* {
    box-sizing: border-box;
}
body {
    display: flex;
    margin: 0;
    padding: 0;
    align-items: center;
    justify-content: center;
    background-color: #cacaca;
    width: 100vw;
    height: 100vh;
    overflow: hidden;
}
body > div {
    display: block;
    background-color: #fff;
    border-radius: 20px;
    overflow: hidden;
}
h1,h2 {
    margin-bottom: 0;
    line-height: 1em;
}
h1 {
    margin-top: -1.5rem;
}
body {
    font-family: "Source Sans Pro";
}
div.contentDiv {
    padding: 0 0 0.5rem; 
    text-align: center;
    max-width: min( calc( 100vh - 15rem ),calc( 100vw - 20px ));
}
div.contentDiv img {
    height: 8rem;
    width: auto;
}
div.imgDiv {
    max-width: min( calc( 100vh - 15rem ),calc( 100vw - 20px ));
    max-height: min( calc( 100vh - 15rem ),calc( 100vw - 20px ));
}
div.imgDiv img {
    height: 100%;
    width: 100%;
}