/* 1. 배경 영상 설정 */
    .video-background {
        position: fixed;
        top: 0;
        left: 0;
        width: 100vw;
        height: 100vh;
        z-index: -1;
        overflow: hidden;
        background-color: #000;
    }

    .video-background iframe {
        position: absolute;
        top: 50%;
        left: 50%;
        width: 100vw;
        height: 56.25vw;
        min-height: 100vh;
        min-width: 177.77vh;
        transform: translate(-50%, -50%);
        pointer-events: none; /* 클릭 차단으로 유튜브 로고 방지 */
    }

    /* 2. 영상 위 어두운 오버레이 (가독성 향상) */
    .video-overlay {
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100%;
        z-index: 0;
        background: rgba(0, 0, 0, 0.4);
        pointer-events: none;
    }

    /* 3. START 버튼 컨테이너 (정중앙 배치) */
    .start-button-wrapper {
        position: fixed;
        top: 50%;
        left: 50%;
        transform: translate(-50%, -50%);
        z-index: 100;
        text-align: center;
    }

    /* 4. START 버튼 디자인 */
    .btn-start {
        display: inline-block;
        padding: 15px 50px;
        font-size: 24px;
        font-weight: 800;
        color: #fff;
        background: transparent;
        border: 2px solid #fff;
        border-radius: 50px;
        text-transform: uppercase;
        letter-spacing: 2px;
        transition: all 0.3s ease;
        text-decoration: none !important;
        cursor: pointer;
        box-shadow: 0 0 15px rgba(255,255,255,0.3);
    }

    /* 마우스 호버 효과 */
    .btn-start:hover {
        background: #fff;
        color: #000;
        box-shadow: 0 0 30px rgba(255,255,255,0.6);
        transform: scale(1.05);
    }

    /* 기존 레이아웃 투명화 */
    .main, .wrapper { background: transparent !important; }