move theme toggle to fixed bottom-right corner

Repositions the dark/light mode button from the header to a fixed
position in the bottom-right corner (always visible). Bumps size
to 44px for WCAG touch target compliance. Also makes login text
and icon white in dark mode.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

groups/home/bootstrap5/home1.css

@@ -128,6 +128,10 @@
     margin-left: 5px;
   }
 
+  [data-bs-theme="dark"] #login-div {
+    color: white;
+  }
+
   /* Accessible focus indicators for primary navigation elements */
   #hamburger:focus,
   #hamburger:focus-visible,
@@ -532,20 +536,23 @@
 
   /* dark mode toggle button */
   #theme-toggle {
-    float: right;
+    position: fixed;
+    bottom: 20px;
+    right: 20px;
+    z-index: 9999;
     background: none;
     border: 2px solid var(--kbccblue);
     color: var(--kbccblue);
     border-radius: 50%;
-    width: 40px;
-    height: 40px;
+    width: 44px;
+    height: 44px;
     font-size: 1.2em;
     cursor: pointer;
     display: flex;
     align-items: center;
     justify-content: center;
     transition: background-color 0.3s ease, color 0.3s ease, border-color 0.3s ease;
-    margin-top: 5px;
+    background-color: var(--bg);
   }
   #theme-toggle:hover {
     background-color: var(--kbccblue);