I tried to created a custom color palette as shown below. However, the two rows (in red) with 8-digit Hex codes didn't work. But I need to add the level of transparency to these two colors. Any solutions? Many thanks!
<color-palette name="My Categorical Palette" type="regular">
No, Tableau only supports the 6 digit codes. You can set the transparency on the sheet when you're using that colour.