v10.0.0-beta.3

Two player fixes lead this release. The HTML player now injects a light-DOM base.css stylesheet that sets display: contents on <video-player> and sizes the player and media elements correctly, fixing layout shift and styling issues with non-video elements (#881). Picture-in-picture state now resolves against the resolved media target, so PiP detection and request/exit paths work with proxied media hosts, trying the standard exit path before the WebKit fallback (#883). The skins shed leftover markup: commented-out error dialog blocks (#865) and legacy caption artifacts (#882). On the site, blog posts can set a custom OG image, served from the custom domain on production deploys (#878, #880); HTML demo videos gained the missing slot="media" attribute (#867); and Netlify aliases became redirects (#868).