fix: use iconfamily eye for timetable toggle

src/css/injected.scss

@@ -285,8 +285,13 @@ select {
   }
 }
 
-.timetable-zoom {
+.timetable-zoom,
+.timetable-hide {
   font-size: 14px !important;
+  line-height: 1 !important;
+  display: inline-flex !important;
+  align-items: center;
+  justify-content: center;
 }
 
 #main > .dashboard {

src/plugins/built-in/timetable/index.ts

@@ -130,7 +130,7 @@ function handleTimetableAssessmentHide(): void {
 
   const hideOn = document.createElement("button");
   hideOn.className = "uiButton timetable-hide iconFamily";
-  hideOn.innerHTML = "👁";
+  hideOn.innerHTML = "";
 
   hideControls.appendChild(hideOn);