JSFiddle - React, Tailwind, and code Playground

HTML

<div id="c">
    <span class="ico">ico</span>
    
    <input type="text" />
</div>

CSS

body { background: #CACACA }
#c { background: gray }
#c .ico {
    background: lime; 
    color: lime; 
    display:inline-block 
}
#c input {
    width: 100%;
}