feat: update style

Author: SSShooter

src/index.less

@@ -36,7 +36,7 @@
     height: 0px;
   }
   .selected {
-    box-shadow: 0 0 0 2px #4dc4ff;
+    box-shadow: 0 0 0 3px #4dc4ff;
   }
   .lhs {
     direction: rtl;
@@ -223,8 +223,8 @@
     top: 0;
     left: 0;
     padding: var(--topic-padding);
-    background-color: #fff;
-    color: #666666;
+    color: var(--color);
+    background-color: var(--bgcolor);
     width: max-content; // let words expand the div and keep max length at the same time
     max-width: 800px;
     z-index: 11;