Changed drawer background from var(--mui-palette-background-paper) to
var(--mui-palette-background-default) which properly adapts to dark mode.
Also removed fallback values that were preventing theme variables from
working correctly.
Generated with [Claude Code](https://claude.ai/code)
via [Happy](https://happy.engineering)
Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>
Chris Farhood