body { margin: 0;}

.manual__nav { position: absolute; width: 100%;}
.toc__nav { position: relative; }
.manual__nav .manual__next {float: right; margin-top: 30px;}

.manual__back {display: block;}
.manual__next {display: block;}
.manual__random {display: block; flex: auto;}

.manual__back img {height: 8vw; max-height: 80px;}
.manual__next img {height: 8vw; max-height: 80px;}
.manual__random img {
    height: 8vw;
    max-height: 80px; 
    left: 50%;
    position: relative;
    transform: translate(-50%);
}
.manual__line {
    height: 5vw;
    max-height: 50px;
    width: 100%;
    max-width: 1000px;
    left: 50%;
    position: relative;
    transform: translate(-50%);
}

.manual__nav--page {
    overflow: auto;
    margin-top: 30px;
    position: relative;
    z-index: 99;
    width: 100%;
    display: flex; 
    max-width: 1000px;
    left: 50%;
    transform: translate(-50%);
}

.manual__container { 
    height: calc(100vh - 164px);
    overflow: auto;
}
.manual__toc-container { height: 100vh; overflow: auto; }

.manual__cover {
    position: relative;
    left: 50%;
    transform: translate(-50%, calc(-50% - 100px));
    top: 50%;
    display: block;
    width: 100%;
    max-width: max-content;
}
.manual__toc {
    position: relative;
    left: 50%;
    transform: translate(-50%);
    display: block;
    width: 100%;
    max-width: max-content;
}

.manual__page {
    margin-top: 80px;
    position: relative;
    left: 50%;
    transform: translate(-50%);
    display: block;
    width: 75%;
    max-width: 800px;
}