JSFiddle - React, Tailwind, and code Playground

HTML

<header style="background-color: black;">
        <img class="img-fluid" src="https://via.placeholder.com/1000x100" />
    </header>

    <main id="red" role="main">        
      <div class="container">
          Red
      </div>
    </main>

CSS

#red {
    margin-top: -10px;
    background-color: red;
    height: 100px;
    z-index: 100;
}

.img-fluid {
    max-width: 100%;
    height: auto;
}