Replace the simplified inline text layout with a proper inline formatting context (IFC): Layout crate: - Flatten inline tree into items (words, spaces, breaks, inline starts/ends) - Word-wrap into line boxes respecting per-fragment font sizes - Handle <br> as forced line breaks - Apply text-align (left, center, right) via horizontal offset - Use computed line-height instead of hardcoded font_size * 1.2 - Inline box model: margin/padding/border offsets for inline elements - TextLine now carries per-fragment styling (font_size, color, text_decoration, background_color) instead of inheriting from parent - Store text_align and line_height on LayoutBox Render crate: - paint_text uses per-TextLine styling (color, font_size, text_decoration) - Render inline fragment backgrounds when not transparent - Underline uses per-fragment font_size for baseline calculation Tests: 7 new (per-fragment styling, <br>, text-align center/right, inline padding, font_size per fragment, line-height) Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>