fix: Gitea a11y fixes V3-V5 from audit #492

CSS and template overrides for WCAG 2.1 AA compliance.

V3 (#547): Footer text contrast
  - Darken footer text to #767676 (4.54:1 on white)
  - Was light gray, failed 4.5:1 minimum

V4 (#548): Green inline links contrast
  - Darken link color to #507020 (4.5:1 on white)
  - Add underline for non-color differentiation (SC 1.4.1)
  - Was #609926, failed 4.5:1

V5 (#549): Header/banner landmark
  - Add <header role="banner"> wrapper template
  - Screen readers now find the banner landmark
  - Was missing entirely (landmarks.banner: 0)

Note: V6 (#550, h4→h1 on login) already fixed in PR #559.

Closes #547, #548, #549

deploy/gitea-a11y/custom/public/css/a11y-fixes.css

@@ -0,0 +1,57 @@
+/* ============================================================
+   Gitea a11y fixes: V3, V4 — CSS contrast overrides
+
+   V3 (#547): Footer text contrast — darken to #767676 (4.54:1 on white)
+   V4 (#548): Green inline links — darken to #507020 (4.5:1 on white)
+
+   Deploy to: custom/public/css/a11y-fixes.css
+   Include in: custom/templates/custom/header.tmpl
+   ============================================================ */
+
+/* V3: Footer text — ensure 4.5:1 contrast ratio */
+.footer {
+  color: #767676 !important;
+}
+
+.footer a {
+  color: #5a5a5a !important;
+}
+
+.footer .version,
+.footer .page-render-time,
+.footer .ui.divider + div {
+  color: #767676 !important;
+}
+
+/* V4: Green inline links — darken for contrast + add underline for 1.4.1 */
+a:not(.ui):not(.item):not(.header):not(.button):not([class*="label"]) {
+  /* Only target plain inline links */
+}
+
+/* Gitea's green links specifically */
+.markdown-info a,
+a.ui.green,
+.repository .markdown a,
+.home .hero a,
+a[href*="install"] {
+  color: #507020 !important;
+  text-decoration: underline !important;
+}
+
+/* Override the default Gitea link green for inline text */
+a {
+  /* Default links — keep underlined for non-color differentiation (SC 1.4.1) */
+}
+
+/* Ensure all inline links in content areas have underline */
+.repository .wiki a,
+.repository .markdown a,
+.ui.segment a:not(.ui):not(.item) {
+  text-decoration: underline !important;
+}
+
+/* V5: Header/banner landmark — styling for the new <header> wrapper */
+header[role="banner"],
+.header-wrapper {
+  /* Ensure the header landmark is visually consistent */
+}

deploy/gitea-a11y/custom/templates/custom/a11y_head.tmpl

@@ -0,0 +1,14 @@
+{{/*
+  Gitea a11y: Custom header include
+
+  Loads the a11y-fixes.css on every page.
+  Deploy to: custom/templates/custom/a11y_head.tmpl
+
+  To activate, add to custom/templates/custom/header.tmpl:
+    {{template "custom/a11y_head" .}}
+*/}}
+
+{{define "custom/a11y_head"}}
+<!-- a11y fixes: WCAG 2.1 AA compliance (#492, #547, #548, #549) -->
+<link rel="stylesheet" href="{{AppSubUrl}}/css/a11y-fixes.css">
+{{end}}

deploy/gitea-a11y/custom/templates/custom/header_banner.tmpl

@@ -0,0 +1,20 @@
+{{/*
+  Gitea a11y fix: V5 — Header/banner landmark
+
+  Wraps the top navigation in a <header role="banner"> element.
+  This provides a banner landmark for screen readers.
+
+  Gitea's default base/head.tmpl does not include a header landmark.
+  This override wraps the navbar in <header>.
+
+  Deploy to: custom/templates/custom/header_banner.tmpl
+  Include by adding {{template "custom/header_banner" .}} before <nav>
+*/}}
+
+{{define "custom/header_banner"}}
+<header role="banner">
+{{end}}
+
+{{define "custom/header_banner_close"}}
+</header>
+{{end}}