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

html, body {
    width: 100%;
    height: 100%;
    overflow: hidden;
    background: #000;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

.bg-video {
    position: fixed;
    inset: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}

@media (max-aspect-ratio: 9/16) {
    .bg-video {
        object-fit: contain;
    }
}

.sound-btn {
    position: fixed;
    bottom: 32px;
    right: 32px;
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 14px 22px;
    background: rgba(0, 0, 0, 0.6);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 100px;
    color: #fff;
    font-size: 15px;
    font-weight: 500;
    cursor: pointer;
    z-index: 10;
    transition: all 0.25s ease;
    animation: pulse 2s ease-in-out infinite;
}

.sound-btn:hover {
    background: rgba(0, 0, 0, 0.8);
    border-color: rgba(255, 255, 255, 0.4);
    transform: scale(1.05);
}

.sound-btn.hidden {
    opacity: 0;
    pointer-events: none;
    transform: scale(0.9);
}

@keyframes pulse {
    0%, 100% { box-shadow: 0 0 0 0 rgba(255, 255, 255, 0.4); }
    50% { box-shadow: 0 0 0 12px rgba(255, 255, 255, 0); }
}

@media (max-width: 600px) {
    .sound-btn {
        bottom: 20px;
        right: 20px;
        padding: 12px 18px;
        font-size: 13px;
    }
    .sound-btn svg {
        width: 22px;
        height: 22px;
    }
}