Possibly get an offline version ??
Viewing post in CoMiGo's Palette Generator comments
Option 1: Install plugin to your Browser that let you download web applications.
Option 2: Install itch app itch.io/app and use it like steam. It creates replicas of web apps and have sandbox option, for protection.
Also, for this, when using itch.io/app , run from index.html file for stability.