.search-input {
  width: 70px;
  box-sizing: border-box;
  border: 2px solid #ccc;
  border-radius: 4px;
  font-size: 16px;
  background-color: white;
  background-image: url("../img/search-alt-regular-24.png");
  background-position: 10px 10px; 
  background-repeat: no-repeat;
  padding: 12px 20px 12px 40px;
  -webkit-transition: width 0.4s ease-in-out;
  transition: width 0.4s ease-in-out;
}

.search-input:focus {
  width: 100%;
}