/* ============================================
   UI Layout V1.0 — App Shell & Page Structure
   Aplica cuando body tiene .ui-shell.
   Sin .ui-shell, estos estilos son inertes
   (feature flag CSS-only).
   ============================================ */

/* === App Shell (grid sidebar + main) === */
body.ui-shell {
  display: grid;
  grid-template-columns: var(--ui-sidebar-w) 1fr;
  min-height: 100vh;
  background: var(--ui-bg);
}

/* === Sidebar enhancements (when shell active) === */
body.ui-shell > .sidebar {
  position: sticky;
  top: 0;
  height: 100vh;
  overflow-y: auto;
  background: radial-gradient(1200px 600px at 30% 10%, rgba(109, 74, 255, 0.08), transparent 55%),
              linear-gradient(180deg, var(--ui-sb-bg), var(--ui-sb-bg-2));
  border-right: 1px solid var(--ui-sb-border);
  color: var(--ui-sb-text);
  padding: var(--ui-s-5) var(--ui-s-4);
  width: auto;
  scrollbar-width: thin;
  scrollbar-color: rgba(255, 255, 255, 0.12) transparent;
}

body.ui-shell > .sidebar::-webkit-scrollbar { width: 4px; }
body.ui-shell > .sidebar::-webkit-scrollbar-track { background: transparent; }
body.ui-shell > .sidebar::-webkit-scrollbar-thumb { background: rgba(255, 255, 255, 0.12); border-radius: 4px; }

/* Nav item upgrade (when shell active) */
body.ui-shell .nav-buttons button {
  border-radius: 12px;
  border: 1px solid transparent;
  transition: all 150ms ease;
  font-size: var(--ui-text-md);
}

body.ui-shell .nav-buttons button:hover {
  background: var(--ui-sb-hover-bg);
}

body.ui-shell .nav-buttons button.active {
  background: var(--ui-sb-active-bg);
  border-color: var(--ui-sb-active-border);
}

body.ui-shell .nav-label {
  font-size: var(--ui-text-xs);
  letter-spacing: 0.10em;
  color: var(--ui-sb-muted);
}

/* === Main content area === */
body.ui-shell > .main-content {
  display: grid;
  grid-template-rows: auto 1fr;
  margin-left: 0 !important;
  width: auto;
  min-width: 0;
}

/* === Topbar enhancements === */
body.ui-shell .topbar {
  height: var(--ui-topbar-h);
  display: flex;
  align-items: center;
  padding: 0 var(--ui-s-6);
  background: rgba(255, 255, 255, 0.65);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--ui-border);
  position: sticky;
  top: 0;
  z-index: 100;
}

/* === Content area === */
body.ui-shell .content {
  padding: var(--ui-s-7) var(--ui-s-6);
}

/* === Page wrapper === */
.ui-page {
  max-width: var(--ui-content-max);
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: var(--ui-s-5);
}

.ui-page__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--ui-s-4);
}

.ui-page__title {
  font-size: var(--ui-text-2xl);
  font-weight: 700;
  color: var(--ui-text);
  line-height: var(--ui-lh-tight);
  margin: 0;
}

/* === Grid layouts === */
.ui-grid-2 {
  display: grid;
  grid-template-columns: 1fr 360px;
  gap: var(--ui-s-5);
  align-items: start;
}

.ui-grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--ui-s-5);
}

.ui-grid-auto {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: var(--ui-s-5);
}

/* === Responsive === */
@media (max-width: 1100px) {
  body.ui-shell {
    grid-template-columns: 240px 1fr;
  }
  .ui-grid-2 { grid-template-columns: 1fr; }
  .ui-grid-3 { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  body.ui-shell {
    grid-template-columns: 1fr;
  }
  body.ui-shell > .sidebar {
    display: none;
  }
  .ui-grid-3 { grid-template-columns: 1fr; }
}

/* === Wizard header === */
.ui-wizard-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--ui-s-5);
}

.ui-wizard-steps {
  display: flex;
  align-items: center;
  gap: var(--ui-s-2);
}