The stepper SSR output IS correct (273 bytes, identical to Quart, no raw ~cssx/tw). The test was checking textContent which included text outside the island boundary (the code-view documentation text). Fixed to check innerHTML for HTML elements and class attributes. 5/5 island SSR tests pass. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>