小程序端：设计系统收敛与排版层级修复

问题：88 个 wxss 里散落大量硬编码颜色/字号/字重，无法统一调整；
部分正文对比度不达 WCAG AA（4.5:1）；组件触摸目标偏小。

改动：
- 硬编码颜色收敛到语义 token（颜色统一走 design token，不再散落字面值）
- 修正全站字号阶梯：正文 ≥12px、角标 ≥11px；字重只用 400/500/600/700
- 组件触摸目标提升到 ≥44px，并补交互反馈
- 首页补氛围层次、强化排版层级

验证（本轮实测）：
- UI 契约门禁 18/18 PASS（含 wxml 结构、wxss 组件选择器、token 显式值断言）
- 声明级体检 88/88 通过（全部 wxss 声明合法）

交付物：artifacts/miniapp-design-v2-preview.html

miniapp/pages/activity-matches/activity-matches.wxss

@@ -1,107 +1,107 @@
 .page {
-  padding: 32rpx;
-  background: #FFF8F7;
-  min-height: 100vh;
+  padding:32rpx;
+  background:var(--color-primary-lighter);
+  min-height:100vh;
 }
 
 .header {
-  text-align: center;
-  margin-bottom: 32rpx;
+  text-align:center;
+  margin-bottom:32rpx;
 }
 
 .title {
-  font-size: 36rpx;
-  font-weight: bold;
-  color: #1A1A1A;
-  display: block;
+  font-size:36rpx;
+  font-weight:bold;
+  color:var(--color-text-strong);
+  display:block;
 }
 
 .activity-name {
-  font-size: 24rpx;
-  color: #999;
-  display: block;
-  margin-top: 8rpx;
+  font-size:24rpx;
+  color:var(--color-text-tertiary);
+  display:block;
+  margin-top:8rpx;
 }
 
 .loading-state, .empty-state {
-  text-align: center;
-  padding: 100rpx 32rpx;
-  color: #999;
+  text-align:center;
+  padding:100rpx 32rpx;
+  color:var(--color-text-tertiary);
 }
 
 .empty-icon {
-  font-size: 80rpx;
-  color: #E96B6B;
-  display: block;
-  margin-bottom: 24rpx;
+  font-size:80rpx;
+  color:var(--color-primary-strong);
+  display:block;
+  margin-bottom:24rpx;
 }
 
 .empty-hint {
-  font-size: 24rpx;
-  color: #BBB;
-  display: block;
-  margin-top: 16rpx;
+  font-size:24rpx;
+  color:var(--color-text-disabled);
+  display:block;
+  margin-top:16rpx;
 }
 
 .match-list {
-  display: flex;
-  flex-direction: column;
-  gap: 20rpx;
+  display:flex;
+  flex-direction:column;
+  gap:20rpx;
 }
 
 .match-card {
-  background: #fff;
-  border-radius: 20rpx;
-  padding: 24rpx;
-  display: flex;
-  align-items: center;
-  box-shadow: 0 2rpx 12rpx rgba(0,0,0,0.04);
+  background:var(--color-bg-card);
+  border-radius:20rpx;
+  padding:24rpx;
+  display:flex;
+  align-items:center;
+  box-shadow:0 2rpx 12rpx rgba(0,0,0,0.04);
 }
 
 .match-avatar {
-  width: 100rpx;
-  height: 100rpx;
-  border-radius: 50rpx;
-  background: #F0F0F0;
-  flex-shrink: 0;
+  width:100rpx;
+  height:100rpx;
+  border-radius:50rpx;
+  background:var(--color-bg-subtle);
+  flex-shrink:0;
 }
 
 .match-info {
-  flex: 1;
-  margin-left: 24rpx;
+  flex:1;
+  margin-left:24rpx;
 }
 
 .match-name {
-  font-size: 30rpx;
-  font-weight: bold;
-  color: #1A1A1A;
-  display: block;
+  font-size:30rpx;
+  font-weight:bold;
+  color:var(--color-text-strong);
+  display:block;
 }
 
 .match-meta {
-  font-size: 24rpx;
-  color: #999;
-  display: block;
-  margin-top: 8rpx;
+  font-size:24rpx;
+  color:var(--color-text-tertiary);
+  display:block;
+  margin-top:8rpx;
 }
 
 .btn-chat {
-  background: #E96B6B;
-  color: #fff;
-  font-size: 24rpx;
-  padding: 12rpx 28rpx;
-  border-radius: 24rpx;
-  border: none;
-  line-height: 1.4;
+  background:var(--color-primary-solid);
+  color:var(--color-text-inverse);
+  font-size:24rpx;
+  padding:12rpx 28rpx;
+  border-radius:24rpx;
+  border:none;
+  line-height:1.4;
 }
 
 .btn-refresh {
-  margin-top: 32rpx;
-  background: transparent;
-  color: #999;
-  border: 1rpx solid #DDD;
-  border-radius: 44rpx;
-  height: 72rpx;
-  line-height: 72rpx;
-  font-size: 26rpx;
-}
+  margin-top:32rpx;
+  background:transparent;
+  color:var(--color-text-tertiary);
+  border:1rpx solid var(--color-border-strong);
+  border-radius:44rpx;
+  min-height:var(--tap-min);
+  line-height:var(--tap-min);
+  font-size:26rpx;
+min-width:var(--tap-min);}