JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
    <div class="element"></div>
    <div class="element"></div>
    <div class="element"></div>
    <div class="element"></div>

	<div class="ads"> 
		<div class="ads_element"></div>
		<div class="ads_element"></div>
		<div class="ads_element"></div>
		<div class="ads_element"></div>	
	</div>

    <div class="element"></div>
    <div class="element"></div>
    <div class="element"></div>
    <div class="element"></div>
</div>

CSS

html, body 
{
  background-color: #ffeead;
  margin: 10px;
}
.container > div:nth-child(even) 
{
  background-color: red;
}

.container > div:nth-child(odd) 
{
  background-color: blue;
}
.container
{
	max-width: 500px;
	margin: auto;
	border: 5px solid #ffcc5c;
	display: flex;
	flex-wrap: wrap;
	justify-content: space-between;
}
.element
{
    box-sizing: border-box;
    border: 1px solid #edeeee;
    width: calc(50% - 5px);
    margin: 5px 0px;
    height: 200px;
    box-shadow: 0 0 5px 0 #edeeee;
    border-radius: 5px 5px 5px 5px;
}
.ads
{
	
}
.ads_element
{
	width: calc(25% - 5px);
	height: 100px;
	background-color:green;
}