fix: invert toggle logic and add styling

src/app/components/SideBar.module.css

@@ -133,11 +133,11 @@
 }
 
 input:checked+.slider {
-  background-color: #05254a;
+  background-color: #64adac;
 }
 
 input:focus+.slider {
-  box-shadow: 0 0 1px #05254a;
+  box-shadow: 0 0 1px #64adac;
 }
 
 input:checked+.slider:before {

src/app/components/SideBar.tsx

@@ -113,6 +113,7 @@ export default function SideBar({
               setTheme(theme === 'light' ? 'dark' : 'light')
             }
             type="checkbox"
+            checked={theme === 'dark'}
           />
           <span
             className={`${styles.slider} ${styles.round}`}