diff --git a/app.py b/app.py
index ffc487a..fa22768 100644
--- a/app.py
+++ b/app.py
@@ -4835,8 +4835,9 @@ def admin_delete_contest(contest_id):
         return jsonify({'success': False, 'message': '请先废止杯赛再删除'}), 400
     # 清理关联数据（无 cascade 的需手动处理）
     ContestRegistration.query.filter_by(contest_id=contest_id).delete()
-    ContestApplication.query.filter_by(contest_id=contest_id).delete()
     QuestionBankItem.query.filter_by(contest_id=contest_id).delete()
+    # 删除该杯赛的帖子
+    Post.query.filter_by(contest_id=contest_id).delete()
     # 删除该杯赛教师申请的邀请码
     ta_ids = [ta.id for ta in TeacherApplication.query.filter_by(contest_id=contest_id).all()]
     if ta_ids:
diff --git a/templates/register.html b/templates/register.html
index 9f1298e..4cd38a9 100644
--- a/templates/register.html
+++ b/templates/register.html
@@ -2,15 +2,20 @@
 {% block title %}注册 - 智联青云{% endblock %}
 {% block navbar %}{% endblock %}
 {% block content %}
-<div class="min-h-screen bg-slate-50 flex flex-col justify-center py-12 sm:px-6 lg:px-8">
+<!-- 覆盖全局背景，确保全屏填充 -->
+<div class="fixed inset-0 z-[-1] bg-gradient-to-b from-sky-400 via-sky-200 to-white"></div>
+<!-- 云团动态背景画布 -->
+<canvas id="cloudCanvas" class="fixed inset-0 z-[-1] pointer-events-none w-full h-full"></canvas>
+
+<div class="relative z-10 flex flex-col justify-center min-h-screen py-12 sm:px-6 lg:px-8">
     <div class="sm:mx-auto sm:w-full sm:max-w-md">
-        <h2 class="mt-6 text-center text-3xl font-extrabold bg-gradient-to-r from-blue-600 via-purple-600 to-pink-600 bg-clip-text text-transparent animate-pulse">注册新账户</h2>
-        <p class="mt-2 text-center text-sm text-slate-600">
-            已有账户？ <a href="/login" class="font-medium text-primary hover:text-blue-500 transition-all duration-300 hover:scale-110 inline-block">立即登录</a>
+        <h2 class="mt-6 text-center text-4xl font-extrabold text-white drop-shadow-md tracking-tight">注册新账户</h2>
+        <p class="mt-2 text-center text-sm text-sky-800 font-medium">
+            已有账户？ <a href="/login" class="font-bold text-blue-600 hover:text-blue-800 transition-all duration-300 hover:scale-110 inline-block drop-shadow-sm">立即登录</a>
         </p>
     </div>
-    <div class="mt-8 sm:mx-auto sm:w-full sm:max-w-md">
-        <div class="futuristic-card py-8 px-4 sm:px-10">
+    <div class="relative z-10 mt-8 sm:mx-auto sm:w-full sm:max-w-md">
+        <div class="bg-white/70 backdrop-blur-xl py-8 px-4 sm:px-10 rounded-3xl shadow-[0_8px_30px_rgb(0,0,0,0.1)] border border-white/60">
             <!-- 选项卡 -->
             <div class="flex border-b border-slate-200 mb-6">
                 <button id="tab-phone" onclick="switchTab('phone')" class="flex-1 pb-4 text-sm font-medium text-center text-primary border-b-2 border-primary transition-all duration-300 hover:scale-105">手机号注册</button>
@@ -259,5 +264,153 @@ async function handleEmailRegister(e) {
 
 // 初始化图形验证码（默认手机选项卡）
 fetchCaptcha('phone');
+
+// ========== 云团动态背景动画 ==========
+const canvas = document.getElementById('cloudCanvas');
+const ctx = canvas.getContext('2d');
+let width, height;
+let clouds = [];
+let mouse = { x: -1000, y: -1000 };
+
+function resize() {
+    width = canvas.width = window.innerWidth;
+    height = canvas.height = window.innerHeight;
+}
+window.addEventListener('resize', resize);
+resize();
+
+window.addEventListener('mousemove', (e) => {
+    mouse.x = e.clientX;
+    mouse.y = e.clientY;
+});
+window.addEventListener('mouseleave', () => {
+    mouse.x = -1000;
+    mouse.y = -1000;
+});
+
+// 预渲染柔和的云朵粒子，提升性能和真实感
+const puffCanvas = document.createElement('canvas');
+puffCanvas.width = 200;
+puffCanvas.height = 200;
+const pctx = puffCanvas.getContext('2d');
+const grad = pctx.createRadialGradient(100, 100, 0, 100, 100, 100);
+grad.addColorStop(0, 'rgba(255, 255, 255, 1)');
+grad.addColorStop(0.2, 'rgba(255, 255, 255, 0.8)');
+grad.addColorStop(0.5, 'rgba(255, 255, 255, 0.3)');
+grad.addColorStop(1, 'rgba(255, 255, 255, 0)');
+pctx.fillStyle = grad;
+pctx.beginPath();
+pctx.arc(100, 100, 100, 0, Math.PI * 2);
+pctx.fill();
+
+class Cloud {
+    constructor() {
+        this.reset(true);
+    }
+    
+    reset(initial = false) {
+        this.size = Math.random() * 150 + 100; // 更大的云团
+        this.x = initial ? Math.random() * width : -this.size * 2;
+        this.y = Math.random() * height * 0.8; // 主要分布在上方
+        this.speedX = Math.random() * 0.5 + 0.2;
+        this.speedY = (Math.random() - 0.5) * 0.1;
+        this.baseOpacity = Math.random() * 0.5 + 0.3;
+        this.opacity = this.baseOpacity;
+        this.scattered = false;
+        
+        // 生成云朵形状（由多个柔和粒子组成）
+        this.parts = [];
+        const numParts = Math.floor(Math.random() * 6) + 6;
+        for (let i = 0; i < numParts; i++) {
+            // 云朵底部较平，顶部不规则
+            const nx = (Math.random() - 0.5) * this.size * 1.5;
+            const ny = (Math.random() * 0.5 - 0.8) * this.size * 0.5;
+            this.parts.push({
+                offsetX: nx,
+                offsetY: ny,
+                radius: Math.random() * this.size * 0.5 + this.size * 0.4,
+                vx: 0,
+                vy: 0
+            });
+        }
+    }
+
+    update() {
+        if (!this.scattered) {
+            this.x += this.speedX;
+            this.y += this.speedY;
+            
+            // 鼠标交互（散开效果）
+            const dx = this.x - mouse.x;
+            const dy = this.y - mouse.y;
+            const dist = Math.sqrt(dx * dx + dy * dy);
+            
+            // 鼠标靠近时触发散开
+            if (dist < 250) {
+                this.scattered = true;
+                // 给每个粒子一个远离鼠标的速度
+                for (let part of this.parts) {
+                    const pdx = (this.x + part.offsetX) - mouse.x;
+                    const pdy = (this.y + part.offsetY) - mouse.y;
+                    const pdist = Math.sqrt(pdx * pdx + pdy * pdy) || 1;
+                    const force = Math.max(0, 300 - pdist) / 300;
+                    part.vx = (pdx / pdist) * force * (Math.random() * 6 + 2);
+                    part.vy = (pdy / pdist) * force * (Math.random() * 6 + 2);
+                }
+            }
+        } else {
+            // 散开状态：粒子移动并淡出
+            this.opacity -= 0.015;
+            for (let part of this.parts) {
+                part.offsetX += part.vx;
+                part.offsetY += part.vy;
+                part.radius += 0.5; // 散开时稍微膨胀
+                // 增加空气阻力
+                part.vx *= 0.95;
+                part.vy *= 0.95;
+            }
+        }
+
+        // 边界检测或完全淡出后重置
+        if (this.x > width + this.size * 2 || this.opacity <= 0 || this.y < -this.size * 2 || this.y > height + this.size * 2) {
+            this.reset();
+        }
+    }
+
+    draw() {
+        if (this.opacity <= 0) return;
+        ctx.save();
+        ctx.globalAlpha = Math.max(0, this.opacity);
+        
+        for (let part of this.parts) {
+            const cx = this.x + part.offsetX;
+            const cy = this.y + part.offsetY;
+            const r = part.radius;
+            
+            // 视野外不绘制
+            if (cx + r < 0 || cx - r > width || cy + r < 0 || cy - r > height) continue;
+            
+            // 使用预渲染的柔和云朵粒子
+            ctx.drawImage(puffCanvas, cx - r, cy - r, r * 2, r * 2);
+        }
+        
+        ctx.restore();
+    }
+}
+
+// 初始化云朵
+for (let i = 0; i < 12; i++) {
+    clouds.push(new Cloud());
+}
+
+function animate() {
+    ctx.clearRect(0, 0, width, height);
+    for (let cloud of clouds) {
+        cloud.update();
+        cloud.draw();
+    }
+    requestAnimationFrame(animate);
+}
+animate();
 </script>
 {% endblock %}
\ No newline at end of file