响应式认证表单

Create a responsive authentication form component with three states: login, signup, and forgot password. Use shadcn/ui components (Input, Button, Card, Label). Include form validation, loading states, and error handling. The form should be centered on the page with a clean, modern design. Use Tailwind CSS for styling. Include a toggle between login and signup states.

创建一个响应式认证表单组件，包含三个状态：登录、注册和忘记密码。使用 shadcn/ui 组件（Input、Button、Card、Label）。包含表单验证、加载状态和错误处理。表单应在页面居中显示，采用简洁现代的设计。使用 Tailwind CSS 进行样式设计。包含登录和注册状态之间的切换。