<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Css Search Box Practice</title>
<!--  font awesome  -->
  <link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.8.1/css/all.css" integrity="sha384-50oBUHEmvpQ+1lW4y57PTFmhCaXp0ML5d60M1M7uH2+nqUivzIebhndOJK28anvf" crossorigin="anonymous">
  
</head>
<body>
  <div class="container">
      <input type="text" id="box" placeholder="Search anything..." class="search__box">
      <i class="fas fa-search search__icon" id="icon" onclick="toggleShow()"></i>
  </div>
</body>
</html>
html {
    font-size: 62.5%;
}

*,*::before,*::after {
  margin: 0;
  padding: 0;
  line-height: inherit;
  box-sizing: inherit;
}

body {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  height: 100vh;
  background-color: #ff5e57;
  line-height: 2;
}

.container {
  width: 350px;
  height: auto;
  background-color: #1e272e;
/*   margin: 20vh auto; */
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  border-radius: 4rem;
  padding: 10px;
}

.search__box {
  float: left;
  width: 0;
  height: 4rem;
/*   display: inline; */
  background: none;
  color: #f7f7f7;
  font-size: 1.5rem;
  border-radius: 2rem;
  outline: none;
  border: none;
  position: relative;
  opacity: 1;
  transition: all .75s ease-in;
  cursor: pointer;
/*   border: 2px solid tomato; */
/*   margin-top: 5px; */
}

/* .search__box:focus, .search__box:hover {
  background-color: #f1f2f6;
} */

.search__icon {
  box-sizing: border-box;
  float: right;
  font-size: 2.5rem;
  display: inline-block;
/*   justify-content: center;
  align-items: center; */
  margin-left: .8rem;
  margin-top: 0;
  cursor: pointer;
  position: absolute;
  color: #fa983a;
  transition: all .25s ease-in;
  padding: .7rem;
  border-radius: 50%;
}

.container:hover > .search__box {
  width: 85%;
  padding: 0 1rem;
}

.container:hover > .search__icon {
  background-color: #eee;
}

.show {
  width: 85%;
  border: 1px solid red;
}




function toggleShow () {
  var el = document.getElementById("box");
  el.classList.toggle("show");
}

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.