refactor(css): restructure stylesheet, remove duplicates, and improve maintainability

* reorganized CSS into clear sections (Root, Base, Layout, Typography, Components, Utilities)
* removed redundant and duplicate rules (header, branding, search, media, etc.)
* consolidated repeated selectors into single sources of truth
* unified form styles (comments + CF7)
* cleaned up sidebar/widget styles and resolved conflicting rules
* fixed related posts grid issue (min-width: 0 for grid children)
* improved TOC structure and extracted shared calculations
* simplified social links and hover behavior
* removed unsafe global performance hint (will-change)
* added prefers-reduced-motion support for accessibility
* improved overall cascade predictability and reduced specificity conflicts

No visual changes intended (safe refactor).

functions.php

@@ -698,3 +698,11 @@ function zeitfresser_responsive_image_sizes( $sizes, $size ) {
     return $sizes;
 }
 add_filter( 'wp_calculate_image_sizes', 'zeitfresser_responsive_image_sizes', 10, 2 );
+
+/**
+ * Delete Cookie Button
+ */
+ add_filter( 'comment_form_default_fields', function( $fields ) {
+    unset( $fields['cookies'] );
+    return $fields;
+});