/* Base Styles */
:root {
    /* Light mode variables */
    --bg-primary: #f8fafc;
    --bg-secondary: #ffffff;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --text-muted: #94a3b8;
    --accent-primary: #3b82f6;
    --accent-secondary: #2563eb;
    --accent-hover: #1e40af;
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --input-bg: #ffffff;
    --card-bg: #ffffff;
    --grid-pattern: rgba(0, 0, 0, 0.03);
    --grid-pattern-light: rgba(0, 0, 0, 0.01);
    --video-bg: #000000;
    --tooltip-bg: #0f172a;
    --tooltip-text: #f8fafc;
    --format-tag-bg: #f1f5f9;
    --format-tag-text: #475569;
    --format-tag-border: #e2e8f0;
    --error-color: #ef4444;
    --error-bg: #fee2e2;
    --success-color: #10b981;
    --success-bg: #d1fae5;
    --transition-normal: all 0.3s ease;
    --transition-fast: all 0.15s ease;
    --transition-slow: all 0.5s ease;
    --border-radius-sm: 0.375rem;
    --border-radius-md: 0.5rem;
    --border-radius-lg: 0.75rem;
    --border-radius-xl: 1rem;
    --border-width: 1px;
    --demo-button-bg: #f1f5f9;
    --demo-button-text: #475569;
    --demo-button-border: #e2e8f0;
    --demo-button-hover: #e2e8f0;
    --demo-button-active: #cbd5e1;
    --accordion-bg: #ffffff;
    --accordion-border: #e2e8f0;
    --accordion-divider: #f1f5f9;
    --footer-bg: #f1f5f9;
    --footer-text: #64748b;
    --show-more-bg: #edf2f7;
    --show-more-text: #2d3748;
    --toggle-button-bg: #e0f2fe;
    --toggle-button-text: #0369a1;
    --toggle-button-border: #bae6fd;
    --toggle-button-hover: #bae6fd;
    --toggle-button-active: #93c5fd;
    --focus-ring: 0 0 0 3px rgba(59, 130, 246, 0.5);
    --focus-ring-offset: 2px;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    background-color: var(--bg-primary);
    color: var(--text-primary);
    font-size: 16px;
    line-height: 1.5;
    transition: var(--transition-normal);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem 1rem;
}

.main-content {
    flex-grow: 1;
}

/* Header */
header {
    text-align: center;
    margin-bottom: 2.5rem;
    position: relative;
}

header::after {
    content: '';
    position: absolute;
    bottom: -1rem;
    left: 50%;
    transform: translateX(-50%);
    width: 6rem;
    height: 0.25rem;
    background: var(--accent-primary);
    border-radius: 9999px;
}

h1 {
    font-size: 2.5rem;
    font-weight: 800;
    letter-spacing: -0.025em;
    margin-bottom: 0.75rem;
    background: linear-gradient(to right, var(--accent-primary), var(--accent-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-fill-color: transparent;
}

.subtitle {
    color: var(--text-secondary);
    font-size: 1.125rem;
    max-width: 35rem;
    margin: 0 auto;
}

/* Player Card */
.player-card {
    background-color: var(--card-bg);
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-md);
    overflow: hidden;
    margin-bottom: 2rem;
    border: var(--border-width) solid var(--border-color);
    transition: var(--transition-normal);
}

.video-container {
    position: relative;
    padding-top: 56.25%; /* 16:9 Aspect Ratio */
    width: 100%;
    background-color: var(--video-bg);
    background-image: 
        linear-gradient(var(--grid-pattern) 1px, transparent 1px),
        linear-gradient(90deg, var(--grid-pattern) 1px, transparent 1px);
    background-size: 20px 20px;
    transition: var(--transition-normal);
}

#videoPlayer {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    outline: none;
}

/* Controls Section */
.controls-section {
    padding: 1.5rem;
}

.url-form {
    display: flex;
    gap: 0.75rem;
    margin-bottom: 1.5rem;
    position: relative;
}

#videoUrl {
    flex: 1;
    padding: 0.875rem 1.25rem;
    border: var(--border-width) solid var(--border-color);
    border-radius: var(--border-radius-md);
    font-size: 1rem;
    background-color: var(--input-bg);
    color: var(--text-primary);
    outline: none;
    transition: var(--transition-fast);
}

#videoUrl:focus {
    border-color: var(--accent-primary);
    box-shadow: var(--focus-ring);
}

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

button {
    background-color: var(--accent-primary);
    color: white;
    border: none;
    border-radius: var(--border-radius-md);
    padding: 0.875rem 1.5rem;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 600;
    transition: var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    box-shadow: var(--shadow-sm);
}

button:hover {
    background-color: var(--accent-secondary);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

button:active {
    transform: translateY(0);
    box-shadow: var(--shadow-sm);
}

/* Keyboard Focus States */
button:focus-visible,
input:focus-visible,
.accordion-header:focus-visible,
.demo-button:focus-visible {
    outline: none;
    box-shadow: var(--focus-ring);
    position: relative;
    z-index: 1;
}

.error-message {
    background-color: var(--error-bg);
    border-left: 4px solid var(--error-color);
    color: var(--error-color);
    margin: 1rem 0;
    padding: 1rem 1.25rem;
    border-radius: var(--border-radius-md);
    font-size: 0.875rem;
    display: none;
    box-shadow: var(--shadow-sm);
}

.section-divider {
    height: 1px;
    background-color: var(--border-color);
    margin: 1.5rem 0;
}

.controls-section h3 {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.controls-section h3 i {
    color: var(--accent-primary);
}

/* Demo Grid and Buttons */
.demo-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
    gap: 0.75rem;
    margin-bottom: 1.5rem;
}

.demo-button {
    background-color: var(--demo-button-bg);
    color: var(--demo-button-text);
    padding: 0.75rem 1rem;
    font-size: 0.875rem;
    touch-action: manipulation;
    border-radius: var(--border-radius-md);
    border: var(--border-width) solid var(--demo-button-border);
    transition: var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: flex-start;
    gap: 0.5rem;
    font-weight: 500;
    cursor: pointer;
}

.demo-button i {
    font-size: 0.75rem;
}

.demo-button:hover {
    background-color: var(--demo-button-hover);
    border-color: var(--accent-primary);
    transform: translateY(-1px);
    box-shadow: var(--shadow-sm);
}

.demo-button:active {
    background-color: var(--demo-button-active);
    transform: translateY(0);
    box-shadow: none;
}

/* Toggle Buttons */
.toggle-button {
    background-color: var(--toggle-button-bg);
    color: var(--toggle-button-text);
    border: var(--border-width) solid var(--toggle-button-border);
    padding: 0.75rem 1rem;
    font-size: 0.875rem;
    border-radius: var(--border-radius-md);
    transition: var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: flex-start;
    gap: 0.5rem;
    font-weight: 500;
    cursor: pointer;
}

.toggle-button:hover {
    background-color: var(--toggle-button-hover);
    border-color: var(--toggle-button-text);
    transform: translateY(-1px);
    box-shadow: var(--shadow-sm);
}

.toggle-button:active {
    background-color: var(--toggle-button-active);
    transform: translateY(0);
    box-shadow: none;
}

/* Formats Section */
.formats-section {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    align-items: center;
}

.formats-section h3 {
    margin-bottom: 0;
    margin-right: 0.5rem;
    font-size: 0.875rem;
    white-space: nowrap;
}

.format-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.format-tag {
    background-color: var(--format-tag-bg);
    color: var(--format-tag-text);
    padding: 0.25rem 0.75rem;
    border-radius: 9999px;
    font-size: 0.75rem;
    border: var(--border-width) solid var(--format-tag-border);
    font-weight: 500;
}

/* Mode Toggle */
.mode-toggle {
    position: absolute;
    top: 0;
    right: 0;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--text-secondary);
    font-size: 0.875rem;
    font-weight: 500;
    background: transparent;
    border: none;
    box-shadow: none;
    padding: 0.5rem;
    border-radius: var(--border-radius-md);
    transition: var(--transition-fast);
}

.mode-toggle:hover {
    color: var(--accent-primary);
    background: transparent;
    transform: none;
    box-shadow: none;
}

/* Info Section */
.info-section {
    margin-top: 2rem;
}

/* Accordion */
.accordion-container {
    background-color: var(--accordion-bg);
    border-radius: var(--border-radius-md);
    border: var(--border-width) solid var(--accordion-border);
    overflow: hidden;
    box-shadow: var(--shadow-md);
    transition: var(--transition-normal);
}

.accordion {
    transition: var(--transition-normal);
}

.accordion:not(:last-child) {
    border-bottom: 1px solid var(--accordion-divider);
}

.accordion-header {
    width: 100%;
    text-align: left;
    padding: 1.25rem;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-weight: 600;
    color: var(--text-primary);
    background-color: transparent;
    border: none;
    transition: var(--transition-fast);
}

.accordion-header:hover {
    background-color: var(--grid-pattern-light);
}

.accordion-icon {
    transition: transform 0.3s ease;
}

.accordion-content {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease, padding 0.3s ease;
    padding: 0 1.25rem;
}

.accordion[aria-expanded="true"] .accordion-icon {
    transform: rotate(-180deg);
}

.accordion[aria-expanded="true"] .accordion-content {
    max-height: 500px;
    padding-bottom: 1.25rem;
    padding-top: 0.75rem;
}

.accordion-content p {
    margin-bottom: 1rem;
    color: var(--text-secondary);
    font-size: 0.9375rem;
    line-height: 1.6;
}

.accordion-content p:last-child {
    margin-bottom: 0;
}

/* Footer */
footer {
    background-color: var(--footer-bg);
    color: var(--footer-text);
    padding: 1.5rem 0;
    text-align: center;
    font-size: 0.875rem;
    margin-top: 3rem;
    border-top: var(--border-width) solid var(--border-color);
    transition: var(--transition-normal);
}

.footer-content {
    max-width: 768px;
    margin: 0 auto;
    padding: 0 1rem;
}

.footer-title {
    font-size: 1rem;
    font-weight: bold;
    margin-bottom: 0.875rem;
}

.footer-info {
    font-size: 0.75rem;
    margin-bottom: 0.5rem;
}

.footer-note {
    font-size: 0.75rem;
    opacity: 0.8; /* Slightly faded for subtle emphasis */
}

footer a {
    color: var(--footer-text);
    text-decoration: none;
}

footer a:hover {
    text-decoration: underline;
    color: var(--accent-primary);
}

/* Loading Indicator */
.loading-indicator {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    display: none;
    z-index: 10;
}

.loading-indicator::after {
    content: '';
    display: block;
    width: 2.5rem;
    height: 2.5rem;
    border-radius: 50%;
    border: 0.25rem solid rgba(255, 255, 255, 0.2);
    border-top-color: var(--accent-primary);
    animation: spinner 1s linear infinite;
}

@keyframes spinner {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Hide items beyond initial limit */
.hidden-item {
    display: none;
}

/* Hidden demos container */
.hidden-demos {
    display: contents;
}

/* Manual Play Button */
#manualPlayButton {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    padding: 12px 24px;
    font-size: 16px;
    background-color: rgba(0, 0, 0, 0.7);
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    z-index: 20;
    display: none;
}

#manualPlayButton:hover {
    background-color: rgba(0, 0, 0, 0.8);
}

/* Media Queries */
@media (max-width: 768px) {
    .container {
        padding: 1.5rem 1rem;
    }

    h1 {
        font-size: 2rem;
    }

    .subtitle {
        font-size: 1rem;
    }

    .controls-section {
        padding: 1.25rem;
    }

    .url-form {
        flex-direction: column;
    }

    .demo-grid {
        grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
        gap: 0.5rem;
    }
    
    .mode-toggle {
        position: static;
        margin: 0.5rem auto 1rem;
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .demo-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .formats-section {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.75rem;
    }

    .formats-section h3 {
        margin-right: 0;
    }
}