In your view, you can conditionally apply classes to your html element by using the ngClass directive. Documentation here.
You'll want to create a css class with the styling that you want, and then apply that class when some condition is met, using an expression inside ng-class.
An example from the documentation:
CSS
.base-class {
transition:all cubic-bezier(0.250, 0.460, 0.450, 0.940) 0.5s;
}
.base-class.my-class {
color: red;
font-size:3em;
}
View
<input id="setbtn" type="button" value="set" ng-click="myVar='my-class'">
<input id="clearbtn" type="button" value="clear" ng-click="myVar=''">
<br>
<span class="base-class" ng-class="myVar">Sample Text</span>
Plunker from docs