Is there a way to set multiple CSS properties to one value?
border-left, border-right: 1px solid #E2E2E2;
The way that you can do with selectors?
.wrapper, .maindiv { ... }
Nope. But for your example, you can do this:
border: solid #E2E2E2;
border-width: 0 1px;
The attributes where there can be separate values for top, right, bottom, and left (eg, border-*, margin, padding) can usually be combined in a single attribute.