Refresh player and export/settings UI

[Erimaru11]

Hi, I'm a product designer/developer and a big fan of LosslessCut. I put together a UI refresh focused on improving visual consistency and perceived quality, without changing logic or functionality.

Summary
This PR refreshes the player and related UI without changing application logic.

Changes

• redesigned player controls and timeline chrome
• updated export and settings dialogs
• refreshed tracks/streams popups and overlays
• unified buttons, selects, switches, and dialog styling
• improved spacing, alignment, and visual consistency across key screens

Notes

• UI/UX only
• no intended logic or workflow changes

[mifi]

Hi! This is quite a large PR. I see that you replaced a lot of var(--x-N) variables with hard coded colors. Did you test both dark and light mode? because I believe this might break those

[Erimaru11]

Thanks, good catch. I did a cleanup pass on the redesign layer.

The updated player/export/segment chrome no longer uses local hard-coded colors in the changed components. Those parts now read from centralized semantic --player-* theme tokens, with light/dark values defined in src/renderer/src/main.css.

I also toned down the light theme surfaces/shadows and removed the stronger glass/halo treatment there, since that was too heavy compared to the original light theme.

So the theme-specific styling is now centralized instead of scattered through the redesigned components.

[Erimaru11]

I found one additional theme-specific hard-coded area after the previous push: the dialog/alert overlay styling. That has now been moved to the same centralized --player-* token layer as the rest of the redesigned chrome.

I also tested both dark and light mode on macOS and Windows, and the updated UI renders and behaves correctly across both themes on both platforms.

[lukefiji]

Hey @Erimaru11! I'm big on UI/UX as well - just wondering if you you could share some screenshots of what you're working on :)

[Erimaru11]

Hi, yes, of course. I’ve submitted a slightly updated UI (in both dark and light themes) to the request pool; I’ve tried to keep the icons and colour scheme chosen by the original creator, so as not to make any drastic changes straight away. The updated UI simply refreshes the look, makes the buttons larger, and adds a ‘frosted glass’ effect to some elements. I’m using the updated version myself, and I like everything so far. I’m sending you screenshots of some of the screens