IV-107 Flatten scientific-modern surfaces and move liquidity into navigation

[heyinterspace]

What changed

• removed the decorative ambient gradient field and grain
• made generic glass, tenets, CTA, buttons, inputs, and media placeholders flat by default
• standardized the three tenet cards and broader scientific-modern surface treatment
• kept neobrutalist borders, square geometry, and selective tactile shadows
• added one liquid marker that travels between Install, Source, and Showcase
• added a thin navbar progress rail connecting movement through page areas
• retained liquid motion for tabs, filters, menus, overlays, progress, and state changes
• preserved and integrated the latest staging terminology: the framework is expressed as three tenets, not pillars
• updated agent guidance, repository memory, llms.txt, design docs, distributable CSS, and generated registry artifacts

Design decision

Structured Framing owns the physical surface.
Liquid Motion owns transitions and continuity.
Scientific Clarity owns hierarchy and legibility.

Gradients are no longer used as shorthand for liquidity. The remaining distributable gradient declarations are functional patterns: the technical grid, progress/skeleton motion, and the unit-economics hatch.

Validation

• repository TypeScript build
• artifact TypeScript no-emit check
• Vite production build
• registry drift and shadcn schema validation (88 generated items)
• adopter validation
• git diff check

Delivery

Targets staging only. main remains unchanged.

Linear: https://linear.app/interspaceventures/issue/IV-107/reframe-structured-liquidity-around-scientific-clarity