/* ========== 统一导航系统 ========== */

/* 顶部 Header Bar（由nav.js动态创建） */
.app-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 52px;
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid rgba(0,0,0,0.06);
  display: flex;
  align-items: center;
  padding: 0 16px;
  z-index: 9999;
  padding-top: env(safe-area-inset-top, 0px);
}

.app-header-back {
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: none;
  background: rgba(0,0,0,0.04);
  border-radius: 10px;
  cursor: pointer;
  color: #1e293b;
  -webkit-tap-highlight-color: transparent;
  transition: background 0.2s;
}

.app-header-back:active {
  background: rgba(0,0,0,0.08);
}

.app-header-back svg {
  width: 18px;
  height: 18px;
  stroke: currentColor;
  fill: none;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.app-header-title {
  flex: 1;
  text-align: center;
  font-size: 16px;
  font-weight: 600;
  color: #1e293b;
  margin: 0 8px;
}

.app-header-spacer {
  width: 36px;
}

/* 内容页面顶部预留 Header 空间 */
body:not(.is-3d-page) .header-spacer {
  height: calc(52px + env(safe-area-inset-top, 0px));
}