would it be possible to change the colors of the little blue and orange rectangle thingys

.profile .contact .heading,
.profile .table-section .heading,
.home-actions .heading,
.col.w-40 h1,
.profile .blurbs .heading,
.profile .friends .heading,
.blog-preview h4 {
  margin: 0;
  background: #0000AF;
  color: white;
  font-size: 13px;
  text-align: center;
  height: 19px;
  border-bottom: 1px solid black;
  background-image: url(https://i.imgur.com/vKWtNvj.png);
  background-repeat: no-repeat;
  font-smooth: never;
  -webkit-font-smoothing: none;
}   

Yes, but you'll need to code it into the layout. You can see profile for reference. This code block contains the code from my profile responsible for the section heading rules, specifically: 

background: #0000AF;

See if you can find a similar section in your layout code and alter the background color. Or you can use the above code section to write your own rules to change the appearance. Hope that helps.