fix: misc issues

frontend/src/components/LiveClass.vue

@@ -46,6 +46,7 @@
 					{{ __('Start') }}
 				</a>
 				<a
+					v-if="cls.date <= dayjs().format('YYYY-MM-DD')"
 					:href="cls.join_url"
 					target="_blank"
 					class="w-full cursor-pointer inline-flex items-center justify-center gap-2 transition-colors focus:outline-none text-gray-800 bg-gray-100 hover:bg-gray-200 active:bg-gray-300 focus-visible:ring focus-visible:ring-gray-400 h-7 text-base px-2 rounded"

frontend/src/components/VideoBlock.vue

@@ -4,6 +4,7 @@
 			@timeupdate="updateTime"
 			@ended="videoEnded"
 			@click="togglePlay"
+			oncontextmenu="return false"
 			class="rounded-lg border border-gray-100 group cursor-pointer"
 			ref="videoRef"
 		>

frontend/src/pages/CourseDetail.vue

@@ -67,7 +67,7 @@
 					<CourseCardOverlay :course="course" class="md:hidden mb-4" />
 					<div
 						v-html="course.data.description"
-						class="course-description"
+						class="ProseMirror prose prose-table:table-fixed prose-td:p-2 prose-th:p-2 prose-td:border prose-th:border prose-td:border-gray-300 prose-th:border-gray-300 prose-td:relative prose-th:relative prose-th:bg-gray-100 prose-sm max-w-none !whitespace-normal"
 					></div>
 					<div class="mt-10">
 						<CourseOutline :courseName="course.data.name" :showOutline="true" />
@@ -131,26 +131,6 @@ const pageMeta = computed(() => {
 updateDocumentTitle(pageMeta)
 </script>
 <style>
-.course-description p {
-	margin-bottom: 1rem;
-	line-height: 1.7;
-}
-.course-description li {
-	line-height: 1.7;
-}
-
-.course-description ol {
-	list-style: auto;
-	margin: revert;
-	padding: revert;
-}
-
-.course-description ul {
-	list-style: disc;
-	margin: revert;
-	padding: revert;
-}
-
 .avatar-group {
 	display: inline-flex;
 	align-items: center;