feat(layout): More reasonnable column sizes

The width of the menu bar depends on the largest item.
This may be brittle.

docs/css/width_tweak.css

@@ -0,0 +1,9 @@
+:root {
+	--page-width: 120em
+}
+
+@media only screen and (min-width: 70em) {
+    .terminal-mkdocs-main-grid {
+        grid-template-columns: max-content 10fr;
+    }
+}

mkdocs.yml

@@ -4,6 +4,10 @@ theme:
  name: terminal
  custom_dir: overrides
 # features: navigation.top.hide
+
+extra_css:
+ - css/width_tweak.css
+
 nav:
  - Projets:
    - Borne d'arcade: projects/arcade.md