PowerApps Modern & Minimalistic Design Tip #1 – Box Shadows | Business Applications & O365 musings
Code Kata: Throbbing Buttons Using box-shadow Animation In CSS
How to animate box-shadow with silky smooth performance | Tobias Ahlin
How to Animate CSS Box Shadows and Optimize Performance — SitePoint
GitHub - alexpeattie/shadow-animation: With this jQuery plugin, you can extend the animate function to support the CSS box shadow-property. You can animate the color, the x- and y-offset, the blur-radius and spread-radius.