fix: remove superfluous theme/color mechanism

This is technically a breaking change but trivial
to resolve in configs: No more special implicit treatment
of "theme" to resolve a "style".

Just use regular variables like
```
style:
  primary_text_colour: {{ theme.off_black }}
  secondary_text_colour: {{ theme.off_white }}

theme:
  off_black: "#2d2a2b"
  off_white: "#f5f5f5"
```

Author: dannyadair

src/pdfbaker/config/__init__.py

@@ -89,12 +89,6 @@ class ImageSpec(PathSpec):
     data: str | None = None
 
 
-class StyleDict(BaseModel):
-    """Style configuration."""
-
-    highlight_color: str | None = None
-
-
 class Directories(BaseModel):
     """Directories configuration."""
 

src/pdfbaker/render.py

@@ -10,7 +10,7 @@
 import jinja2
 
 from . import processing
-from .config import ImageSpec, StyleDict
+from .config import ImageSpec
 
 __all__ = [
     "create_env",
@@ -94,24 +94,12 @@ def create_env(
 def prepare_template_context(
     context: dict[str], images_dir: Path | None = None
 ) -> dict[str]:
-    """Prepare template context with variables/styles/images
-
-    Resolves variables, styles and encodes images.
+    """Encode images for template context
 
     Args:
-        config: Configuration with optional styles and images
+        config: Configuration with optional images
         images_dir: Directory containing images to encode
     """
-    # Resolve style references to actual theme colors
-    if "style" in context and "theme" in context:
-        style = context["style"]
-        theme = context["theme"]
-        resolved_style: StyleDict = {}
-        for key, value in style.items():
-            resolved_style[key] = theme[value]
-        context["style"] = resolved_style
-
-    # Process image references
     if context.get("images") is not None:
         context["images"] = encode_images(context["images"], images_dir)
 

tests/test_render.py

@@ -51,16 +51,6 @@ def test_highlighting_template_no_style() -> None:
 
 
 # Context preparation tests
-def test_prepare_template_context_styles() -> None:
-    """Test style resolution in template context."""
-    config = {
-        "style": {"color": "primary"},
-        "theme": {"primary": "#ff0000"},
-    }
-    context = prepare_template_context(config)
-    assert context["style"]["color"] == "#ff0000"
-
-
 def test_prepare_template_context_images(tmp_path: Path) -> None:
     """Test image processing in template context."""
     # Create test image