diff --git a/SD/20240326_9_课后作业/_extensions b/SD/20240328_9_课后作业/_extensions
similarity index 100%
rename from SD/20240326_9_课后作业/_extensions
rename to SD/20240328_9_课后作业/_extensions
diff --git a/SD/20240326_9_课后作业/index.qmd b/SD/20240328_9_课后作业/index.qmd
similarity index 86%
rename from SD/20240326_9_课后作业/index.qmd
rename to SD/20240328_9_课后作业/index.qmd
index 5826487..e566d0d 100644
--- a/SD/20240326_9_课后作业/index.qmd
+++ b/SD/20240328_9_课后作业/index.qmd
@@ -1,5 +1,5 @@
 ---
-title: "课后作业7"
+title: "课后作业8"
 subtitle: 《区域水环境污染数据分析实践》<br>Data analysis practice of regional water environment pollution
 author: 苏命、王为东<br>中国科学院大学资源与环境学院<br>中国科学院生态环境研究中心
 date: today
@@ -35,12 +35,12 @@ require(tidyverse)
 require(learnr)
 ```
 
-## 第7次课后作业
+## 第8次课后作业
 
 1. 根据`airqualitydf.xlsx`，按采样点统计白天（8:00-20:00）与夜晚（20:00-8:00）中空气质量指数（AQI）中位数，按城市统计低于所有采样点AQI30%分位值的采样点占比，列出上述占比最高的10个城市（不考虑采样点数低于5个的城市）。
 2. 按照不同城市分组，统计白天与夜晚AQI中位数是否具有显著差异。
 
-作业模板：[第7次课后作业_模板.qmd](https://drwater.rcees.ac.cn/git/course/RWEP/raw/branch/main/SD/20240326_9_课后作业/第7次课后作业_模板.qmd)
+作业模板：[第8次课后作业_模板.qmd](https://drwater.rcees.ac.cn/git/course/RWEP/raw/branch/main/SD/20240328_9_课后作业/第8次课后作业_模板.qmd)
 
 
 ## 欢迎讨论！{.center}
diff --git a/SD/20240326_9_课后作业/第7次课后作业_模板.qmd b/SD/20240328_9_课后作业/第8次课后作业_模板.qmd
similarity index 96%
rename from SD/20240326_9_课后作业/第7次课后作业_模板.qmd
rename to SD/20240328_9_课后作业/第8次课后作业_模板.qmd
index 7f9d54d..b7925dd 100644
--- a/SD/20240326_9_课后作业/第7次课后作业_模板.qmd
+++ b/SD/20240328_9_课后作业/第8次课后作业_模板.qmd
@@ -1,5 +1,5 @@
 ---
-title: 课后作业7
+title: 课后作业8
 author: 姓名
 format: html
 ---
diff --git a/_quarto.yml b/_quarto.yml
index c6b52a9..efd4286 100644
--- a/_quarto.yml
+++ b/_quarto.yml
@@ -24,7 +24,7 @@ website:
   page-navigation: true
   page-footer: "Copyright 2024, [Ming Su](https://drwater.rcees.ac.cn)"
   navbar:
-    background: "light"
+    background: "grey"
     search: true
     right:
       - icon: house
diff --git a/data/writexldemo.xlsx b/data/writexldemo.xlsx
index 76f0290..2ea0117 100644
Binary files a/data/writexldemo.xlsx and b/data/writexldemo.xlsx differ
diff --git a/index.qmd b/index.qmd
index 341f68c..41743e0 100644
--- a/index.qmd
+++ b/index.qmd
@@ -19,4 +19,4 @@ subtitle: "课程简介"
 
 - 网页公开：[https://drwater.rcees.ac.cn/course/public/RWEP/\@PUB/index.html](https://drwater.rcees.ac.cn/course/public/RWEP/@PUB/index.html)
 - 课件代码：[https://drwater.rcees.ac.cn/git/course/RWEP.git](https://drwater.rcees.ac.cn/git/course/RWEP.git)
-- 代码web界面：[https://on.tty-share.com/s/ny3JVrMuvUNOmnuioS3I7YEeVCi5Hk3Qc9vgz2QdX0FE2cYAQZFW2MUOkQyG0P5ZUR8/](https://on.tty-share.com/s/ny3JVrMuvUNOmnuioS3I7YEeVCi5Hk3Qc9vgz2QdX0FE2cYAQZFW2MUOkQyG0P5ZUR8/)
+- 代码web界面：[https://on.tty-share.com/s/KHxahtDKk7EIIMFFA60dQfh4-YgnWkkXRjzkaFV_7pSj96kDw_VxTC6Qa76UpG4Yee8/](https://on.tty-share.com/s/KHxahtDKk7EIIMFFA60dQfh4-YgnWkkXRjzkaFV_7pSj96kDw_VxTC6Qa76UpG4Yee8/)