Editing Module:Side box/styles.css

/* {{pp|small=y}} */
.side-box {
	margin: 4px 0;
	box-sizing: border-box;
	border: 1px solid #aaa;
	font-size: 88%;
	line-height: 1.25em;
	background-color: var(--background-color-interactive-subtle, #f8f9fa);
    display: flow-root;
}
/* embedded side boxes need larger font */
.infobox .side-box {
	font-size: 100%;
}

.side-box-abovebelow,
.side-box-text {
	padding: 0.25em 0.9em;
}

.side-box-image {
	/* @noflip */
	padding: 2px 0 2px 0.9em;
	text-align: center;
}

.side-box-imageright {
	/* @noflip */
	padding: 2px 0.9em 2px 0;
	text-align: center;
}

/* roughly the skin's sidebar + size of side box */
@media (min-width: 500px) {
	.side-box-flex {
		display: flex;
		align-items: center;
	}
	
	.side-box-text {
		flex: 1;
		min-width: 0;
	}
}

@media (min-width: 720px) {
	.side-box {
		width: 238px;
	}
	
	.side-box-right {
		/* @noflip */
		clear: right;
		/* @noflip */
		float: right;
		/* @noflip */
		margin-left: 1em;
	}
	
	/* derives from mbox classes, which do not float left in mbox-small-left
	 * so far as I can tell, that was a deliberate decision, since only .ambox
	 * supports mbox-left
	 */
	.side-box-left {
		/* @noflip */
		margin-right: 1em;
	}
}