style.css

@import url('https://fonts.googleapis.com/css2?family=Crimson+Text&display=swap');

body {
    font-family: sans-serif;
    background: linear-gradient(to bottom right, #2266ce, #ce43ce);
    height: 100vh;
    width: 100vw;
    padding: 0;
    margin: 0;
}

#Canvas3D {
    position: fixed;
    top: 0;
    left: 0;
}

#page {
    width: calc(100vw - 5vh - 450px);
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
}

#menu {
    width: 450px;
    height: 90vh;
    position: fixed;
    background-color: #fffa;
    top: 5vh;
    right: 5vh;
    border-radius: 1em;
    display: flex;
    flex-direction: column;
    justify-content: space-evenly;
    align-items: center;
}

#menu > div {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}

#dim_toggle_box {
    position: fixed;
    top: 1rem;
    left: 1rem;
    display: flex;
    justify-content: space-evenly;
    align-items: center;
    color: #fff;
    z-index: 10;
}

/* The switch - the box around the slider */
.switch {
    position: relative;
    display: inline-block;
    width: 60px;
    height: 34px;
    margin: 0 0.4rem;
}

/* Hide default HTML checkbox */
.switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

/* The slider */
.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: #000;
    -webkit-transition: .4s;
    transition: .4s;
}

.slider:before {
    position: absolute;
    content: "";
    height: 26px;
    width: 26px;
    left: 4px;
    bottom: 4px;
    background-color: white;
    -webkit-transition: .4s;
    transition: .4s;
}

input:checked + .slider {
    background-color: #000;
}

input:focus + .slider {
    box-shadow: 0 0 1px #000;
}

input:checked + .slider:before {
    -webkit-transform: translateX(26px);
    -ms-transform: translateX(26px);
    transform: translateX(26px);
}

/* Rounded sliders */
.slider.round {
    border-radius: 34px;
}

.slider.round:before {
    border-radius: 50%;
}