:root {
    color-scheme: dark;
    --shell-green: #00ff00;
    --shell-black: #000000;
}

* {
    box-sizing: border-box;
}

html,
body {
    margin: 0;
    width: 100%;
    height: 100%;
    background: var(--shell-black);
    font-family: "Courier New", monospace;
}

body {
    overflow: hidden;
}

.game-frame {
    display: block;
    width: 100%;
    height: 100vh;
    border: 0;
    background: var(--shell-black);
}