增加悼念模式CSS

src/assets/styles/grayscale.scss

+// 悼念模式，必要时引用
+
+html {
+    filter: grayscale(100%);
+    -webkit-filter: grayscale(100%);
+    -moz-filter: grayscale(100%);
+    -ms-filter: grayscale(100%);
+    -o-filter: grayscale(100%);
+    filter: url("data:image/svg+xml;utf8,<svg xmlns=\'http://www.w3.org/2000/svg\'><filter id=\'grayscale\'><feColorMatrix type=\'matrix\' values=\'0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0 0 0 1 0\'/></filter></svg>#grayscale");
+    filter: progid:DXImageTransform.Microsoft.BasicImage(grayscale=1);
+    -webkit-filter: grayscale(1);
+}
\ No newline at end of file

src/assets/styles/index.scss

 @import url('@/assets/fonts/font.css');
 @import url('./animations.scss');
-
 /**适应移动端 */
 @media screen and (max-width: 500px) {