style.css

@font-face {
    font-family: "Montserrat";
    src: local("Montserrat"),
        url("/fonts/Montserrat-Regular.woff2") format("woff2");
}

@font-face {
    font-family: "Roboto Slab";
    src: local("Roboto Slab"),
        url("/fonts/RobotoSlab-Regular.woff2") format("woff2");
}

:root {
    --bg: #111;
    --fg: #ccc;
    --primary: #83cc14;
    --secondary: #527a0c;
    --panel: #222;
    --controls: #e5a016;
}

body {
    background: var(--bg);
    color: var(--fg);
    display: grid;
    font-family: "Montserrat", sans-serif;
    grid-template:
        "main hd" auto
        "main item" auto
        "main ctrl" auto
        "main ." 1fr
        "main ft" auto / 1fr minmax(240px, auto);
    margin: 0;
    min-height: 100vh;
}

main {
    grid-area: main;
}

header {
    grid-area: hd;
    padding: 16px 32px;
}

#item, #controls {
    background: var(--panel);
    border-radius: 18px;
    padding: 12px;
}

#item {
    grid-area: item;
    margin-bottom: 20px;
}

#controls {
    grid-area: ctrl;
}

footer {
    grid-area: ft;
}

canvas {
    display: block;
}

.center, h1, h2 {
    text-align: center;
}

h1, h2 {
    font-family: "Roboto Slab", serif;
}

h1 {
    color: var(--primary);
}

h2 {
    color: var(--secondary);
}

ul {
    list-style: none;
    margin: 0;
    padding: 0;
}

.control {
    color: var(--controls);
}

a:link, a:visited {
    color: var(--fg);
}