[nihalpasham]

Summary

• Lighten and desaturate the @media (prefers-color-scheme: dark) filler colors across the dual-theme SVGs in cuda-oxide-book/ so amber, purple, teal, coral, and neutral containers render as subtle muted slate tones instead of heavy dark brown/indigo fills.
• Lift the dark-mode canvas and inner .k-box pill backgrounds so nested pills remain clearly readable against container fills.
• Replace two hardcoded #5c5c5c text fills in zipped-divide-and-slice.svg and host-device-tma-type-agreement.svg with the theme-aware .ts class.

Test plan

• just -f cuda-oxide/Justfile book builds with zero warnings
• Verified rendered dark-mode diagrams in the local book preview