body {
    background-color: #1a1a1a;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
}

.container {
    text-align: center; /* 讓圖片跟文字都置中 */
}

.secret-img {
    width: 70%;   /* 圖片寬度最多佔螢幕 80% */
}