[improvement] Progress、Search: add less vars

packages/progress/index.less

@@ -2,9 +2,9 @@
 
 .van-progress {
   position: relative;
-  height: 4px;
-  background: @gray-light;
-  border-radius: 4px;
+  height: @progress-height;
+  background: @progress-background-color;
+  border-radius: @progress-height;
 
   &__portion {
     position: absolute;
@@ -24,12 +24,12 @@
     right: 0;
     box-sizing: border-box;
     min-width: 2em;
-    padding: 0 5px;
-    font-size: 10px;
-    line-height: 1.6;
+    padding: @progress-pivot-padding;
+    font-size: @progress-pivot-font-size;
+    line-height: @progress-pivot-line-height;
     text-align: center;
     word-break: keep-all;
-    background-color: @gray-light;
+    background-color: @progress-pivot-background-color;
     border-radius: 1em;
     transform: translate(100%, -50%);
   }