:root {
    interpolate-size: allow-keywords;
}

details {
    padding-left: 30px;
    overflow: hidden;
}    

details::details-content {
    block-size: 0;
    border-left: solid 1px hsl(222, 32%, 15%);
    transition: 
        block-size .5s, 
        content-visibility .5s;
    transition-behavior: allow-discrete;
}

details[open]::details-content {
    block-size: auto;
}

body {
    background: hsl(205, 65%, 90%);
}

ul {
    margin-block-start: 0px; margin-block-end: 0px;
}

div {
    padding-left: 30px;
}

#displaymode {
    position: absolute;
    margin-left: 90%;
    background-color:hsl(222, 32%, 15%);
    color:hsl(205, 65%, 90%);
    border-radius: 10%;
    height:40px
}