Can you apply styles using class names and can you change it at run time?

Answer:

Yes, you can apply style to different elements or different style to a single element in a class depending on the elements used. With the help of element IDs, you can also apply style to the element on a Web form.

Suppose you have created a style for a class, and then it automatically add a style definition to the style sheet using .classname identifier.

You can apply style to HTML elements by using the class attribute and to server control elements by using the CssClass attribute.

Yes, we can change the style sheet at runtime.