Replace the colons title rule with a double dotted border

A row of ":" characters did not read as a rule. "Double dots" is what the
reference site does: the 3px dotted border and an absolutely positioned
::after carrying a second one 2px above it.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Sd8UPWrvyYCLj97JexNw3A

1 files changed, 3 insertions, 2 deletions

diff --git a/AGENTS.md b/AGENTS.md
index 148bc91..4cf36a3 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -184,8 +184,9 @@ internal/web/         server.go (host router, middleware, render helpers)
   as tall as the brand and old browsers agree) in `currentColor`, i.e. the
   header text colour; hidden on phones so a long title can wrap. `NavStyle`
   `plain` is regular weight + underline for the menu links (blog.css makes
-  them bold). `TitleRule` (`none` | `line` | `dots` | `colons` | `stripes`) is the header
-  rule's kinds, plus a row of ":" (an `::after` with a long clipped string), under page and post titles (`.page-title`, `.post-title`): a body
+  them bold). `TitleRule` (`none` | `line` | `dots` | `dots2` | `stripes`) is the header
+  rule's kinds, plus a double dotted row (`dots2`: the border and an
+  absolutely positioned `::after` with a second one 2px above), under page and post titles (`.page-title`, `.post-title`): a body
   class from `Theme.TitleRuleClass` (`titles-<kind>`) that blog.css draws
   (border width/style only — never the shorthand, or it would reset the
   colour; stripes are an `::after` gradient in `currentColor`), coloured