fix(website): fix visual regressions

[ndizazzo]

There was a white line in the middle of the site after recent changes
tweaks the opening aperture start so it's not so long
fixed the nav appearing the middle of the white screen mode white the split is being demonstrated

Summary by CodeRabbit

• Style
  • Adjusted hero mesh grid positioning for a cleaner background alignment
  • Refined navigation transitions with reduced-motion support for smoother/accessible behavior
  • Polished aperture, overlay and mesh-zoom visuals for stage‑2 hero/workspace
• New Features
  • Improved desktop vs. touch scroll timing for aperture entry and stage progress
  • Header geometry is now synced to layout so overlays and animations align more reliably

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 87fb7169-ab92-431b-b214-e30e4d7e391e

📥 Commits

Reviewing files that changed from the base of the PR and between cfda627 and 8f172a7.

📒 Files selected for processing (1)

• website/src/assets/site.css

🚧 Files skipped from review as they are similar to previous changes (1)

• website/src/assets/site.css

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📝 Walkthrough

Walkthrough

Refines stage-2 hero visuals: adds aperture opening timing and desktop scroll mapping, syncs top chrome height into CSS variables, toggles an aperture-active body class, shifts mesh-grid SVG alignment, and refactors CSS backgrounds to use new aperture/grid variables.

Changes

Stage-2 Aperture Animation System

Layer / File(s)	Summary
Aperture timing and desktop scroll mapping website/src/assets/model-slicing.js	Adds APERTURE_OPEN_START, APERTURE_OPEN_END, and DESKTOP_APERTURE_ENTRY_SCROLL_FACTOR. Replaces linear scroll↔stage progress conversion with desktop-aware conditional mapping when useTouchScrollProfile() is false.
Chrome metrics synchronization website/src/assets/model-slicing.js	Introduces syncHeroChromeMetrics() to measure navigation chrome height and write pixel CSS variables. Calls added in init() and handleGeometryChange() to keep metrics current.
Aperture visual timing and active state website/src/assets/model-slicing.js, website/src/assets/hero-viz.js	Applies APERTURE_OPEN_START/APERTURE_OPEN_END to aperture fade-in and mesh zoom timing. Toggles is-stage2-aperture-active body class in non-reduced-motion flows. Adjusts SVG #mesh-grid patternTransform to translate by 18 18.
Navigation behavior and transitions website/src/assets/model-slicing.js, website/src/assets/site.css	Nav return logic now uses a threshold (stageProgress >= SCRUBBER_END) instead of eased aperture-close. nav.top transition now explicitly animates opacity and transform with will-change, and is disabled under prefers-reduced-motion.
CSS variable refactoring for aperture and grid styling website/src/assets/site.css	Replaces inline gradients with --stage2-aperture-* and --stage2-hero-grid-*-pos variables and composes radial and grid background layers from those variables, including active-state (--stage2-aperture-active-*) positioning.

Sequence Diagram

sequenceDiagram
  participant Scroll
  participant ModelSlicing
  participant Document as Document/CSS
  participant HeroViz as hero-viz

  Scroll->>ModelSlicing: produce scrollProgress
  ModelSlicing->>ModelSlicing: compute stageProgress (desktop-aware mapping)
  ModelSlicing->>Document: set CSS vars (--stage2-*) via syncHeroChromeMetrics()
  ModelSlicing->>Document: toggle body class is-stage2-aperture-active
  ModelSlicing->>HeroViz: drive visual timing (aperture/mesh zoom)
  HeroViz->>HeroViz: set SVG `#mesh-grid` patternTransform (translate 18 18)

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Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The PR title 'fix(website): fix visual regressions' accurately describes the main purpose of the changeset, which addresses visual issues including a white line regression and navigation visibility problems during the stage-2 aperture animation.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/landing-aperture-line-regression

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@website/src/assets/site.css`:
- Line 4971: Add the required blank line before the CSS declaration 'content:
"";' in the updated aperture/grid rule blocks to satisfy stylelint's
declaration-empty-line-before; locate the 'content: "";' declarations (used
inside the aperture/grid selector blocks) and insert a single empty line
immediately above each 'content' line so the declaration is preceded by a blank
line as required by the linter.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 5cdb083b-11b8-43f0-b52e-0213944b2689

📥 Commits

Reviewing files that changed from the base of the PR and between f25aa0d and cfda627.

📒 Files selected for processing (3)

• website/src/assets/hero-viz.js
• website/src/assets/model-slicing.js
• website/src/assets/site.css