Smart Social Share Panel

I’m updating my web app and need a compact, reusable share-panel that lets users post their own images and videos straight to Twitter and Instagram. The component must slot easily into any page, detect the asset type (image or video), generate the correct preview, and hand the content off to each platform through their latest APIs or an approved third-party service.

Core flow
1. A user clicks the “Share” button that opens the panel.
2. The panel shows Twitter and Instagram as the available destinations; future hooks for Facebook or LinkedIn should stay in the codebase but remain hidden for now.
3. After the user selects a platform, your script authenticates, uploads the media, and returns the success / error callback so I can track shares in my analytics layer.

Please keep the styling minimal—plain CSS variables so I can match my UI later—and write clean, well-commented JavaScript (vanilla or React; I’m happy with either). When you hand it over, I’ll test by dropping it into my staging site, connecting my own API keys, and sharing a sample PNG and MP4. If both reach the correct platform feed with the caption intact, the job is done.