Control the font used for book buttons in RAB books (BL-16351)

[StephenMcConnel]

Devin review

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This change is 

[greptile-apps]

Greptile Summary

This PR adds a single CSS rule to basePage-sharedRules.less that sets the font properties for book-button label <p> elements when they appear inside a .bloom-link-grid on a canvas element.

• Introduces font-size: var(--DefaultBookButtonFontSize, 10pt), giving a CSS-variable hook for overriding the label size, with a 10pt default (≈13.3 px, slightly above the current 13 px set in navigationButtonsAndGrid.less). The new selector's higher specificity (four class selectors vs. one) means it wins the cascade.
• Sets font-family: Andika, NotoSans, sans-serif, consistent with the project's existing web-font strategy: NotoSans is deliberately registered under that name via @font-face in bloomWebFonts.less (covering Devanagari, Thai, and Bengali scripts).

Important Files Changed

Filename	Overview
src/content/bookLayout/basePage-sharedRules.less	Adds a CSS rule controlling font-size (via CSS variable with 10pt fallback) and font-family for .bloom-bookButton p elements nested inside canvas elements; font name NotoSans is intentional and consistent with @font-face declarations elsewhere in the codebase

_{Reviews (1): Last reviewed commit: "Control the font used for book buttons i..." | Re-trigger Greptile}

[hatton]

@hatton made 1 comment.
Reviewable status: 0 of 1 files reviewed, 1 unresolved discussion (waiting on StephenMcConnel).

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src/content/bookLayout/basePage-sharedRules.less line 293 at r1 (raw file):

.bloom-canvas .bloom-canvas-element .bloom-link-grid .bloom-bookButton p {
    font-size: var(--DefaultBookButtonFontSize, 10pt);
    font-family: Andika, NotoSans, sans-serif;

What if their language needs a different font? It doesn't seem like any fixed list will do here.