Drupal Vite Theme (Vite + Tailwind v4 + SDC)

A server-rendered Drupal theme where Vite owns bundling, the drupal/vite module maps library source paths to content-hashed build output, Tailwind v4 supplies utilities and design tokens, and SDC components carry their own CSS. The goal is a theme that stays fast as it grows: page-cacheable anonymous pages, near-zero JS, per-route CSS that grows sublinearly.

This is a patterns-and-pitfalls skill, not a tutorial. Each lesson is rule → why → detect/fix.

Verified against: drupal/vite 1.5.1, Drupal core 11.4, Vite 6.4, Tailwind CSS 4.3 (@tailwindcss/vite 4.3). Re-check version-bound claims when you upgrade.