HTML elements overlapping - html

Question

So I'm using hero image for my website which is 100 vh high. Now the image is positioned absolutely, so I could position other elements like logo, nav and text on the image relatively to it. After this section, I want to start new section with new image and other text, but once I start new row, column and try to put new image with h1 text, it's hiding behind earlier image. What I mean is that I want a new section with new image and <h1> text appear under the hero image and not overlap it or hide under it as it is now hiding. It's not floated or anything, my floats are cleared, so I don't get it why is this hapenning.
Here is some codepen so you would understand what is hapenning.
<div class="container-fluid clearfix">
<div class="row">
<div class="col-lg-12">
<div class="hero_img">
<img class="logo" src="assets/logo.png"></img>
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target=".collapse">
☰
</button>
<div class="collapse">
<div class="col-xs-12">
<ul class="nav">
<li class="nav-item">
<a class="nav-link" href="#">Lorem</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Lorem</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Lorem</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Lorem</a>
</li>
</ul>
</div>
</div>
<div class="black_box clearfix"><h1>Kolding Bike Marathon</h1></div>
<div class="black_box_sub clearfix"><p>Bring activity to your life again</p></div>
<button type="button" class="btn btn-outline-secondary">Register now</button>
<button type="button" class="btn btn-success">Learn more</button>
</div>
</div>
</div>
</div>
</div>
<div class="section_one">
<h1>heyyyyy</h1>
</div>
.hero_img {
background-image: url("assets/hero.jpg");
width: auto;
height: 100vh;
background-size: cover;
position: absolute;
top: 0;
left: 0;
z-index: 999;
overflow: hidden;
clear: both;
}
.hero_img {
width: 100%;
height: 100vh;
position: absolute;
top: 0;
}
.logo {
position: relative;
left: 20px;
top: 20px;
z-index: 1002;
width: 5%;
min-width: 50px;
}
.nav {
position: relative;
top: 0;
z-index: 1000;
margin-top: 20px;
/*margin-right: 15px;*/
padding: 20px;
/*float: right;*/
width: auto;
flex-direction: column;
background: #555;
/*width: 100%;*/
filter: opacity(0.93);
}
a {
text-decoration: none;
color: white;
display: block;
border-bottom: 1px solid #444;
}
a:hover {
color: #999;
}
.nav-item {
display: block;
}
.navbar-toggler {
/*float: right;*/
display: flex;
justify-content: right;
position: relative;
z-index: 1000;
margin-top: 15px;
margin-right: 15px;
color: white;
float: right;
}
.black_box {
position: relative;
width: 45%;
min-width: 400px;
text-align: center;
z-index: 1000;
background: black;
margin-top: 10%;
padding: 10px 30px;
clear: both;
}
.black_box h1 {
color: white;
/*font-family: 'PT Sans', sans-serif;*/
font-family: 'Montserrat', sans-serif;
font-weight: 600;
letter-spacing: 1.5px;
}
.black_box_sub {
position: relative;
width: 30%;
min-width: 310px;
text-align: center;
z-index: 1001;
background: black;
margin-top: 2%;
clear: both;
margin-left: 90px;
}
.black_box_sub p {
color: white;
padding: 5px 25px;
font-family: 'Montserrat', sans-serif;
text-transform: uppercase;
padding-top: 10px;
padding-bottom: 0px;
}
Codepen: http://codepen.io/Limpuls/pen/NpbwYp

Answer 1

There are multiple items to clean up in the code, but to keep the images from overlapping you can remove both entries of position: absolute; from the .hero_img class.
After that, remove the padding left and right from all of the media queries of container-fluid. This may affect and other padding that was needed in that container but would be a quick path to do what you are asking.