readability improvements and diff formatting

[trevor-coleman]

CSS Styling Adjustments (custom.css)

• Updated @font-face for NotoSans-Mono to support variable font properties.
• Increased font weight in pre tags to 490 from 400
• Improved legibility of sidebar in dark mode.

Font File Management

• Removed all static variations of "NotoSansMono" font files and replaced with a single variable font.

Code Theme Enhancements in ir-code Themes (dark.ts and light.ts)

• Fine-tuned the syntax highlighting theme in both light and dark modes to improve code legibility
• Separated and improved formatting for diff blocks

Before and Afters

TSX

Light Mode

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After:

Dark Mode

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After:

Diff

Light Mode

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After:

Dark Mode

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Sidebar

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After: