JSFiddle - React, Tailwind, and code Playground

HTML

<div class="cont">
  <input class="input" type="text">
  <i class="icon"></i>
</div>

CSS

.cont {
    width: 300px;
    display: flex;
    background: #ccc;
    padding: 10px;
}

.input {
    flex-grow: 2;
}

.icon {
    width: 16px;
    height: 16px;
    display: block;
    background-color: red;
}