JSFiddle - React, Tailwind, and code Playground
HTML
<form action="/search/" method="get" target="_self" id="search">
<input name="q" type="text" size="40" placeholder="Поиск" />
</form>
CSS
#search input[type="text"] {
outline: none;
background: url(/upload/happyfishing/skin/img/search-dark.png) no-repeat 10px 6px #fff;
border: 0 none;
color: #777;
width: 150px;
padding: 6px 15px 6px 35px;
-webkit-border-radius: 20px;
-moz-border-radius: 20px;
border-radius: 20px;
-webkit-box-shadow: 0 1px 0 rgba(255, 255, 255, 0.1), 0 1px 3px rgba(0, 0, 0, 0.2) inset;
-moz-box-shadow: 0 1px 0 rgba(255, 255, 255, 0.1), 0 1px 3px rgba(0, 0, 0, 0.2) inset;
box-shadow: 0 1px 0 rgba(255, 255, 255, 0.1), 0 1px 3px rgba(0, 0, 0, 0.2) inset;
-webkit-transition: all 0.7s ease 0s;
-moz-transition: all 0.7s ease 0s;
-o-transition: all 0.7s ease 0s;
transition: all 0.7s ease 0s;
-webkit-appearance: none;
}
#search input[type="text"]:focus {
width: 200px;
-webkit-appearance: none;
}