local vids readme

Author: dschaele

README.md

@@ -101,7 +101,12 @@ Carousel items already run through `relative_url`, so `/static/...` works there.
 
 ## Videos
 
-Embed YouTube/Vimeo with Markdown links, or add `video:` in front matter to show the button. For inline embeds, paste the iframe HTML into Markdown if needed.
+Embed YouTube/Vimeo with Markdown links, or add `video:` in front matter to show the button. For inline embeds, paste the iframe HTML into Markdown if needed. For local videos, put the file under `static/` and use a video tag, e.g.:
+```html
+<video controls width="100%">
+  <source src="{{ '/static/video/demo.mp4' | relative_url }}" type="video/mp4">
+</video>
+```
 
 ## Equations