inital working version

frontend/src/components/ui/Button.tsx

@@ -0,0 +1,57 @@
+import { ButtonHTMLAttributes, forwardRef } from 'react';
+import Link from 'next/link';
+import LoadingSpinner from './LoadingSpinner';
+
+interface ButtonProps extends ButtonHTMLAttributes<HTMLButtonElement> {
+  variant?: 'primary' | 'secondary' | 'ghost' | 'danger';
+  size?: 'sm' | 'md' | 'lg';
+  loading?: boolean;
+  href?: string;
+  children: React.ReactNode;
+}
+
+const Button = forwardRef<HTMLButtonElement, ButtonProps>(
+  ({ variant = 'primary', size = 'md', loading = false, href, className = '', children, disabled, ...props }, ref) => {
+    const baseClasses = 'inline-flex items-center justify-center rounded-lg font-medium transition-colors focus:outline-none focus:ring-2 focus:ring-offset-2 disabled:opacity-50 disabled:cursor-not-allowed';
+    
+    const variantClasses = {
+      primary: 'theme-accent-bg text-white hover:theme-accent-bg focus:ring-theme-accent',
+      secondary: 'theme-card theme-text border theme-border hover:bg-opacity-80 focus:ring-theme-accent',
+      ghost: 'theme-text hover:bg-gray-100 dark:hover:bg-gray-800 focus:ring-theme-accent',
+      danger: 'bg-red-600 text-white hover:bg-red-700 focus:ring-red-500',
+    };
+    
+    const sizeClasses = {
+      sm: 'px-3 py-1.5 text-sm',
+      md: 'px-4 py-2 text-sm',
+      lg: 'px-6 py-3 text-base',
+    };
+
+    const combinedClasses = `${baseClasses} ${variantClasses[variant]} ${sizeClasses[size]} ${className}`;
+
+    if (href) {
+      return (
+        <Link href={href} className={combinedClasses}>
+          {loading && <LoadingSpinner size="sm" className="mr-2" />}
+          {children}
+        </Link>
+      );
+    }
+
+    return (
+      <button
+        ref={ref}
+        className={combinedClasses}
+        disabled={disabled || loading}
+        {...props}
+      >
+        {loading && <LoadingSpinner size="sm" className="mr-2" />}
+        {children}
+      </button>
+    );
+  }
+);
+
+Button.displayName = 'Button';
+
+export default Button;