.delete-btn {
    background: #dc3545;
    color: white;
}

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

/* Responsive Design */
@media (max-width: 768px) {
    .nav-container {
        padding: 1rem;
    }
    
    .nav-menu {
        gap: 1rem;
    }
    
    .hero h1 {
        font-size: 2rem;
    }
    
    .upload-grid {
        grid-template-columns: 1fr;
    }
    
    .container {
        padding: 1rem;
    }
    
    .examples-grid {
        grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    }
    
    .result-actions {
        flex-direction: column;
        align-items: center;
    }
    
    .history-grid {
        grid-template-columns: 1fr;
    }
}

/* Loading Animation */
@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.loading {
    animation: spin 1s linear infinite;
}

/* Modal Styles */
.modal {
    display: none;
    position: fixed;
    z-index: 2000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.8);
    backdrop-filter: blur(5px);
}

.modal-content {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    max-width: 90%;
    max-height: 90%;
    background: white;
    border-radius: 15px;
    overflow: hidden;
}

.modal-content img,
.modal-content video {
    width: 100%;
    height: auto;
    max-height: 80vh;
    object-fit: contain;
}

.modal-close {
    position: absolute;
    top: 15px;
    right: 20px;
    color: white;
    font-size: 2rem;
    font-weight: bold;
    cursor: pointer;
    background: rgba(0, 0, 0, 0.5);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.modal-close:hover {
    background: rgba(0, 0, 0, 0.7);
}

/* Error Notification */
.error-notification {
    position: fixed;
    top: 20px;
    right: 20px;
    background: #dc3545;
    color: white;
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(220, 53, 69, 0.3);
    z-index: 3000;
    max-width: 400px;
    animation: slideInRight 0.3s ease-out;
}

.error-content {
    display: flex;
    align-items: center;
    padding: 1rem;
    gap: 0.75rem;
}

.error-content i.fa-exclamation-triangle {
    font-size: 1.2rem;
    flex-shrink: 0;
}

.error-content span {
    flex: 1;
    font-weight: 500;
}

.error-close {
    background: none;
    border: none;
    color: white;
    cursor: pointer;
    padding: 0.25rem;
    border-radius: 4px;
    transition: background-color 0.2s ease;
    flex-shrink: 0;
}

.error-close:hover {
    background: rgba(255, 255, 255, 0.2);
}

@keyframes slideInRight {
    from {
        transform: translateX(100%);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}