https://www.polymer-project.org/platform/custom-elements.html has a 404 for the "Shadow dom" button

[ebidel]

From @Pomax on November 26, 2014 2:21

It looks like it's still pointing to the old style URLs (https://www.polymer-project.org/docs/start/shadow-dom.html instead of https://www.polymer-project.org/platform/shadow-dom.html), which might in fact be the case for tons of buttons on other pages and probably warrants a quick grep

Copied from original issue: Polymer/polymer#967

[arthurevans]

Fixed on site now.