Changing the Font sizes for the header

I am using a child theme for zerif lite. I’ve tried editing the headers, but for some reason they remain the same size and font color.

Here is the code i am using:

/* header stuff */

.intro-text{
text-align: left;
color: #000;
margin-top: 25%;
line-height: 65px;
z-index: 0;
text-transform: uppercase;
font-size: 200px;
float:none;
}

The original Font Size is 50px but I want it to just be bigger.

I’ve put /* */ around the code in the parent theme, but there still are no changes.