refactor(canvas-lms): rewrite

[pynappo]

(reopening because I didn't name my branch properly, apologies)

🔧 What does this fix? 🔧

• Borders are themed to less standout colors
• User content (i.e. text with user-added highlights/text color) will keep their original styles when needed
• Course-specific colors are preserved
• Links are themed
• Most buttons are themed and have proper hover color changes
• Accent color is more prominent wherever appropriate/possible
• color-scheme variable fixed
• Might fix #368 although I haven't seen the issue with the old nor the new userstyle, seems like the quiz UI is a little different on canvas now
• etc.

Before/After on Catppuccin Mocha with Green accent color

(white borders on the screenshot are my browser not the userstyles)

Dashboard

Before

After

Example Course Homepage

Before

After

Example Quiz

Before

After

Example Course Modules

Before

After

I've themed the main pages that I've used as a student during my summer courses:

• quizzes
• discussions
• course modules/pages
• grades
• calendar
• inbox
• dashboard
• announcements
• people
• most UI components such as overlays/text editing toolbars/buttons/etc.
• probably some more that I'm forgetting

(A lot of the canvas CSS is autogenerated but with stable suffixes/prefixes/children, hence the high use of attribute selectors and such)

🗒 Checklist 🗒

• [x] I have read and followed Catppuccin's contributing guidelines.
• [x] I have updated the version appropriately in the ==UserStyle== header of the catppuccin.user.css file.
• [ ] Add webp
• [ ] Clean up the CSS
• [ ] Theme less-used pages (Canvas Studio, instructor-side UI, etc)
• [ ] Test Latte theme
• [ ] See if anything should be added to the userstyles.yml readme