/* 公共顶栏组件：尺寸、圆角、账户入口和菜单只在这里维护。 */
.site-header-ui {
  --header-control-size: 34px;
  --header-control-radius: 8px;
  --header-control-gap: 8px;
  --header-text: var(--dd-text, var(--text));
  --header-muted: var(--dd-muted, var(--muted));
  --header-line: var(--dd-line, var(--line));
  --header-surface: var(--dd-surface, var(--surface-bg));
  --header-subtle: var(--dd-surface-subtle, var(--input-bg));
  --header-hover: var(--dd-soft, var(--input-bg));
  --header-accent: var(--dd-accent, var(--accent));
  --header-selected: var(--dd-accent-subtle, var(--badge-bg));
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}
.site-header-ui .header-actions,
.site-header-ui .header-account {
  display: flex;
  flex-shrink: 0;
  align-items: center;
  gap: var(--header-control-gap);
  white-space: nowrap;
}
.site-header-ui [hidden] { display: none !important; }
.site-header-ui .header-button,
.site-header-ui .header-profile,
.site-header-ui .locale-ctrl {
  box-sizing: border-box;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  gap: 6px;
  min-width: var(--header-control-size);
  height: var(--header-control-size);
  min-height: var(--header-control-size);
  padding: 0 10px;
  border: 1px solid var(--header-line);
  border-radius: var(--header-control-radius);
  background: var(--header-surface);
  color: var(--header-text);
  font-size: 12px;
  line-height: 1;
  white-space: nowrap;
  text-decoration: none;
}
.site-header-ui .header-button { cursor: pointer; }
.site-header-ui .header-button:hover { background: var(--header-hover); }
.site-header-ui .btn-primary { background: var(--header-accent); color: #fff; }
.site-header-ui .btn-primary:hover { background: var(--dd-accent-hover, var(--accent-hover)); }
.site-header-ui .header-nav-link { background: var(--header-selected); color: var(--header-accent); border-color: color-mix(in srgb, var(--header-accent) 22%, transparent); }
.site-header-ui .header-nav-link:hover { background: var(--header-selected); border-color: var(--header-accent); }
.site-header-ui .header-login-button:hover { color: var(--header-accent); }
.site-header-ui .header-logout-button:hover { color: var(--error-text, var(--header-accent)); }
.site-header-ui .wechat-icon { width: 18px; height: 18px; flex-shrink: 0; fill: #07c160; }
.site-header-ui .header-profile { padding: 3px 8px; background: var(--header-subtle); }
.site-header-ui .header-account-avatar,
.site-header-ui .header-account-fallback { width: 26px; height: 26px; flex-shrink: 0; border-radius: var(--header-control-radius); object-fit: cover; }
.site-header-ui .header-account-fallback { padding: 3px; background: var(--header-hover); color: var(--header-muted); }
.header-profile:has(.header-account-avatar:not([hidden])) .header-account-fallback { display: none; }
.header-account-label { max-width: 100px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; unicode-bidi: plaintext; }
.header-account-label:empty { display: none; }

.site-header-ui .theme-switch {
  position: relative;
  box-sizing: border-box;
  display: inline-flex;
  align-items: center;
  flex-shrink: 0;
  height: var(--header-control-size);
  padding: 2px;
  gap: 2px;
  border: 1px solid var(--header-line);
  border-radius: var(--header-control-radius);
  background: var(--header-subtle);
}
.site-header-ui .theme-switch button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: calc(var(--header-control-size) - 6px);
  height: calc(var(--header-control-size) - 6px);
  min-height: 0;
  padding: 0;
  border: 0;
  border-radius: var(--header-control-radius);
  background: transparent;
  color: var(--header-muted);
  font: inherit;
  cursor: pointer;
}
.site-header-ui .theme-switch button:hover { background: var(--header-hover); color: var(--header-text); }
.site-header-ui .theme-switch button[aria-pressed="true"],
.site-header-ui .theme-trigger[aria-expanded="true"] { background: var(--header-selected); color: var(--header-accent); }
.site-header-ui .theme-switch svg { width: 15px; height: 15px; fill: none; stroke: currentColor; stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round; }
.theme-switch [data-theme-choice="dark"] svg,
.theme-trigger[data-theme-icon="dark"] svg { fill: currentColor; stroke-width: 0; }
.site-header-ui .theme-switch .theme-trigger,
.theme-menu-label { display: none; }
.theme-menu { display: flex; gap: 2px; }
.site-header-ui .theme-switch[data-compact="true"] { width: var(--header-control-size); }
.site-header-ui .theme-switch[data-compact="true"] .theme-trigger { display: inline-flex; }
.site-header-ui .theme-switch[data-compact="true"] .theme-menu,
.site-header-ui .locale-menu {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  display: none;
  width: 156px;
  padding: 6px;
  border: 1px solid var(--header-line);
  border-radius: 10px;
  background: #1e1f23;
  box-shadow: 0 16px 36px rgba(0, 0, 0, 0.45), 0 0 0 1px var(--header-line);
  z-index: 40;
}
:root:not([data-theme="dark"]) .site-header-ui .theme-switch[data-compact="true"] .theme-menu,
:root:not([data-theme="dark"]) .site-header-ui .locale-menu {
  background: #ffffff;
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.12), 0 0 0 1px var(--header-line);
}
.site-header-ui .theme-switch[data-compact="true"] .theme-menu.is-open,
.site-header-ui .locale-menu.is-open { display: flex; flex-direction: column; gap: 4px; }
.site-header-ui .theme-switch[data-compact="true"] .theme-menu-item,
.site-header-ui .locale-menu-item {
  box-sizing: border-box;
  display: flex;
  align-items: center;
  justify-content: flex-start;
  width: 100%;
  height: 32px;
  min-height: 32px;
  padding: 0 10px;
  gap: 8px;
  border: 0;
  border-radius: 6px;
  background: transparent;
  color: var(--header-text);
  font-size: 13px;
  font-weight: 400;
  cursor: pointer;
  transition: background 0.12s ease, color 0.12s ease;
}
.site-header-ui .theme-switch[data-compact="true"] .theme-menu-label { display: inline; font-size: 13px; }
.site-header-ui .theme-switch[data-compact="true"] [aria-pressed="true"]::after,
.site-header-ui .locale-menu-item[aria-checked="true"]::after { content: "✓"; margin-left: auto; font-weight: 700; color: var(--header-accent); }
.site-header-ui .theme-switch[data-compact="true"] .theme-menu-item[aria-pressed="true"],
.site-header-ui .locale-menu-item[aria-checked="true"] {
  background: transparent;
  color: var(--header-accent);
  font-weight: 600;
}
.site-header-ui .theme-switch[data-compact="true"] .theme-menu-item:hover,
.site-header-ui .locale-menu-item:hover,
.site-header-ui .theme-switch[data-compact="true"] .theme-menu-item:focus-visible,
.site-header-ui .locale-menu-item:focus-visible {
  background: color-mix(in srgb, var(--header-text) 10%, transparent);
  color: var(--header-text);
}
.site-header-ui .theme-switch[data-compact="true"] .theme-menu-item[aria-pressed="true"]:hover,
.site-header-ui .locale-menu-item[aria-checked="true"]:hover,
.site-header-ui .theme-switch[data-compact="true"] .theme-menu-item[aria-pressed="true"]:focus-visible,
.site-header-ui .locale-menu-item[aria-checked="true"]:focus-visible {
  background: color-mix(in srgb, var(--header-text) 10%, transparent);
  color: var(--header-accent);
}
.site-header-ui .locale-ctrl { position: relative; padding: 0; z-index: 30; }
.site-header-ui .locale-ctrl .lang-icon { width: 16px; height: 16px; color: var(--header-muted); flex-shrink: 0; pointer-events: none; }
.site-header-ui .locale-ctrl .dropdown-arrow { width: 8px; height: 8px; stroke: var(--header-muted); fill: none; stroke-width: 1.6; stroke-linecap: round; stroke-linejoin: round; flex-shrink: 0; pointer-events: none; }
.site-header-ui .locale-ctrl select { width: auto; margin: 0; padding: 0; border: 0; background: transparent; font-size: 12px; }
.locale-native-select { display: none; }
.site-header-ui .locale-trigger { display: inline-flex; align-items: center; justify-content: center; width: 100%; height: 100%; min-height: 0; padding: 0 10px; gap: 5px; border: 0; border-radius: inherit; background: transparent; color: var(--header-text); font-size: 12px; white-space: nowrap; cursor: pointer; }
.site-header-ui .locale-trigger-label { display: inline-block; max-width: 100px; overflow: hidden; text-overflow: ellipsis; }
.site-header-ui .locale-menu-item { height: auto; min-height: 34px; padding-block: 8px; white-space: normal; overflow-wrap: anywhere; text-align: start; }
.site-header-ui .locale-menu { max-height: min(60vh, 360px); overflow-y: auto; overscroll-behavior: contain; }
.site-header-ui .locale-trigger .dropdown-arrow { display: block; width: 7px; height: 7px; }
.site-header-ui button:focus-visible,
.site-header-ui a:focus-visible { outline: 2px solid var(--header-accent); outline-offset: 3px; }

@media (pointer: coarse) { .site-header-ui { --header-control-size: 44px; } }
@media (max-width: 1100px) { .viewer-header.site-header-ui { --header-control-gap: 6px; } }
@media (max-width: 900px) {
  .viewer-header .header-account-label,
  .viewer-header .header-login-label { display: none; }
  .viewer-header .header-login-button { width: var(--header-control-size); padding: 0; }
}
@media (max-width: 640px) {
  .site-header-ui .locale-ctrl { width: var(--header-control-size); }
  .site-header-ui .locale-trigger { padding: 0; gap: 3px; }
  .site-header-ui .locale-trigger-label,
  .site-header-ui .header-account-label { display: none; }
  .guide-header .header-login-label { display: none; }
  .guide-header .header-login-button { width: var(--header-control-size); padding: 0; }
}
@media (max-width: 520px) {
  .site-header-ui .brand-viewer-tag { width: var(--header-control-size); padding: 0; }
  .site-header-ui .brand-viewer-tag span { display: none; }
  .site-header .header-login-label { display: none; }
  .site-header .header-login-button { width: var(--header-control-size); padding: 0; }
}
@media (max-width: 360px) {
  /* 窄屏登录状态仍保留打开文件文字及完整触摸高度，为多语文案留出横向空间。 */
  .viewer-header.site-header-ui #btn-open-files { padding-inline: 4px; gap: 2px; }
}
/* 菜单初始化前也为当前外观保留单个图标的位置，避免窄屏首帧挤压。 */
@media (max-width: 640px) {
  .theme-switch:not([data-menu-ready]) [data-theme-choice]:not([aria-pressed="true"]) { display: none; }
}
@media (max-width: 1100px) {
  .theme-switch[data-compact-at="1100"]:not([data-menu-ready]) [data-theme-choice]:not([aria-pressed="true"]) { display: none; }
}