<div class="search">
  <input type="search" class="search-box" />
  <span class="search-button">
    <span class="search-icon"></span>
  </span>
</div>

$background-color: #2A2E37;
$search-bg-color: #242628;
$icon-color: #00FEDE;
$transition: all .5s ease;
* {
  box-sizing: border-box;
}

body {
  background: $background-color;
}

.search {
  width: 100px;
  height: 100px;
  margin: 40px auto 0;
  background-color: $search-bg-color;
  position: relative;
  overflow: hidden;
  transition: $transition;
  &:before {
    content: '';
    display: block;
    width: 3px;
    height: 100%;
    position: relative;
    background-color: $icon-color;
    transition: $transition;
  }
  &.open {
    width: 420px;
    &:before {
      height: 60px;
      margin: 20px 0 20px 30px;
      position: absolute;
    }
  }
}

.search-box {
  width: 100%;
  height: 100%;
  box-shadow: none;
  border: none;
  background: transparent;
  color: #fff;
  padding: 20px 100px 20px 45px;
  font-size: 40px;
  &:focus {
    outline: none;
  }
}

.search-button {
  width: 100px;
  height: 100px;
  display: block;
  position: absolute;
  right: 0;
  top: 0;
  padding: 20px;
  cursor: pointer;
}

.search-icon {
  width: 40px;
  height: 40px;
  border-radius: 40px;
  border: 3px solid $icon-color;
  display: block;
  position: relative;
  margin-left: 5px;
  transition: $transition;
  &:before {
    content: '';
    width: 3px;
    height: 15px;
    position: absolute;
    right: -2px;
    top: 30px;
    display: block;
    background-color: $icon-color;
    transform: rotate(-45deg);
    transition: $transition;
  }
  &:after {
    content: '';
    width: 3px;
    height: 15px;
    position: absolute;
    right: -12px;
    top: 40px;
    display: block;
    background-color: $icon-color;
    transform: rotate(-45deg);
    transition: $transition;
  }
  .open & {
    margin: 0;
    width: 60px;
    height: 60px;
    border-radius: 60px;
    &:before {
      transform: rotate(52deg);
      right: 22px;
      top: 23px;
      height: 18px;
    }
    &:after {
      transform: rotate(-230deg);
      right: 22px;
      top: 13px;
      height: 18px;
    }
  }
}

$('.search-button').click(function(){
  $(this).parent().toggleClass('open');
});