完善产品购买页面，抽取公共组件，优化导航链接

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' | 'danger'
+  variant?: 'default' | 'outline' | 'gradient' | 'danger' | 'accent'
 }
 
 function Button(rawProps: ButtonProps) {
@@ -22,9 +22,10 @@ function Button(rawProps: ButtonProps) {
         'aria-invalid:ring-destructive/20 dark:aria-invalid:ring-destructive/40 aria-invalid:border-destructive',
         {
           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',
+          default: 'bg-primary text-primary-foreground hover:bg-primary/90',
+          accent: 'bg-accent text-accent-foreground hover:bg-accent/90',
+          danger: 'bg-destructive text-white hover:bg-destructive/90',
+          outline: 'border bg-background hover:bg-secondary hover:text-secondary-foreground dark:bg-input/30 dark:border-input dark:hover:bg-input/50',
         }[variant ?? 'default'],
         className,
       )}

src/components/ui/form.tsx

@@ -28,7 +28,11 @@ function Form<T extends FieldValues>(rawProps: FormProps<T>) {
 
   return (
     <FormProvider {...form}>
-      <form {...props} onSubmit={form.handleSubmit(onSubmit)}>
+      <form {...props} onSubmit={event => {
+        event.preventDefault()
+        form.handleSubmit(onSubmit)(event)
+        event.stopPropagation()
+      }}>
         {children}
       </form>
     </FormProvider>