Template:Columns/styles.css

.columns-row {
	display: flex;
	flex-direction: row;
	flex-flow: row wrap;
	justify-content: space-between;
}

.columns-col {
	flex: 1;
	min-width: 250px;
	padding-right: 15px;
	padding-left: 15px;
}

.columns-col-2 {
	flex: 2;
}

.columns-col-3 {
	flex: 3;
}