Merge pull request #48 from QingWei-Li/fix/steps

Steps: fix line

packages/theme-default/src/step.css

@@ -30,12 +30,10 @@
       position: absolute;
       border-color: inherit;
       background-color: #c0ccda;
-      z-index: -1;
 
       @when icon {
         @when horizontal {
-          width: 55%;
-          margin-left: 35px;
+          right: 4px;
         }
 
         @when vertical {
@@ -47,15 +45,15 @@
       @when horizontal {
         top: 15px;
         height: 2px;
-        width: 100%;
-        margin-right: -14px;
+        left: 32px;
+        right: 0;
       }
 
       @when vertical {
         width: 2px;
-        height: 100%;
         box-sizing: border-box;
-        padding-top: 28px;
+        top: 32px;
+        bottom: 0;
       }
     }