/**
 * VideoFlow Main Stylesheet
 * Modern, responsive, production-ready CSS
 */

/* ========== CSS VARIABLES ========== */
:root {
    /* Colors */
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #818cf8;
    --secondary: #10b981;
    --secondary-dark: #059669;
    --danger: #ef4444;
    --danger-dark: #dc2626;
    --warning: #f59e0b;
    --info: #3b82f6;
    --dark: #1e293b;
    --darker: #0f172a;
    --light: #f8fafc;
    --gray: #64748b;
    --gray-light: #94a3b8;
    --gray-dark: #475569;
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-2xl: 1.5rem;
    --radius-full: 9999px;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1);
    
    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-normal: 300ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 500ms cubic-bezier(0.4, 0, 0.2, 1);
    
    /* Z-Index Layers */
    --z-dropdown: 1000;
    --z-sticky: 1020;
    --z-modal: 1050;
    --z-popover: 1060;
    --z-tooltip: 1070;
    --z-toast: 1080;
}

/* ========== RESET & BASE ========== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--light);
    color: var(--dark);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ========== TYPOGRAPHY ========== */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.25;
    color: var(--dark);
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }
h5 { font-size: 1.125rem; }
h6 { font-size: 1rem; }

a {
    color: var(--primary);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--primary-dark);
}

/* ========== LAYOUT ========== */
.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

.section {
    padding: var(--spacing-2xl) 0;
}

.section-title {
    font-size: 1.875rem;
    font-weight: 700;
    margin-bottom: var(--spacing-xl);
    text-align: center;
}

/* ========== BUTTONS ========== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-lg);
    font-size: 0.875rem;
    font-weight: 600;
    line-height: 1.5;
    text-align: center;
    text-decoration: none;
    white-space: nowrap;
    border-radius: var(--radius-md);
    border: none;
    cursor: pointer;
    transition: all var(--transition-fast);
}

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

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

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

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

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

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

.btn-outline {
    background-color: transparent;
    border: 2px solid var(--primary);
    color: var(--primary);
}

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

.btn-sm {
    padding: var(--spacing-xs) var(--spacing-md);
    font-size: 0.75rem;
}

.btn-lg {
    padding: var(--spacing-md) var(--spacing-xl);
    font-size: 1rem;
}

.btn-block {
    width: 100%;
    display: flex;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
}

/* ========== FORMS ========== */
.form-group {
    margin-bottom: var(--spacing-lg);
}

.form-label {
    display: block;
    margin-bottom: var(--spacing-sm);
    font-weight: 500;
    color: var(--dark);
}

.form-control {
    width: 100%;
    padding: var(--spacing-md);
    font-size: 1rem;
    line-height: 1.5;
    color: var(--dark);
    background-color: white;
    border: 1px solid #e2e8f0;
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
}

.form-control:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.form-control.is-invalid {
    border-color: var(--danger);
}

.form-control.is-invalid:focus {
    box-shadow: 0 0 0 3px rgba(239, 68, 68, 0.1);
}

.form-error {
    margin-top: var(--spacing-xs);
    font-size: 0.75rem;
    color: var(--danger);
}

.form-help {
    margin-top: var(--spacing-xs);
    font-size: 0.75rem;
    color: var(--gray);
}

/* ========== CARDS ========== */
.card {
    background-color: white;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    overflow: hidden;
    transition: transform var(--transition-normal), box-shadow var(--transition-normal);
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-xl);
}

.card-header {
    padding: var(--spacing-lg);
    border-bottom: 1px solid #e2e8f0;
    background-color: white;
}

.card-body {
    padding: var(--spacing-lg);
}

.card-footer {
    padding: var(--spacing-lg);
    border-top: 1px solid #e2e8f0;
    background-color: var(--light);
}

/* ========== VIDEO GRID ========== */
.video-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: var(--spacing-lg);
    margin-top: var(--spacing-xl);
}

.video-card {
    background-color: white;
    border-radius: var(--radius-lg);
    overflow: hidden;
    cursor: pointer;
    transition: all var(--transition-normal);
    box-shadow: var(--shadow-sm);
}

.video-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.video-thumbnail {
    position: relative;
    overflow: hidden;
    background-color: var(--darker);
    aspect-ratio: 16 / 9;
}

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

.video-card:hover .video-thumbnail img {
    transform: scale(1.05);
}

.video-duration {
    position: absolute;
    bottom: var(--spacing-sm);
    right: var(--spacing-sm);
    padding: 2px 6px;
    background-color: rgba(0, 0, 0, 0.75);
    color: white;
    font-size: 0.75rem;
    border-radius: var(--radius-sm);
}

.video-info {
    padding: var(--spacing-md);
}

.video-title {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.video-meta {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    margin-top: var(--spacing-sm);
    font-size: 0.75rem;
    color: var(--gray);
}

.video-creator {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-sm);
}

.creator-avatar {
    width: 28px;
    height: 28px;
    border-radius: 50%;
    object-fit: cover;
}

.badge {
    display: inline-flex;
    align-items: center;
    padding: 2px 8px;
    font-size: 0.6875rem;
    font-weight: 600;
    border-radius: var(--radius-full);
}

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

.badge-success {
    background-color: var(--secondary);
    color: white;
}

.badge-warning {
    background-color: var(--warning);
    color: white;
}

.badge-danger {
    background-color: var(--danger);
    color: white;
}

/* ========== VIDEO PLAYER ========== */
.video-player-container {
    position: relative;
    background-color: black;
    border-radius: var(--radius-lg);
    overflow: hidden;
}

.video-player {
    width: 100%;
    height: auto;
    display: block;
}

.video-controls {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    background: linear-gradient(to top, rgba(0, 0, 0, 0.9), transparent);
    padding: var(--spacing-md);
    opacity: 0;
    transition: opacity var(--transition-normal);
}

.video-player-container:hover .video-controls {
    opacity: 1;
}

.progress-bar {
    position: relative;
    width: 100%;
    height: 4px;
    background-color: rgba(255, 255, 255, 0.2);
    cursor: pointer;
    margin-bottom: var(--spacing-md);
}

.progress-filled {
    position: absolute;
    left: 0;
    top: 0;
    height: 100%;
    background-color: var(--primary);
    width: 0%;
}

.progress-buffered {
    position: absolute;
    left: 0;
    top: 0;
    height: 100%;
    background-color: rgba(255, 255, 255, 0.3);
    width: 0%;
}

.controls-bottom {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

.control-btn {
    background: none;
    border: none;
    color: white;
    cursor: pointer;
    padding: var(--spacing-xs);
    font-size: 1.25rem;
}

.volume-slider {
    width: 80px;
    height: 4px;
    -webkit-appearance: none;
    background: rgba(255, 255, 255, 0.2);
    border-radius: var(--radius-full);
}

.volume-slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 12px;
    height: 12px;
    background: white;
    border-radius: 50%;
    cursor: pointer;
}

.time-display {
    font-size: 0.875rem;
    color: white;
    font-family: monospace;
}

/* ========== MODAL ========== */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0, 0, 0, 0.75);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: var(--z-modal);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-normal);
}

.modal.active {
    opacity: 1;
    visibility: visible;
}

.modal-content {
    background-color: white;
    border-radius: var(--radius-lg);
    max-width: 90%;
    width: 500px;
    max-height: 90vh;
    overflow-y: auto;
    transform: translateY(-20px);
    transition: transform var(--transition-normal);
}

.modal.active .modal-content {
    transform: translateY(0);
}

.modal-header {
    padding: var(--spacing-lg);
    border-bottom: 1px solid #e2e8f0;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-body {
    padding: var(--spacing-lg);
}

.modal-footer {
    padding: var(--spacing-lg);
    border-top: 1px solid #e2e8f0;
    display: flex;
    justify-content: flex-end;
    gap: var(--spacing-sm);
}

.modal-close {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--gray);
}

/* ========== ALERTS ========== */
.alert {
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-lg);
}

.alert-success {
    background-color: #d1fae5;
    border: 1px solid #a7f3d0;
    color: #065f46;
}

.alert-danger {
    background-color: #fee2e2;
    border: 1px solid #fecaca;
    color: #991b1b;
}

.alert-warning {
    background-color: #fef3c7;
    border: 1px solid #fde68a;
    color: #92400e;
}

.alert-info {
    background-color: #dbeafe;
    border: 1px solid #bfdbfe;
    color: #1e40af;
}

/* ========== LOADING STATES ========== */
.spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--light);
    border-top-color: var(--primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.skeleton {
    background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
    background-size: 200% 100%;
    animation: loading 1.5s infinite;
}

@keyframes loading {
    0% { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}

/* ========== NAVIGATION ========== */
.navbar {
    background-color: white;
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: var(--z-sticky);
}

.navbar-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-md) var(--spacing-lg);
    max-width: 1280px;
    margin: 0 auto;
}

.navbar-logo {
    font-size: 1.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

.navbar-menu {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
}

.navbar-link {
    color: var(--gray);
    transition: color var(--transition-fast);
}

.navbar-link:hover,
.navbar-link.active {
    color: var(--primary);
}

.navbar-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
}

/* ========== BREADCRUMBS ========== */
.breadcrumb {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) 0;
    margin-bottom: var(--spacing-lg);
    list-style: none;
}

.breadcrumb-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.breadcrumb-item:not(:last-child)::after {
    content: '/';
    color: var(--gray);
}

.breadcrumb-link {
    color: var(--gray);
}

.breadcrumb-link:hover {
    color: var(--primary);
}

.breadcrumb-active {
    color: var(--dark);
    font-weight: 500;
}

/* ========== PAGINATION ========== */
.pagination {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-xl);
}

.page-link {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 36px;
    height: 36px;
    padding: 0 var(--spacing-sm);
    border-radius: var(--radius-md);
    background-color: white;
    color: var(--gray);
    transition: all var(--transition-fast);
}

.page-link:hover,
.page-link.active {
    background-color: var(--primary);
    color: white;
}

/* ========== TOAST NOTIFICATIONS ========== */
.toast-container {
    position: fixed;
    bottom: var(--spacing-lg);
    right: var(--spacing-lg);
    z-index: var(--z-toast);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.toast {
    background-color: white;
    border-radius: var(--radius-md);
    padding: var(--spacing-md) var(--spacing-lg);
    box-shadow: var(--shadow-lg);
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    animation: slideInRight var(--transition-normal);
}

.toast-success {
    border-left: 4px solid var(--secondary);
}

.toast-error {
    border-left: 4px solid var(--danger);
}

.toast-warning {
    border-left: 4px solid var(--warning);
}

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

/* ========== DARK MODE ========== */
@media (prefers-color-scheme: dark) {
    :root {
        --light: #1e293b;
        --dark: #f8fafc;
    }
    
    body {
        background-color: #0f172a;
    }
    
    .card,
    .modal-content,
    .navbar {
        background-color: #1e293b;
    }
    
    .form-control {
        background-color: #334155;
        border-color: #475569;
        color: white;
    }
}