/* ==========================================================================
   Layout — application shell
   Desktop : [ rail | appbar ]   Mobile : appbar / stage / rail (bottom tabs)
              [ rail | stage  ]
   ========================================================================== */

.shell {
  display: grid;
  grid-template-columns: var(--rail-w) minmax(0, 1fr);
  grid-template-rows: var(--appbar-h) minmax(0, 1fr);
  grid-template-areas:
    "rail appbar"
    "rail stage";
  min-height: 100vh;
  min-height: 100dvh;
}

/* ---------- app bar ---------- */
.appbar {
  grid-area: appbar;
  position: sticky;
  top: 0;
  z-index: 30;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--s-4);
  padding: 0 clamp(16px, 3vw, 34px);
  padding-top: env(safe-area-inset-top);
  height: calc(var(--appbar-h) + env(safe-area-inset-top));
  border-bottom: 1px solid var(--line);
  background: var(--bg);
  background: color-mix(in srgb, var(--bg) 78%, transparent);
  backdrop-filter: saturate(1.4) blur(16px);
}

.brand { display: inline-flex; align-items: center; gap: 11px; }
.brand-mark {
  display: grid;
  place-items: center;
  width: 34px;
  height: 34px;
  border-radius: 11px;
  background: var(--accent);
  background: linear-gradient(150deg, var(--accent), color-mix(in srgb, var(--accent) 62%, var(--ok)));
  color: var(--accent-on);
  box-shadow: 0 6px 18px var(--accent-ring);
}
.brand-mark .icon { width: 18px; height: 18px; stroke-width: 2; }
.brand-text strong {
  display: block;
  font-size: 14px;
  font-weight: 750;
  letter-spacing: .1em;
}
.brand-text small {
  display: block;
  margin-top: 1px;
  color: var(--ink-3);
  font-size: 10px;
  font-weight: 600;
  letter-spacing: .16em;
  text-transform: uppercase;
}

.appbar-end { display: flex; align-items: center; gap: var(--s-2); min-width: 0; }

/* ---------- rail / bottom tabs ---------- */
.rail {
  grid-area: rail;
  position: sticky;
  top: 0;
  align-self: start;
  z-index: 40;
  display: flex;
  flex-direction: column;
  gap: 6px;
  height: 100vh;
  height: 100dvh;
  padding: calc(var(--s-4) + env(safe-area-inset-top)) 10px var(--s-4);
  border-right: 1px solid var(--line);
  background: var(--surface);
  background: color-mix(in srgb, var(--surface) 55%, transparent);
  backdrop-filter: blur(14px);
}

.rail-tab {
  position: relative;
  display: grid;
  gap: 5px;
  justify-items: center;
  padding: 11px 4px 9px;
  border-radius: var(--r-md);
  color: var(--ink-3);
  font-size: 11px;
  font-weight: 620;
  transition: color var(--fast), background var(--fast);
}
.rail-tab .icon { width: 21px; height: 21px; }
.rail-tab:hover { color: var(--ink); background: var(--surface-3); }
.rail-tab.is-active { color: var(--accent); background: var(--accent-soft); }
.rail-tab.is-active::before {
  content: "";
  position: absolute;
  left: -10px;
  top: 50%;
  width: 3px;
  height: 22px;
  border-radius: 0 3px 3px 0;
  background: var(--accent);
  transform: translateY(-50%);
}
.rail-badge {
  position: absolute;
  top: 6px;
  right: calc(50% - 22px);
  min-width: 17px;
  padding: 0 5px;
  border-radius: var(--r-pill);
  background: var(--accent);
  color: var(--accent-on);
  font-size: 10px;
  font-style: normal;
  font-weight: 700;
  line-height: 17px;
  text-align: center;
}

/* ---------- stage ---------- */
.stage {
  grid-area: stage;
  min-width: 0;
  padding: clamp(20px, 3.2vw, 38px) clamp(16px, 3vw, 34px) var(--s-7);
}

.view {
  width: min(100%, var(--stage-max));
  margin: 0 auto;
  display: grid;
  gap: var(--s-5);
  align-content: start;
}
.view.is-active { animation: view-in .26s var(--ease) both; }
@keyframes view-in {
  from { opacity: 0; transform: translateY(6px); }
}

.view-head {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: var(--s-4);
}
.view-head h1 {
  margin-top: 4px;
  font-size: clamp(24px, 3.4vw, 30px);
  font-weight: 740;
  letter-spacing: -.02em;
}

/* ==========================================================================
   Responsive — below 860px the rail becomes a bottom tab bar
   ========================================================================== */
@media (max-width: 860px) {
  .shell {
    grid-template-columns: minmax(0, 1fr);
    grid-template-rows: auto minmax(0, 1fr) auto;
    grid-template-areas: "appbar" "stage" "rail";
  }

  .rail {
    position: fixed;
    inset: auto 0 0 0;
    flex-direction: row;
    align-self: stretch;
    height: auto;
    padding: 6px 8px calc(6px + env(safe-area-inset-bottom));
    border-right: 0;
    border-top: 1px solid var(--line);
    background: var(--bg);
    background: color-mix(in srgb, var(--bg) 86%, transparent);
  }
  .rail-tab { flex: 1; padding: 7px 4px 5px; font-size: 10px; }
  .rail-tab.is-active { background: transparent; }
  .rail-tab.is-active::before {
    left: 50%;
    top: 0;
    width: 22px;
    height: 3px;
    border-radius: 0 0 3px 3px;
    transform: translateX(-50%);
  }
  .rail-badge { right: calc(50% - 20px); top: 2px; }

  .stage { padding: var(--s-5) var(--s-4) calc(var(--tabbar-h) + var(--s-6) + env(safe-area-inset-bottom)); }
  .view { gap: var(--s-4); }
}

@media (max-width: 460px) {
  .appbar { padding-inline: var(--s-4); gap: var(--s-2); }
  .brand-text small { display: none; }
  .view-head { align-items: flex-start; }
}

@media (max-width: 360px) {
  .brand-text { display: none; }
}