diff --git a/src/pages/cours/[slug]/[module]/[chapitre].astro b/src/pages/cours/[slug]/[module]/[chapitre].astro
index 0144e91..e774ce8 100644
--- a/src/pages/cours/[slug]/[module]/[chapitre].astro
+++ b/src/pages/cours/[slug]/[module]/[chapitre].astro
@@ -8,21 +8,21 @@ import { sanitizeHtml } from '../../../../lib/sanitize';
 const course = bySlug(Astro.params.slug ?? '');
 const mMatch = /^module-(\d+)$/.exec(Astro.params.module ?? '');
 const cMatch = /^chapitre-(\d+)$/.exec(Astro.params.chapitre ?? '');
-if (!course || !course.published || !mMatch || !cMatch) return Astro.redirect('/404');
+if (!course || !course.published || !mMatch || !cMatch) return Astro.rewrite('/404');
 
 let modules;
 try { modules = await getCourseBooks(course.id); }
-catch { return new Response('Formation momentanément indisponible.', { status: 503 }); }
+catch { return new Response('Formation momentanément indisponible.', { status: 503, headers: { 'Content-Type': 'text/plain; charset=utf-8' } }); }
 
 const mi = Number(mMatch[1]) - 1;
 const ci = Number(cMatch[1]) - 1;
 const mod = modules[mi];
 const chapter = mod?.chapters[ci];
-if (!mod || !chapter) return Astro.redirect('/404');
+if (!mod || !chapter) return Astro.rewrite('/404');
 
 let html;
 try { html = sanitizeHtml(await getChapterHtml(chapter.fileUrl)); }
-catch { return new Response('Chapitre momentanément indisponible.', { status: 503 }); }
+catch { return new Response('Chapitre momentanément indisponible.', { status: 503, headers: { 'Content-Type': 'text/plain; charset=utf-8' } }); }
 
 const prev = ci > 0 ? `/cours/${course.slug}/module-${mi + 1}/chapitre-${ci}`
   : mi > 0 ? `/cours/${course.slug}/module-${mi}/chapitre-${modules[mi - 1].chapters.length}` : null;
diff --git a/src/pages/cours/[slug]/index.astro b/src/pages/cours/[slug]/index.astro
index fabd013..3cdaa66 100644
--- a/src/pages/cours/[slug]/index.astro
+++ b/src/pages/cours/[slug]/index.astro
@@ -6,13 +6,13 @@ import { bySlug } from '../../../config/courses';
 import { getCourseBooks } from '../../../lib/moodle';
 
 const course = bySlug(Astro.params.slug ?? '');
-if (!course || !course.published) return Astro.redirect('/404');
+if (!course || !course.published) return Astro.rewrite('/404');
 
 let modules;
 try {
   modules = await getCourseBooks(course.id);
 } catch {
-  return new Response('Formation momentanément indisponible — réessayez dans quelques minutes.', { status: 503 });
+  return new Response('Formation momentanément indisponible — réessayez dans quelques minutes.', { status: 503, headers: { 'Content-Type': 'text/plain; charset=utf-8' } });
 }
 const hubData = {
   slug: course.slug,