The original release was missing the "palettes" folder (and the palette files therein), which is mentioned in the guide.

I've uploaded it here as a free separate download to make it easy to access if you need it. It contains both color palettes mentioned in the guide:

• Original - These are the colors used for the separate elements pieces, they're designed to be distinct colors to allow for easy recoloring of individual pieces, and are not intended to look good on a final sprite.
• General - These are the colors that are used for the final recolored pieces, and can serve as a starting point for your own colors and sprites. Note that the Elements style doesn't use a strictly limited color palette, so this selection is a little messy (or as I might put it: intentionally flexible😅) and also you are welcome to add to it as needed.

Both palettes are included in the folder as .pal files and as .png images.

Thanks.