初始提交：AI医疗展示网站，包含回到顶部按钮功能（排除大文件）

src/components/Header.jsx

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+import React, { useState, useEffect } from 'react';
+import { motion } from 'framer-motion';
+import { Menu, X, Brain, Heart, Activity } from 'lucide-react';
+
+const Header = () => {
+  const [isMenuOpen, setIsMenuOpen] = useState(false);
+  const [isScrolled, setIsScrolled] = useState(false);
+
+  useEffect(() => {
+    const handleScroll = () => {
+      setIsScrolled(window.scrollY > 50);
+    };
+    window.addEventListener('scroll', handleScroll);
+    return () => window.removeEventListener('scroll', handleScroll);
+  }, []);
+
+  const scrollToSection = (sectionId) => {
+    const element = document.getElementById(sectionId);
+    if (element) {
+      element.scrollIntoView({ behavior: 'smooth' });
+    }
+    setIsMenuOpen(false);
+  };
+
+  const navItems = [
+    { id: 'hero', label: '首页' },
+    { id: 'company', label: '关于我们' },
+    { id: 'products', label: '产品矩阵' },
+    { id: 'scenarios', label: 'AI应用' },
+    { id: 'architecture', label: '系统架构' },
+    { id: 'vision', label: '未来愿景' },
+    { id: 'contact', label: '总结展望' }
+  ];
+
+  return (
+    <motion.header
+      className={`fixed top-0 left-0 right-0 z-50 transition-all duration-300 ${
+        isScrolled ? 'bg-white/95 backdrop-blur-md shadow-lg' : 'bg-transparent'
+      }`}
+      initial={{ y: -100 }}
+      animate={{ y: 0 }}
+      transition={{ duration: 0.5 }}
+    >
+      <div className="container-custom">
+        <div className="flex items-center justify-between py-4">
+          {/* Logo */}
+          <motion.div
+            className="flex items-center space-x-3"
+            whileHover={{ scale: 1.05 }}
+            transition={{ type: "spring", stiffness: 400, damping: 10 }}
+          >
+            <div className="relative">
+              <div className="w-10 h-10 medical-gradient rounded-lg flex items-center justify-center">
+                <Brain className="w-6 h-6 text-white" />
+              </div>
+              <div className="absolute -top-1 -right-1 w-4 h-4 bg-blue-500 rounded-full flex items-center justify-center">
+                <Activity className="w-2 h-2 text-white" />
+              </div>
+            </div>
+            <div>
+              <h1 className={`text-xl font-bold ${isScrolled ? 'text-gray-900' : 'text-white'}`}>
+                数耀科技
+              </h1>
+              <p className={`text-sm ${isScrolled ? 'text-gray-600' : 'text-white/80'}`}>
+                AI赋能医疗与健康
+              </p>
+            </div>
+          </motion.div>
+
+          {/* Desktop Navigation */}
+          <nav className="hidden md:flex items-center space-x-8">
+            {navItems.map((item, index) => (
+              <motion.button
+                key={item.id}
+                onClick={() => scrollToSection(item.id)}
+                className={`text-sm font-medium transition-colors hover:text-blue-600 ${
+                  isScrolled ? 'text-gray-700' : 'text-white'
+                }`}
+                whileHover={{ scale: 1.05 }}
+                whileTap={{ scale: 0.95 }}
+                initial={{ opacity: 0, y: -20 }}
+                animate={{ opacity: 1, y: 0 }}
+                transition={{ delay: index * 0.1 }}
+              >
+                {item.label}
+              </motion.button>
+            ))}
+          </nav>
+
+          {/* Mobile Menu Button */}
+          <motion.button
+            className={`md:hidden p-2 rounded-lg ${
+              isScrolled ? 'text-gray-700' : 'text-white'
+            }`}
+            onClick={() => setIsMenuOpen(!isMenuOpen)}
+            whileTap={{ scale: 0.95 }}
+          >
+            {isMenuOpen ? <X className="w-6 h-6" /> : <Menu className="w-6 h-6" />}
+          </motion.button>
+        </div>
+
+        {/* Mobile Navigation */}
+        {isMenuOpen && (
+          <motion.nav
+            className="md:hidden py-4 border-t border-white/20"
+            initial={{ opacity: 0, height: 0 }}
+            animate={{ opacity: 1, height: 'auto' }}
+            exit={{ opacity: 0, height: 0 }}
+            transition={{ duration: 0.3 }}
+          >
+            <div className="space-y-3">
+              {navItems.map((item, index) => (
+                <motion.button
+                  key={item.id}
+                  onClick={() => scrollToSection(item.id)}
+                  className={`block w-full text-left py-2 px-4 rounded-lg transition-colors ${
+                    isScrolled 
+                      ? 'text-gray-700 hover:bg-gray-100' 
+                      : 'text-white hover:bg-white/10'
+                  }`}
+                  initial={{ opacity: 0, x: -20 }}
+                  animate={{ opacity: 1, x: 0 }}
+                  transition={{ delay: index * 0.1 }}
+                >
+                  {item.label}
+                </motion.button>
+              ))}
+            </div>
+          </motion.nav>
+        )}
+      </div>
+    </motion.header>
+  );
+};
+
+export default Header;
+