fix(layout): align color scheme, content width and fonts with reference theme

- Color scheme: zibll field order/labels, theme_skin_custom overrides palette,
  hex palette swatches, dark_theme_skin_custom, light/dark background images,
  close_backdrop via body.fps-accelerat, theme_main_radius drives --main-radius
- Emit --theme-color / --focus-shadow-color / --focus-color-opacity* vars
- Drop border_radius, primary_color readers and legacy value maps
- Content max width: free 1200-2200 number field; fix font family/custom stack

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/Core/ScriptsPart2.php

@@ -112,6 +112,11 @@ trait ScriptsPart2 {
             $classes[] = 'auth-page';
         }
 
+        // 对齐参考主题 close_backdrop：fps-accelerat 由 main.css 统一关闭 backdrop-filter。
+        if (class_exists('\AKSRT\Settings\Settings') && \AKSRT\Settings\Settings::close_backdrop()) {
+            $classes[] = 'fps-accelerat';
+        }
+
         // legacy site-layout-1/2/3 (no sidebar / right / left).
         if (function_exists('aksrt_body_layout_classes')) {
             foreach (aksrt_body_layout_classes() as $layout_class) {