body {
    margin: 0;
    padding: 0;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    font-family: 'Roboto Mono', monospace;
    box-sizing: border-box;
}

#h {
    text-align: center;
    color: #fff;
    font-size: 2rem;
    padding: 4rem 0;
    color: purple;
    background-color: #eee;
}
#h h1 {
    border-color: #4ddb5b;
    border-width: .25rem 0;
    border-style: solid;
    text-transform: uppercase;
}
#h hr {
    border-color: #4ddb5b;
    border-style: solid;
    border-width: .25rem 0 0;
    margin:0;
    padding: 0;
}

#content {
    background-color: red;
    flex: 1;
    height: 100%;
    font-size: 3rem
}

#row1 {
    width:100%;
    height: 40%;
    background-color: orange;
    display: flex;
    flex-direction: row;
}
#row2 {
    width:100%;
    height: 60%;
    background-color: blue;
    display: flex;
    flex-direction: row;
}
#row2-column1 {
    background-color: #de57bc
}
#row1-column3 {
    display: flex;
    flex-direction: column;
    height: 100%;
    background-color: red;
}

.row > section, #row1-column3 > section {
    flex: 1;
    background-size: contain;
    background-position: center center;
    background-repeat: no-repeat;
}