/* Presence navigation stability only — no colors, backgrounds, or content styling. */
body.app-on #app > nav.rail{
  box-sizing:border-box;
  overscroll-behavior:contain;
  scrollbar-gutter:stable;
}

body.app-on #app #rail,
body.app-on #app #subRail{
  min-width:0;
}

body.app-on #app #rail .gtab,
body.app-on #app #subRail .stab,
body.app-on #app .botbar button{
  box-sizing:border-box;
  touch-action:manipulation;
  -webkit-tap-highlight-color:transparent;
  contain:layout paint;
}

@media (min-width:980px){
  body.app-on #app > nav.rail{
    overflow-x:hidden;
    overflow-y:auto;
  }

  body.app-on #app #rail .gtab,
  body.app-on #app #subRail .stab{
    transform:translateZ(0);
  }
}

@media (max-width:979px){
  body.app-on #app > nav.rail{
    scrollbar-gutter:auto;
  }

  body.app-on #app #rail,
  body.app-on #app #subRail .subrail-compact{
    overscroll-behavior-x:contain;
  }
}

@media (max-width:1199px){
  body.app-on #app #subRail .stab{
    min-height:44px;
  }

  body.app-on #app #subRail .subrail-compact,
  body.app-on #app #subRail .subrail-section > div{
    gap:8px;
  }
}

@media (prefers-reduced-motion:reduce){
  body.app-on #app #rail .gtab,
  body.app-on #app #subRail .stab{
    transition-duration:.01ms!important;
  }
}