The practice of combining web design with instructional design has fallen out of favor in the last few years. The Industrial giants who create the most popular LMS systems have made this more and more challenging for developers. Partly because they are catering to the lowest-common denominator of tech ability. Partly, these LMS companies want to trap all of the materials you or your institution develops in their platform's database and proprietary structure.
- If you are dependant on their system, their format, and their tools to use your own material, then you are less likely to leave and go to a competitor.
- If switching LMS platforms means re-building everything from scratch, you are less likely to leave.
- If switching LMS platforms means you can export your content, but it will be partially broken, requiring editing every single page manually, you are less likely to leave.
However, if you have the ability, developing course materials in HTML and CSS gives you independence and freedom. You can back up your own files anywhere and use them almost anywhere. The downside is that this requires more tech savvy. That's why this approach is only used by advanced Instructional Designers. It requires everything that good web design requires: CSS, HTML, maybe Javascript (if you're lucky), good backup practices, etc. On top of general good web design practice, it also requires learning to deal with Quirks Mode, LMS permissions restrictions, LMS path rewrites, etc. The common phrase is: "with great power comes great responsibility". With Instructional Design, it should be "to have great power requires you to be savvy".