Update styles and images in courses-cn.html

Author: riverfor

docs/courses-cn.html

@@ -18,14 +18,14 @@
                 </div>
             </a>
             <!-- Image 2 -->
-            <a href="#" onclick="milib.openUrl('https://www.bilibili.com/video/BV1bw4m1C7bP/')" class="block bg-white rounded-lg shadow-lg overflow-hidden">
+            <a href="#" onclick="milib.openUrl('https://www.bilibili.com/video/BV1bw4m1C7bP/')" class="block bg-grey-100 rounded-lg shadow-lg overflow-hidden">
                 <img src="https://edu.qpython.org/static/qpython2.jpeg" alt="QPython起源" class="w-full">
-                <div class="p-4">
+                <div class="p-4 bg-white">
                     <h2 class="text-xl font-bold text-center">QPython起源</h2>
                 </div>
             </a>
             <a href="#" onclick="milib.openUrl('https://www.bilibili.com/video/BV1Gi9iYYE6b/')" class="block bg-grey-100 rounded-lg shadow-lg overflow-hidden">
-                <img src="https://edu.qpython.org/static/qiyuan.png" alt="QPython使用介绍" class="w-full">
+                <img src="https://edu.qpython.org/static/shiyong-nobg.png" alt="QPython使用介绍" class="w-full">
                 <div class="p-4 bg-white">
                     <h2 class="text-xl font-bold text-center">QPython使用介绍</h2>
                 </div>