The Operator Instructions panel had a hardcoded inline style
(background: #f8f9fa) which became a white-on-dark unreadable blob
in dark mode. Replaced with a CSS class backed by an SCSS file that
branches at compile-time via $o-webclient-color-scheme — registered
in both web.assets_backend (light) and web.assets_web_dark (dark)
bundles per the CLAUDE.md pattern.
Tokens: panel bg #f8f9fa light / #22262d dark; border #d8dadd /
#3a3f47; text #212529 / #e8eaed.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
