mirror-os9/css/button.css

:root {
    --button-box-shadow: inset -1px -1px #777,
    inset -2px -2px #aaa,
    inset 1px 1px #ddd,
    inset 2px 2px #fff;
    --button-default: 0 0 0 1px #aaa,
    0 0 0 2px #ddd,
    0 0 0 3px #000;
}

button {
    font-size: 12px;
    font-family: 'Charcoal';
    height: 20px;
    background: #dedede;
    /*margin-bottom: 7px;
    margin-left: 14px;*/
    border-radius: 3px;
    border: 1px solid #000;
    box-shadow: var(--button-box-shadow);
    min-width: 58px;
}

button.default {
    box-shadow: var(--button-box-shadow), var(--button-default);
}

button:active {
    color: #fff;
    background: #666;
}

button:not(.default):active {
    box-shadow: inset -1px -1px #888,
    inset -2px -2px #777,
    inset 1px 1px #444,
    inset 2px 2px #555;
}

button.default:active {
    box-shadow: var(--button-default),
    inset -1px -1px #888,
    inset -2px -2px #777,
    inset 1px 1px #444,
    inset 2px 2px #555;
}