Fix theme consistency, i18n completeness, CSS variable naming, and hardcoded strings

src/app/admin/radio/banners/page.tsx

@@ -101,7 +101,7 @@ export default async function AdminRadioBannersPage() {
       <section className="mt-6">
         <h2 className="admin-section-title">{t("banners.addBanner")}</h2>
         <form action={createRadioBanner} className="admin-card">
-          <div className="grid cols-2">
+          <div className="grid grid-cols-1 gap-4 md:grid-cols-2">
             <div>
               <label htmlFor="new_imagePath" style={{ display: 'block', fontWeight: 700 }}>
                 {t("banners.form.imagePath")}
@@ -185,7 +185,7 @@ export default async function AdminRadioBannersPage() {
 
                 <form action={updateRadioBanner}>
                   <input type="hidden" name="id" value={String(b.id)} />
-                  <div className="grid cols-2">
+                  <div className="grid grid-cols-1 gap-4 md:grid-cols-2">
                     <div>
                       <label
                         htmlFor={`img_${b.id}`}