.tag {
    background-color: transparent;
}

/* When the input field gets focus, change its width to 100% */
input[type=text]:focus {
    width: 100%;
}

input {
    width: 400px;
    margin: 10px;
    box-sizing: border-box;
    border: 2px solid #ccc;
    border-radius: 4px;
    font-size: 16px;
    background-color: white;
    background-position: 10px 12px;
    background-repeat: no-repeat;
    padding: 12px 20px 12px 40px;
    -webkit-transition: width .4s ease-in-out;
    transition: width .4s ease-in-out;
}