[Draft] Indigo Dark Theme Enhancements

[hinakhadim]

DRAFT Issue - WIP
Following are the enhancements discovered during Sumac Upgrade and working with other teams.

• Introduce replaceable logos and their URLs in Indigo Footer
  The Open edX footer supports dynamic customization of logos and links through provided URLs or configuration settings. However, the Indigo footer currently uses static logos and links, making it less flexible. Recently, a team wanted to add their own logo and URLs to the Indigo footer but were unable to do so without forking the footer and republishing it to npm. Introducing support for dynamic configuration in the Indigo footer would be a valuable enhancement, saving teams from needing to fork and customize it for such changes.
• Introduce Dark theme in discussion sidebar
  During Sumac testing, it was discovered that the discussion sidebar in the Learning MFE continues to display in the light theme, even when the user switches to dark mode. The issue arises because the discussion sidebar is rendered via an iframe src, and styling changes cannot be directly applied to an iframe's content. Additionally, the dark theme across the platform is implemented through the header and footer, and the iframe or sidebar does not have header and footer component. As a result, the dark theme does not apply to the sidebar. Proposed Solution: Wait for a plugin slot to be introduced in the Discussion MFE to enable a consistent dark theme application on Discussion Sidebar.
• Image Explorer
  The Image Explorer appears in the light theme even when the user switches to dark mode. While the rest of the page transitions to the dark theme, the Image Explorer retains a white background with white text, significantly reducing readability.
• ORA Grading MFE + Course Authoring MFE + Communications MFE + Gradebook MFE
  The Indigo theme currently supports the dark theme on the Learner Dashboard, Learning, Account, Profile, and Discussions MFEs. However, the Authn MFE does not yet support the dark theme due to the absence of plugin slots. For the remaining MFEs that lack dark theme support, we will determine which ones to prioritize and include in future development plans based on their significance.
  If anyone has thoughts that why we need to applying brand to these MFEs. Here's the answer:
  - https://discuss.openedx.org/t/applying-lms-branding-in-course-authoring-frontend-for-consistent-user-experience/14299
• Code Refactoring
  Discussion in Progress
• Implement dark theme in Open edX default Xblocks
  Discussion in Progress
• Dynamic theme that doesn't require image building and publishing packages [Res]
  Discussion in Progress - Just jotting down my thought that if we use somewhat hosted CSS links in both legacy pages and MFEs.
• Multiple theme support [Res]
  Discussion in Progress
  • https://discuss.openedx.org/t/mfe-and-theme-bootstrap/14356
• Update edly Academy docs
  Our team has written https://edly.io/academy/tutorindigo/ blog a while ago when dark-theme was initially implemented. Over the time, we've made lot of changes in indigo theme and we've to update this blog with the latest changes because it helps users to customize their own theme using indigo easily.