header, body{
    font-family: "Quicksand";
    margin: 0 auto;
    text-align: center;
}

h1, h2{
    color: #626567;
    text-decoration: underline;
}


.rectangle{
   margin: 0 auto;
   background-color: royalblue;
   width: 400px;
   height: 300px;
   border-radius: 30px;
   transition: background-color .5s;
}

.rectangle.important{
    background-color: firebrick;
}

.rectangle.good{
    background-color: limegreen;
}

.hidden{
    display: none;
}