Override them using the same technique you used to make the DIV's background color red. Web developers usually keep all CSS code in a document's style section or in external style sheets.

The CSS Filter Effects specification, which is backed by Adobe, defines a mechanism for applying common graphical filters to Web content. It can be used to adjust brightness, saturation, hue, and ...

In a tutorial [Bramus] takes us through using the trigonometric functions in CSS. These are supported in all major browsers since Chrome 111, Firefox 108 and Safari 15.4.

If a section feels boring, add a bold feature. As you continue learning HTML, CSS and JavaScript, keep practising and experimenting. You will gain confidence and improve your coding skills.