Update readme, add potentiometer controls

README.md

@@ -47,11 +47,29 @@ Abstracts window creation, event polling, menus, clipboard, and native handles b
 
 A thin wrapper around [Clay](https://github.com/nicbarker/clay) (v0.14), a single-header C layout library. Clay uses macros (`CLAY()`, `CLAY_TEXT()`, etc.) for declarative layout with automatic sizing, flex-like child arrangement, and built-in text measurement.
 
-- `ui_core.h` / `ui_core.cpp` — Defines `UI_Context` and `UI_Theme`, handles Clay initialization, lifecycle (`ui_begin_frame` / `ui_end_frame`), text measurement bridge, and error handling. `CLAY_IMPLEMENTATION` is defined here.
-- `ui_widgets.h` / `ui_widgets.cpp` — Widget abstractions (currently stubs, reserved for future use).
+- `ui_core.h` / `ui_core.cpp` — Defines `UI_Context` and `UI_Theme`, handles Clay initialization, lifecycle (`ui_begin_frame` / `ui_end_frame`), text measurement bridge, theme/accent management, and error handling. `CLAY_IMPLEMENTATION` is defined here.
+- `ui_widgets.h` / `ui_widgets.cpp` — Immediate-mode widget library: buttons, checkboxes, radio groups, text inputs (with selection, clipboard, Tab cycling), dropdowns, tab bars, draggable windows, and modal dialogs.
+- `ui_icons.h` / `ui_icons.cpp` — SVG icon atlas rasterized at startup via lunasvg. Icons are rendered as custom Clay elements.
 
 The application layout is built in `main.cpp` using Clay macros directly. Panel builder functions (`build_browser_panel`, `build_main_panel`, etc.) compose the UI each frame.
 
+#### Theme system
+
+The UI supports a full theme system managed through `UI_Theme` (`ui_core.h`) with live switching at runtime:
+
+- **Base themes**: Dark and Light, selectable via `ui_set_theme()`. Each defines a full palette — backgrounds, borders, text, accent colors, title bars, scrollbars, tab colors, and drop shadow opacity.
+- **Accent palettes**: 7 color options (Blue, Turquoise, Orange, Purple, Pink, Red, Green) applied via `ui_set_accent()`. Each palette provides coordinated accent, hover, tab gradient, button text, and tab text colors tuned for both dark and light base themes.
+- **Corner radius**: Configurable at runtime (None / Small / Medium / Large) via `g_theme.corner_radius`. All widgets read `CORNER_RADIUS` which scales with `uis()`.
+- **UI scale**: Cmd+/Cmd- (Ctrl on Windows) zoom from 0.5x to 3.0x. All widget sizes, padding, font sizes, and corner radii scale via `uis()` / `uip()` / `uifs()` helpers.
+
+#### Visual depth
+
+Interactive elements use subtle visual effects for a DAW-style look:
+
+- **Gradients**: Buttons, title bars, dropdown headers, and tab bars use vertical gradients via Clay's `CLAY_RENDER_COMMAND_TYPE_CUSTOM` system and a per-frame `CustomGradientData` pool. Buttons and title bars are lighter on top (raised), text inputs are darker on top (inset/recessed).
+- **Drop shadows**: Floating windows, modals, and dropdown lists cast soft multi-layer shadows. 7 concentric rects with linearly decreasing opacity simulate a gaussian blur, offset down-right for directional lighting.
+- **Panel highlights**: 1px lighter lines at the top of panel content areas simulate beveled edges.
+
 ### Renderer (`src/renderer/`)
 
 Custom SDF-based pipeline for UI rendering. Processes Clay's `Clay_RenderCommandArray` output directly — no intermediate scene graph.
@@ -102,9 +120,10 @@ src/
     renderer_dx12.cpp              DirectX 12 implementation
     renderer_metal.mm              Metal implementation
   ui/
-    ui_core.h                      Clay wrapper types and lifecycle API
-    ui_core.cpp                    Clay init, text measurement bridge, theme
-    ui_widgets.h / .cpp            Widget stubs (reserved)
+    ui_core.h                      Clay wrapper, UI_Theme, scale helpers, custom render types
+    ui_core.cpp                    Clay init, text measurement bridge, theme/accent palettes
+    ui_widgets.h / .cpp            Immediate-mode widgets (button, checkbox, radio, text input, dropdown, tab bar, window, modal)
+    ui_icons.h / .cpp              SVG icon atlas (check, close, chevron) via lunasvg
   audio/
     audio.h                        Audio device and playback API
     audio_asio.cpp                 Windows ASIO implementation
@@ -142,3 +161,4 @@ All dependencies are vendored as source. On Windows, nothing to install beyond t
 
 - [nob.h](https://github.com/tsoding/nob.h) — build system
 - [Clay](https://github.com/nicbarker/clay) — single-header C layout library (v0.14, with MSVC C++ patches)
+- [LunaSVG](https://github.com/nicbarker/lunasvg) — SVG rendering library (MIT, by Samuel Ugochukwu) used to rasterize icon SVGs into an R8 texture atlas at startup. Icons (close, check, chevron, knob) are defined as inline SVG strings in `ui_icons.cpp` and rendered at a fixed pixel size into a packed atlas. The atlas is uploaded to the GPU once and sampled by the renderer for icon and rotated-icon custom elements. Bundled with [PlutoVG](https://github.com/nicbarker/plutovg) as its 2D vector graphics backend.