doc: theme & logo tweak, grey to slightly darker

This commits tweaks the material orange theme to use the exact color hue
of Jackys footies.  To match this and give a slightly better contrast we
also change Jacksy border and logo text color to a slightly darker tone.

The original logo.svg is retained for reference, the new logo is logo2,
which all the .png variants have now been updated to.

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

Author: troglobit

doc/extra.css

@@ -0,0 +1,12 @@
+.md-header__title {
+    font-size: 1.1rem;
+    line-height: 2.6rem;
+}
+
+[data-md-color-primary="orange"] {
+    --md-primary-fg-color: #ff7f2a;
+    --md-primary-bg-color: #5c5f5c;
+}
+[data-md-color-primary="black"] {
+    --md-primary-bg-color: #5c5f5c;
+}

doc/jack.png

@@ -6,6 +6,8 @@ repo_name: kernelkit/infix
 copyright: Copyright © 2022-2025 The KernelKit Team
 docs_dir: doc/
 edit_uri: edit/master/doc/
+extra_css:
+  - extra.css
 
 exclude_docs: |
   ChangeLog.md