upgrade

frontend/src/main.tsx

@@ -0,0 +1,77 @@
+import { StrictMode } from 'react'
+import { createRoot } from 'react-dom/client'
+import './index.css'
+import App from './App.tsx'
+
+createRoot(document.getElementById('root')!).render(
+  <StrictMode>
+    <App />
+  </StrictMode>,
+)
+
+// Lightweight scroll-reveal setup for elements with `.section` or `[data-reveal]`.
+// Respects prefers-reduced-motion and observes dynamically added nodes.
+function setupReveal() {
+  const w = window as unknown as { __revealSetupDone?: boolean }
+  if (w.__revealSetupDone) return
+  w.__revealSetupDone = true
+
+  const prefersReduced = window.matchMedia('(prefers-reduced-motion: reduce)').matches
+  const selector = '.section, [data-reveal]'
+
+  // If reduced motion is preferred, mark everything visible and skip observers
+  if (prefersReduced) {
+    document.querySelectorAll(selector).forEach((el) => el.classList.add('reveal-visible'))
+    return
+  }
+
+  const seen = new WeakSet<Element>()
+  const io = new IntersectionObserver(
+    (entries) => {
+      for (const entry of entries) {
+        if (entry.isIntersecting) {
+          entry.target.classList.add('reveal-visible')
+          io.unobserve(entry.target)
+        }
+      }
+    },
+    { threshold: 0.12, rootMargin: '0px 0px -10% 0px' },
+  )
+
+  const observeExisting = () => {
+    document.querySelectorAll(selector).forEach((el) => {
+      if (!seen.has(el)) {
+        seen.add(el)
+        io.observe(el)
+      }
+    })
+  }
+
+  // Observe current DOM
+  observeExisting()
+
+  // Observe future DOM mutations (e.g., route changes render new sections)
+  const mo = new MutationObserver((mutations) => {
+    let needsScan = false
+    for (const m of mutations) {
+      if (m.type === 'childList' && (m.addedNodes?.length ?? 0) > 0) {
+        needsScan = true
+      }
+      if (needsScan) break
+    }
+    if (needsScan) observeExisting()
+  })
+  mo.observe(document.documentElement, { childList: true, subtree: true })
+
+  // Cleanup on HMR disposal (Vite dev) to avoid duplicate observers
+  if (import.meta && import.meta.hot) {
+    import.meta.hot.dispose(() => {
+      io.disconnect()
+      mo.disconnect()
+      w.__revealSetupDone = false
+    })
+  }
+}
+
+// Initialize after first render tick
+queueMicrotask(setupReveal)