fix: improve Sessionize widget visibility in dark mode

Add CSS rules to ensure Sessionize schedule tab navigation links are
visible in dark mode. The widget's inline styles were causing inactive
tabs to appear nearly invisible (dark text on dark background).

Changes:
- Apply --text-color to inactive Sessionize tab links in dark mode
- Apply white color to active tab links for better contrast
- Include :link and :visited pseudo-classes for comprehensive coverage
- Add hover/focus states for consistent interaction feedback

Fixes #198

Author: matrixise

pythonie/core/static/css/style.css

@@ -320,10 +320,28 @@ footer .well {
         color: var(--nav-text);
         padding: 10px 15px 10px 25px;
     }
-    
+
     .navbar-default .navbar-nav .open .dropdown-menu > li > a:hover,
     .navbar-default .navbar-nav .open .dropdown-menu > li > a:focus {
         background-color: var(--nav-hover-bg);
         color: var(--link-hover-color);
     }
 }
+
+/* Sessionize widget dark mode support */
+html.dark .sz-tabs__link,
+html.dark .sz-tabs__link:link,
+html.dark .sz-tabs__link:visited {
+    color: var(--text-color) !important;
+}
+
+html.dark .sz-tabs__item--active .sz-tabs__link,
+html.dark .sz-tabs__item--active .sz-tabs__link:link,
+html.dark .sz-tabs__item--active .sz-tabs__link:visited {
+    color: #fff !important;
+}
+
+html.dark .sz-tabs__link:hover,
+html.dark .sz-tabs__link:focus {
+    color: var(--link-hover-color) !important;
+}