Woo! I fixed my link slider over on raphcrow.tumblr.com. I didn’t think of using flexbox to fix the fluctuating width problem I had before. Now it works beautifully! And it’s 100% responsive up to mobile view (at which point it’s still fluid, but too small to be practical). However since tumblr themes have a mobile layout, I’m not worried.
I posted the example on my website, with the HTML and CSS up for grabs.
Want to implement the link slider on your tumblr theme?
1) Follow the link to my site and copy the code. To paste the HTML, go to Edit Theme > Edit HTML and find an appropriate place to put it. Usually tumblr themes are well commented, so they’ll indicate what part is what. (To understand this better, you can read about the markup here.)
2) To paste the CSS, go back to Edit Theme and scroll down until you see Advanced Options. Click that sucker and scroll down the pane until you see “Custom CSS”. Slap the CSS code from my site at the bottom of whatever code you may or may not have in there (so that it overrides anything else).
3) To upload your images for the link cards, replace the URL in the HTML bit with your own URL. You can upload tumblr theme assets here or use imgur, photobucket, what have you.
4) Lastly, remove the dummy text with your own content.
Feel free to message me for whatever or whatever.