Fix FEDX-167: Both math inputs and adaptive hints are sized correctly

common/lib/xmodule/xmodule/css/capa/display.scss

@@ -749,14 +749,12 @@ div.problem {
 // ====================
 .problem {
   .capa_inputtype.textline, .inputtype.formulaequationinput {
-    display: inline-block;
 
     input {
       @include box-sizing(border-box);
       border: 2px solid $gray-l4;
       border-radius: 3px;
       min-width: 160px;
-      width: calc(100% - 45px);
       height: 46px;
     }
 
@@ -815,6 +813,14 @@ div.problem {
       }
     }
   }
+
+  .inputtype.formulaequationinput {
+    display: inline-block;
+
+    input {
+      width: calc(100% - 45px);
+    }
+  }
 }