h4 Text Size Changes Display in Widget

When I use this css to change the text size, it gets all messed up like this: https://snag.gy/s6R3uD.jpg

.searchandfilter h4 {
margin:15px 0;
font-size:16px !important;
color:#F9AA1E;
text-transform: uppercase;
}

When I remove the !important my theme css takes over and it displays nicely again. But the header “Post Types” I want to be smaller than the “Search”.
See here: https://snag.gy/VD3AP5.jpg

I am using the css under your comment /* If in a widget area make a single column by adding display block */

Can you help me with this?

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