CSS Tutorial 10 - Setting Height and Width
In this tutorial I go over how to set height and width to the HTML elements. You can also use max-height and max-width for setting what the maximum width and height the elements will have.
I also go over the difference between width and max-width.
You can also use min-height and min-width to specify the minimum height and width for your element. With this, the elements will not go lower in width or height than what you have set up.