index.css

html, body{
    margin: 20px;
    padding: 0;
    font-family: Karla;
}

#box{
    padding: 10px;
    display: block;
    text-align: center;
    margin: 20px;
    padding: 20px;
    background: #ECF2FF;
    font-size: 30px;
}

#emoji-container{
    font-size: 50px;
}

#box::focus{
    background: #CFDFFF;
}

#help-text{
    display: none;
    text-align: center;
}

#box::focus #help-text{
    display: block;
}