update teaching video

templates/SLClassroom.html

@@ -306,10 +306,10 @@
 
                 <div class="lesson-card in-progress">
                     <div class="lesson-header">
-                        <span class="lesson-title">第二课：谢谢</span>
+                        <span class="lesson-title">第二课：介绍</span>
                         <i class="fas fa-hourglass-half progress-icon"></i>
                     </div>
-                    <iframe src="https://player.bilibili.com/player.html?bvid=BV1LW411s7gR&page=1" width="100%"
+                    <iframe src="https://player.bilibili.com/player.html?bvid=BV1LW411s7gR&page=2" width="100%"
                         height="315" frameborder="0" allowfullscreen></iframe>
                     <div class="lesson-progress">
                         <div class="progress-bar" style="width: 50%;"></div>
@@ -318,11 +318,13 @@
 
                 <div class="lesson-card locked">
                     <div class="lesson-header">
-                        <span class="lesson-title">第三课：再见</span>
+                        <span class="lesson-title">第三课：欢迎</span>
                         <i class="fas fa-lock lock-icon"></i>
                     </div>
-                    <p class="locked-message">完成前面课程即可解锁！</p>
-                </div>
+                    <iframe src="https://player.bilibili.com/player.html?bvid=BV1LW411s7gR&page=3" width="100%"
+                        height="315" frameborder="0" allowfullscreen></iframe>
+                    <div class="lesson-progress">
+                        <div class="progress-bar" style="width: 50%;"></div>
             </div>
         </div>