Remove flex shorthand

sass/elements/form.sass

@@ -127,7 +127,7 @@
   +mobile
     margin-bottom: 5px
   +tablet
-    flex: 1
+    flex-grow: 1
     margin-right: 20px
     padding-top: 7px
     text-align: right
@@ -161,7 +161,7 @@
         select
           border-radius: 0 $radius $radius 0
       &.is-expanded
-        flex: 1
+        flex-grow: 1
     &.has-addons-centered
       justify-content: center
     &.has-addons-right
@@ -170,7 +170,7 @@
       .button,
       .input,
       .select
-        flex: 1
+        flex-grow: 1
   &.has-icon
     & > .fa
       +fa(14px, 24px)
@@ -233,7 +233,7 @@
         margin-bottom: 0
         margin-right: 10px
       &.is-expanded
-        flex: 1
+        flex-grow: 1
     &.is-grouped-centered
       justify-content: center
     &.is-grouped-right
@@ -243,7 +243,7 @@
       display: flex
       & > .control
         display: flex
-        flex: 5
+        flex-grow: 5
   &.is-loading
     &:after
       @extend .loader