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

body {
    background-color: #456;
    color: #eee;
}

h1 {
    position: absolute; top: 160px; right: 20px;
    font-size: 14pt;
    font-weight: normal;
    color: #89A;
    font-family: Verdana, Geneva, Tahoma, sans-serif;
}

main {
    position: absolute;
    top: 50%; width: 100%;
    transform: translateY(-50%);
    display: flex;
    flex-flow: row wrap;
    justify-content: space-evenly;
}

/* child selector */
main > div {
    background-color: pink;
    flex: 0 0 30%;
    aspect-ratio: 1;
    border-radius: 4px;
}

#featured {
    position: relative;
    background-color: transparent;
}

#featured > div {
    background-color: #ff0;
    width: 45%; height: 45%;
    position: absolute;
    border-radius: 4px;
}

#featured > div:nth-child(1) {
    top: 0; left: 0;
}

#featured > div:nth-child(2) {
    top: 0; right: 0;
}

#featured > div:nth-child(3) {
    bottom: 0; left: 0;
}

#featured > div:nth-child(4) {
    bottom: 0; right: 0;
}

nav {
    display: flex;
    flex-flow: row wrap;
    justify-content: space-evenly;
    padding-top: 8px;
    gap: 12px;
}

nav > a {
    background-color: #ff0;
    padding: 12px 16px;
    flex: 1 0 auto;
    text-align: center;
    border-radius: 4px;
    text-decoration: none;
}

/* styles for mobile users */
@media screen and (max-width: 750px) {

    nav > a {
        flex: 0 0 40%;
    }

    main {
        position: static;
        transform: translateY(0%);
        padding-top: 40px;
    }
    
    /* child selector */
    main > div {
        flex: 0 0 96%;
        margin-bottom: 40px;
    }
    
    #featured {
        position: relative;
        background-color: transparent;
    }
    
    #featured > div {
        background-color: #ff0;
        width: 45%; height: 45%;
        position: absolute;
        border-radius: 4px;
    }
    
    #featured > div:nth-child(1) {
        top: 0; left: 0;
    }
    
    #featured > div:nth-child(2) {
        top: 0; right: 0;
    }
    
    #featured > div:nth-child(3) {
        bottom: 0; left: 0;
    }
    
    #featured > div:nth-child(4) {
        bottom: 0; right: 0;
    }
}