Cut the v0.3.1 release notes

Move the Unreleased fix into a dated 0.3.1 section, update the compare
links, and add a v0.3.1 summary to the docs release-notes page. This
patch redirects / to the main page so a mirror whose entry point is a
nested page keeps its CSS and images when served.

CHANGELOG.md

@@ -6,6 +6,22 @@ All notable changes to kage are recorded here. The format follows
 
 ## [Unreleased]
 
+## [0.3.1] - 2026-06-15
+
+### Fixed
+
+- A served mirror whose entry point is a nested page no longer loses its CSS and
+  images when opened at the root. kage saves each page's asset links as
+  mirror-relative paths (`../_kage/...`) computed for that page's own location,
+  but the viewer answered `/` with the main page's bytes in place, so the browser
+  resolved those relative URLs against `/` and missed every one. A
+  `developer.apple.com/documentation` mirror, whose main page is
+  `developer.apple.com/documentation/index.html`, landed at `/` completely
+  unstyled. kage now redirects `/` to the main page's canonical content path, the
+  way the archive's `W/mainPage` redirect already does, so the browser resolves
+  the page's relative assets correctly. Kiwix was unaffected because it follows
+  that redirect itself.
+
 ## [0.3.0] - 2026-06-15
 
 ### Added
@@ -180,7 +196,8 @@ can browse offline, with every script stripped out.
   a multi-arch container image on GHCR (Chromium bundled), checksums, SBOMs, and
   a cosign signature, all cut from one version tag by GoReleaser.
 
-[Unreleased]: https://github.com/tamnd/kage/compare/v0.3.0...HEAD
+[Unreleased]: https://github.com/tamnd/kage/compare/v0.3.1...HEAD
+[0.3.1]: https://github.com/tamnd/kage/compare/v0.3.0...v0.3.1
 [0.3.0]: https://github.com/tamnd/kage/compare/v0.2.1...v0.3.0
 [0.2.1]: https://github.com/tamnd/kage/compare/v0.2.0...v0.2.1
 [0.2.0]: https://github.com/tamnd/kage/compare/v0.1.2...v0.2.0

docs/content/reference/release-notes.md

@@ -6,6 +6,12 @@ weight: 40
 
 The authoritative, commit-level history lives in [`CHANGELOG.md`](https://github.com/tamnd/kage/blob/main/CHANGELOG.md) and on the [releases page](https://github.com/tamnd/kage/releases). This page summarises each version.
 
+## v0.3.1
+
+A fix for broken styling when a packed mirror's home page is a nested page.
+
+- **`/` redirects to the main page instead of serving it in place.** A page's saved asset links are mirror-relative (`../_kage/...`), computed for that page's own location. The viewer was answering `/` with the main page's bytes directly, so the browser resolved those links against `/` and 404ed the page's CSS and images. A `developer.apple.com/documentation` mirror opened at `/` came up completely unstyled. kage now redirects `/` to the main page's canonical path, the way the archive's `W/mainPage` redirect does, so relative assets resolve correctly. Kiwix already followed that redirect, so it was never affected.
+
 ## v0.3.0
 
 Leaner mirrors, and a way to publish one as a dataset. A clone now keeps the assets that make a site readable offline and leaves the bulk downloads on the live web, and a packed archive converts to a columnar table that drops straight into dataset tooling.

pack/pack_test.go

@@ -326,6 +326,24 @@ func TestHandler(t *testing.T) {
 	if code, body := get("/"); code != 200 || !bytes.Contains([]byte(body), []byte("Example Home")) {
 		t.Errorf("GET / = %d %.30q", code, body)
 	}
+
+	// "/" must redirect to the main page's canonical content path, not serve its
+	// bytes in place, so the page's mirror-relative asset URLs resolve against the
+	// right base instead of 404ing.
+	noFollow := &http.Client{CheckRedirect: func(*http.Request, []*http.Request) error {
+		return http.ErrUseLastResponse
+	}}
+	resp, err := noFollow.Get(srv.URL + "/")
+	if err != nil {
+		t.Fatal(err)
+	}
+	_ = resp.Body.Close()
+	if resp.StatusCode != http.StatusFound {
+		t.Errorf("GET / status = %d, want 302", resp.StatusCode)
+	}
+	if loc := resp.Header.Get("Location"); loc != "/index.html" {
+		t.Errorf("GET / Location = %q, want %q", loc, "/index.html")
+	}
 	if code, _ := get("/about/index.html"); code != 200 {
 		t.Errorf("GET /about/index.html = %d", code)
 	}

pack/serve.go

@@ -8,14 +8,24 @@ import (
 	"github.com/tamnd/kage/zim"
 )
 
-// Handler serves a ZIM archive over HTTP. "/" maps to the archive's main page;
-// "/a/b.png" maps to the C/a/b.png content entry. Because the saved HTML's links
-// are mirror-relative paths, and those are exactly the C urls, a click in a
+// Handler serves a ZIM archive over HTTP. "/" redirects to the archive's main
+// page; "/a/b.png" maps to the C/a/b.png content entry. Because the saved HTML's
+// links are mirror-relative paths, and those are exactly the C urls, a click in a
 // served page hits the right entry with no rewriting. A miss is a plain 404.
 func Handler(r *zim.Reader) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
 		p := strings.TrimPrefix(req.URL.Path, "/")
 		if p == "" {
+			// The main page's saved HTML carries mirror-relative asset URLs
+			// (../_kage/...) computed for its own nested location, so serving its
+			// bytes at "/" would resolve them against the wrong base and 404 the
+			// page's CSS and images. Redirect to the page's canonical content path
+			// instead, the way the archive's W/mainPage redirect does, so the
+			// browser resolves those relative URLs correctly.
+			if ns, url, ok := r.MainPageRef(); ok && ns == zim.NamespaceContent {
+				http.Redirect(w, req, "/"+url, http.StatusFound)
+				return
+			}
 			blob, err := r.MainPage()
 			if err != nil {
 				http.NotFound(w, req)