JSFiddle - React, Tailwind, and code Playground

HTML

<form action='/search' method='GET'>
    <input type='text' name='search_user' placeholder='Поиск по имени и фамилии' />
      <div class='inline-button width100 center' id='start-search-button'>Поиск</div>
    </form>

CSS

.inline-button{
  background:#58a2ff url('images/button-25-gradient.png') repeat-x;
  border:1px solid #045fd1;
  border-radius:3px;
  color:#fff;
  cursor:pointer;
  display:inline-block;
  padding:5px;
}

.inline-button:hover{
  background:#58a2ff url('images/button-25-gradient-hover.png') repeat-x;
}

.width100{
  width:100px;
}

.center{
  text-align:center;
}