Two more styles: pastel-ui and y2k-chrome (31 in all)

[ZLHad]

Why

Two of the five community films in cases/oneshot-five.md work in registers the style library lacked:

• a light, friendly UI explainer (科了个喵's "3 seconds");
• late-90s liquid-chrome pop (FunTech's showreel).

What

styles/pastel-ui/ (浅色界面讲解)

• Look: a pastel wallpaper, white rounded cards, one colour per concept carried through the whole swatch.
• Swatch: the title is typed into a chat bar and sent. The three cards step forward one at a time on a progress rail. The 初版 card then opens to full screen as the end frame.
• Learning objects: the 科了个喵 film (2026), and Material You (Google I/O, 2021-05-18).
• Sound: kalimba, Rhodes, plucked upright bass, string pad, finger snaps, UI foley.

styles/y2k-chrome/ (Y2K 铬面)

• Look: inflated liquid chrome on acid yellow, reflecting an unseen studio (dark ground, silver horizon).
• Swatch: a chrome blob splashes into the title and stays on as the anchor. It hops onto three level tiles on the beat, gets swept off by a chrome tube, and regrows as "Y2K".
• Learning objects: FunTech Showreel 2026, Wipeout (1995, The Designers Republic), Mac OS X Aqua (2000-01-05).
• Sound: bubblegum dance at 150 BPM; pops, a rubbery hop squash, sticker slaps, a metallic sweep.

Both presets

• STYLE.md is written in the non-rigid voice: what the swatch does and why, with 容易翻车的地方 in place of a 禁止项 list.
• Text sizes follow the target tiers (Spec up front: Watch on sets the text-size floor; 4K is a render setting #47).
• They are references, not templates (Style presets are references, not templates #48).

Library updates

• styles/README.md: count, index rows and sound rows.
• Both READMEs now say 31.
• playbook/04-audio.md: transition table.
• styles/gallery.jpg and gallery.mp4 are regenerated (31 swatches × 1.5 s).

How they were checked

Process: each preset was built by a subagent and reviewed three times by a fresh reviewer.

Review history:

• Round 1, pastel-ui: a purple glow-orb hook, a 2 s freeze, a flat ending.
• Round 1, y2k-chrome: labels under the text-size floor, a vanishing anchor, chrome that read as candy.
• Round 2 scores (concept / hook / readable / motion / variety / composition / accuracy / sync):
  • pastel-ui: 7 / 7 / 8 / 8 / 8 / 7 / 8 / 8
  • y2k-chrome: 8 / 9 / 8 / 8 / 8 / 7 / 8 / 8
  • All floors pass.
• Final small fixes, checked on the contact sheets: an overlapped label, an empty end frame, a crowded tile corner, one repeated sound.

Checks:

• render.sh passes for both, including audio qa.
• determinism.sh passes for both: 150/150 frames identical across 1 and 3 workers.
• tools/ci.sh --committed, also run with VH_BASH=/bin/bash: all passed.