Top Nav (Top-header) won't overlay onto Slider (top-slider)

I have tried everything and I cannot get my site to work. As I said in the title, I can’t get to top navigation links and logo to appear overlayed on top of the slider. (like it appears here) I’ve tried adjusting css for top-header & top-slider with no luck. Here’s my site to look at.
And here’s the custom CSS I’ve already used in the “General Settings>CSS Code” area. Can anyone help me out here??? Thank you!

/* SCROLL BAR */
::-webkit-scrollbar-track {
  background-color: rgba(40, 40, 40, 0.9);
}
::-webkit-scrollbar-thumb {
  background-color: #2790b0;
}
::-webkit-scrollbar-thumb:hover {
  background-color: #aaa;
}
/* TOP HEADER BEFORE */
.top-header:before {
  background-color: transparent;
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  z-index: 1;
}
.top-header nav {
  float: right;
}
.top-header nav ul li a {
  color:black;
  -webkit-transition: color 0.3s ease-in-out;
  transition: color 0.3s ease-in-out;
  font-weight:bold;
}
/* TOP HEADER AFTER */
.fixed-menu {
background-color: #ffffff;
}
.fixed-menu a {
color: #000000;
font-weight:bold;
}
/* FEATURED CONTENT */
.featured-content {
  position: absolute;
  color: BLACK;
  top: 29%;
  width: 100%;
  text-align: center;
}
.featured-content .featured-text {
  width: 70%;
  margin: auto;
}
.featured-content .featured-line {
  width: 300px;
  height: 2px;
  background-color: #2790b0;
  margin: auto;
  margin-top: 2em;
  margin-bottom: 2em;
}
.featured-content .btn {
  border-color: #2790b0;
  color: #2790b0;
  margin-top: 2em;
}
.featured-content .btn:hover {
  background-color: #ff9d4c;
  color: white;
}
/* HIDE BLOG */
.section-blog {
display: none;
}