core&ui: problem_main: support sort

packages/ui-default/pages/problem_main.page.styl

@@ -204,7 +204,7 @@
   color: #000000
 
 .search > button
-  width: 40px
+  width: 37px
   height: 36px
   border: 1px solid #00B4CC
   background: #00B4CC
@@ -215,6 +215,16 @@
 
 .search > div
   position: absolute
-  right: 50px
-  top: 8px
-  font-size: rem(17px)
+  right: 170px
+  top: 10px
+  font-size: rem(17px)
+
+.search-sort
+  position: absolute
+  border: none
+  top: 1px
+  height: 34px
+  right: 37px
+  color: #000000
+  cursor: pointer
+  width: 120px