Single post in Guide to CSS: Beginner to Expert

The tabs are done with flexboxes, so flex-basis is probably your best bet. It can seem a bit intimidating if you're new to flex, but it shouldn't be that bad. [style] /* default settings - box sizing keeps the tabs from wrapping */ .tabbed_interface>ul>li { flex-basis: 25%; box-sizing: border-box; } /* first tab */ .tabbed_interface>ul>li:nth-of-type(1) { flex-basis: 50%; } [/style]