优化登录流程，添加白名单管理功能，调整页面布局与样式

src/components/ui/button.tsx

@@ -3,7 +3,7 @@ import {Slot} from '@radix-ui/react-slot'
 import {merge} from '@/lib/utils'
 
 type ButtonProps = React.ComponentProps<'button'> & {
-  variant?: 'default' | 'outline' | 'gradient'
+  variant?: 'default' | 'outline' | 'gradient' | 'danger'
 }
 
 function Button(rawProps: ButtonProps) {
@@ -23,6 +23,7 @@ function Button(rawProps: ButtonProps) {
         {
           gradient: 'bg-gradient-to-r from-blue-400 to-cyan-300 text-white ring-offset-2',
           default: 'bg-primary text-primary-foreground shadow-xs hover:bg-primary/90',
+          danger: 'bg-destructive text-white shadow-xs hover:bg-destructive/90',
           outline: 'border bg-background shadow-xs hover:bg-accent hover:text-accent-foreground dark:bg-input/30 dark:border-input dark:hover:bg-input/50',
         }[variant ?? 'default'],
         className,