Cross-Browser Slider Bug Fix

I have two separate webpages that share the same image slider, and that slider is misbehaving across all major browsers—Chrome, Firefox and Safari. The core files involved are script.js, open-modal.js, and app.css (plus the page-level CSS).

What I need you to do is:
• Audit those files, spot any CSS or JavaScript errors, and correct them.
• Make sure the slider behaves identically in Chrome, Firefox and Safari.
• Follow the interaction and timing shown on a reference website I’ll provide once we start.

Please return the repaired code (or clearly commented edits) together with a brief change log so I can see what was adjusted. I’ll verify by replacing the files on the server and testing the slider live in each browser. If everything matches the reference site and runs cleanly without console errors, the job is done.