/* shell.css — app frame: left rail + top bar + content mount. builder-1 owns. */

.app {
  display: grid;
  grid-template-columns: var(--rail-w) 1fr;
  grid-template-rows: 100vh;
  min-height: 100vh;
}

/* ---- Left rail ---------------------------------------------------------- */
.rail {
  grid-column: 1;
  background: var(--surface-1);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  height: 100vh;
  position: sticky;
  top: 0;
  overflow-y: auto;
}

.rail__brand {
  display: flex;
  align-items: center;
  gap: var(--s3);
  padding: var(--s5) var(--s4) var(--s4);
}
.rail__mark {
  width: 30px; height: 30px; flex: none;
  border-radius: var(--r-1);
  display: grid; place-items: center;
  background: linear-gradient(150deg, var(--attack) 0%, #b8323f 52%, var(--player-a) 100%);
  box-shadow: var(--shadow-1);
}
.rail__mark svg { width: 17px; height: 17px; }
.rail__brand-text { display: flex; flex-direction: column; line-height: 1.15; }
.rail__title { font-family: var(--font-display); font-weight: var(--fw-semi); font-size: 0.95rem; letter-spacing: var(--ls-tight); }
.rail__sub   { font-family: var(--font-mono); font-size: var(--fs-xs); color: var(--ink-faint); letter-spacing: 0.02em; }

.rail__nav { display: flex; flex-direction: column; gap: 2px; padding: var(--s2) var(--s3); }
.rail__section-label {
  font-family: var(--font-mono); font-size: var(--fs-xs);
  letter-spacing: var(--ls-eyebrow); text-transform: uppercase;
  color: var(--ink-faint); padding: var(--s4) var(--s3) var(--s2);
}

.navitem {
  display: flex; align-items: center; gap: var(--s3);
  min-height: 44px; padding: 0 var(--s3);
  border-radius: var(--r-1);
  color: var(--ink-muted);
  font-size: var(--fs-body); font-weight: var(--fw-med);
  transition: background var(--dur-1) var(--ease), color var(--dur-1) var(--ease);
  position: relative;
}
.navitem:hover { background: var(--surface-2); color: var(--ink); }
.navitem__icon { width: 18px; height: 18px; flex: none; color: currentColor; opacity: 0.85; }
.navitem__icon svg { width: 100%; height: 100%; }
.navitem[aria-current="page"] {
  background: var(--surface-2);
  color: var(--ink);
}
.navitem[aria-current="page"]::before {
  content: ""; position: absolute; left: -1px; top: 50%; transform: translateY(-50%);
  width: 3px; height: 20px; border-radius: var(--r-pill);
  background: var(--gold);
}
.navitem[aria-current="page"] .navitem__icon { opacity: 1; color: var(--gold); }

.rail__spacer { flex: 1; }
.rail__foot { padding: var(--s3) var(--s3) var(--s5); border-top: 1px solid var(--border-faint); margin-top: var(--s3); }

/* ---- Top bar ------------------------------------------------------------ */
.main {
  grid-column: 2;
  display: flex;
  flex-direction: column;
  height: 100vh;
  overflow: hidden;
}
.topbar {
  height: var(--topbar-h); flex: none;
  border-bottom: 1px solid var(--border);
  background: color-mix(in srgb, var(--surface-1) 78%, transparent);
  backdrop-filter: blur(8px);
  display: flex; align-items: center; justify-content: space-between;
  padding: 0 var(--s6);
  gap: var(--s4);
  z-index: 5;
}
.topbar__crumbs { display: flex; align-items: center; gap: var(--s2); font-size: var(--fs-sm); color: var(--ink-faint); min-width: 0; }
.topbar__crumbs strong { color: var(--ink); font-weight: var(--fw-med); font-family: var(--font-display); }
.topbar__crumbs .sep { color: var(--border-strong); }

.content {
  flex: 1;
  overflow-y: auto;
  scroll-behavior: smooth;
}
.content__inner {
  max-width: var(--content-max);
  margin: 0 auto;
  padding: var(--s7) var(--s6) var(--s8);
}

/* Wide bleed for signature surfaces (Map Lab) */
.content__inner--wide { max-width: none; padding-left: var(--s6); padding-right: var(--s6); }

/* ---- Responsive: rail collapses under 900px ----------------------------- */
@media (max-width: 900px) {
  .app { grid-template-columns: 1fr; grid-template-rows: auto 1fr; }
  .rail {
    grid-column: 1; grid-row: 1;
    flex-direction: row; align-items: center; height: auto; position: static;
    overflow-x: auto; overflow-y: hidden;
    border-right: none; border-bottom: 1px solid var(--border);
  }
  .rail__brand { padding: var(--s3) var(--s4); }
  .rail__nav { flex-direction: row; padding: var(--s2); }
  .rail__section-label, .rail__spacer, .rail__foot { display: none; }
  .navitem { padding: 0 var(--s3); white-space: nowrap; }
  .navitem[aria-current="page"]::before { left: 50%; top: auto; bottom: -1px; transform: translateX(-50%); width: 20px; height: 3px; }
  .main { grid-column: 1; grid-row: 2; height: auto; }
  .content__inner { padding: var(--s5) var(--s4) var(--s7); }
  .topbar { padding: 0 var(--s4); }
}