* {
    margin: 0; padding: 0; border: 0;
    box-sizing: border-box;
}

h1 {
    color: cadetblue;
    text-align: center;
    text-shadow: 3px 1px orangered;
    font-size: 50px;
}

p {
    color: cadetblue;
    text-align: center;
    font-size: 30px;
    text-shadow: 3px 1px #222;
}

body {
    background-color: slategray;
}

.container {
    display: flex;
    flex-flow: row wrap;
    position: relative;
}

.topleft {
    flex: 1 0 50%;
    background-color: indigo;
    height: 50vh;
}

.topright {
    flex: 1 0 50%;
    background-color: teal;
    height: 50vh;
}

.bottomleft {
    flex: 1 0 50%;
    background-color: greenyellow;
    height: 50vh;
}

.bottomright {
    flex: 1 0 50%;
    background-color: deeppink;
    height: 50vh;
}