:root {
    /* Colors */
    --primary-color: #3b82f6;
    --primary-hover: #2563eb;
    --primary-active: #1d4ed8;
    --secondary-bg: #f1f5f9;
    --secondary-hover: #e2e8f0;
    
    --bg-color: #f8fafc;
    --surface-color: #ffffff;
    
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --text-tertiary: #94a3b8;
    
    --border-color: #e2e8f0;
    --divider-color: #cbd5e1;
    
    --success-color: #10b981;
    --error-color: #ef4444;
    --warning-color: #f59e0b;

    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    
    /* Layout */
    --container-width: 1000px;
    --border-radius-sm: 0.375rem;
    --border-radius-md: 0.75rem;
    --border-radius-lg: 1rem;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);

    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-normal: 0.3s ease;
}

/* Reset & Base Styles */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.6;
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
}

button, input, textarea {
    font-family: inherit;
    font-size: inherit;
}

/* Utilities */
.hidden { display: none !important; }
.btn-block { display: block; width: 100%; }

/* Layout Containers */
.app-container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: var(--spacing-md);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.app-main {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xl);
}

/* Header */
.app-header {
    text-align: center;
    padding: var(--spacing-xl) 0;
    margin-bottom: var(--spacing-md);
}

.app-title {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: var(--spacing-xs);
    letter-spacing: -0.02em;
}

.app-subtitle {
    color: var(--text-secondary);
    font-size: 1rem;
}

/* Mode Selector */
.mode-selector {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-md);
    justify-content: center;
    margin-bottom: var(--spacing-lg);
    background: var(--surface-color);
    padding: var(--spacing-sm);
    border-radius: var(--border-radius-md);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
}

.mode-option {
    position: relative;
    cursor: pointer;
}

.mode-option input {
    position: absolute;
    opacity: 0;
    width: 0;
    height: 0;
}

.mode-label {
    display: inline-block;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--border-radius-sm);
    color: var(--text-secondary);
    font-weight: 500;
    transition: all var(--transition-fast);
    user-select: none;
}

.mode-option input:checked + .mode-label {
    background-color: var(--primary-color);
    color: white;
    box-shadow: var(--shadow-sm);
}

.mode-option:hover .mode-label:not(:active) {
    background-color: var(--secondary-bg);
    color: var(--text-primary);
}

.mode-option input:checked:hover + .mode-label {
    background-color: var(--primary-hover);
    color: white;
}

/* Input Group */
.input-group {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.input-wrapper {
    position: relative;
    flex: 1;
}

input[type="url"] {
    width: 100%;
    padding: var(--spacing-md) var(--spacing-lg);
    padding-right: 2.5rem; /* Space for clear btn */
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius-md);
    background-color: var(--surface-color);
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

input[type="url"]:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

.clear-btn {
    position: absolute;
    right: var(--spacing-sm);
    top: 50%;
    transform: translateY(-50%);
    background: none;
    border: none;
    color: var(--text-tertiary);
    cursor: pointer;
    padding: var(--spacing-xs);
    font-size: 1rem;
    line-height: 1;
}

.clear-btn:hover { color: var(--text-secondary); }

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: 0.75rem 1.5rem;
    border-radius: var(--border-radius-md);
    font-weight: 600;
    text-decoration: none;
    cursor: pointer;
    border: none;
    transition: all var(--transition-fast);
}

.btn-primary {
    background-color: var(--primary-color);
    color: white;
}

.btn-primary:hover {
    background-color: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.btn-primary:active {
    transform: translateY(0);
    background-color: var(--primary-active);
}

.btn-secondary {
    background-color: var(--secondary-bg);
    color: var(--text-primary);
}

.btn-secondary:hover {
    background-color: var(--secondary-hover);
}

.btn:disabled {
    opacity: 0.7;
    cursor: not-allowed;
    transform: none !important;
}

/* Status Sections */
.status-section {
    text-align: center;
    padding: var(--spacing-lg);
    animation: fadeIn var(--transition-normal);
}

.spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--border-color);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    margin: 0 auto var(--spacing-md);
    animation: spin 0.8s linear infinite;
}

.status-text { color: var(--text-secondary); font-weight: 500; }

.error-card {
    background-color: #fef2f2;
    border: 1px solid #fee2e2;
    border-radius: var(--border-radius-md);
    padding: var(--spacing-md);
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-md);
    color: var(--error-color);
}

.error-icon { font-size: 1.5rem; }

/* Result Card */
.video-card {
    background: var(--surface-color);
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--border-color);
    animation: slideUp var(--transition-normal);
}

.video-header {
    margin-bottom: var(--spacing-lg);
    text-align: center;
}

.video-title {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-xs);
    line-height: 1.4;
}

.video-meta {
    display: flex;
    justify-content: center;
    gap: var(--spacing-sm);
    font-size: 0.875rem;
}

.author-badge {
    background: var(--secondary-bg);
    padding: 0.25rem 0.75rem;
    border-radius: 999px;
    color: var(--text-secondary);
}

/* Media Preview */
.media-preview {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-xl);
}

.preview-container {
    position: relative;
    width: 100%;
    background: black;
    border-radius: var(--border-radius-md);
    overflow: hidden;
    aspect-ratio: 16/9;
    display: flex;
    align-items: center;
    justify-content: center;
}

.preview-container img {
    width: 100%;
    height: 100%;
    object-fit: contain;
}

.play-overlay {
    position: absolute;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(0,0,0,0.3);
    cursor: pointer;
    transition: background var(--transition-fast);
}

.play-overlay:hover { background: rgba(0,0,0,0.2); }

.play-icon {
    font-size: 3rem;
    color: white;
    filter: drop-shadow(0 2px 4px rgba(0,0,0,0.5));
}

.action-bar {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-md);
}

/* Images Grid */
.images-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-xl);
}

.image-item {
    position: relative;
    border-radius: var(--border-radius-md);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    aspect-ratio: 1;
}

.image-item img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform var(--transition-normal);
}

.image-item:hover img { transform: scale(1.05); }

.download-icon {
    position: absolute;
    bottom: var(--spacing-xs);
    right: var(--spacing-xs);
    background: rgba(255,255,255,0.9);
    width: 32px;
    height: 32px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    text-decoration: none;
    box-shadow: var(--shadow-sm);
    transition: transform var(--transition-fast);
}

.download-icon:hover { transform: scale(1.1); }

/* Raw Data */
.raw-data-section {
    border-top: 1px solid var(--border-color);
    padding-top: var(--spacing-lg);
}

.json-details summary {
    cursor: pointer;
    color: var(--text-secondary);
    font-weight: 500;
    margin-bottom: var(--spacing-sm);
    user-select: none;
}

.code-wrapper {
    position: relative;
    background: #1e293b;
    border-radius: var(--border-radius-md);
    overflow: hidden;
}

pre {
    padding: var(--spacing-md);
    color: #e2e8f0;
    font-family: 'Fira Code', monospace;
    font-size: 0.875rem;
    overflow-x: auto;
    margin: 0;
}

.copy-btn {
    position: absolute;
    top: var(--spacing-sm);
    right: var(--spacing-sm);
    background: rgba(255,255,255,0.1);
    border: none;
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: var(--border-radius-sm);
    font-size: 0.75rem;
    cursor: pointer;
}

.copy-btn:hover { background: rgba(255,255,255,0.2); }

/* Footer */
.app-footer {
    text-align: center;
    color: var(--text-tertiary);
    font-size: 0.875rem;
    margin-top: auto;
    padding-top: var(--spacing-xl);
}

/* Animations */
@keyframes spin { to { transform: rotate(360deg); } }
@keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }
@keyframes slideUp { from { opacity: 0; transform: translateY(20px); } to { opacity: 1; transform: translateY(0); } }

/* Responsive */
@media (min-width: 640px) {
    .input-group {
        flex-direction: row;
    }
    
    .btn-loader {
        /* Add styling for loading state in button if needed */
    }
}

@media (min-width: 768px) {
    .media-preview {
        flex-direction: row;
        align-items: flex-start;
    }
    
    .preview-container {
        flex: 3;
        aspect-ratio: 16/9;
    }
    
    .action-bar {
        flex: 2;
        display: flex;
        flex-direction: column;
    }
    
    .app-title { font-size: 3rem; }
}

@media (max-width: 480px) {
    :root {
        --spacing-md: 0.75rem;
        --spacing-lg: 1rem;
        --spacing-xl: 1.5rem;
    }
    
    .app-title { font-size: 2rem; }
    
    .mode-selector {
        flex-direction: column;
        width: 100%;
    }
    
    .mode-label {
        display: block;
        text-align: center;
        width: 100%;
    }
    
    .action-bar {
        grid-template-columns: 1fr;
    }
}