w3schools overlay code example

Example 1: make background overlay css

#element-with-background-image {
   position: relative;
   background-image: url("//spin.atomicobject.com/wp-content/uploads/20170324102432/portfolio-tips-feature-image.jpg");
}
 
#color-overlay {
   position: absolute;
   top: 0;
   left: 0;
   width: 100%;
   height: 100%;
   background-color: black;
   opacity: 0.6;
}

Example 2: css overlay

#hero{
  background-image:url();
  background-size:cover;
  background-position:top center;
  position:relative;
}

#hero::after{
  content:'';
  position:absolute;
  left:0;
  top:0;
  height:100%;
  width:100%;
  background-color:black;
  opacity:0.7;
}

Example 3: overlay html template

<div class="imagebg" data-overlay="5">
	<div class="background-image-holder">
		<img alt="background" src="img/file.jpg" />
	</div>
	<div class="container">
		Content
	</div>
</div>

Example 4: html overlay django

{% for instance in object_list %}
    <div align="center">
        <a href="#overlay{{ instance.pk }}">{{ instance.international_title }}</a>
    </div>
    <div id="overlay{{ instance.pk }}">
    <p>{{ instance.international_short_description }}<p>
    </div>
{% endfor %}