Fix styling in private key modal

ui/app/components/modals/export-private-key-modal.js

@@ -66,7 +66,6 @@ ExportPrivateKeyModal.prototype.renderPasswordInput = function (privateKey) {
       })
     : h('input.private-key-password-input', {
       type: 'password',
-      placeholder: 'Type password',
       onChange: event => this.setState({ password: event.target.value }),
     })
 }

ui/app/css/itcss/components/modal.scss

@@ -372,6 +372,7 @@
   resize: none;
   padding: 9px 13px 8px;
   text-transform: uppercase;
+  font-weight: 300;
 }