One important interaction indicator on the web is the mouse cursor. The default cursor arrow changes into a pointing hand when you hover over links for example, which indicates they are indeed links and can be clicked on. It also changes into other things to differentiate context, for example it can change into a text input cursor when hovering over text fields to indicate you can type there.
When styling your website with CSS, in some cases you may lose the correct cursor type for certain elements. It’s important to retain this indicator as it will inform the user about how the item they’re hovering over can be used (see affordances). The solution is easy: if the cursor type is wrong, specify it using the CSS “cursor” property…