rmcg.dev/FrontendMentor/single-price-grid-component-master/css/style.css

@import url('https://fonts.googleapis.com/css2?family=Karla:wght@400;700&display=swap');

:root {
    /* setting base to 20px to make my life nicer working with rem */
    font-size: 20px;
    /* primary site colours */
    --site-cyan: hsl(179, 62%, 43%);
    --site-bright-yellow: hsl(71, 73%, 54%);
    /* neutral site colours */
    --site-light-gray: hsl(204, 43%, 93%);
    --site-grayish-blue: hsl(218, 22%, 67%);
}

* {
    margin: 0;
    padding: 0;
}

body {
    /* per the style guide, the body copy is 16px */
    font-size: 16px;
    font-family: 'Karla', sans-serif;
    width: 90vw;
    height: 100vh;
    margin: 0 auto;

    display: flex;
    flex-direction: column;
    justify-content: center;
    align-content: center;
    /* align-items: center; */

    background-color: var(--site-light-gray);
}

.box {
    box-sizing: border-box;
    padding-left: 0.8rem;
    padding-right: 0.8rem;
    padding-top: 0.7rem;
    padding-bottom: 0.7rem;
}

.topRow {
    padding-top: 1rem;
    padding-bottom: 1rem;
    background-color: white;
}
.heading {
    /* margin-top: 1.5rem;  */
    color: white;
}

.topRow .heading {
    color: var(--site-cyan);
}

.quickSell {
    color: var(--site-bright-yellow);
}
.sellBlurb {
    color: var(--site-light-gray);
}
.bottomRow {
    flex-direction: column;

    display: flex;
}
.pricingBox {
    background-color: var(--site-cyan);    
}
.priceRow {
    display: flex;
}
.price {
    color: white;
}
.pricePeriod {
    color: var(--site-cyan)
}
.sell {
    color: white;
}
.signupButton {
    background-color: var(--site-bright-yellow);
    color: white;
}
.whyUsBox {
    background-color: rgb(0, 195, 192);
}
.blurb {
}

.blurb .unstyledList {
    list-style: none;
    font-size: 10px;
    color: var(--site-light-gray)
}

/* Feel free to remove these styles or customise in your own stylesheet 👍 */
    .attribution { font-size: 11px; text-align: center; }
    .attribution a { color: hsl(228, 45%, 44%); }

/** 
* * style guide has 2 designs, one aimed for 375x870, and the other 1440x800
* TODO: Tweak transition point later
*/ 
@media screen and (max-width: 500px) {

}

@media screen and (min-width: 500px) and (max-width: 800px) {
    body {
        /* roughly half way, arbitrary for the moment */
        width: 78vw;
    }
}

@media screen and (min-width: 800px) {
    body {
        width: 45vw;
    }

    .topRow {
    }
    .heading {
    }
    .quickSell {
    }
    .sellBlurb {
    }
    .bottomRow {
        flex-direction: row;
        /* flex: 0 50%; */
    }
    .pricingBox {
        width: 50%;
    }
    .priceRow {
    }
    .price {
    }
    .pricePeriod {
    }
    .sell {
    }
    .signupButton {
    }
    .whyUsBox {
        width: 50%;
    }
    .blurb {
    }
}