JSFiddle - React, Tailwind, and code Playground

by Felype Rennan

HTML

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/font-awesome/4.6.3/css/font-awesome.min.css">
<div class="double-search">
        <div class="input-container">
                <input type="text" placeholder="Campo da esquerda" class="left" />
                <input type="text" placeholder="Campo da direita" class="right" />
        </div>
        <button class="search"><i class="fa fa-search"></i></button>
</div>

SCSS

$btn-width: 40px;
$ds-h-padding: 8px;
$ds-total-h-padding: 16px;
$ds-height: calc( 1em + 16px );

.double-search {
  position: relative;
  width: 100%;
  height: $ds-height;
  .input-container {
    height: $ds-height;
    position: absolute;
    top: 0;
    bottom: 0;
    left: 0;
    right: $btn-width;
    display: flex;
    overflow: hidden;
    input {
      width: 50%;
      height: 100%;
      margin: 0;
      padding: 0 8px;
      height: $ds-height;
      line-height: $ds-height;
      position: absolute;
      z-index: 2;
      
      &.left {
        right: 50%;
        left: 0;
        transition: 250ms ease-in-out;
        background: #f5f5f5;
        &:focus, &:not(:empty) {
          right:20%;
          width: 80%;
          z-index: 3;
          background: white;
          + .right {
            left: 82%;
          }
        }
      }
      &.right {
        right: 0;
        left: 50%;
        transition: 250ms ease-in-out;
        background: #f5f5f5;
        &:focus, &:not(:empty) {
          left:20%;
          width: 80%;
          z-index: 3;
          background: white;
        }
      }
    }
  }
  .search {
    position: absolute;
    background: black;
    display: block;
    right: 0;
    top: 0;
    outline: none;
    color: white; 
    width: $btn-width;
    height: $ds-height;
    transition: 100ms ease-out;
    border: 0;
    cursor: pointer;
    &:hover {
      background: #00809C;
      color: white;
    }
  }
}