feat: 创建数字计数动画组件

- 创建 AnimatedNumber 组件支持平滑计数动画
- 使用 easeOutQuart 缓动函数
- 支持前缀和后缀
- 支持延迟和持续时间配置
- 创建 StatCard 统计卡片组件
- 支持滚动进入视口时触发动画

src/components/ui/animated-number.tsx

@@ -0,0 +1,103 @@
+'use client';
+
+import { useEffect, useState, useRef } from 'react';
+import { motion, useInView } from 'framer-motion';
+
+interface AnimatedNumberProps {
+  value: number;
+  duration?: number;
+  delay?: number;
+  suffix?: string;
+  prefix?: string;
+  className?: string;
+}
+
+export function AnimatedNumber({
+  value,
+  duration = 2000,
+  delay = 0,
+  suffix = '',
+  prefix = '',
+  className = '',
+}: AnimatedNumberProps) {
+  const [count, setCount] = useState(0);
+  const ref = useRef<HTMLSpanElement>(null);
+  const isInView = useInView(ref, { once: true, margin: '-100px' });
+  const hasAnimated = useRef(false);
+
+  useEffect(() => {
+    if (!isInView || hasAnimated.current) return;
+    
+    hasAnimated.current = true;
+    
+    const startTime = Date.now() + delay;
+    const endTime = startTime + duration;
+    
+    const animate = () => {
+      const now = Date.now();
+      
+      if (now < startTime) {
+        requestAnimationFrame(animate);
+        return;
+      }
+      
+      if (now >= endTime) {
+        setCount(value);
+        return;
+      }
+      
+      const progress = (now - startTime) / duration;
+      const easeOutQuart = 1 - Math.pow(1 - progress, 4);
+      const currentValue = Math.floor(easeOutQuart * value);
+      
+      setCount(currentValue);
+      requestAnimationFrame(animate);
+    };
+    
+    requestAnimationFrame(animate);
+  }, [isInView, value, duration, delay]);
+
+  return (
+    <motion.span
+      ref={ref}
+      initial={{ opacity: 0, scale: 0.5 }}
+      animate={isInView ? { opacity: 1, scale: 1 } : {}}
+      transition={{ duration: 0.5, delay: delay / 1000 }}
+      className={className}
+    >
+      {prefix}{count}{suffix}
+    </motion.span>
+  );
+}
+
+interface StatCardProps {
+  value: number;
+  label: string;
+  suffix?: string;
+  prefix?: string;
+  index?: number;
+}
+
+export function StatCard({ value, label, suffix = '', prefix = '', index = 0 }: StatCardProps) {
+  return (
+    <motion.div
+      initial={{ opacity: 0, y: 20 }}
+      whileInView={{ opacity: 1, y: 0 }}
+      viewport={{ once: true }}
+      transition={{ duration: 0.5, delay: index * 0.1 }}
+      className="text-center group cursor-default"
+    >
+      <div className="text-3xl sm:text-4xl font-bold tech-gradient-text mb-2">
+        <AnimatedNumber
+          value={value}
+          suffix={suffix}
+          prefix={prefix}
+          delay={index * 100}
+        />
+      </div>
+      <div className="text-sm text-[var(--color-text-muted)] group-hover:text-[var(--color-text-tertiary)] transition-colors">
+        {label}
+      </div>
+    </motion.div>
+  );
+}