Creating a sticky sidebar with CSS can enhance the user experience by keeping important content visible while scrolling through a webpage. This technique involves setting the position of the element to "sticky" and specifying the top property, which allows it to stick to the top of the viewport. However, there are some common issues that can prevent this functionality from working as expected.

To create a sticky sidebar, you'll need to set the display property to flex for the container element and position: sticky for the sidebar element. You should also specify the top property and height of the sidebar element. Additionally, ensure that the parent element allows overflow by setting its display property to block or flex.

Source: https://dev.to/lindaayaya/creating-a-sticky-sidebar-with-css-5d55