Add utility functions for enhanced attrs and styles functionality

[Snehadas2005]

Add new utility functions to improve developer experience when working with data attributes and CSS functions.

Proposed Changes

attrs package

• MergeDataAttrs: Create multiple data attributes from a map in one go

  attrs.MergeDataAttrs(map[string]string{"id": "123", "role": "admin"})
  // Returns: Props{"data-id": "123", "data-role": "admin"}

styles package

• Calc: CSS calc() function wrapper
• Min: CSS min() function wrapper
• Max: CSS max() function wrapper
• Clamp: CSS clamp() function for responsive values
• IsValidHexColor: Validate hex color format (#RGB or #RRGGBB)
• IsValidRGBColor: Validate RGB color format

Benefits

• Simplifies working with multiple data attributes
• Type-safe CSS math functions for responsive design
• Built-in color validation for error prevention
• Maintains consistency with existing API patterns

Testing

• Comprehensive unit tests for all new functions
• Edge case coverage for validators
• 100% test coverage for new code

Documentation

• Function documentation with examples
• Updated README files for both packages

---

I had worked on this contribution under the label of Hacktoberfest 2025.

[chasefleming]

Thank you for the additions! I think the merge method and validity checkers might not fit the scope of the library. Can we remove those and just keep the CSS helpers? Those are very useful and work well with this.

[chasefleming]

I'm not sure this is necessary.

The current API already handles this use case cleanly with the existing DataAttr() helper and Props type.

For creating multiple data attributes:

  userAttrs := attrs.Props{
      attrs.DataAttr("user-id"):   "123",
      attrs.DataAttr("user-name"): "john",
      attrs.DataAttr("role"):      "admin",
  }

If you need to combine data attributes with other attributes:

  buttonAttrs := attrs.Merge(
      attrs.Props{
          attrs.Class: "user-button",
          attrs.ID:    "user-123",
      },
      attrs.Props{
          attrs.DataAttr("user-id"): "123",
          attrs.DataAttr("role"):    "admin",
      },
  )

Or combining multiple attribute sets:

  finalAttrs := attrs.Merge(
      baseAttrs,
      attrs.Props{
          attrs.DataAttr("user-id"):   "123",
          attrs.DataAttr("user-name"): "john",
      },
  )

[chasefleming]

These CSS helpers are great. These would fit nicely in the library.

[chasefleming]

Unfortunately, I don't think this fits the scope of the library.

[Snehadas2005]

Ok, I will make changes accordingly. I will just keep the CSS part, and the rest of them will be restored to the initial one.

[chasefleming]

Thank you!

[Snehadas2005]

I had made changes, kindly check

[chasefleming]

I still see this in

[chasefleming]

Can you remove this too please?

[Snehadas2005]

Kindly check once again.