header {
    width: 100%;
    height: 150px;
    background-color: yellow;
}

nav {
    width: 100%;
    height: 50px;
    background-color: green;
}

main {
    width: 100%;
}

aside {
    width: 30%;
    /* width: calc(50% - 16px); */
    height: 300px;
    background-color: skyblue;
    color: red;
}

section {
    /* width: calc(50% - 16px); */
    width: 70%;
    height: 500px;
    background-color: orange;
}

footer {
    width: 100%;
    height: 100px;
    background-color: aqua;
}