header {
    position: relative;
    width: 100%;
    height: 50vh;
    overflow: hidden;
}

video {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 100%;
    height: 100%;
    object-fit: cover;
    opacity: 0;
    transition: opacity 1.5s ease-in-out;
}

/* 表示中の動画 */
.video.active {
    opacity: 1;
}

.logo {
    position: absolute;
    top: 0px;  /* 上からの距離 */
    left: 20px; /* 左からの距離 */
    width: 400px;  /* ロゴのサイズ（適宜調整） */
    height: auto;
    z-index: 10; /* 動画の上に配置 */
}

h1 {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    color: white;
    font-size: 3rem;
    text-shadow: 2px 2px 10px rgba(0, 0, 0, 0.7);
}
body {
    background-color: #1a1a1a;
    color: #ffffff;
    font-family: Arial, sans-serif;
    text-align: center;
    margin: 0;
    padding: 0;
}
.logo-image-container {
    width: 100%;
    height: fit-content;
    overflow: hidden;
    background-color: white;
}
.logo-image {
    width: 30%;
    height: 30%;
    object-fit: cover;
    display: block;
}
.top-image-container {
    width: 100%;
    /*height: 300px; /* ここで高さを指定（変更可能） */
    overflow: hidden;
}
.top-image {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}
.container {
    max-width: 800px;
    margin: auto;
    padding: 20px;
}
.thumbnails {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
    margin-top: 20px;
}
.video {
    width: 100%;
    aspect-ratio: 16 / 9; /* 16:9の比率を維持 */
    border-radius: 8px;
    overflow: hidden;
}
iframe {
    width: 100%;
    height: 100%;
    border: none;
}
.contact {
    margin-top: 30px;
    padding: 20px;
    background: #333;
    border-radius: 8px;
}
.contact a {
    color: #ffcc00;
    text-decoration: none;
    font-size: 18px;
}