/* 老城既有页签与章内目录接入公共章节导航；仅增强后启用。 */
.old-city-navigation { position: sticky; top: var(--section-nav-top, 0px); z-index: 30; width: var(--page-content-width); margin: 0 auto; background: var(--color-bg); box-shadow: var(--shadow-sm); }
.old-city-navigation .section-nav { position: static; width: 100%; max-width: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(var(--section-nav-columns, 8), minmax(0, 1fr)); gap: 0; overflow: visible; border: 1px solid var(--color-border); background: var(--color-bg); box-shadow: none; }
.old-city-navigation .section-nav[hidden] { display: none; }
/* 长景名需要完整单行呈现时启用；超出容器后在目录内横向滚动。 */
.old-city-navigation .section-nav--nowrap { display: flex; overflow-x: auto; overscroll-behavior-x: contain; }
.old-city-navigation .section-nav--nowrap > a { flex: 1 0 auto; white-space: nowrap; }
.old-city-navigation .section-nav > a, .old-city-navigation .section-nav > .tab-btn { display: flex; justify-content: center; align-items: center; min-width: 0; min-height: 48px; margin: 0; padding: 8px 4px; border: 0; border-right: 1px solid var(--color-border); border-bottom: 3px solid transparent; border-radius: 0; background: transparent; color: var(--color-surface-deep); font: 500 var(--fs-body)/1.5 var(--font-body); letter-spacing: 0; text-align: center; text-decoration: none; box-shadow: none; transform: none; }
.old-city-navigation .section-nav > .tab-btn::before, .old-city-navigation .section-nav > .tab-btn::after { display: none; }
.old-city-navigation .section-nav > a:hover, .old-city-navigation .section-nav > .tab-btn:hover { background: var(--color-white); }
.old-city-navigation .section-nav > a[aria-current="location"], .old-city-navigation .section-nav > .tab-btn[aria-selected="true"] { background: var(--color-surface-deep); color: var(--color-white); border-bottom-color: var(--color-accent); font-weight: 600; }
.old-city-navigation .section-nav > a:focus-visible, .old-city-navigation .section-nav > .tab-btn:focus-visible { outline: 3px solid var(--color-accent); outline-offset: -3px; }
.old-city-navigation .section-nav > .tab-btn .tab-btn-label { font: inherit; }
.old-city-navigation-page [id] { scroll-margin-top: calc(var(--section-nav-top, 70px) + var(--section-nav-height, 0px) + 16px); }
.old-city-navigation-page .history-memory__layout { grid-template-columns: minmax(0, 1fr); }
.old-city-navigation-page .history-memory__panels { grid-column: 1; }
.old-city-navigation-page .history-memory__directory, .old-city-navigation-page .history-memory__picker,
.old-city-navigation-page .history-memory__directory-anchor, .old-city-navigation-page .transport-directory,
.old-city-navigation-page .qianhu-directory { display: none; }
.old-city-navigation-page .history-memory__layout > :not(.history-memory__directory):not(.history-memory__directory-anchor) { grid-column: 1; }
.old-city-navigation-page .war-context { top: calc(var(--section-nav-top, 70px) + var(--section-nav-height, 0px) + 16px); }
@media (max-width: 900px) {
  .old-city-navigation .section-nav { grid-template-columns: repeat(var(--old-city-mobile-columns, 4), minmax(0, 1fr)); }
  .old-city-navigation .section-nav > a, .old-city-navigation .section-nav > .tab-btn { font-size: 14px; min-height: 46px; border-top: 1px solid var(--color-border); }
}