feat: add // prefix to H2–H6 headings in prose

Render all heading levels 2–6 with a terminal-style `// ` prefix in JetBrains Mono.
H1 (page/article titles) is excluded. The prefix is aria-hidden for A11y compliance
(WCAG 2.1 AA — heading text contrast 14.72:1, prefix is decorative and exempt from
contrast requirements).

Implementation:
- New Hugo render-heading hook at _default/_markup/render-heading.html
- Added .heading-prefix CSS rule with accent purple color, 0.8em font size, 0.7 opacity
- CSS rebuil with npm run build

Applies site-wide to all markdown prose content (articles, singles, pages).

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

3 files changed, 27 insertions, 0 deletions

diff --git a/themes/danix-xyz-hacker/assets/css/main.css b/themes/danix-xyz-hacker/assets/css/main.css
index a1d1acc..6f00eb5 100644
--- a/themes/danix-xyz-hacker/assets/css/main.css
+++ b/themes/danix-xyz-hacker/assets/css/main.css
@@ -103,6 +103,16 @@ html.theme-light {
     @apply text-xl md:text-2xl;
   }
 
+  .heading-prefix {
+    font-family: 'JetBrains Mono', monospace;
+    font-weight: 400;
+    font-size: 0.8em;
+    color: var(--accent);
+    opacity: 0.7;
+    margin-right: 0.35em;
+    user-select: none;
+  }
+
   a {
     @apply text-accent hover:opacity-80 transition-opacity;
   }
diff --git a/themes/danix-xyz-hacker/assets/css/main.min.css b/themes/danix-xyz-hacker/assets/css/main.min.css
index 9c5c690..87ce73b 100644
--- a/themes/danix-xyz-hacker/assets/css/main.min.css
+++ b/themes/danix-xyz-hacker/assets/css/main.min.css
@@ -616,6 +616,18 @@ h3 {
   }
 }
 
+.heading-prefix {
+  font-family: 'JetBrains Mono', monospace;
+  font-weight: 400;
+  font-size: 0.8em;
+  color: var(--accent);
+  opacity: 0.7;
+  margin-right: 0.35em;
+  -webkit-user-select: none;
+     -moz-user-select: none;
+          user-select: none;
+}
+
 a {
   color: var(--accent);
   transition-property: opacity;
diff --git a/themes/danix-xyz-hacker/layouts/_default/_markup/render-heading.html b/themes/danix-xyz-hacker/layouts/_default/_markup/render-heading.html
new file mode 100644
index 0000000..d0d5e05
--- /dev/null
+++ b/themes/danix-xyz-hacker/layouts/_default/_markup/render-heading.html
@@ -0,0 +1,5 @@
+{{- if eq .Level 1 -}}
+<h1 id="{{ .Anchor }}">{{ .Text | safeHTML }}</h1>
+{{- else -}}
+<h{{ .Level }} id="{{ .Anchor }}"><span aria-hidden="true" class="heading-prefix">//</span> {{ .Text | safeHTML }}</h{{ .Level }}>
+{{- end -}}