/* ==========================================================================
   Oddech — layout: app shell (app bar, nav, mobile tab bar), page, grid
   Breakpoints (mobile first): 480 sm · 768 md · 1024 lg · 1280 xl · 1536 2xl
   ========================================================================== */

.app { min-height: 100dvh; display: flex; flex-direction: column; overflow-x: clip; } /* clip (not hidden): the aurora bleeds sideways, sticky still works */

/* ---- App bar (sticky, glass) ------------------------------------------ */
.appbar {
  position: sticky; top: 0; z-index: 40;
  height: var(--appbar-h);
  display: flex; align-items: center; gap: var(--s-4);
  padding: 0 var(--page-pad);
  background: var(--surface-glass);
  -webkit-backdrop-filter: var(--blur); backdrop-filter: var(--blur);
  border-bottom: 1px solid var(--border);
}
.brand { display: inline-flex; align-items: center; gap: 10px; font-weight: 650; font-size: 18px; letter-spacing: -0.03em; color: var(--text); }
.brand__mark {
  width: 32px; height: 32px; border-radius: 10px; display: grid; place-items: center;
  background: var(--brand-gradient); color: var(--text-on-accent); box-shadow: var(--shadow-glow);
}
.brand__mark svg { width: 20px; height: 20px; }
.brand__sub { font-weight: 500; color: var(--text-faint); font-size: var(--fs-sm); letter-spacing: 0; }

.nav { display: none; align-items: center; gap: 2px; margin-left: var(--s-4); }
.nav__link {
  position: relative; display: inline-flex; align-items: center; gap: 8px;
  height: 36px; padding: 0 12px; border-radius: var(--r-pill);
  color: var(--text-muted); font-size: var(--fs-sm); font-weight: 550;
  transition: color var(--dur-2) var(--ease), background var(--dur-2) var(--ease);
}
.nav__link:hover { color: var(--text); background: var(--surface-3); }
.nav__link[aria-current="page"] { color: var(--text); background: var(--surface); box-shadow: var(--shadow-sm), inset 0 0 0 1px var(--border); }
.nav__link .icon { width: 16px; height: 16px; }

.appbar__actions { margin-left: auto; display: flex; align-items: center; gap: var(--s-2); }
.search-trigger {
  display: inline-flex; align-items: center; gap: 10px;
  height: 38px; padding: 0 8px 0 12px; min-width: 0;
  border-radius: var(--r-pill); border: 1px solid var(--border);
  background: var(--surface); color: var(--text-faint); font-size: var(--fs-sm);
  box-shadow: var(--shadow-xs);
  transition: border-color var(--dur-2) var(--ease), box-shadow var(--dur-2) var(--ease);
}
.search-trigger:hover { border-color: var(--border-strong); box-shadow: var(--shadow-sm); color: var(--text-muted); }
.search-trigger__label { display: none; }
.search-trigger kbd { display: none; }

/* ---- Mobile tab bar (bottom) ------------------------------------------- */
.tabbar {
  position: fixed; left: 0; right: 0; bottom: 0; z-index: 45;
  height: calc(var(--tabbar-h) + env(safe-area-inset-bottom));
  padding: 6px 8px env(safe-area-inset-bottom);
  display: grid; grid-template-columns: repeat(5, 1fr);
  background: var(--surface-glass-strong);
  -webkit-backdrop-filter: var(--blur); backdrop-filter: var(--blur);
  border-top: 1px solid var(--border);
}
.tabbar__item {
  display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 3px;
  border-radius: var(--r-md); color: var(--text-faint);
  font-size: 10.5px; font-weight: 600; letter-spacing: .01em;
}
.tabbar__item .icon { width: 22px; height: 22px; stroke-width: 1.8; }
.tabbar__item[aria-current="page"] { color: var(--accent); }
.tabbar__item[aria-current="page"] .icon { filter: drop-shadow(0 4px 10px var(--accent-ring)); }

/* ---- Page ------------------------------------------------------------- */
.main { flex: 1 0 auto; padding-bottom: calc(var(--tabbar-h) + env(safe-area-inset-bottom) + var(--s-8)); }
.page { width: 100%; max-width: var(--page-max); margin: 0 auto; padding: var(--s-6) var(--page-pad) var(--s-12); }
.page--wide { max-width: 1680px; }
.page--flush { max-width: none; padding: 0; }
.page-head { display: flex; flex-direction: column; gap: var(--s-3); margin-bottom: var(--s-6); }
.page-head__row { display: flex; align-items: flex-end; justify-content: space-between; gap: var(--s-4); flex-wrap: wrap; }
.page-head .lead { margin-top: var(--s-1); }
.breadcrumb { display: flex; align-items: center; gap: 6px; color: var(--text-faint); font-size: var(--fs-sm); }
.breadcrumb a:hover { color: var(--text); }

.section { margin-top: var(--s-12); }
.section__head { display: flex; align-items: flex-end; justify-content: space-between; gap: var(--s-4); margin-bottom: var(--s-4); flex-wrap: wrap; }
.section__head p { color: var(--text-muted); font-size: var(--fs-sm); max-width: 70ch; }

/* ---- Grid (12 columns ≥ md, 1 column below) ---------------------------- */
.grid { display: grid; gap: var(--gap); grid-template-columns: minmax(0, 1fr); }
.grid--2, .grid--3, .grid--4 { grid-template-columns: minmax(0, 1fr); }
.grid--kpi { grid-template-columns: repeat(2, minmax(0, 1fr)); }

/* ---- Two-column page with sticky section nav (station view) ---------- */
.with-aside { display: grid; gap: var(--s-8); grid-template-columns: minmax(0, 1fr); }
.section-nav { display: none; }
.section-nav__title { margin-bottom: var(--s-2); }
.section-nav a {
  display: block; padding: 6px 12px; border-left: 2px solid var(--border);
  color: var(--text-muted); font-size: var(--fs-sm); transition: color var(--dur-2), border-color var(--dur-2);
}
.section-nav a:hover { color: var(--text); }
.section-nav a[aria-current="true"] { color: var(--text); border-left-color: var(--accent); font-weight: 550; }

/* ---- Sticky sub-header (station name + pollutant tabs) ------------------ */
.subhead {
  position: sticky; top: var(--appbar-h); z-index: 30;
  margin: 0 calc(-1 * var(--page-pad)); padding: var(--s-3) var(--page-pad);
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  -webkit-backdrop-filter: var(--blur); backdrop-filter: var(--blur);
  border-bottom: 1px solid var(--divider);
}

/* ---- Footer ------------------------------------------------------------ */
.footer {
  border-top: 1px solid var(--border); color: var(--text-faint); font-size: var(--fs-sm);
  padding: var(--s-8) var(--page-pad) calc(var(--tabbar-h) + var(--s-8));
}
.footer__inner { max-width: var(--page-max); margin: 0 auto; display: flex; flex-wrap: wrap; gap: var(--s-4) var(--s-8); justify-content: space-between; }
.footer a { color: var(--text-muted); } .footer a:hover { color: var(--text); }

/* ---- View transitions -------------------------------------------------- */
.view { animation: view-in var(--dur-3) var(--ease) both; }
@keyframes view-in { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }
::view-transition-old(root), ::view-transition-new(root) { animation-duration: var(--dur-2); }

/* ======================= Breakpoints ======================= */
@media (min-width: 480px) {
  .search-trigger__label { display: inline; }
}
@media (min-width: 768px) {
  .grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .grid--3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .grid--4, .grid--kpi { grid-template-columns: repeat(4, minmax(0, 1fr)); }
  .grid--12 { grid-template-columns: repeat(12, minmax(0, 1fr)); }
  .span-3 { grid-column: span 3; } .span-4 { grid-column: span 4; } .span-5 { grid-column: span 5; }
  .span-6 { grid-column: span 6; } .span-7 { grid-column: span 7; } .span-8 { grid-column: span 8; }
  .span-12 { grid-column: 1 / -1; }
  .search-trigger { min-width: 220px; }
  .search-trigger kbd { display: inline-flex; margin-left: auto; }
}
@media (min-width: 1024px) {
  .nav { display: flex; }
  .tabbar { display: none; }
  .main { padding-bottom: var(--s-8); }
  .footer { padding-bottom: var(--s-8); }
  .grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
}
@media (min-width: 1280px) {
  .with-aside { grid-template-columns: minmax(0, 1fr) 200px; }
  .section-nav { display: block; position: sticky; top: calc(var(--appbar-h) + 96px); align-self: start; }
}
@media (max-width: 1023.98px) {
  .hide-mobile { display: none !important; }
}
@media (min-width: 1024px) {
  .hide-desktop { display: none !important; }
}