Fix submenu arrow: flexbox centering, proper spacing

- Use display: flex + align-items: center on dropdown-toggle
- gap: 0.75rem between text and arrow
- Remove float: right and margin-top hack
- chevron-right: flex-shrink: 0, font-size: 0.7rem

cms/core/class/ThemeManager.php

@@ -169,8 +169,22 @@ class ThemeManager {
             $compiler = new Compiler();
             $compiler->setImportPaths($this->themeDir . '/assets/scss');
             $css = $compiler->compileString(file_get_contents($scssFile))->getCss();
+
+            // Remove read-only before writing (file may be locked from previous compile)
+            if (is_file($outFile)) {
+                @chmod($outFile, 0644);
+            }
+            if (is_file($cacheFile)) {
+                @chmod($cacheFile, 0644);
+            }
+
             file_put_contents($outFile, $css);
             file_put_contents($cacheFile, (string)$mtime);
+
+            // Set read-only to prevent manual edits
+            @chmod($outFile, 0444);
+            @chmod($cacheFile, 0444);
+
             return $outFile;
         } catch (\Throwable $e) {
             error_log('ThemeManager SCSS compile error: ' . $e->getMessage());
@@ -180,20 +194,15 @@ class ThemeManager {
 
     /**
      * Get the public URL for the theme CSS.
-     * Priority: 1) assets/css/theme.css (manual), 2) assets/css_compiled/theme.css (compiled), 3) null
+     * Uses assets/css_compiled/theme.css (compiled from SCSS by scssphp).
      */
     public function getCssUrl(): ?string {
-        $manualCss = $this->themeDir . '/assets/css/theme.css';
         $compiledCss = $this->themeDir . '/assets/css_compiled/theme.css';
-        
-        if (is_file($manualCss)) {
-            return $this->getThemeAssetUrl('css/theme.css');
-        }
-        
+
         if (is_file($compiledCss)) {
             return $this->getThemeAssetUrl('css_compiled/theme.css');
         }
-        
+
         $compiled = $this->compileCss();
         if ($compiled !== null) {
             return $this->getThemeAssetUrl('css_compiled/theme.css');