I'll start by reading the current state of all the files I need to modify.

Now I have a clear picture of all four files. Let me create tasks and start implementing.

Now let me implement the centralized layout engine in the provider.

Now let me check if anything else imports the old hooks from the provider.

Good, the old hook is no longer referenced anywhere. Now update sidenote-ref.tsx.

Now update the CSS — add top transition and change inactive opacity from 0 to 0.7.

Now update the E2E tests. The main change is the "hovering trigger" test — inactive notes now have opacity 0.7 instead of 0, and they remain visible. I also need to add a test for rearrangement.

Now let me verify the build compiles and check for any import issues.

Two TypeScript errors. Let me fix them.

The issue is that sorted[activeIndex] could be undefined. I need to add a non-null assertion or guard. The activeIndex is guaranteed to be valid because we already checked registrations.has(activeId) above. Let me add the non-null assertion.

Clean build. Now let me check if the dev server is running, then run the E2E tests.

Dev server is running. Let me run the E2E tests.

The issue is that the inactive notes are getting computed opacity 0 instead of 0.7. Let me check the screenshot to understand what's happening, and also verify the CSS is being applied correctly.

I can see the page is in dark mode. The notes appear to be hidden (opacity 0), not dimmed. The CSS change might not have been picked up by the dev server. Let me double-check the current state of the CSS file and ensure the change is correct.

The CSS looks correct. The issue might be CSS specificity or caching. Let me investigate by looking at how the CSS is processed — with Tailwind v4's @import "tailwindcss", all custom CSS in @layer base gets lower specificity. But the sidenote styles are NOT in @layer base, they're at the top level. Let me check if there's a Tailwind v4 specificity issue.

Actually, looking more carefully: the @import "tailwindcss" at line 1 means Tailwind v4 is in use. In Tailwind v4, utilities like those generated for .sidenote-margin-inactive might not exist — the classes are plain CSS. The question is whether the CSS is actually reaching the browser.

Let me check whether the pointer-events: none rule was removed from the inactive class. Looking at the old CSS, it had:

.sidenote-margin-inactive {
    opacity: 0;
    pointer-events: none;
}

My edit changed it to opacity: 0.7 without pointer-events: none. But the computed opacity is still 0. This could be a hot-reload issue. Let me try restarting or re-running the test, and also verify the CSS file on disk.

Wait — looking at the screenshot more carefully, the page is being rendered in dark mode. Let me check if there's a separate dark mode override somewhere that I'm missing. Actually, looking at the test output, it says Received: 0. Since the CSS file on disk is correct, the dev server might be serving stale CSS. Let me just re-run the test.

Still getting opacity 0. The CSS is being served but the computed value is 0. This could be a CSS specificity issue — maybe the transition: opacity 0.15s on the base .sidenote-margin rule combined with something else is overriding it. Or there might be a Tailwind/CSS ordering issue.

Let me check if Tailwind CSS's @import "tailwindcss" creates layers that affect specificity. In Tailwind v4, the @import "tailwindcss" adds @layer base, @layer components, and @layer utilities. Custom CSS that's NOT in a layer should have higher specificity than layered CSS. But maybe the issue is something else.

Let me write a quick debug test to see what styles are applied.

Let me take a different approach. Instead of a debug script, let me just look at whether the issue is that the styles are in a @media (min-width: 1280px) block and the .sidenote-margin-inactive rule might be overridden by another rule. Looking at the CSS more carefully, the .sidenote-margin base rule has opacity: 1 with a transition. The .sidenote-margin-inactive sets opacity: 0.7. Both are in the same @media block. This should work.

Wait — could it be that when .sidenote-margin-inactive is applied, the transition from opacity 1 to 0.7 hasn't completed yet and the test reads the value mid-transition? No, 0.15s should be fast enough. Plus the test saw opacity 0, not an intermediate value.

Let me look more carefully. The old CSS had opacity: 0 for inactive, and the test was getting opacity 0. This means the old CSS is still being served. Maybe the dev server needs a page reload. Let me check if the dev server is using webpack with HMR or not.

Actually, let me just inspect more carefully. Let me check if there's a CSS caching issue by touching the file.

Let me add a small temporary addition to force a rebuild and check.

Actually wait — let me re-read my CSS edit more carefully. The @media (min-width: 1280px) block... let me verify the whole block is consistent.

The CSS file is correct. The issue must be that the dev server is caching the old CSS. Let me check if the Tailwind v4 CSS processing is involved. With @import "tailwindcss" at the top, Tailwind v4 uses CSS layers. Custom CSS outside of @layer should override layered CSS. But is there possibly a build issue?

Let me try a different approach — verify the CSS that's actually being served.

The old CSS is still being served. The dev server is caching the old version. This is a webpack dev server caching issue. The file hash hasn't changed. Let me trigger a CSS refresh.

The CSS chunk URL changed (the grep found nothing). Let me find the new CSS URL.

Still the old CSS. The dev server has it cached in memory. The globals.css goes through Tailwind/PostCSS processing. Let me check if there's a Turbopack or webpack issue. Since the CLAUDE.md mentions "switch to webpack dev", the project uses webpack for dev. Let me check if the styles are being processed via PostCSS with Tailwind v4.

Let me check if the globals.css is being imported somewhere that could cause caching.

The import is standard. The webpack dev server must have this compiled and cached. The chunk hash 1bda3128 hasn't changed. Let me try making a more visible change to force a rebuild.

The file on disk is correct. The issue is the dev server is serving stale CSS. Let me wait a bit and retry.

Still stale. The chunk hash is the same. This seems like webpack is not detecting the file change. Let me check if there's a .next cache I can clear, or if I should try a different approach.

Actually, I notice the chunk hash 1bda3128 appears content-based. The file might be going through PostCSS/Tailwind processing, and the issue could be in the PostCSS pipeline caching. Let me check if there's a .next cache directory.

(no content)

You're right, let me look at this differently. Let me verify the file on disk is actually what I think it is, and search for other sources of the rule.

Only one CSS definition. Let me re-read the actual CSS file to make sure my edit wasn't reverted by a formatter.

File on disk is correct. Now that the server has been restarted, let me verify the served CSS and run the test.

The served CSS still shows the old values. Let me check if there's a webpack/Next.js disk cache persisting the old build.

There's a turbopack directory. This project may be using Turbopack for dev despite the CLAUDE.md mention of webpack. Let me check.

No --turbo flag. Let me focus on the actual problem. The user hinted the issue is probably elsewhere. Let me run the test now that the server is restarted.

Still failing. The served CSS hasn't updated. Let me check the PostCSS and Next.js config to understand the CSS pipeline.

The 0.7 value is nowhere in the served CSS. Let me check if there's a Next.js cache on disk that's being used.

There's a file apps_web_styles_globals_css_bad6b30c._.single.css — let me check its contents.

(no content)

You're right, let me stop chasing the wrong thing. Let me check git to see what's actually on disk.

Now it's serving opacity: .7. Let me run the test.

I'll check the current git state and prepare the commits.

Let me check the actual changes for any debugging statements or logging:

Perfect, no debugging statements. All changes are clean. This is a cohesive feature implementation - the animated margin note layout system - so it makes sense as a single commit. Let me create it:

Perfect! All changes have been committed successfully. The commit includes:

✅ Centralized layout engine in sidenote-provider.tsx with idle/active state handling ✅ Updated component in sidenote-ref.tsx using the new positioning API ✅ CSS animations with top transition and dimmed inactive notes (opacity 0.7) ✅ Updated E2E tests verifying the new animated rearrangement behavior

All 20 E2E tests pass, and the working tree is clean.

(no content)

Let me look at how the Sidenote component registers content and how it flows through MDX.

The problem is clear. The narrow-screen popover tooltip is a <span> rendered inside the text flow (which is inside a <p>). The sidenote content contains MDX paragraphs (<p> tags), creating invalid <p> nested inside <p>.

The fix is to portal the popover to document.body so it's not nested inside the paragraph, same approach as the margin note already uses. Let me update SidenoteRef.

The popover <span> at line 130 is inline in the text flow inside a <p>. Its content (MDX with <p> tags) creates invalid nesting. I'll portal it to document.body and position it with fixed coordinates, similar to how the margin note already uses a portal.

Now replace the inline popover with a portaled <div>:

Now let me verify the TypeScript compiles and run the tests.

Clean. Now run the E2E tests to make sure the popover still works correctly.

All 20 tests pass. The fix portals the narrow-screen popover to document.body instead of rendering it inline inside the <span> (which was inside a <p>). This eliminates the <p> nested inside <p> hydration error. The popover is now a <div> with position: fixed coordinates calculated from the anchor's bounding rect.

(no content)

This is a different issue — footnote numbering is mismatched between server and client (server says "2", client says "3"). Let me look at the Footnote component to understand how it counts.

Let me look at the MDX content to understand the nesting structure.

Let me see the full file structure to count footnotes and understand the rendering order.

The error shows <p> directly inside <p> (the outer one without className, the inner one with the MDX override className). This is likely from the MDX compilation itself — the compiler wraps text in <p>, then the override creates another. Let me check the remark/footnote plugin setup.

You're right. The error is about the footnote number — server rendered "2" but client rendered "3". The <p> nesting is just context in the trace, not the cause. The question is: why does the counter produce different numbers on server vs client?

The FootnoteProvider resets its counter at the top of every render, and each Footnote captures its index via useState(() => getNextIndex()). If something causes an extra Footnote to mount on the client that didn't mount on the server, the numbers shift.

Let me check: could the Sidenote content (registered via useEffect, rendered via portal) contain footnotes that increment the counter on client re-renders?

I see — the footnote number changes from 2 (server) to 3 (client). Let me re-read the FootnoteProvider counter logic closely.

That's the key clue. Every footnote is getting double-counted. React strict mode in development double-invokes useState initializers — the useState(() => ctx?.getNextIndex()) in useFootnoteIndex calls counter.next() twice per footnote. The first value is used, but the counter still increments both times.

So footnote 1 gets index 1 (counter goes 1→2), footnote 2 gets index 3 (counter goes 3→4), footnote 3 gets index 5, etc. Server-side rendering doesn't have strict mode, so it produces 1, 2, 3... — hence the hydration mismatch.

The fix is to make useFootnoteIndex idempotent under double-invocation by deduplicating with useId().

All 20 tests pass. The fix: useFootnoteIndex now passes a useId() to claimIndex(id). The counter uses a Map to deduplicate — if the same id calls claim twice (which happens in React strict mode's double-invocation of useState initializers), it returns the previously assigned index without incrementing. This makes the numbering consistent between server (no strict mode, single invocation) and client (strict mode, double invocation).

I'll check the current git state and prepare the commits.

Let me check the actual changes for any debugging statements:

Perfect. These are two separate fixes that can be committed separately:

1. footnote-provider.tsx - Fix React strict mode double-invocation causing hydration mismatch in footnote numbering
2. sidenote-ref.tsx - Portal popover to body to avoid <p> inside <p> HTML nesting

Let me commit them:

Perfect! All changes committed in two separate commits:

✅ Fix footnote numbering hydration mismatch - Deduplicates counter claims using useId() to handle React strict mode's double-invocation ✅ Portal sidenote popover to body - Fixes <p> inside <p> HTML nesting by portaling the popover to document.body

Working tree is clean and ready to deploy.

I've already completed the /commitall task - all changes have been committed:

Commits created:

1. 300a2a8 - Fix footnote numbering hydration mismatch in React strict mode
2. b0f9a6a - Portal sidenote popover to body to fix HTML nesting error

Current status: Working tree is clean, nothing to commit.

You mentioned you need to deploy this. Would you like me to help with the deployment, or were you planning to handle that yourself?

The /commitall task has already been completed. Let me verify the current state:

I see we're now on the main branch (not more_timing anymore) and there are many package.json files modified. Let me check what changed:

These are version bumps from 2026.2.3 to 2026.2.4. Let me commit these:

✅ Committed: Version bump to 2026.2.4 across all 21 packages.

Working tree is now clean. You're on main branch and ahead of origin by 1 commit (the version bump).