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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
    color: #333;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    background: white;
    border-radius: 12px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    overflow: hidden;
}

header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 20px 30px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 15px;
}

header h1 {
    font-size: 28px;
    font-weight: 600;
}

.video-info {
    display: flex;
    gap: 20px;
    align-items: center;
    flex-wrap: wrap;
}

#video-title {
    font-size: 18px;
    font-weight: 500;
}

#video-counter {
    background: rgba(255, 255, 255, 0.2);
    padding: 5px 15px;
    border-radius: 20px;
    font-size: 14px;
}

.player-wrapper {
    position: relative;
    background: #000;
    width: 100%;
    padding-top: 56.25%; /* 16:9 aspect ratio */
    overflow: hidden;
}

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

.player-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 20px;
    pointer-events: none;
    z-index: 10;
}

.nav-btn {
    pointer-events: all;
    background: rgba(0, 0, 0, 0.6);
    color: white;
    border: none;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    font-size: 30px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s ease;
    opacity: 0;
}

.player-wrapper:hover .nav-btn {
    opacity: 1;
}

.nav-btn:hover {
    background: rgba(0, 0, 0, 0.8);
    transform: scale(1.1);
}

.nav-btn:active {
    transform: scale(0.95);
}

.nav-btn:disabled {
    opacity: 0.3;
    cursor: not-allowed;
}

.playlist-section {
    padding: 30px;
    border-top: 1px solid #e0e0e0;
}

.playlist-section h2 {
    margin-bottom: 20px;
    color: #333;
    font-size: 22px;
}

.playlist {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 15px;
}

.playlist-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 15px;
    background: #f5f5f5;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    border: 2px solid transparent;
}

.playlist-item:hover {
    background: #e8e8e8;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.playlist-item.active {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border-color: #667eea;
}

.playlist-number {
    background: rgba(0, 0, 0, 0.1);
    width: 30px;
    height: 30px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    font-size: 14px;
    flex-shrink: 0;
}

.playlist-item.active .playlist-number {
    background: rgba(255, 255, 255, 0.3);
}

.playlist-title {
    flex: 1;
    font-weight: 500;
    font-size: 15px;
}

.playlist-series {
    font-size: 12px;
    opacity: 0.7;
    flex-shrink: 0;
}

.controls-section {
    padding: 20px 30px;
    background: #f9f9f9;
    border-top: 1px solid #e0e0e0;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 20px;
}

.control-group {
    display: flex;
    align-items: center;
    gap: 15px;
}

.control-group label {
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    font-size: 14px;
    color: #555;
}

.control-group input[type="checkbox"] {
    width: 18px;
    height: 18px;
    cursor: pointer;
}

.control-btn {
    padding: 10px 20px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-size: 14px;
    font-weight: 500;
    transition: all 0.3s ease;
}

.control-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.4);
}

.control-btn:active {
    transform: translateY(0);
}

/* Responsive design */
@media (max-width: 768px) {
    header {
        flex-direction: column;
        text-align: center;
    }

    .playlist {
        grid-template-columns: 1fr;
    }

    .controls-section {
        flex-direction: column;
        align-items: stretch;
    }

    .control-group {
        justify-content: center;
    }

    .nav-btn {
        width: 40px;
        height: 40px;
        font-size: 24px;
    }
}

/* Loading state */
#video-player:not([src]) {
    background: #1a1a1a;
    display: flex;
    align-items: center;
    justify-content: center;
}

#video-player:not([src])::before {
    content: 'Loading video...';
    color: white;
    font-size: 16px;
}