JSFiddle - React, Tailwind, and code Playground

HTML

<div class="inline-button-input">
   <input type="submit" value="Submit"/>
   <div>
      <input type="text"/>
   </div>
</div>

CSS

input[type=text] {
    width: 100%;
}
.inline-button-input {
   width: 100%;
   float: right;
}
.inline-button-input div {
   overflow: hidden;
   padding-right: .5em;
}
.inline-button-input input[type=submit] {
   float: right;
}