div {
float: left;
clear: both;
}


#container {
font-size: 15px;
background-color: yellow;
min-height: 2660px;
float: left;
min-width: 80%;
/* margin auto should not be added, it's not compatiable with float. */
/* float is required to make websites mobile-friendly with percentages. */
}

.sidebarofmenus {
width: 160px;
margin-top: 10px;
margin-left: 3%;
background-color: pink;
height: 350px;
clear: none;
}

.contentstuff {
background-color: tomato;

/* Padding is unable to be added if width exceeds anywhere past 100%. */
width: 755px;
margin-left: 5%;
height: 2650px;
margin-top: 10px;
clear: none;
}