style: 优化登录页面布局（方案 A - 紧凑型）

布局调整：
- 内容区域改为 flex-start 对齐，从顶部 18vh 处开始
- 登录卡片内边距 64rpx → 48rpx
- 标题区域底部间距 64rpx → 48rpx

尺寸优化：
- 标题字号 48rpx → 42rpx
- 副标题字号 28rpx → 24rpx
- 输入框高度 92rpx → 80rpx
- 输入框内边距 32rpx → 28rpx
- 输入框字号 28rpx → 26rpx
- 验证码按钮 220rpx×92rpx → 200rpx×80rpx
- 登录按钮高度 100rpx → 88rpx
- 登录按钮字号 30rpx → 28rpx

间距优化：
- 表单底部间距 48rpx → 40rpx
- 输入组间距 32rpx → 24rpx
- 标签底部间距 16rpx → 12rpx
- 登录按钮底部间距 32rpx → 24rpx

其他：
- 输入框添加 box-sizing: border-box 防止溢出

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

mini-program/src/pages/login/index.vue

@@ -198,11 +198,11 @@ const handleLogin = async () => {
   z-index: 1;
   min-height: 100vh;
   display: flex;
-  align-items: center;
+  align-items: flex-start;
   justify-content: center;
-  padding: 40rpx;
+  padding: 18vh 40rpx;
-  padding-top: calc(40rpx + constant(safe-area-inset-top));
+  padding-top: calc(18vh + constant(safe-area-inset-top));
-  padding-top: calc(40rpx + env(safe-area-inset-top));
+  padding-top: calc(18vh + env(safe-area-inset-top));
 }
 
 .login-card {
@@ -212,56 +212,57 @@ const handleLogin = async () => {
   backdrop-filter: blur(40rpx);
   border: 1px solid rgba(168, 85, 247, 0.15);
   border-radius: 48rpx;
-  padding: 64rpx 40rpx;
+  padding: 48rpx 40rpx;
 }
 
 .header {
   text-align: center;
-  margin-bottom: 64rpx;
+  margin-bottom: 48rpx;
 }
 
 .title {
   display: block;
-  font-size: 48rpx;
+  font-size: 42rpx;
   font-weight: 300;
   color: rgba(255, 255, 255, 0.9);
   letter-spacing: 6rpx;
-  margin-bottom: 16rpx;
+  margin-bottom: 12rpx;
 }
 
 .subtitle {
   display: block;
-  font-size: 28rpx;
+  font-size: 24rpx;
   color: rgba(255, 255, 255, 0.4);
   font-style: italic;
 }
 
 .form {
-  margin-bottom: 48rpx;
+  margin-bottom: 40rpx;
 }
 
 .input-group {
-  margin-bottom: 32rpx;
+  margin-bottom: 24rpx;
 }
 
 .input-label {
   display: block;
   font-size: 18rpx;
   color: rgba(255, 255, 255, 0.35);
-  margin-bottom: 16rpx;
+  margin-bottom: 12rpx;
   letter-spacing: 4rpx;
   text-transform: uppercase;
 }
 
 .glass-input {
   width: 100%;
-  height: 92rpx;
+  height: 80rpx;
   background: rgba(255, 255, 255, 0.05);
   border: 1px solid rgba(255, 255, 255, 0.1);
   border-radius: 24rpx;
-  padding: 0 32rpx;
+  padding: 0 28rpx;
   color: #F3E8FF;
-  font-size: 28rpx;
+  font-size: 26rpx;
+  box-sizing: border-box;
 }
 
 .glass-input::placeholder {
@@ -283,13 +284,13 @@ const handleLogin = async () => {
 }
 
 .code-btn {
-  width: 220rpx;
+  width: 200rpx;
-  height: 92rpx;
+  height: 80rpx;
   background: linear-gradient(135deg, rgba(147, 51, 234, 0.5), rgba(124, 58, 237, 0.4));
   border: 1px solid rgba(168, 85, 247, 0.4);
   border-radius: 24rpx;
   color: rgba(255, 255, 255, 0.95);
-  font-size: 22rpx;
+  font-size: 20rpx;
   display: flex;
   align-items: center;
   justify-content: center;
@@ -316,18 +317,18 @@ const handleLogin = async () => {
 
 .btn-primary {
   width: 100%;
-  height: 100rpx;
+  height: 88rpx;
   background: linear-gradient(135deg, #9333EA 0%, #7C3AED 100%);
   border-radius: 32rpx;
   color: white;
   font-weight: 600;
-  font-size: 30rpx;
+  font-size: 28rpx;
   display: flex;
   align-items: center;
   justify-content: center;
   border: none;
   box-shadow: 0 8rpx 32rpx rgba(168, 85, 247, 0.3);
-  margin-bottom: 32rpx;
+  margin-bottom: 24rpx;
 }
 
 .btn-primary.disabled {