@keyframes fadeOut {
    from {
        opacity: 1;
    }
    to {
        display: none;
        opacity: 0;
        z-index: -1;
    }
}

#loader {
    width: 100vw;
    height: 100vh;
    background-color: #1B1B1E;
    position: fixed;
    top: 0;
    left: 0;
    z-index: 1000;
    /* 環境によって「z-index」追加 */
}
/* 読み込み完了後に「loaded」を付与する */
#loader.loaded {
    animation: fadeOut 1.5s forwards ease-out;
    -webkit-animation: fadeOut 1.5s forwards ease-out;
}

#loader p {
    font-size: 7vw;
    position: absolute;
    left: calc((100vw - 7vw * 6) / 2);
    top: calc((100vh - 7vw) / 2 - 3vw)
}