Use CSS Overflow "Auto" - Not Overflow "Scroll" - When Clipping Most Fixed-Size Containers
html - Vertical scrollbar inside a div without overflow-y: scroll - Stack Overflow
Ivan Akulov on Twitter: "CSS tip: if you use `overflow: scroll`, it's likely you actually want `overflow: auto`. “overflow: scroll” means “*always* show scrollbars”. You won't see the difference on a Mac
Customize website's scrollbar with CSS | by Hyouk Seo | spemer | Medium
How to Create a Beautiful Custom Scrollbar for Your Site in Plain CSS - DEV Community 👩💻👨💻