/* Core Structural Layout Layouts */
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: #0f172a; /* Sleek dark mode for modern media contrast */
    margin: 0; padding: 20px; color: #f8fafc;
}
.container { max-width: 1200px; margin: 0 auto; }
h1, h3 { text-align: center; color: #f1f5f9; }
.nav-link {
    color: #38bdf8; text-decoration: none; font-weight: 500;
}
.nav-link:hover { text-decoration: underline; }

/* Ingestion Control Interface UI Styles */
.upload-section {
    background: #1e293b; padding: 30px; border-radius: 12px;
    box-shadow: 0 4px 10px rgba(0,0,0,0.3); margin: 40px auto;
    text-align: center; max-width: 500px;
}
input[type="file"] { margin: 15px 0; display: block; width: 100%; color: #94a3b8; }
button {
    background: #0284c7; color: white; border: none; padding: 12px 24px;
    border-radius: 6px; cursor: pointer; font-size: 14px; width: 100%;
}
button:hover { background: #0369a1; }
.success { color: #4ade80; margin-bottom: 15px; }
.error { color: #f87171; margin-bottom: 15px; }
.empty-text { grid-column: 1 / -1; text-align: center; color: #64748b; }

/* Multi-Format Adaptive Photo & Video Grid Layout */
.gallery-grid {
    display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 20px; padding: 20px 0;
}
.gallery-item { position: relative; overflow: hidden; }
.thumbnail {
    width: 100%; height: 180px; object-fit: cover;
    border-radius: 8px; box-shadow: 0 4px 6px rgba(0,0,0,0.2);
    transition: transform 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    background: #000; display: block;
}
.thumbnail:hover { transform: scale(1.04); cursor: pointer; }

/* Video Play Overlay Indicator badge */
.video-thumbnail-container { position: relative; }
.play-overlay-icon {
    position: absolute; bottom: 10px; right: 10px;
    background: rgba(0, 0, 0, 0.7); color: #fff;
    width: 32px; height: 32px; display: flex;
    align-items: center; justify-content: center;
    border-radius: 50%; font-size: 14px; pointer-events: none;
}

/* Adaptive Responsive Pure-CSS Media Modal Overlay Module */
.lightbox-overlay {
    display: none; position: fixed; top: 0; left: 0;
    width: 100%; height: 100%; background: rgba(0, 0, 0, 0.95);
    z-index: 9999; justify-content: center; align-items: center;
}
.lightbox-overlay:target { display: flex; }
.lightbox-content { position: relative; max-width: 90vw; max-height: 85vh; }
.lightbox-content img, .full-size-video {
    max-width: 90vw; max-height: 85vh; object-fit: contain;
    border-radius: 6px; box-shadow: 0 10px 30px rgba(0,0,0,0.5);
}
.close-button {
    position: absolute; top: -50px; right: 0;
    color: #94a3b8; font-size: 42px; text-decoration: none;
    transition: color 0.2s;
}
.close-button:hover { color: #f1f5f9; }