Changed the default body text color from @hacker-primary-light (contrast ratio 4.32:1 on black, not WCAG compliant) to @hacker-primary-lighter (contrast ratio 7.42:1)
- Dim body text, more heading emphasis
- Replace state colors with variants closer to primary/gray tones
- `pre` border color matches pre background
- Buttons lighten instead of darken on hover (stronger effect on dark theme)
- Replace table colors to more closely match pagination and tabs
- Edit form legend and disabled input colors
- Breadcrumb active item emphasis
- Improve visibility of close button on alerts and modals