feat: add tech-inspired animated background component

Add dynamic background with gradient, particles, and theme support

Co-authored-by: Simon <85533298+handsomezhuzhu@users.noreply.github.com>

components/tech-background.tsx

@@ -0,0 +1,172 @@
+"use client"
+
+import { useEffect, useRef } from "react"
+
+export function TechBackground() {
+  const canvasRef = useRef<HTMLCanvasElement>(null)
+
+  useEffect(() => {
+    const canvas = canvasRef.current
+    if (!canvas) return
+
+    const ctx = canvas.getContext("2d")
+    if (!ctx) return
+
+    let animationFrameId: number
+    let particles: Particle[] = []
+
+    const resize = () => {
+      canvas.width = window.innerWidth
+      canvas.height = window.innerHeight
+    }
+
+    class Particle {
+      x: number
+      y: number
+      vx: number
+      vy: number
+      size: number
+      opacity: number
+
+      constructor(width: number, height: number) {
+        this.x = Math.random() * width
+        this.y = Math.random() * height
+        this.vx = (Math.random() - 0.5) * 0.3
+        this.vy = (Math.random() - 0.5) * 0.3
+        this.size = Math.random() * 2 + 1
+        this.opacity = Math.random() * 0.5 + 0.1
+      }
+
+      update(width: number, height: number) {
+        this.x += this.vx
+        this.y += this.vy
+
+        if (this.x < 0 || this.x > width) this.vx *= -1
+        if (this.y < 0 || this.y > height) this.vy *= -1
+      }
+
+      draw(ctx: CanvasRenderingContext2D, isDark: boolean) {
+        ctx.beginPath()
+        ctx.arc(this.x, this.y, this.size, 0, Math.PI * 2)
+        ctx.fillStyle = isDark 
+          ? `rgba(100, 200, 255, ${this.opacity})` 
+          : `rgba(50, 100, 150, ${this.opacity * 0.5})`
+        ctx.fill()
+      }
+    }
+
+    const initParticles = () => {
+      particles = []
+      const particleCount = Math.floor((canvas.width * canvas.height) / 15000)
+      for (let i = 0; i < particleCount; i++) {
+        particles.push(new Particle(canvas.width, canvas.height))
+      }
+    }
+
+    const drawGrid = (isDark: boolean) => {
+      const gridSize = 50
+      ctx.strokeStyle = isDark 
+        ? "rgba(100, 200, 255, 0.03)" 
+        : "rgba(50, 100, 150, 0.05)"
+      ctx.lineWidth = 1
+
+      for (let x = 0; x <= canvas.width; x += gridSize) {
+        ctx.beginPath()
+        ctx.moveTo(x, 0)
+        ctx.lineTo(x, canvas.height)
+        ctx.stroke()
+      }
+
+      for (let y = 0; y <= canvas.height; y += gridSize) {
+        ctx.beginPath()
+        ctx.moveTo(0, y)
+        ctx.lineTo(canvas.width, y)
+        ctx.stroke()
+      }
+    }
+
+    const drawConnections = (isDark: boolean) => {
+      const maxDistance = 120
+      for (let i = 0; i < particles.length; i++) {
+        for (let j = i + 1; j < particles.length; j++) {
+          const dx = particles[i].x - particles[j].x
+          const dy = particles[i].y - particles[j].y
+          const distance = Math.sqrt(dx * dx + dy * dy)
+
+          if (distance < maxDistance) {
+            const opacity = (1 - distance / maxDistance) * 0.2
+            ctx.beginPath()
+            ctx.moveTo(particles[i].x, particles[i].y)
+            ctx.lineTo(particles[j].x, particles[j].y)
+            ctx.strokeStyle = isDark 
+              ? `rgba(100, 200, 255, ${opacity})` 
+              : `rgba(50, 100, 150, ${opacity * 0.5})`
+            ctx.lineWidth = 1
+            ctx.stroke()
+          }
+        }
+      }
+    }
+
+    const animate = () => {
+      const isDark = document.documentElement.classList.contains("dark")
+      
+      ctx.clearRect(0, 0, canvas.width, canvas.height)
+
+      // Draw subtle gradient overlay
+      const gradient = ctx.createRadialGradient(
+        canvas.width / 2,
+        canvas.height / 2,
+        0,
+        canvas.width / 2,
+        canvas.height / 2,
+        canvas.width / 1.5
+      )
+      
+      if (isDark) {
+        gradient.addColorStop(0, "rgba(30, 60, 100, 0.1)")
+        gradient.addColorStop(1, "rgba(10, 20, 40, 0)")
+      } else {
+        gradient.addColorStop(0, "rgba(200, 230, 255, 0.2)")
+        gradient.addColorStop(1, "rgba(255, 255, 255, 0)")
+      }
+      
+      ctx.fillStyle = gradient
+      ctx.fillRect(0, 0, canvas.width, canvas.height)
+
+      drawGrid(isDark)
+
+      // Update and draw particles
+      for (const particle of particles) {
+        particle.update(canvas.width, canvas.height)
+        particle.draw(ctx, isDark)
+      }
+
+      drawConnections(isDark)
+
+      animationFrameId = requestAnimationFrame(animate)
+    }
+
+    resize()
+    initParticles()
+    animate()
+
+    window.addEventListener("resize", () => {
+      resize()
+      initParticles()
+    })
+
+    return () => {
+      cancelAnimationFrame(animationFrameId)
+      window.removeEventListener("resize", resize)
+    }
+  }, [])
+
+  return (
+    <canvas
+      ref={canvasRef}
+      className="fixed inset-0 pointer-events-none -z-10"
+      aria-hidden="true"
+    />
+  )
+}