I changed all http into https but this continues to pop up: "Uh oh! We couldn't save your theme. Looks like your custom theme references assets from non-HTTPS URLs. Please try again using only HTTPS URLs."
Link to my theme code: pastebin(.)com/raw/0Rr9nHcy
I've just had this same issue on Tumblr. Here's how to resolve it.
If you get the error "Uh oh! We couldn't save your theme. Looks like your custom theme references assets from non-HTTPS URLs. Please try again using only HTTPS URLs." when you save do the following:
Disclaimer: I am not responsible if you delete your theme's HTML without having saved it somewhere first - please follow the instructions carefully!