bugfix: reader nav sticks under the app header instead of behind it (0.21.1)

$(top offset was 44px (header's 60px minus var(--space-4)), placing the bar inside the layout header. Now sticks at var(--app-header-h).)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

backend/Cargo.lock

@@ -1033,7 +1033,7 @@ checksum = "5e5032e24019045c762d3c0f28f5b6b8bbf38563a65908389bf7978758920897"
 
 [[package]]
 name = "mangalord"
-version = "0.21.0"
+version = "0.21.1"
 dependencies = [
  "anyhow",
  "argon2",

backend/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "mangalord"
-version = "0.21.0"
+version = "0.21.1"
 edition = "2021"
 
 [lib]

frontend/package.json

@@ -1,6 +1,6 @@
 {
   "name": "mangalord-frontend",
-  "version": "0.21.0",
+  "version": "0.21.1",
   "private": true,
   "type": "module",
   "scripts": {

frontend/src/routes/manga/[id]/chapter/[n]/+page.svelte

@@ -574,14 +574,14 @@
 {/if}
 
 <style>
-    /* Sticky under the fixed layout header. The bar takes its natural
-       box at the top of `main`; once the reader scrolls past, it
-       sticks just below where the layout header sits in the viewport.
-       Focus mode slides it up off-screen via a transform AND clips its
-       height to 0 so the chapter pages get the full top of the viewport. */
+    /* Sticky directly under the fixed layout header. `top: var(--app-header-h)`
+       pins the bar's top edge to the bottom edge of the layout
+       header so it never slides under it. Focus mode slides it up
+       off-screen via a transform AND clips its height to 0 so the
+       chapter pages get the full top of the viewport. */
     .reader-nav {
         position: sticky;
-        top: calc(var(--app-header-h, 60px) - var(--space-4));
+        top: var(--app-header-h);
         z-index: 10;
         display: flex;
         justify-content: space-between;