JSFiddle - React, Tailwind, and code Playground

HTML

<div class="parent">
    <div class="child_class" id="child1"></div>
</div>

CSS

.parent {
    border: 1px solid #5B5B5B;
    height: 30px;
    width: 80%;
    right: 0%;
    position: relative;
    margin-right: auto;
    margin-left: auto;
    border-radius: 25px;   
    overflow: hidden;
}
    .child_class {
        width: 100%;
        height: 100%;
        border-: 1px;
        box-sizing: border-box;
        background-color: #ddd;
    }