*{
    box-sizing: border-box;
}
body{
    background-color: aquamarine;
}
.container{
    margin: 0px auto;
    width: 90%;
}
header {
    background-color:yellow;
    padding-top: 2em;
    text-align: center;
    height: 200px;
    width: 100%;
}
main{
    display: flex;
    flex-wrap: wrap;
}
.red{
    width: 100%;
    height: 100px;
    background-color: red;
}

.blue{
    width: 100%;
    height: 100px;
    background-color:blue;
}


.green{
    width: 100%;
    height: 100px;
    background-color: green;
}

.purple{
    width: 100%;
    height: 100px;
    background-color: purple;
}

.pink{
    width: 100%;
    height: 100px;
    background-color: pink;
}

.black{
    width: 100%;
    height: 100px;
    background-color: black;
}

.brown{
    width: 100%;
    height: 100px;
    background-color: brown;
}

.yellow{
    width: 100%;
    height: 100px;
    background-color: yellow;
}

.grey{
    width: 100%;
    height: 100px;
    background-color: grey;
}

@media screen and (min-width: 576px) and (max-width: 992px){
    main{
        display: flex;
        flex-wrap: wrap;
    }
    .red, .blue, .purple , .pink , .black , .brown , .yellow , .grey{
        width: 50%;
        height: 200px;
    }
    .green {
        display: none;
    }
}

@media screen and (min-width: 993px){
    main{
        flex-direction: row-reverse;
        display: flex;
        flex-wrap: wrap;
    }
    .red , .brown , .purple {
        width: 33%;
    }
     .pink , .blue , .yellow {
        width: 33%;
     } 
    .black , .grey , .green {
        width: 34%;
    }
}

/*@media screen and (min-width: 1050px){
    main{
        display: flex;
        flex-wrap: wrap;
    }
    .red, .blue{
        width: 33%;
    }
    .green{
        width: 34%;
    }
}*/

@media screen and (orientation:landscape){
    header{
        background-color: orange;
        color: green;
    }
    .red,.blue,.green{
        height: 100px;
        border: 5px;
    }
}