/**
 * WCAG 2.1 AA Compliant Accessible Video Player Styles
 * Implements:
 * - WCAG 2.4.7: Focus Visible - 3px solid outline on all interactive elements
 * - WCAG 1.4.3: Contrast (Minimum) - All text/caption themes meet 4.5:1 ratio
 * - WCAG 1.4.4: Resize Text - Caption size variants from 14px to 32px
 * - WCAG 2.4.1: Bypass Blocks - Skip-to-controls link
 * - prefers-reduced-motion: Respects user motion preferences
 */

/* ========================================
   CSS Variables
   ======================================== */
:root {
    --avp-primary: #6C3CE1;
    --avp-primary-hover: #8710d8;
    --avp-focus-color: #4A90D9;
    --avp-bg-dark: rgba(0, 0, 0, 0.9);
    --avp-bg-overlay: rgba(0, 0, 0, 0.6);
    --avp-text: #ffffff;
    --avp-text-muted: rgba(255, 255, 255, 0.7);
    --avp-progress-bg: rgba(255, 255, 255, 0.3);
    --avp-progress-buffered: rgba(255, 255, 255, 0.5);
    --avp-progress-played: var(--avp-primary);
    --avp-control-size: 40px;
    --avp-transition: 0.2s ease;
    --avp-border-radius: 8px;
    --avp-shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
}

/* ========================================
   Screen Reader Only (visually hidden)
   ======================================== */
.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;
}

/* ========================================
   Skip Link (WCAG 2.4.1)
   ======================================== */
.avp-skip-link {
    position: absolute;
    top: -40px;
    left: 0;
    background: var(--avp-primary);
    color: var(--avp-text);
    padding: 8px 16px;
    z-index: 100;
    text-decoration: none;
    font-weight: 600;
    border-radius: 0 0 4px 0;
    transition: top 0.2s;
}

.avp-skip-link:focus {
    top: 0;
    outline: 3px solid var(--avp-focus-color);
    outline-offset: 2px;
}

/* ========================================
   Main Container
   ======================================== */
.accessible-video-player {
    position: relative;
    width: 100%;
    outline: none;
}

.avp-video-area {
    position: relative;
    width: 100%;
    max-width: 100%;
    background: #000;
    border-radius: var(--avp-border-radius);
    overflow: hidden;
    aspect-ratio: 16 / 9;
}

.avp-video-area.avp-fullscreen {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    max-width: none;
    border-radius: 0;
    z-index: 9999;
    aspect-ratio: auto;
}

.avp-video-element {
    width: 100%;
    height: 100%;
    object-fit: contain;
    background: #000;
}

/* ========================================
   Focus Indicators (WCAG 2.4.7)
   3px solid outline with 4px box-shadow spread
   for all interactive elements
   ======================================== */
.accessible-video-player button:focus-visible,
.accessible-video-player input:focus-visible,
.accessible-video-player [role="slider"]:focus-visible,
.accessible-video-player a:focus-visible {
    outline: 3px solid var(--avp-focus-color);
    outline-offset: 2px;
    box-shadow: 0 0 0 4px rgba(74, 144, 217, 0.3);
}

/* Ensure focus is visible on dark backgrounds */
.avp-controls-overlay button:focus-visible,
.avp-controls-overlay input:focus-visible {
    outline-color: #FFFFFF;
    box-shadow: 0 0 0 4px rgba(255, 255, 255, 0.4);
}

/* ========================================
   Loading Overlay
   ======================================== */
.avp-loading-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--avp-bg-overlay);
    z-index: 10;
}

.avp-loading-spinner {
    width: 50px;
    height: 50px;
    border: 4px solid var(--avp-progress-bg);
    border-top-color: var(--avp-primary);
    border-radius: 50%;
    animation: avp-spin 1s linear infinite;
}

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

/* ========================================
   Big Play Button
   ======================================== */
.avp-big-play-button {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 80px;
    height: 80px;
    background: var(--avp-primary);
    border: none;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--avp-shadow);
    transition: transform var(--avp-transition), background var(--avp-transition);
    z-index: 5;
}

.avp-big-play-button:hover {
    transform: translate(-50%, -50%) scale(1.1);
    background: var(--avp-primary-hover);
}

.avp-big-play-button svg {
    width: 40px;
    height: 40px;
    color: var(--avp-text);
    margin-left: 4px;
}

/* ========================================
   Caption Overlay (WCAG 1.2.2, 1.4.3, 1.4.4)
   ======================================== */
.avp-caption-overlay {
    position: absolute;
    bottom: 70px;
    left: 50%;
    transform: translateX(-50%);
    max-width: 80%;
    text-align: center;
    pointer-events: none;
    z-index: 15;
}

.avp-caption-text {
    display: inline;
    padding: 4px 12px;
    line-height: 1.5;
    border-radius: 4px;
    /* Defaults (overridden by inline style from GetCaptionStyle) */
    color: #FFFFFF;
    background-color: rgba(0, 0, 0, 0.75);
}

/* Caption size variants (WCAG 1.4.4) */
.caption-size-small .avp-caption-text { font-size: 14px; }
.caption-size-medium .avp-caption-text { font-size: 18px; }
.caption-size-large .avp-caption-text { font-size: 24px; }
.caption-size-xlarge .avp-caption-text { font-size: 32px; }

/* Caption theme overrides (WCAG 1.4.3 - minimum 4.5:1 contrast ratio) */
/* Default: White on semitransparent black - contrast ~15:1 */
.caption-theme-default .avp-caption-text {
    color: #FFFFFF;
    background-color: rgba(0, 0, 0, 0.75);
}

/* High Contrast: White on solid black - contrast 21:1 */
.caption-theme-highcontrast .avp-caption-text {
    color: #FFFFFF;
    background-color: #000000;
}

/* Yellow on Black: #FFD700 on black - contrast ~12:1 */
.caption-theme-yellow .avp-caption-text {
    color: #FFD700;
    background-color: #000000;
}

/* Inverted: Black on white - contrast 21:1 */
.caption-theme-inverted .avp-caption-text {
    color: #000000;
    background-color: rgba(255, 255, 255, 0.95);
}

/* Caption font variants */
.caption-font-sans-serif .avp-caption-text { font-family: 'Arial', 'Helvetica', sans-serif; }
.caption-font-serif .avp-caption-text { font-family: 'Georgia', 'Times New Roman', serif; }
.caption-font-monospace .avp-caption-text { font-family: 'Courier New', 'Consolas', monospace; }

/* ========================================
   Controls Overlay
   ======================================== */
.avp-controls-overlay {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    padding: 60px 16px 16px;
    background: linear-gradient(transparent, var(--avp-bg-dark));
    opacity: 0;
    visibility: hidden;
    transition: opacity var(--avp-transition), visibility var(--avp-transition);
    z-index: 20;
}

.avp-controls-overlay.visible,
.avp-video-area:hover .avp-controls-overlay,
.avp-video-area:focus-within .avp-controls-overlay {
    opacity: 1;
    visibility: visible;
}

/* ========================================
   Progress Bar (WCAG slider pattern)
   ======================================== */
.avp-progress-wrapper {
    margin-bottom: 12px;
}

.avp-progress-container {
    position: relative;
    width: 100%;
    height: 4px;
    background: var(--avp-progress-bg);
    border-radius: 2px;
    cursor: pointer;
    transition: height var(--avp-transition);
}

.avp-progress-container:hover,
.avp-progress-container:focus-visible {
    height: 8px;
}

.avp-progress-buffered {
    position: absolute;
    top: 0;
    left: 0;
    height: 100%;
    background: var(--avp-progress-buffered);
    border-radius: 2px;
    transition: width 0.1s linear;
}

.avp-progress-played {
    position: absolute;
    top: 0;
    left: 0;
    height: 100%;
    background: var(--avp-progress-played);
    border-radius: 2px;
    transition: width 0.1s linear;
}

.avp-progress-thumb {
    position: absolute;
    right: -6px;
    top: 50%;
    transform: translateY(-50%) scale(1);
    width: 14px;
    height: 14px;
    background: var(--avp-primary);
    border: 2px solid var(--avp-text);
    border-radius: 50%;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
    transition: transform var(--avp-transition);
}

.avp-progress-container:hover .avp-progress-thumb,
.avp-progress-container:focus-visible .avp-progress-thumb {
    transform: translateY(-50%) scale(1.2);
}

/* Bookmark Markers */
.avp-bookmark-marker {
    position: absolute;
    top: -4px;
    width: 4px;
    height: 12px;
    background: #ffd700;
    border-radius: 2px;
    cursor: pointer;
    z-index: 5;
}

/* ========================================
   Controls Row
   ======================================== */
.avp-controls-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 8px;
}

.avp-controls-left,
.avp-controls-right {
    display: flex;
    align-items: center;
    gap: 4px;
}

/* ========================================
   Control Buttons
   ======================================== */
.avp-control-btn {
    width: var(--avp-control-size);
    height: var(--avp-control-size);
    background: transparent;
    border: none;
    border-radius: 50%;
    color: var(--avp-text);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background var(--avp-transition), transform var(--avp-transition);
    /* Minimum touch target size (WCAG 2.5.8 - AAA, good practice for AA) */
    min-width: 44px;
    min-height: 44px;
}

.avp-control-btn:hover {
    background: rgba(255, 255, 255, 0.15);
}

.avp-control-btn:active {
    transform: scale(0.9);
}

.avp-control-btn svg {
    width: 24px;
    height: 24px;
}

.avp-control-btn.avp-active {
    color: var(--avp-primary);
}

.avp-control-btn.avp-speed-btn {
    width: auto;
    padding: 0 12px;
    border-radius: 4px;
    font-size: 14px;
    font-weight: 500;
}

/* ========================================
   Volume Control
   ======================================== */
.avp-volume-control {
    display: flex;
    align-items: center;
    gap: 4px;
}

.avp-volume-slider {
    width: 0;
    opacity: 0;
    transition: width var(--avp-transition), opacity var(--avp-transition);
    -webkit-appearance: none;
    appearance: none;
    height: 4px;
    background: var(--avp-progress-bg);
    border-radius: 2px;
    cursor: pointer;
}

.avp-volume-control:hover .avp-volume-slider,
.avp-volume-slider:focus-visible {
    width: 80px;
    opacity: 1;
}

.avp-volume-slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 14px;
    height: 14px;
    background: var(--avp-text);
    border-radius: 50%;
    cursor: pointer;
}

.avp-volume-slider::-moz-range-thumb {
    width: 14px;
    height: 14px;
    background: var(--avp-text);
    border: none;
    border-radius: 50%;
    cursor: pointer;
}

/* ========================================
   Time Display
   ======================================== */
.avp-time-display {
    font-size: 13px;
    font-family: 'Roboto Mono', 'SF Mono', monospace;
    color: var(--avp-text);
    padding: 0 8px;
    white-space: nowrap;
}

/* ========================================
   Speed Menu
   ======================================== */
.avp-speed-control,
.avp-caption-settings-control {
    position: relative;
}

.avp-speed-menu {
    position: absolute;
    bottom: calc(100% + 8px);
    right: 0;
    min-width: 120px;
    background: var(--avp-bg-dark);
    border-radius: var(--avp-border-radius);
    box-shadow: var(--avp-shadow);
    padding: 8px 0;
    z-index: 30;
}

.avp-speed-option {
    width: 100%;
    padding: 10px 16px;
    background: transparent;
    border: none;
    color: var(--avp-text);
    font-size: 14px;
    text-align: left;
    cursor: pointer;
    transition: background var(--avp-transition);
}

.avp-speed-option:hover {
    background: rgba(255, 255, 255, 0.1);
}

.avp-speed-option.active {
    color: var(--avp-primary);
}

/* ========================================
   Caption Settings Panel
   ======================================== */
.avp-caption-settings-panel {
    position: absolute;
    bottom: calc(100% + 8px);
    right: 0;
    width: 320px;
    max-height: 400px;
    overflow-y: auto;
    background: var(--avp-bg-dark);
    border-radius: var(--avp-border-radius);
    box-shadow: var(--avp-shadow);
    padding: 0;
    z-index: 30;
}

.avp-settings-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 12px 16px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.avp-settings-header h3 {
    margin: 0;
    font-size: 15px;
    font-weight: 600;
    color: var(--avp-text);
}

.avp-settings-close {
    background: transparent;
    border: none;
    color: var(--avp-text-muted);
    cursor: pointer;
    padding: 4px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    min-width: 30px;
    min-height: 30px;
}

.avp-settings-close:hover {
    background: rgba(255, 255, 255, 0.1);
    color: var(--avp-text);
}

.avp-settings-section {
    padding: 12px 16px;
    border: none;
    margin: 0;
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.avp-settings-section legend {
    font-size: 11px;
    font-weight: 600;
    color: var(--avp-text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 8px;
    padding: 0;
}

.avp-settings-options {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
}

.avp-settings-option {
    padding: 6px 12px;
    background: rgba(255, 255, 255, 0.08);
    border: 1px solid rgba(255, 255, 255, 0.15);
    border-radius: 4px;
    color: var(--avp-text);
    font-size: 13px;
    cursor: pointer;
    transition: background var(--avp-transition), border-color var(--avp-transition);
}

.avp-settings-option:hover {
    background: rgba(255, 255, 255, 0.15);
}

.avp-settings-option.active {
    background: var(--avp-primary);
    border-color: var(--avp-primary);
    color: var(--avp-text);
}

/* ========================================
   Keyboard Shortcuts Help Dialog
   ======================================== */
.avp-keyboard-help {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.8);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 10000;
}

.avp-keyboard-help-content {
    background: #1a1a1a;
    border-radius: 12px;
    padding: 24px 32px;
    max-width: 480px;
    width: 90%;
    color: var(--avp-text);
    position: relative;
}

.avp-keyboard-help-content h3 {
    margin: 0 0 20px;
    font-size: 18px;
    font-weight: 600;
}

.avp-help-close {
    position: absolute;
    top: 16px;
    right: 16px;
    background: transparent;
    border: none;
    color: var(--avp-text-muted);
    cursor: pointer;
    padding: 4px;
    border-radius: 50%;
    display: flex;
    min-width: 32px;
    min-height: 32px;
    align-items: center;
    justify-content: center;
}

.avp-help-close:hover {
    background: rgba(255, 255, 255, 0.1);
    color: var(--avp-text);
}

.avp-shortcuts-list {
    margin: 0;
    padding: 0;
}

.avp-shortcut-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 8px 0;
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.avp-shortcut-item:last-child {
    border-bottom: none;
}

.avp-shortcut-item dt {
    font-weight: 400;
}

.avp-shortcut-item dd {
    margin: 0;
    color: var(--avp-text-muted);
    font-size: 14px;
}

.avp-shortcut-item kbd {
    display: inline-block;
    padding: 2px 8px;
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 4px;
    font-family: 'Roboto Mono', 'SF Mono', monospace;
    font-size: 12px;
    color: var(--avp-text);
    min-width: 28px;
    text-align: center;
}

/* ========================================
   Error Overlay
   ======================================== */
.avp-error-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--avp-bg-dark);
    z-index: 25;
}

.avp-error-content {
    text-align: center;
    color: var(--avp-text);
    padding: 24px;
}

.avp-error-icon {
    width: 48px;
    height: 48px;
    color: #ef4444;
    margin-bottom: 16px;
}

.avp-error-content p {
    margin: 0 0 16px;
    font-size: 16px;
}

.avp-retry-btn {
    padding: 10px 24px;
    background: var(--avp-primary);
    color: var(--avp-text);
    border: none;
    border-radius: 4px;
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: background var(--avp-transition);
}

.avp-retry-btn:hover {
    background: var(--avp-primary-hover);
}

/* ========================================
   Responsive Design
   ======================================== */
@media (max-width: 768px) {
    .avp-video-area {
        border-radius: 0;
    }

    .avp-controls-overlay {
        padding: 40px 12px 12px;
    }

    .avp-controls-row {
        flex-wrap: wrap;
    }

    .avp-controls-left,
    .avp-controls-right {
        gap: 2px;
    }

    .avp-control-btn {
        width: 36px;
        height: 36px;
        min-width: 44px;
        min-height: 44px;
    }

    .avp-control-btn svg {
        width: 20px;
        height: 20px;
    }

    .avp-time-display {
        font-size: 12px;
        padding: 0 4px;
    }

    .avp-volume-control:hover .avp-volume-slider {
        width: 60px;
    }

    .avp-big-play-button {
        width: 60px;
        height: 60px;
    }

    .avp-big-play-button svg {
        width: 30px;
        height: 30px;
    }

    .avp-caption-settings-panel {
        width: 280px;
    }

    .avp-caption-overlay {
        max-width: 95%;
        bottom: 60px;
    }
}

/* ========================================
   Reduced Motion Preference (WCAG)
   ======================================== */
@media (prefers-reduced-motion: reduce) {
    .avp-progress-thumb,
    .avp-control-btn,
    .avp-volume-slider,
    .avp-big-play-button,
    .avp-controls-overlay,
    .avp-speed-option,
    .avp-settings-option {
        transition: none;
    }

    .avp-loading-spinner {
        animation: avp-pulse 2s ease-in-out infinite;
    }

    @keyframes avp-pulse {
        0%, 100% { opacity: 1; }
        50% { opacity: 0.5; }
    }
}

/* ========================================
   High Contrast Mode (Windows)
   ======================================== */
@media (forced-colors: active) {
    .avp-control-btn {
        border: 1px solid ButtonText;
    }

    .avp-control-btn:focus-visible {
        outline: 3px solid Highlight;
    }

    .avp-progress-played {
        background: Highlight;
    }

    .avp-progress-thumb {
        background: ButtonText;
        border-color: Highlight;
    }

    .avp-caption-text {
        forced-color-adjust: none;
    }
}

/* ========================================
   Print (hide video player)
   ======================================== */
@media print {
    .accessible-video-player {
        display: none;
    }
}