* {
    box-sizing: border-box;
}
html, body {
    padding: 0;
    margin: 0;
    height: 100%;
    min-height: 100%;
    font-family: 'Roboto', sans-serif;
}
.wrapper {
    width: 100%;
    height: 100%;
    background-color: #333;
    display: flex;
    justify-content: space-around;
    align-items: center;
}
.half-width {
    width: 48%;
    min-width: 300px;
    height: 80%;
    min-height: 400px;
    background-color: #fff;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    border-radius: 5px;
}

@media(max-width:800px) {
    .wrapper {
        display: block;
    }
    .half-width {
        width: 100%;
        border-radius: 0;
    }
}