add same css to both class but only one attribute diff code example
Example 1: css multiple classes
//HTML Code
<div class = 'firstClass secondClass'></div>
//CSS Code
.firstClass.secondClass {
}
Example 2: css assign multiple classes to one element
To specify multiple classes, separate the class names with a space,
e.g. <span class="classA classB">.
This allows you to combine several CSS classes for one HTML element.