MediaWiki:Common.css

/* CSS placed here will be applied to all skins */
:root {
	--lt-color-background-default: #37383e;
	--background-color-base: #37383e;
}
#mw-panel {
    width: 10px;  /* Shrinks sidebar */
    overflow: hidden;
    transition: width 0.3s ease-in-out;
}

#mw-panel:hover {
    width: 180px; /* Expand on hover */
}

/* Change background color */
body {
    background-color: #730c0c !important;
    color: #fff !important;
}

/* Set background image */
body {
    /*background-image: url('/images/custom-background.png');*/
    background-size: cover;
    background-attachment: fixed;
}