Address code review feedback - improve accessibility and contrast

Co-authored-by: ulysses4ever <[email protected]>

Author: Copilot

docs/assets/css/dark-mode.css

@@ -40,7 +40,7 @@ body.dark-mode code:not(.label, .function, .type, .class, .law) {
 
 body.dark-mode pre > code {
     background-color: #0d0d0d;
-    color: #00ff00;
+    color: #90ee90;
 }
 
 body.dark-mode .hintbox {
@@ -83,7 +83,7 @@ body.dark-mode .errata {
     position: fixed;
     top: 40px;
     right: 20px;
-    z-index: 9999;
+    z-index: 10000;
     background-color: #333;
     color: white;
     border: 2px solid #555;

docs/assets/js/dark-mode.js

@@ -41,11 +41,13 @@
 
     function updateButtonIcon(button) {
         if (document.body.classList.contains('dark-mode')) {
-            button.innerHTML = '☀️';
+            button.textContent = '☀️';
             button.setAttribute('title', 'Switch to light mode');
+            button.setAttribute('aria-label', 'Switch to light mode');
         } else {
-            button.innerHTML = '🌙';
+            button.textContent = '🌙';
             button.setAttribute('title', 'Switch to dark mode');
+            button.setAttribute('aria-label', 'Switch to dark mode');
         }
     }