/**
 * FB Video Downloader - Stylesheet
 *
 * Modern, responsive, mobile-first design with dark/light mode support.
 * Uses CSS custom properties for theming.
 *
 * @package FB_Video_Downloader
 * @version 1.0.0
 */

/* ============================================================
   CSS Custom Properties (Design Tokens)
   ============================================================ */
:root {
    /* Colors - Light mode */
    --fbvd-primary: #1877F2;
    --fbvd-primary-hover: #1565D8;
    --fbvd-primary-light: rgba(24, 119, 242, 0.08);
    --fbvd-primary-glow: rgba(24, 119, 242, 0.25);

    --fbvd-success: #00C851;
    --fbvd-success-hover: #00A844;
    --fbvd-warning: #FF8800;
    --fbvd-danger: #FF3D57;
    --fbvd-danger-light: rgba(255, 61, 87, 0.08);

    --fbvd-bg: #F0F2F5;
    --fbvd-surface: #FFFFFF;
    --fbvd-surface-hover: #F8F9FA;
    --fbvd-border: #E4E6EB;
    --fbvd-border-focus: #1877F2;

    --fbvd-text: #1C1E21;
    --fbvd-text-secondary: #65676B;
    --fbvd-text-muted: #8A8D91;
    --fbvd-text-on-primary: #FFFFFF;

    --fbvd-shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --fbvd-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
    --fbvd-shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.12);
    --fbvd-shadow-glow: 0 4px 20px rgba(24, 119, 242, 0.3);

    --fbvd-radius-sm: 8px;
    --fbvd-radius: 12px;
    --fbvd-radius-lg: 16px;
    --fbvd-radius-xl: 20px;
    --fbvd-radius-full: 9999px;

    --fbvd-font: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;

    --fbvd-transition: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    --fbvd-transition-slow: 0.35s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ============================================================
   Dark Mode
   ============================================================ */
.fbvd-wrapper[data-theme="dark"] {
    --fbvd-bg: #18191A;
    --fbvd-surface: #242526;
    --fbvd-surface-hover: #303031;
    --fbvd-border: #3A3B3C;
    --fbvd-text: #E4E6EB;
    --fbvd-text-secondary: #B0B3B8;
    --fbvd-text-muted: #8A8D91;
    --fbvd-shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.2);
    --fbvd-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
    --fbvd-shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.4);
    --fbvd-primary-light: rgba(24, 119, 242, 0.15);
    --fbvd-danger-light: rgba(255, 61, 87, 0.15);
}

/* Auto dark mode (system preference) */
@media (prefers-color-scheme: dark) {
    .fbvd-wrapper[data-theme="auto"] {
        --fbvd-bg: #18191A;
        --fbvd-surface: #242526;
        --fbvd-surface-hover: #303031;
        --fbvd-border: #3A3B3C;
        --fbvd-text: #E4E6EB;
        --fbvd-text-secondary: #B0B3B8;
        --fbvd-text-muted: #8A8D91;
        --fbvd-shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.2);
        --fbvd-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
        --fbvd-shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.4);
        --fbvd-primary-light: rgba(24, 119, 242, 0.15);
        --fbvd-danger-light: rgba(255, 61, 87, 0.15);
    }
}

/* ============================================================
   Base / Reset
   ============================================================ */
.fbvd-wrapper {
    font-family: var(--fbvd-font);
    color: var(--fbvd-text);
    max-width: 720px;
    margin: 0 auto;
    padding: 24px 16px 48px;
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.fbvd-wrapper *,
.fbvd-wrapper *::before,
.fbvd-wrapper *::after {
    box-sizing: border-box;
}

.fbvd-sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* ============================================================
   Breadcrumb
   ============================================================ */
.fbvd-breadcrumb {
    font-size: 13px;
    color: var(--fbvd-text-muted);
    margin-bottom: 24px;
    padding: 0;
}

.fbvd-breadcrumb a {
    color: var(--fbvd-primary);
    text-decoration: none;
    transition: color var(--fbvd-transition);
}

.fbvd-breadcrumb a:hover {
    color: var(--fbvd-primary-hover);
    text-decoration: underline;
}

.fbvd-breadcrumb-sep {
    margin: 0 6px;
    opacity: 0.5;
}

/* ============================================================
   Hero Section
   ============================================================ */
.fbvd-hero {
    text-align: center;
    margin-bottom: 28px;
    padding: 8px 0;
}

.fbvd-hero-icon {
    margin-bottom: 16px;
    animation: fbvdFloat 3s ease-in-out infinite;
}

@keyframes fbvdFloat {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-6px); }
}

.fbvd-title {
    font-size: 28px;
    font-weight: 800;
    margin: 0 0 8px;
    letter-spacing: -0.5px;
    background: linear-gradient(135deg, var(--fbvd-primary), #6C5CE7);
    background-clip: text;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    line-height: 1.2;
}

.fbvd-subtitle {
    font-size: 15px;
    color: var(--fbvd-text-secondary);
    margin: 0;
    max-width: 500px;
    margin: 0 auto;
    line-height: 1.5;
}

/* ============================================================
   Cards
   ============================================================ */
.fbvd-card {
    background: var(--fbvd-surface);
    border: 1px solid var(--fbvd-border);
    border-radius: var(--fbvd-radius-lg);
    padding: 24px;
    margin-bottom: 20px;
    box-shadow: var(--fbvd-shadow);
    transition: box-shadow var(--fbvd-transition);
}

.fbvd-card-main {
    border: 2px solid var(--fbvd-border);
    padding: 28px;
}

/* ============================================================
   Form / Input
   ============================================================ */
.fbvd-form {
    margin: 0;
    padding: 0;
}

.fbvd-input-group {
    display: flex;
    gap: 10px;
    align-items: stretch;
}

.fbvd-input-wrapper {
    flex: 1;
    position: relative;
    display: flex;
    align-items: center;
}

.fbvd-input-icon {
    position: absolute;
    left: 14px;
    color: var(--fbvd-text-muted);
    pointer-events: none;
    display: flex;
    align-items: center;
    z-index: 1;
    transition: color var(--fbvd-transition);
}

.fbvd-input {
    width: 100%;
    padding: 14px 44px 14px 44px;
    border: 2px solid var(--fbvd-border);
    border-radius: var(--fbvd-radius);
    font-size: 15px;
    font-family: var(--fbvd-font);
    color: var(--fbvd-text);
    background: var(--fbvd-surface);
    outline: none;
    transition: all var(--fbvd-transition);
    -webkit-appearance: none;
    appearance: none;
}

.fbvd-input::placeholder {
    color: var(--fbvd-text-muted);
}

.fbvd-input:focus {
    border-color: var(--fbvd-primary);
    box-shadow: 0 0 0 3px var(--fbvd-primary-glow);
}

.fbvd-input:focus + .fbvd-paste-btn,
.fbvd-input:focus ~ .fbvd-input-icon {
    color: var(--fbvd-primary);
}

.fbvd-input.fbvd-input-error {
    border-color: var(--fbvd-danger);
    box-shadow: 0 0 0 3px rgba(255, 61, 87, 0.15);
}

.fbvd-paste-btn {
    position: absolute;
    right: 10px;
    background: none;
    border: none;
    color: var(--fbvd-text-muted);
    cursor: pointer;
    padding: 6px;
    border-radius: 6px;
    display: flex;
    align-items: center;
    transition: all var(--fbvd-transition);
}

.fbvd-paste-btn:hover {
    color: var(--fbvd-primary);
    background: var(--fbvd-primary-light);
}

/* ============================================================
   Buttons
   ============================================================ */
.fbvd-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 14px 24px;
    font-size: 15px;
    font-weight: 600;
    font-family: var(--fbvd-font);
    border: none;
    border-radius: var(--fbvd-radius);
    cursor: pointer;
    transition: all var(--fbvd-transition);
    text-decoration: none;
    white-space: nowrap;
    line-height: 1;
    -webkit-appearance: none;
}

.fbvd-btn-primary {
    background: linear-gradient(135deg, #1877F2, #1565D8);
    color: var(--fbvd-text-on-primary);
    box-shadow: var(--fbvd-shadow), 0 2px 8px rgba(24, 119, 242, 0.3);
    min-width: 140px;
}

.fbvd-btn-primary:hover:not(:disabled) {
    background: linear-gradient(135deg, #1565D8, #0D47A1);
    box-shadow: var(--fbvd-shadow-lg), 0 4px 16px rgba(24, 119, 242, 0.4);
    transform: translateY(-1px);
}

.fbvd-btn-primary:active:not(:disabled) {
    transform: translateY(0);
}

.fbvd-btn-primary:disabled {
    opacity: 0.65;
    cursor: not-allowed;
    transform: none;
}

.fbvd-btn-download {
    padding: 10px 18px;
    font-size: 14px;
    border-radius: var(--fbvd-radius-sm);
}

.fbvd-btn-hd {
    background: linear-gradient(135deg, #00C851, #00A844);
    color: white;
    box-shadow: 0 2px 8px rgba(0, 200, 81, 0.3);
}

.fbvd-btn-hd:hover {
    background: linear-gradient(135deg, #00A844, #00893A);
    box-shadow: 0 4px 12px rgba(0, 200, 81, 0.4);
    transform: translateY(-1px);
    color: white;
}

.fbvd-btn-sd {
    background: linear-gradient(135deg, #1877F2, #1565D8);
    color: white;
    box-shadow: 0 2px 8px rgba(24, 119, 242, 0.3);
}

.fbvd-btn-sd:hover {
    background: linear-gradient(135deg, #1565D8, #0D47A1);
    box-shadow: 0 4px 12px rgba(24, 119, 242, 0.4);
    transform: translateY(-1px);
    color: white;
}

.fbvd-btn-copy {
    background: var(--fbvd-surface-hover);
    color: var(--fbvd-text-secondary);
    border: 1px solid var(--fbvd-border);
    padding: 10px 12px;
    border-radius: var(--fbvd-radius-sm);
}

.fbvd-btn-copy:hover {
    background: var(--fbvd-primary-light);
    color: var(--fbvd-primary);
    border-color: var(--fbvd-primary);
}

.fbvd-btn-copy.copied {
    background: rgba(0, 200, 81, 0.1);
    color: var(--fbvd-success);
    border-color: var(--fbvd-success);
}

/* ============================================================
   Hint Text
   ============================================================ */
.fbvd-hint {
    font-size: 12px;
    color: var(--fbvd-text-muted);
    margin: 10px 0 0;
    padding-left: 2px;
}

/* ============================================================
   Loading Spinner
   ============================================================ */
.fbvd-spinner {
    animation: fbvdSpin 1s linear infinite;
}

@keyframes fbvdSpin {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

/* ============================================================
   Alert / Error
   ============================================================ */
.fbvd-alert {
    display: flex;
    align-items: flex-start;
    gap: 10px;
    padding: 14px 16px;
    border-radius: var(--fbvd-radius-sm);
    font-size: 14px;
    margin-top: 16px;
    line-height: 1.5;
    animation: fbvdSlideDown 0.3s ease;
}

.fbvd-alert svg {
    flex-shrink: 0;
    margin-top: 1px;
}

.fbvd-alert-error {
    background: var(--fbvd-danger-light);
    color: var(--fbvd-danger);
    border: 1px solid rgba(255, 61, 87, 0.2);
}

@keyframes fbvdSlideDown {
    from {
        opacity: 0;
        transform: translateY(-8px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ============================================================
   Results Section
   ============================================================ */
.fbvd-results {
    animation: fbvdFadeUp 0.4s ease;
}

@keyframes fbvdFadeUp {
    from {
        opacity: 0;
        transform: translateY(16px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Video Preview */
.fbvd-preview {
    display: flex;
    gap: 16px;
    margin-bottom: 20px;
    padding-bottom: 20px;
    border-bottom: 1px solid var(--fbvd-border);
}

.fbvd-thumbnail-wrap {
    position: relative;
    width: 160px;
    min-width: 160px;
    aspect-ratio: 16 / 9;
    border-radius: var(--fbvd-radius-sm);
    overflow: hidden;
    background: #000;
    flex-shrink: 0;
}

.fbvd-thumbnail-wrap img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}

.fbvd-play-overlay {
    position: absolute;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(0, 0, 0, 0.3);
    opacity: 0.8;
    transition: opacity var(--fbvd-transition);
}

.fbvd-thumbnail-wrap:hover .fbvd-play-overlay {
    opacity: 1;
}

.fbvd-video-info {
    flex: 1;
    min-width: 0;
}

.fbvd-video-title {
    font-size: 16px;
    font-weight: 700;
    margin: 0 0 6px;
    color: var(--fbvd-text);
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
    line-height: 1.4;
}

.fbvd-video-meta {
    font-size: 13px;
    color: var(--fbvd-text-muted);
    margin: 0;
}

/* Download Options */
.fbvd-download-actions {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.fbvd-download-option {
    display: flex;
    align-items: center;
    gap: 14px;
    padding: 14px 16px;
    background: var(--fbvd-surface-hover);
    border-radius: var(--fbvd-radius);
    border: 1px solid var(--fbvd-border);
    transition: all var(--fbvd-transition);
    animation: fbvdFadeUp 0.3s ease;
}

.fbvd-download-option:hover {
    border-color: var(--fbvd-primary);
    box-shadow: 0 0 0 1px var(--fbvd-primary-glow);
}

.fbvd-quality-badge {
    font-size: 13px;
    font-weight: 800;
    padding: 6px 10px;
    border-radius: 6px;
    letter-spacing: 0.5px;
    flex-shrink: 0;
}

.fbvd-badge-hd {
    background: linear-gradient(135deg, #00C851, #00A844);
    color: white;
}

.fbvd-badge-sd {
    background: linear-gradient(135deg, #1877F2, #1565D8);
    color: white;
}

.fbvd-option-info {
    flex: 1;
    min-width: 0;
}

.fbvd-option-label {
    display: block;
    font-weight: 600;
    font-size: 14px;
    color: var(--fbvd-text);
}

.fbvd-option-desc {
    display: block;
    font-size: 12px;
    color: var(--fbvd-text-muted);
    margin-top: 2px;
}

.fbvd-option-buttons {
    display: flex;
    gap: 8px;
    flex-shrink: 0;
}

/* ============================================================
   Toast Notification
   ============================================================ */
.fbvd-toast {
    position: fixed;
    bottom: 24px;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background: var(--fbvd-text);
    color: var(--fbvd-surface);
    padding: 12px 24px;
    border-radius: var(--fbvd-radius-full);
    font-size: 14px;
    font-weight: 500;
    box-shadow: var(--fbvd-shadow-lg);
    transition: transform 0.3s ease;
    z-index: 10000;
    pointer-events: none;
}

.fbvd-toast.fbvd-toast-visible {
    transform: translateX(-50%) translateY(0);
}

/* ============================================================
   How to Section
   ============================================================ */
.fbvd-section-title {
    font-size: 20px;
    font-weight: 700;
    margin: 0 0 20px;
    color: var(--fbvd-text);
    text-align: center;
}

.fbvd-steps {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 16px;
}

.fbvd-step {
    text-align: center;
    padding: 16px 12px;
}

.fbvd-step-num {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--fbvd-primary), #6C5CE7);
    color: white;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-size: 16px;
    font-weight: 800;
    margin-bottom: 12px;
}

.fbvd-step h3 {
    font-size: 15px;
    font-weight: 700;
    margin: 0 0 6px;
    color: var(--fbvd-text);
}

.fbvd-step p {
    font-size: 13px;
    color: var(--fbvd-text-secondary);
    margin: 0;
    line-height: 1.5;
}

/* ============================================================
   FAQ Accordion
   ============================================================ */
.fbvd-accordion-item {
    border: 1px solid var(--fbvd-border);
    border-radius: var(--fbvd-radius-sm);
    margin-bottom: 8px;
    overflow: hidden;
    transition: border-color var(--fbvd-transition);
}

.fbvd-accordion-item:hover {
    border-color: var(--fbvd-primary);
}

.fbvd-accordion-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: 100%;
    padding: 14px 16px;
    border: none;
    background: none;
    font-size: 14px;
    font-weight: 600;
    font-family: var(--fbvd-font);
    color: var(--fbvd-text);
    cursor: pointer;
    text-align: left;
    gap: 12px;
    transition: background var(--fbvd-transition);
}

.fbvd-accordion-header:hover {
    background: var(--fbvd-surface-hover);
}

.fbvd-accordion-icon {
    flex-shrink: 0;
    transition: transform var(--fbvd-transition);
    color: var(--fbvd-text-muted);
}

.fbvd-accordion-item.active .fbvd-accordion-icon {
    transform: rotate(180deg);
    color: var(--fbvd-primary);
}

.fbvd-accordion-body {
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--fbvd-transition-slow), padding var(--fbvd-transition-slow);
}

.fbvd-accordion-item.active .fbvd-accordion-body {
    max-height: 300px;
}

.fbvd-accordion-body p {
    padding: 0 16px 14px;
    margin: 0;
    font-size: 14px;
    color: var(--fbvd-text-secondary);
    line-height: 1.6;
}

/* ============================================================
   Responsive Design (Mobile-First)
   ============================================================ */
@media (max-width: 640px) {
    .fbvd-wrapper {
        padding: 16px 12px 40px;
    }

    .fbvd-title {
        font-size: 22px;
    }

    .fbvd-subtitle {
        font-size: 14px;
    }

    .fbvd-card {
        padding: 18px 14px;
    }

    .fbvd-card-main {
        padding: 20px 16px;
    }

    /* Stack input and button on mobile */
    .fbvd-input-group {
        flex-direction: column;
    }

    .fbvd-btn-primary {
        width: 100%;
        padding: 16px;
    }

    /* Stack preview on mobile */
    .fbvd-preview {
        flex-direction: column;
    }

    .fbvd-thumbnail-wrap {
        width: 100%;
        min-width: auto;
    }

    /* Stack download option */
    .fbvd-download-option {
        flex-wrap: wrap;
        gap: 10px;
    }

    .fbvd-option-buttons {
        width: 100%;
    }

    .fbvd-btn-download {
        flex: 1;
    }

    /* Stack steps */
    .fbvd-steps {
        grid-template-columns: 1fr;
        gap: 8px;
    }

    .fbvd-step {
        display: flex;
        align-items: center;
        text-align: left;
        gap: 14px;
        padding: 12px;
        background: var(--fbvd-surface-hover);
        border-radius: var(--fbvd-radius-sm);
    }

    .fbvd-step-num {
        margin-bottom: 0;
        flex-shrink: 0;
        width: 36px;
        height: 36px;
        font-size: 14px;
    }

    .fbvd-step h3 {
        font-size: 14px;
    }

    .fbvd-step p {
        font-size: 12px;
    }
}

@media (min-width: 641px) and (max-width: 768px) {
    .fbvd-title {
        font-size: 24px;
    }

    .fbvd-thumbnail-wrap {
        width: 140px;
        min-width: 140px;
    }
}

/* ============================================================
   Print Styles
   ============================================================ */
@media print {
    .fbvd-wrapper {
        color: #000;
    }
    .fbvd-btn,
    .fbvd-paste-btn,
    .fbvd-toast {
        display: none !important;
    }
}

/* ============================================================
   Reduced Motion
   ============================================================ */
@media (prefers-reduced-motion: reduce) {
    .fbvd-wrapper *,
    .fbvd-wrapper *::before,
    .fbvd-wrapper *::after {
        animation-duration: 0.01ms !important;
        transition-duration: 0.01ms !important;
    }
}