:root {
    --bg-color: #080a0e;
    --accent-color: #ef4444;
    --card-bg: rgba(255, 255, 255, 0.03);
    --card-border: rgba(255, 255, 255, 0.08);
    --text-main: #ffffff;
    --text-muted: #a1a1aa;
    --font-heading: 'Syne', sans-serif;
    --font-body: 'Lora', serif;
    --font-mono: 'DM Mono', monospace;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    background-color: var(--bg-color);
    color: var(--text-main);
    font-family: var(--font-body);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

header {
    text-align: center;
    padding: 2rem 1rem 2rem;
}

.header-top {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1100px;
    margin: 0 auto 0.5rem;
}

.logo {
    font-family: var(--font-heading);
    font-size: 3rem;
    font-weight: 700;
    letter-spacing: -0.05em;
}

.lang-btn {
    background: transparent;
    color: var(--text-muted);
    border: 1px solid var(--card-border);
    padding: 0.3rem 0.6rem;
    border-radius: 6px;
    cursor: pointer;
    font-family: var(--font-mono);
    font-size: 0.8rem;
    transition: all 0.2s ease;
}

.lang-btn:hover {
    color: var(--text-main);
    border-color: var(--text-main);
}

.logo span {
    color: var(--accent-color);
}

.tagline {
    color: var(--text-muted);
    font-size: 1.1rem;
}

main {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem 4rem;
}

.filters {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 3rem;
    flex-wrap: wrap;
}

.filter-btn {
    background: transparent;
    border: 1px solid var(--card-border);
    color: var(--text-muted);
    padding: 0.5rem 1.5rem;
    border-radius: 9999px;
    font-family: var(--font-heading);
    font-weight: 600;
    font-size: 0.9rem;
    cursor: pointer;
    transition: all 0.3s ease;
}

.filter-btn:hover {
    border-color: var(--text-muted);
    color: var(--text-main);
}

.filter-btn.active {
    background: var(--accent-color);
    border-color: var(--accent-color);
    color: white;
}

.topic-filters {
    margin-top: -1.5rem;
    align-items: center;
}

.filter-label {
    color: var(--text-muted);
    font-size: 0.875rem;
    margin-right: 0.5rem;
}

.topic-btn {
    background: transparent;
    color: var(--text-muted);
    border: 1px solid var(--card-border);
    padding: 0.4rem 1rem;
    border-radius: 6px;
    font-size: 0.8rem;
    cursor: pointer;
    transition: all 0.2s ease;
}

.topic-btn:hover {
    background: var(--card-bg);
    color: var(--text-main);
}

.topic-btn.active {
    background: rgba(239, 68, 68, 0.1);
    color: var(--accent-color);
    border-color: var(--accent-color);
}

.video-grid {
    display: flex;
    flex-direction: column;
    gap: 3rem;
    max-width: 1100px;
    margin: 0 auto;
}

.video-card {
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    border-radius: 16px;
    overflow: hidden;
    backdrop-filter: blur(10px);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    display: flex;
    flex-direction: column;
}

.video-card:hover {
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
    border-color: rgba(255, 255, 255, 0.15);
}

.video-container {
    width: 100%;
    aspect-ratio: 16 / 9;
    background: #000;
    position: relative;
    overflow: hidden;
}

.video-container iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: none;
}

/* Facade Pattern Styles */
.yt-facade {
    position: absolute;
    top: 0; left: 0;
    width: 100%; height: 100%;
    cursor: pointer;
    background-size: cover;
    background-position: center;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: transform 0.2s ease;
}

.yt-play-btn {
    width: 68px; height: 48px;
    background: rgba(33, 33, 33, 0.8);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background 0.2s ease;
}

.yt-facade:hover .yt-play-btn {
    background: #ff0000;
}

.yt-play-btn::before {
    content: '';
    border-style: solid;
    border-width: 10px 0 10px 20px;
    border-color: transparent transparent transparent white;
    margin-left: 5px;
}

/* Desktop Split-View Layout */
@media (min-width: 850px) {
    .video-card {
        flex-direction: row;
        align-items: flex-start; /* Allows left side to be sticky without stretching */
    }
    
    .video-container {
        width: 60%;
        position: sticky;
        top: 2rem; /* Sticks to screen while scrolling long timestamps */
        border-right: 1px solid var(--card-border);
        border-bottom: none;
    }
    
    .card-content {
        width: 40%;
    }
}

.card-content {
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    flex-grow: 1;
}

.card-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.5rem;
}

.channel-tag {
    font-family: var(--font-mono);
    color: var(--accent-color);
    font-size: 0.8rem;
    margin-right: 0.5rem;
}

.badge {
    font-size: 0.65rem;
    font-weight: 700;
    text-transform: uppercase;
    padding: 0.2rem 0.4rem;
    border-radius: 4px;
    vertical-align: middle;
}

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

.badge-watched {
    background: rgba(255, 255, 255, 0.1);
    color: var(--text-muted);
}

.watch-toggle-btn {
    background: transparent;
    border: none;
    color: var(--text-muted);
    font-size: 0.75rem;
    cursor: pointer;
    text-decoration: underline;
    transition: color 0.2s ease;
}

.watch-toggle-btn:hover {
    color: var(--text-main);
}

/* Dim out watched videos slightly */
.video-card.is-watched {
    opacity: 0.7;
    filter: grayscale(20%);
}

.video-card.is-watched:hover {
    opacity: 1;
    filter: none;
}

.card-title {
    font-family: var(--font-heading);
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 1rem;
    line-height: 1.3;
}

.card-summary {
    color: var(--text-muted);
    font-size: 0.95rem;
    margin-bottom: 1.5rem;
    flex-grow: 1;
}

.timestamps h4 {
    font-family: var(--font-heading);
    font-size: 0.9rem;
    margin-bottom: 0.75rem;
    color: var(--text-main);
}

.timestamp-list {
    display: grid;
    grid-template-columns: 1fr;
    gap: 0.5rem;
    align-items: start;
}

@media (min-width: 850px) {
    .timestamp-list {
        grid-template-columns: 1fr 1fr;
    }
}

.timestamp-btn {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    color: var(--text-main);
    padding: 0.4rem 0.8rem;
    border-radius: 6px;
    font-family: var(--font-mono);
    font-size: 0.8rem;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    gap: 0.4rem;
}

.timestamp-btn:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: var(--accent-color);
}

.timestamp-btn span {
    color: var(--accent-color);
}

/* Highlighted state for when a topic filter is active */
.timestamp-btn.highlight {
    background: rgba(239, 68, 68, 0.15);
    border-color: var(--accent-color);
    color: var(--text-main);
}

.timestamp-btn.highlight span {
    color: #fca5a5; /* lighter red */
}