Reusable Button component

[gskorokhod]

We need a reusable button component that handles icons, outline vs solid styles, colours for different states (hover, active, etc), etc. It should encompass both <button> and <a> tags and implement a conisitent design for all of them

[gskorokhod]

Currently working on this. TODO:

• [ ] sort out Colour - we can't dynamically generate Tailwind classnames, so generate our own CSS for colours directly instead?
• [ ] remove the Link interface, replace it with an interface including all props for a Button (ButtonProps?) and use it consistently for sidebars, toolbars, etc

[gskorokhod]

We are using shadcdn-svelte: https://www.shadcn-svelte.com/