/* === 公共基础样式 === */
* { margin: 0; padding: 0; box-sizing: border-box; -webkit-tap-highlight-color: transparent; }
html { height: 100%; }
body {
  font-family: -apple-system, BlinkMacSystemFont, 'PingFang SC', 'Helvetica Neue', 'Segoe UI', sans-serif;
  background: #f0f2f5; color: #333; min-height: 100%;
  -webkit-text-size-adjust: 100%;
}

/* === 平台色条 === */
.platform-bar { height: 4px; }
.platform-bar.ios { background: #4a90d9; }
.platform-bar.android { background: #27ae60; }
.platform-bar.web { background: #9b59b6; }