0772 — Profile scrolling slows as the personal text grows

Superseded by 0773, which eases the slowdown while retaining the same animation and restoration behavior.

Context

The user approved the existing fade after watching it develop and asked for scrolling to slow as the letters grow. Scaling a moving line also multiplies its pixel speed, so reducing the playback rate must account for both effects. This supersedes 0769, retaining its fade, growth, inactivity, restoration, and lifecycle decisions.

Decision

• Keep the five-second delay, 110-second growth/fade, and board-colored background. The proposed white fade was withdrawn before implementation.
• Set the existing CSS loops’ playback rate to 1 / scale². One factor compensates for enlargement; the other makes scrolling slower as size increases. At the largest size, scrolling contributes about 11.5% of its original pixel speed and continues indefinitely.
• Use the browser’s Animation.updatePlaybackRate on both copies, which synchronizes playback position before changing speed. Keep the existing CSS loop rather than changing its duration or restarting it. The Web Animations specification defines the synchronization behavior.
• Set progress and playback speed together in the state class. Activity, hiding the page, or reduced motion restores progress and normal speed; the existing cleanup remains responsible for navigation and teardown.

Consequences

• Growth and slowdown follow the same scale, with no second timer or animation implementation. Both repeated copies keep the same rate.
• The browser flow checks that scrolling speed decreases as scale grows, stays positive, and returns to normal on activity.