JSFiddle - React, Tailwind, and code Playground

HTML

<form>
    <p>
        <label>Username:</label>
        <input/>
    </p>
</form>

CSS

form {
    widht: 400px
     height: 500px ;
    background-color: lightgrey ;
}

label {
    float: left ;
}
input {
    width: 100% ;
    box-sizing: border-box ;
}