培训文档，文档资料代码优化

src/styles/mixin.scss

@@ -31,6 +31,10 @@
     @include flexColumn;
     justify-content: space-between;
 }
+@mixin flexAround(){
+    @include flexColumn;
+    justify-content: space-around;
+}
 @mixin flexColBet(){
     display: flex;
     justify-content: space-between;
@@ -42,4 +46,25 @@
 @mixin flexBetCen{
     @include flexColBet;
     align-items: center;
+}
+@mixin flexTwoCenter(){
+    @include flexCenter;
+    justify-content: center;
+}
+@mixin colorOpa($col,$alpha){
+    color: $col;
+    opacity: $alpha;
+}
+@mixin radiusSizing($rad){
+    border-radius: $rad;
+    box-sizing: border-box;
+}
+@mixin sizingPadding($tb,$lr){
+    box-sizing: border-box;
+    padding: $tb $lr;
+}
+@mixin sizingPadRadius( $tb,$lr,$rad){
+    box-sizing: border-box;
+    padding: $tb $lr;
+    border-radius: $rad;
 }