css/style.css

* {
    box-sizing: border-box;
}

html,
body {
    margin: 0;
    width: 100%;
    min-height: 100%;
}

body {
    background: #0b0d12;
    color: #ffffff;
    font-family: Arial, Helvetica, sans-serif;
}

#app {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 24px;
    padding: 24px;
}

/* Animation stage */

#stage {
    width: min(900px, 100%);
    aspect-ratio: 1 / 1;

    display: flex;
    align-items: center;
    justify-content: center;

    background: #11151d;
    border: 1px solid #252b36;
    border-radius: 12px;

    overflow: hidden;
}

#animation-canvas {
    width: 100%;
    height: 100%;
    display: block;

    image-rendering: pixelated;
}

/* Animation controls */

#controls {
    width: min(900px, 100%);

    display: flex;
    justify-content: center;
    flex-wrap: wrap;

    gap: 10px;
}

#controls button {
    appearance: none;

    padding: 10px 18px;

    background: #171c25;
    color: #ffffff;

    border: 1px solid #303744;
    border-radius: 6px;

    font: inherit;
    cursor: pointer;

    transition:
        background 120ms ease,
        border-color 120ms ease,
        transform 120ms ease;
}

#controls button:hover {
    background: #202733;
    border-color: #4b5565;
}

#controls button:active {
    transform: translateY(1px);
}

#controls button.active {
    background: #ffffff;
    color: #0b0d12;
    border-color: #ffffff;
}

/* Mobile */

@media (max-width: 600px) {
    #app {
        padding: 12px;
        gap: 16px;
    }

    #controls {
        justify-content: flex-start;
    }

    #controls button {
        flex: 1 1 auto;
    }
}

#engine-error {
    width: min(900px, 100%);
    margin: 0;
    padding: 12px 16px;

    color: #ffb4b4;
    background: #2a1518;

    border: 1px solid #70343b;
    border-radius: 6px;

    text-align: center;
}