修复背景图显示

app/javascript/styles/thu/diff.scss

@@ -13,21 +13,29 @@ body {
 	background: rgba(73, 58, 99, 1) url(https://www.tsinghua.edu.cn/publish/thu2018/images/footer.jpg) no-repeat fixed;
 	background-size: cover;
 	background-attachment: fixed;
+  background-position: center;
+  height: 100vh !important;
 }
 body.app-body {
 	background: rgba(73, 58, 99, 1) url(https://www.tsinghua.edu.cn/publish/thu2018/images/footer.jpg) no-repeat fixed;
 	background-size: cover;
 	background-attachment: fixed;
+  background-position: center;
+  height: 100vh !important;
 }
 body.about-body {
 	background: rgba(73, 58, 99, 1) url(https://www.tsinghua.edu.cn/publish/thu2018/images/footer.jpg) no-repeat fixed;
 	background-size: cover;
 	background-attachment: fixed;
+  background-position: center;
+  height: 100vh !important;
 }
 body.admin {
 	background: rgba(73, 58, 99, 1) url(https://www.tsinghua.edu.cn/publish/thu2018/images/footer.jpg) no-repeat fixed;
 	background-size: cover;
 	background-attachment: fixed;
+  background-position: center;
+  height: 100vh !important;
 }
 .regeneration-indicator {
 	background: rgba(73, 58, 99, 1) url(https://www.tsinghua.edu.cn/publish/thu2018/images/footer.jpg) no-repeat fixed;