update

backend/main.py

@@ -2,6 +2,7 @@ from contextlib import asynccontextmanager
 
 from fastapi import FastAPI
 from fastapi.staticfiles import StaticFiles
+from starlette.middleware.gzip import GZipMiddleware
 
 from logsetup import setup_logging
 
@@ -22,9 +23,24 @@ async def lifespan(app: FastAPI):
     await close_db()
 
 
+class CachedStatic(StaticFiles):
+    """StaticFiles mit Cache-Control: gehashte Assets dauerhaft (immutable),
+    index.html nie cachen (verweist immer auf die aktuellen Asset-Hashes)."""
+    async def get_response(self, path, scope):
+        resp = await super().get_response(path, scope)
+        if path.startswith("assets/"):
+            resp.headers["Cache-Control"] = "public, max-age=31536000, immutable"
+        else:
+            resp.headers["Cache-Control"] = "no-cache"
+        return resp
+
+
 app = FastAPI(title="Creator", lifespan=lifespan)
 
+# gzip für JS/CSS-Bundle + große JSON-Antworten (~1,39 MB JS → ~400 KB).
+app.add_middleware(GZipMiddleware, minimum_size=500)
+
 app.include_router(router)
 
 if FRONTEND_DIST.exists():
-    app.mount("/", StaticFiles(directory=FRONTEND_DIST, html=True), name="frontend")
+    app.mount("/", CachedStatic(directory=FRONTEND_DIST, html=True), name="frontend")

frontend/src/components/TopicDetail.vue

@@ -1,5 +1,5 @@
 <script setup>
-import { computed, ref, watch, nextTick, onMounted, onUnmounted } from 'vue'
+import { computed, reactive, ref, watch, nextTick, onMounted, onUnmounted } from 'vue'
 import { fetchGuideContent, chatGuide, fetchBausteinLernstand } from '../api.js'
 import { renderMarkdown } from '../markdown.js'
 import { useChat } from '../composables/useChat.js'
@@ -27,12 +27,47 @@ const loadError = ref(null)
 const scrollEl = ref(null)
 const lernstand = ref({}) // Prüfungs-Stand pro Baustein-Titel — VOR dem immediate-Watch (loadContent nutzt es)
 
+// --- Lazy-Render + Markdown-Cache: nur sichtbare Sections parsen, jede nur einmal.
+// Behebt das Blockieren beim Öffnen (160× marked/highlight.js) und Re-Parse bei jedem Update. ---
+const mdCache = new Map()       // `${modus}:${num}` → html
+const sichtbar = reactive({})   // num → true (bleibt true, sobald je sichtbar)
+let mdObserver = null
+
+function htmlFor(s) {
+  const key = `${props.ansichtModus}:${s.num}`
+  let h = mdCache.get(key)
+  if (h === undefined) {
+    h = renderMarkdown(props.ansichtModus === 'kompakt' ? (s.kompakt || s.md) : s.md)
+    mdCache.set(key, h)
+  }
+  return h
+}
+
+// Sections rendern erst, wenn sie (fast) im Viewport sind — Observer auf den Scroll-Container.
+function setupLazy() {
+  mdObserver?.disconnect()
+  if (!scrollEl.value) return
+  mdObserver = new IntersectionObserver((entries) => {
+    for (const e of entries) {
+      if (!e.isIntersecting) continue
+      sichtbar[Number(e.target.dataset.num)] = true
+      mdObserver.unobserve(e.target)
+    }
+  }, { root: scrollEl.value, rootMargin: '800px 0px' })
+  for (const el of scrollEl.value.querySelectorAll('.section-card')) mdObserver.observe(el)
+}
+
+watch(content, () => nextTick(setupLazy))
+onUnmounted(() => mdObserver?.disconnect())
+
 watch(() => props.previewGuide?.id, loadContent, { immediate: true })
 
 async function loadContent() {
   content.value = null
   loadError.value = null
   lernstand.value = {}
+  mdCache.clear()
+  for (const k in sichtbar) delete sichtbar[k]
   const g = props.previewGuide
   if (!g || g.status !== 'done') return
   try {
@@ -198,6 +233,7 @@ function extractContext() {
             <article
               v-for="s in ch.sections"
               :key="s.num"
+              :data-num="s.num"
               :class="['section-card', lernstand[s.title]?.gemeistert ? 'gemeistert' : (lernstand[s.title]?.verstanden ? 'verstanden' : (lernstand[s.title]?.absolviert ? 'absolviert' : ''))]"
             >
               <h3 :class="{ 'baustein-klick': istPruefbar(s) }" @click="istPruefbar(s) && openFokus(s, 'pruefung')">
@@ -208,7 +244,8 @@ function extractContext() {
                   <span v-else-if="lernstand[s.title]?.absolviert" class="baustein-done" title="Prüfung bestanden">✓ Absolviert</span>
                 </template>
               </h3>
-              <div class="section-body markdown" v-html="renderMarkdown(ansichtModus === 'kompakt' ? (s.kompakt || s.md) : s.md)"></div>
+              <div v-if="sichtbar[s.num]" class="section-body markdown" v-html="htmlFor(s)"></div>
+              <div v-else class="section-body skeleton"></div>
               <BausteinPanel
                 v-if="istPruefbar(s)"
                 mode="trigger"
@@ -444,6 +481,10 @@ function extractContext() {
 .section-card h3.baustein-klick { cursor: pointer; width: fit-content; }
 .section-card h3.baustein-klick:hover { color: var(--accent); }
 
+/* Platzhalter für noch nicht gerenderte Sections (Lazy-Render). Stabile Höhe,
+   damit der IntersectionObserver die folgenden Karten gestaffelt erkennt. */
+.section-body.skeleton { min-height: 160px; }
+
 .empty-preview {
   display: flex;
   align-items: center;