JSFiddle - React, Tailwind, and code Playground

HTML

<div class="header">
    <div class="elem_1">part1</div>
    <div class="elem_2">par2</div>
    <div class="elem_wrap">
        <div class="contacts">
            contacts
        </div>
        <div class="form">
            form
        </div>
    </div>
</div>

CSS

.header{
    width: 400px;
}

.elem_1,.elem_2{
    height: 100px;
    float: left;
}

.elem_1{
    width: 100px;
    background: red;
}

.elem_2{
    width: 200px;
    background: green;
}

.elem_wrap{
    float:right;
    width: 100px;
    height: 100px;
    background: blue;
}

.contacts{
    height: 60px;
    background: yellow;
    margin-bottom:10px;
}
.form{
    height: 30px;
    background:lightblue;
}