.app-container {
  display: flex;
  flex-direction: column;
  height: 100vh;
  overflow: hidden;
}

.app-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 60px;
  background: var(--surface);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0 24px;
  z-index: 100;
}

.app-content {
  flex: 1;
  overflow-y: auto;
  padding: 84px 24px 88px 24px; /* padding top/bottom to clear headers/nav */
}

.nav-bar {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  height: 64px;
  background: var(--surface);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: space-around;
  align-items: center;
  padding-bottom: env(safe-area-inset-bottom);
  z-index: 100;
}

.nav-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  color: var(--text-tertiary);
  cursor: pointer;
  transition: color var(--transition-fast);
  text-decoration: none;
}

.nav-item:hover, .nav-item.active {
  color: var(--accent);
}

.nav-item span {
  font-size: 0.75rem;
  font-weight: 600;
}

.page {
  display: none;
}

.page.active {
  display: block;
  animation: fadeIn 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Utilities */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.flex-between {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.flex-center {
  display: flex;
  justify-content: center;
  align-items: center;
}

.flex-col {
  display: flex;
  flex-direction: column;
}

.gap-sm { gap: 8px; }
.gap-md { gap: 16px; }
.gap-lg { gap: 24px; }

/* Responsive */
@media (max-width: 768px) {
  .grid-2, .grid-3 {
    grid-template-columns: 1fr;
  }
  .app-content {
    padding: 76px 16px 80px 16px;
  }
}