style.css

body {
    font-family: monospace;
    font-size: 10pt;
    overflow: hidden;
}

button {
    font-family: monospace;
    height: 1.5em;
    margin-top: 0.5em;
    border: 1px black solid;
    background-color: #ddd;
}

button:hover {
    background-color: #ccc;
    transform: translate(0, 1px);
}

button:active {
    background-color: #eee;
    transform: translate(0, 1px);
}

button:disabled {
    opacity: 0.7;
    background-color: white;
}

input[type="text"] {
    height: 1.5em;
    font-family: monospace;
    border: 1px solid black;
    background-color: white;
}

input[type="text"]:hover {
    transform: translate(0, 1px);
}

input[type="text"]:focus-visible {
    outline: 1px lightgray;
    transform: translate(0, 1px);
}

div.gameFrame {
    margin: 0.5em;
    position: fixed;
    left: 0;
    top: 0;
    bottom: 0;
    right: 0;
}

@keyframes fizzle {
    90% {
        opacity: 0;
    } to {
        transform: translate(10%, 100%) rotate(10deg);
        opacity: 0;
    }
}

div.fizzle {
    animation: fizzle 5s 1s forwards cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

@keyframes slidein {
    from {
        opacity: 0;
        transform: translate(-20%, 0);
    } 50% {
        opacity: 0;
    } to {
        opacity: 1;
        transform: translate(0, 0);
    }
}

@keyframes slideout {
    from {
        opacity: 1;
        transform: translate(0, 0);
    } 50% {
        opacity: 0;
    } to {
        opacity: 0;
        transform: translate(-20%, 0);
    }
}

#intro-div {
    margin: 0.5em;
    position: fixed;
    left: 0;
    top: 0;
    bottom: 0;
    right: 0;

    animation: slidein 1s forwards, slideout 1s 3s forwards;
}

.intro-title {
    font-weight: bolder;
    font-size: 1.4em;
}

.intro-subtitle {
    font-style: italic;
    margin-top: 1em;
}

#recursion-div {
    animation: slidein 1s forwards;
    margin: 0.5em;
    position: fixed;
    left: 0;
    top: 0;
    bottom: 0;
    right: 0;
}

button#debug-step {
    z-index: 10;
    position: fixed;
    left: 1em;
    bottom: 1em;
}