feat: use shadcn default styles

src/login/pages/QrLoginCanceled.tsx

@@ -17,7 +17,7 @@ export default function QrLoginCanceled(props: PageProps<Extract<KcContext, { pa
             headerNode={msg("consentDenied")}
         >
             <div id="kc-qr-canceled-message" className={classes?.kcFormClass}>
-                <Alert variant="destructive" className="border-white/45 bg-white/40 backdrop-blur-md">
+                <Alert variant="destructive" className="w-full">
                     <AlertTitle>{msg("consentDenied")}</AlertTitle>
                 </Alert>
             </div>

src/login/pages/QrLoginSuccess.tsx

@@ -17,7 +17,7 @@ export default function QrLoginSuccess(props: PageProps<Extract<KcContext, { pag
             headerNode={msg("successQrCodeLoginTitle")}
         >
             <div id="kc-qr-success-message" className={classes?.kcFormClass}>
-                <Alert className="kcQrSuccessMessageClass border-white/45 bg-white/40 backdrop-blur-md">
+                <Alert className="w-full">
                     <AlertTitle>{msg("successQrCodeLoginMessage")}</AlertTitle>
                 </Alert>
             </div>

src/login/pages/QrLoginVerify.tsx

@@ -20,7 +20,7 @@ export default function QrLoginVerify(props: PageProps<Extract<KcContext, { page
             headerNode={msg("doQrCodeVerify")}
         >
             <div id="kc-qr-verify-form" className={classes?.kcFormClass}>
-                <Alert variant="destructive" className="kcQrWarningClass mb-4">
+                <Alert variant="destructive" className="mb-4 w-full">
                     <AlertTitle>{msg("doQrCodeWarning")}</AlertTitle>
                 </Alert>