fix(pdf): keep parallel symbol visible in print rendering

app/Services/ExamPdfExportService.php

@@ -1889,26 +1889,12 @@ class ExamPdfExportService
             .'.katex .mrel .mord{font-family:inherit !important;}'
             .'.katex .mrel.katex-rel-parallel{'
             .'display:inline-block;'
-            .'position:relative;'
-            .'min-width:.68em;'
-            .'height:.92em;'
-            .'line-height:.92em;'
-            .'font-size:0 !important;'
-            .'vertical-align:-.06em;'
-            .'}'
-            .'.katex .mrel.katex-rel-parallel::before,.katex .mrel.katex-rel-parallel::after{'
-            .'content:"";'
-            .'position:absolute;'
-            .'top:.06em;'
-            .'bottom:.06em;'
-            .'width:.08em;'
-            .'border-radius:.02em;'
-            .'background:currentColor;'
+            .'line-height:1;'
+            .'letter-spacing:.08em;'
+            .'vertical-align:-.03em;'
             .'transform:skewX(-18deg);'
             .'transform-origin:center;'
             .'}'
-            .'.katex .mrel.katex-rel-parallel::before{left:.22em;}'
-            .'.katex .mrel.katex-rel-parallel::after{left:.42em;}'
             .'</style>';
 
         if (stripos($html, '</head>') !== false) {