remove unnecessary styles

src/client/js/components/Admin/ExportArchiveData/SelectCollectionsModal.jsx

@@ -192,12 +192,14 @@ class SelectCollectionsModal extends React.Component {
             </div>
             <div className="row mt-4">
               <div className="col-sm-12">
+                {/* FIXME: use something instead of <legend> */}
                 <legend>Page Collections</legend>
                 {this.renderGroups(GROUPS_PAGE)}
               </div>
             </div>
             <div className="row mt-4">
               <div className="col-sm-12">
+                {/* FIXME: use something instead of <legend> */}
                 <legend>User Collections</legend>
                 {this.renderGroups(GROUPS_USER, 'danger')}
                 {this.renderWarnForUser()}
@@ -205,12 +207,14 @@ class SelectCollectionsModal extends React.Component {
             </div>
             <div className="row mt-4">
               <div className="col-sm-12">
+                {/* FIXME: use something instead of <legend> */}
                 <legend>Config Collections</legend>
                 {this.renderGroups(GROUPS_CONFIG)}
               </div>
             </div>
             <div className="row mt-4">
               <div className="col-sm-12">
+                {/* FIXME: use something instead of <legend> */}
                 <legend>Other Collections</legend>
                 {this.renderOthers()}
               </div>

src/client/js/components/Admin/ImportData/GrowiArchive/ImportForm.jsx

@@ -345,6 +345,7 @@ class ImportForm extends React.Component {
     return (
       <div className="mt-4 row">
         <div className="col-12">
+          {/* FIXME: use something instead of <legend> */}
           <legend>{groupName} Collections</legend>
           { wellContent != null && (
             <div className="card well small" role="alert">

src/client/js/components/Admin/ImportDataPage.jsx

@@ -143,6 +143,7 @@ class ImportDataPage extends React.Component {
           role="form"
         >
           <fieldset>
+            {/* FIXME: use something instead of <legend> */}
             <legend>{t('admin:importer_management.import_from', { from: 'esa.io' })}</legend>
             <table className="table table-bordered table-mapping">
               <thead>
@@ -233,6 +234,7 @@ class ImportDataPage extends React.Component {
           role="form"
         >
           <fieldset>
+            {/* FIXME: use something instead of <legend> */}
             <legend>{t('admin:importer_management.import_from', { from: 'Qiita:Team' })}</legend>
             <table className="table table-bordered table-mapping">
               <thead>

src/client/js/components/Admin/UserGroupDetail/UserGroupDetailPage.jsx

@@ -23,9 +23,11 @@ class UserGroupDetailPage extends React.Component {
         <div className="m-t-20 form-box">
           <UserGroupEditForm />
         </div>
+        {/* FIXME: use something instead of <legend> */}
         <legend className="m-t-20">{t('admin:user_group_management.user_list')}</legend>
         <UserGroupUserTable />
         <UserGroupUserModal />
+        {/* FIXME: use something instead of <legend> */}
         <legend className="m-t-20">{t('Page')}</legend>
         <div className="page-list">
           <UserGroupPageList />

src/client/js/components/Admin/UserGroupDetail/UserGroupEditForm.jsx

@@ -63,6 +63,7 @@ class UserGroupEditForm extends React.Component {
     return (
       <form className="form-horizontal" onSubmit={this.handleSubmit}>
         <fieldset>
+          {/* FIXME: use something instead of <legend> */}
           <legend>{t('admin:user_group_management.basic_info')}</legend>
           <div className="form-group">
             <label htmlFor="name" className="col-sm-2 control-label">{t('Name')}</label>

src/client/styles/scss/theme/_apply-colors-dark.scss

@@ -162,11 +162,6 @@ header.affix {
   }
 }
 
-legend {
-  // FIXME:
-  // border-color: lighten($border, 10%);
-}
-
 .wiki {
   h1 {
     // FIXME: