* {
    box-sizing: border-box;
}

body {
    background-color: lightblue;
    display: flex;
    flex-direction: column;
}

header {
    flex: 1;
}

nav ul {
    list-style: none;
    display: flex;
    flex-direction: row;
    justify-content: space-around;
}

nav ul li {
    flex: 1;
    background-color: black;
    border: solid 1px white;
}

nav ul li a {
    background-color: lightcoral;
    display: flex;
    flex-direction: column;
    justify-content: center;
    text-align: center;
    height: 100%;
}

#footer {
    flex: 1;
}

#wrapper {
    display: flex;
    flex-direction: row;
    justify-content: space-around;
}

#main {
    flex-grow: 2;
    background-color: aqua;
}

#rightmain {
    flex-grow: 1;
    background-color: blue;
}