JSFiddle - React, Tailwind, and code Playground

HTML

<div class="search">
    search
    <input type="text" />
</div>
<ul>
    <li>news
    </li>
    <li>Nominate
    </li>
    <li>Trophy
    </li>
</ul>

CSS

body {
    margin-top: 60px;
}
.search {
    float: right;
    position: relative;
}
.search input {
    position: absolute;
    right: 0;
    width: 0;
    top: 0;
    -webkit-transition: width 0.5s;
    -moz-transition: width 0.5s;
    -ms-transition: width 0.5s;
    transition: width 0.5s;
    
}
.search input:focus,
.search:hover input {
    width: 100px;
}
ul {
    float: right;
    margin: 0;
}
li {
    display: inline;
}