New Settings::reduce_transparency_mode (serde-default, Accessibility
toggle row) swaps every GlassSurface's gradients for a flat opaque
BG_ELEVATED fill; high-contrast mode now also boosts the glass fill
opacity and rim luminance to BORDER_SUBTLE_HC levels. Both applied by
settings_plugin::update_glass_surfaces, which retargets the gradients
in place on toggle or on newly spawned glass.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Layered bevy_ui treatment (sheen gradient, specular BorderGradient rim,
BoxShadow) approximating frosted glass without shaders or backdrop
sampling - WebGL2-safe by construction. Layout callers depend only on
glass_surface() + GLASS_BORDER_PX so the material can be swapped later.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>