Limited UI Customization & Styling Control in A2UI (Buttons, Dropdowns, Layout

Description

I am currently using A2UI as the frontend UI layer and Flowise as the backend for running multiple agents.
The agents are working correctly and responses are generated as expected. However, I’m facing major limitations in UI customization and styling, which affects the overall user experience.

Successfully connected Flowise backend with A2UI

Multiple agents run correctly

Outputs are displayed properly in the UI

Currently, A2UI does not allow sufficient control over UI styling, specifically:

1. Cannot change button colors (primary / secondary / hover states)

2. Cannot control dropdown size, spacing, or alignment

3. Limited control over input fields styling

4. No per-component styling (CSS / theme override)

5. UI feels restrictive for production-ready or branded apps

Because of this, the UI does not feel customizable or polished enough, even though the backend functionality is solid.

Expected Behavior

It would be great if A2UI could support:

Theme customization (colors, fonts)

Per-component styling (buttons, dropdowns, inputs)

Ability to override default styles using CSS or config

Better layout control for forms and actions

Look at the A2UI component library structure, likely in src/components for buttons, dropdowns, and inputs. Examine how styles are currently applied (CSS modules, inline styles, or a theme provider). Understand the existing theming system, if any. Check for configuration files or CSS override points. The goal is to design and implement a theming API that allows color, font, and per-component style overrides.

Written by the indexing model from the issue text.