/* =========================================================
   LAYOUT — header, sidebar, bottom navigation, content grid
   Mobile-first; desktop overrides at the bottom.
   ========================================================= */

.app-shell {
  min-height: 100vh;
  width: 100%;
  max-width: 100vw;
  overflow-x: hidden;
  display: flex;
  flex-direction: column;
}

/* ---- Mobile header (Section 11) ---- */
.app-header {
  position: sticky;
  top: 0;
  z-index: 40;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-height);
  padding: 0 var(--space-4);
  padding-top: var(--safe-top);
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
}

.app-header__brand {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font: var(--text-card-heading);
}

.app-header__brand img { height: 28px; width: auto; }

.app-header__actions { display: flex; align-items: center; gap: var(--space-2); }

.icon-btn {
  width: 40px; height: 40px;
  border-radius: var(--radius-pill);
  display: flex; align-items: center; justify-content: center;
  color: var(--color-text-secondary);
  transition: background var(--transition-fast);
}
.icon-btn:hover { background: var(--color-surface-alt); }

/* ---- Main content area ---- */
.app-main {
  flex: 1;
  width: 100%;
  max-width: var(--max-content-width);
  margin: 0 auto;
  padding: var(--space-4);
  padding-bottom: calc(var(--bottom-nav-height) + var(--safe-bottom) + var(--space-6));
  overflow-x: hidden;
  box-sizing: border-box;
}

/* ---- Bottom navigation (mobile, Section 9) ---- */
.bottom-nav {
  position: fixed;
  left: 0; right: 0; bottom: 0;
  z-index: 50;
  display: flex;
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding-bottom: var(--safe-bottom);
  box-shadow: 0 -4px 16px rgba(20, 33, 61, 0.06);
}

.bottom-nav__item {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 2px;
  padding: var(--space-2) 0;
  min-height: 56px;
  color: var(--color-muted);
  font: var(--text-meta);
  transition: color var(--transition-fast);
}

.bottom-nav__item svg { width: 22px; height: 22px; stroke-width: 2px; }

.bottom-nav__item.is-active { color: var(--color-primary); }
.bottom-nav__item.is-active svg { stroke: var(--color-primary); }

/* ---- Desktop sidebar (Section 10) ---- */
.sidebar {
  display: none;
}

/* ---- More / slide-over menu (Section 26) ---- */
.sheet-overlay {
  position: fixed; inset: 0;
  background: rgba(11, 20, 40, 0.45);
  z-index: 60;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-base);
}
.sheet-overlay.is-open { opacity: 1; pointer-events: auto; }

.sheet {
  position: fixed;
  right: 0; top: 0; bottom: 0;
  width: min(360px, 88vw);
  background: var(--color-surface);
  z-index: 61;
  transform: translateX(100%);
  transition: transform var(--transition-slow);
  overflow-y: auto;
  padding: var(--space-6) var(--space-5);
  padding-top: calc(var(--space-6) + var(--safe-top));
}
.sheet.is-open { transform: translateX(0); }

.sheet__section-label {
  font: var(--text-meta);
  color: var(--color-muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  margin: var(--space-5) 0 var(--space-2);
}

.sheet__link {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3) var(--space-2);
  border-radius: var(--radius-md);
  color: var(--color-text);
  font: var(--text-body-medium);
  transition: background var(--transition-fast);
}
.sheet__link:hover { background: var(--color-surface-alt); }
.sheet__link svg { width: 20px; height: 20px; color: var(--color-secondary); }

/* ---- Offline banner (Section 30) ---- */
.offline-banner {
  display: none;
  align-items: center;
  gap: var(--space-2);
  background: var(--color-warning-light);
  color: var(--color-warning);
  font: var(--text-meta);
  padding: var(--space-2) var(--space-4);
  text-align: center;
  justify-content: center;
}
.offline-banner.is-visible { display: flex; }

/* =========================================================
   DESKTOP (>= 1024px): sidebar layout replaces bottom nav
   ========================================================= */
@media (min-width: 1024px) {
  .app-shell { flex-direction: row; }

  .app-header { display: none; }

  .bottom-nav { display: none; }

  .sidebar {
    display: flex;
    flex-direction: column;
    width: var(--sidebar-width);
    flex-shrink: 0;
    height: 100vh;
    position: sticky;
    top: 0;
    background: var(--color-surface);
    border-right: 1px solid var(--color-border);
    padding: var(--space-6) var(--space-4);
  }

  .sidebar__brand {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    padding: 0 var(--space-2) var(--space-6);
  }
  .sidebar__brand img { height: 36px; }
  .sidebar__brand-text { font: 700 15px/1.3 var(--font-family); color: var(--color-primary); }

  .sidebar__nav { flex: 1; display: flex; flex-direction: column; gap: 2px; }

  .sidebar__link {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    padding: var(--space-3) var(--space-3);
    border-radius: var(--radius-md);
    color: var(--color-text-secondary);
    font: var(--text-body-medium);
    transition: background var(--transition-fast), color var(--transition-fast);
  }
  .sidebar__link svg { width: 20px; height: 20px; }
  .sidebar__link:hover { background: var(--color-surface-alt); color: var(--color-text); }
  .sidebar__link.is-active {
    background: var(--color-primary-light);
    color: var(--color-primary);
    font-weight: 600;
  }

  .sidebar__footer {
    border-top: 1px solid var(--color-border);
    padding-top: var(--space-4);
    display: flex;
    align-items: center;
    gap: var(--space-3);
  }

  .app-main {
    padding: var(--space-8) var(--space-10);
    padding-bottom: var(--space-10);
  }

  /* desktop top bar within main content (search / notifications / avatar) */
  .desktop-topbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--space-8);
  }
}

@media (max-width: 1023px) {
  .desktop-topbar { display: none; }
}