Build actual websites. Code a lot. Pick a website every week that fits your definition of "modern web design" and try to clone it. This will be exponentially be

Build actual websites. Code a lot. Pick a website every week that fits your definition of "modern web design" and try to clone it. This will be exponentially better than joining an online course and reading/watching a video about building something. Actual learning happens when you're applying knowledge, not merely ingesting it.