KERNEL-13193 style: 调一下checobox的样式

src/less/base/single/button/button.half.less

@@ -6,10 +6,12 @@
 
   &:after {
     position: absolute;
+    .border-radius(2px);
+    display: table;
     left: 50%;
     top: 50%;
-    width: 50%;
+    width: 70%;
-    height: 50%;
+    height: 70%;
     .transform(translate(-50%, -50%));
     background-color: @color-bi-background-half-button-content;
     content: '';

src/less/base/single/input/checkbox.less

@@ -3,15 +3,17 @@
 .bi-checkbox {
   & .checkbox-content, &.checkbox-content {
     .border-radius(2px);
-    border: 1px solid @color-bi-border-checkbox;
+    border: 2px solid @color-bi-border-checkbox;
     .box-sizing(border-box);
     .transition(all .1s);
+
     &:after {
       position: absolute;
       display: table;
       top: 45%;
       left: 20%;
       border: 2px solid transparent;
+      border: calc(var(--css-scale, 1) * 2px) solid transparent;
       border-top: 0;
       border-left: 0;
       width: 50%;