html {
    box-sizing: border-box;
}
*, *::before, *::after {
    box-sizing: inherit;
}

.flex-col {
    display: flex;
    flex-direction: row;
}

.flex-col section {
    flex: 1;
}

#arena {
    border: 1px solid orangered;
    background-color: rgb(200 200 200);
}

button.halten .play, button.blinken .pause {
    display: block;
}

button.blinken .play, button.halten .pause {
    display: none;
}

#fps {
    display: inline-block;
    width: 2em;
    text-align: right;
}

x-inspector .src {
    min-height: 25ex;
    margin-top: 1ex;
    padding: 1em;
    border: 2px inset lightgray;
    white-space: pre-wrap;
}

x-inspector ::highlight(exec) {
    background-color: yellowgreen;
}

x-inspector .wordlist .ip {
    background-color: yellow;
}

x-inspector x-bytecode {
    display: block;
}

x-inspector x-bytecode::before {
    display: inline-block;
    width: 1em;
    content: attr(x-index);
    text-align: right;
    padding-right: 0.4em;
}

x-inspector x-op {
    display: inline-block;
    padding: 5px;
    border: 1px solid grey;
}