The following is an example of an adjustable width, 3 column / 1 row layout that will respond well to smaller screens such as smartphones and tablets. If you view this code on a smartphone (portrait orientation), it will adjust to a 1 column / 3 row layout. Add or remove columns as desired. Change the percentages of the columns to use the amount of space you need for each one, without going over 100% (including padding width).

I am leaving the css in the style tag for this example, however it is recommended that you put it in a .css file and call them with the class tag.