Here's how you can do this. The "display: inline;" is the key here.
background: linear-gradient(180deg, rgba(255,255,255,0) 50%, #0096ff 50%);
If you want to have the text centered, you'll need to add a "text-align: center" to the parent element.
This is an example from a client site I'm working on and I'm doing a low-light effect. For the highlight look, just remove the gradient and make the background a solid color.
Hope this helps!