City decision cards rendered Chart.js canvases and AI evidence bodies before the user could see or expand those sections. This keeps the card shell visible while delaying chart data/canvas work until the section nears the viewport and skipping the AI evidence body while its details panel is collapsed.
Constraint: Preserve existing decision-card layout and evidence copy.
Rejected: Add list virtualization in the same pass | card-level render costs should be reduced before changing list mechanics.
Confidence: high
Scope-risk: narrow
Reversibility: clean
Tested: npm run build
Not-tested: Runtime scroll benchmark on a large production city set.
2569718930@qq.com