body{
    font-family: 'Times New Roman', Times, serif;
    height: 100vh;
    display: flex;
    flex-direction: column;
}

header{
    background-color: rgb(18, 173, 64);
    height: 60px;
    flex-shrink: 0;
}

body header h1{
    font-size: 35px;
    color:rgb(255, 17, 0);
}

nav{
    background-color:aquamarine;
    height: 30px;
}

nav li{
    display: inline-block;
    list-style: none;
    height: 30px;
}

nav a{
    display: flex;
    align-items: center;
    height: 100%;
    padding: 0 10px 0 10px;
    color: plum;
}

#content{
    display: flex;
    flex: auto;
    flex-direction: row;
}

main{
    width: 70%;
    box-sizing: border-box;
    padding: 15px;
}

aside{
    width: 30%;
    box-sizing: border-box;
    padding: 15px;
    background-color: rgb(151, 82, 207);
}

footer{
    background-color: darkseagreen;
    color: rgb(129, 19, 71);
    flex-shrink: 0;
    font-size: 85%;
}

h1{
    color: rgb(112, 9, 9);
    font-size: 140%;
    margin-bottom: 20px;
}

p{
    margin-bottom: 12px;
}

#menu-button{
    display: none;
}

#mainImg {
    width: 50%;       
    max-width: 400px;
    height: auto;     
    display: block;   
    margin: 0 auto;   
}

@media all and (max-width : 800px){

    header{
        height: 44px;
    }

    #content{
        display:block;
    }

    main, aside{
        width: 100%;
    }

    #menu-button{
        display: block;
        position: absolute;
        top: 0;
        right: 0;
        height: 44px;
        text-align: center;
        line-height: 44px;
        color: yellow;
    }

    nav{
        height: auto;
        display: none;
    }

    nav li{
        display: block;
    }

    nav.open{
        display: block;
    }
}