[Design] Book card polish — darker spine band + vivid accent color

[realproject7]

Parent Ticket

Follow-up polish for #403 (Book Shelf Design Trial)

Reference Design

T1 will upload reference image below.

Reference	Image
Book spine band	(upload here)

Scope

Two targeted visual tweaks to the book cards:

1. Vivid brown accent color for title text

The current gold accent (#DAAA63) is too muted when used as the book title color. Switch to a richer, more vivid brown for accent text on book covers.

Suggestion: Try a deeper warm brown like #8B4513 (saddle brown) or #A0522D (sienna) — something that pops against the cream cover background while staying in the warm palette. Update --accent or add a new --accent-title token.

Files: src/app/globals.css, src/components/StoryCard.tsx (title color class)

2. Dark spine band on left side of book cover

The current spine is a light gold gradient (#A6926F → #C4A87A → #B89E72). It needs to be a dark, contrasting band — like the reference image which shows a dark charcoal/black matte spine that clearly separates from the lighter cover.

Current spine (StoryCard.tsx line ~40):

style={{
  background: "linear-gradient(to right, #A6926F, #C4A87A, #B89E72)",
}}

Target: Dark band — deep charcoal/brown (e.g. #2C1810 or #3A2A1A), wider (current is w-3, try w-4 or w-5), with a subtle texture gradient to simulate matte book cloth. The spine should be the darkest element on the card, creating clear visual contrast.

Also update the inner shadow overlay (StoryCard.tsx line ~69) to blend from this darker spine color.

Files: src/components/StoryCard.tsx

Files to Change

File	Change
src/app/globals.css	Adjust accent color or add --accent-title token
src/components/StoryCard.tsx	Darker/wider spine band, update title color reference

DO NOT

• Do not change layout, grid, or shelf structure
• Do not change any business logic
• Do not change other components — only StoryCard and globals.css

Acceptance Criteria

• Book title text uses a more vivid/deeper brown — readable and eye-catching
• Spine band is dark (charcoal/deep brown), clearly contrasts with cream cover
• Spine is slightly wider for visual weight
• Inner shadow overlay blends naturally from dark spine
• npm run typecheck passes
• npm run lint passes

Branch

task/{issue-number}-book-spine-accent