.app-header {
  position: sticky;
  top: 0;
  height: var(--header-height);
  z-index: var(--z-header);
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  padding: 0 var(--space-lg);
  box-shadow: var(--shadow-sm);
}

.header-inner {
  display: flex;
  align-items: center;
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  gap: var(--space-md);
}

.header-logo {
  font-size: var(--font-size-xl);
  font-weight: 700;
  color: var(--color-primary);
  white-space: nowrap;
}

.header-logo span {
  font-weight: 300;
  color: var(--color-text-secondary);
}

.header-breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  flex: 1;
  min-width: 0;
}

.header-breadcrumb a {
  color: var(--color-primary);
  white-space: nowrap;
}

.header-breadcrumb a:hover {
  text-decoration: underline;
}

.header-breadcrumb .separator {
  color: var(--color-text-muted);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.app-main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--space-xl) var(--space-lg);
  min-height: calc(100vh - var(--header-height) - 80px);
}

.app-footer {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--space-lg);
  text-align: center;
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
}

.card-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-lg);
}

@media (min-width: 576px) {
  .card-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 992px) {
  .card-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.page-title {
  font-size: var(--font-size-2xl);
  font-weight: 700;
  margin-bottom: var(--space-xs);
}

.page-subtitle {
  font-size: var(--font-size-base);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-2xl);
}

.loading-screen {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 50vh;
  gap: var(--space-md);
  color: var(--color-text-secondary);
}

.spinner {
  width: 32px;
  height: 32px;
  border: 3px solid var(--color-border);
  border-top-color: var(--color-primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

.section-title {
  font-size: var(--font-size-lg);
  font-weight: 600;
  margin-bottom: var(--space-md);
  padding-bottom: var(--space-sm);
  border-bottom: 2px solid var(--color-primary);
  display: inline-block;
}

.flex-row {
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

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

.gap-sm { gap: var(--space-sm); }
.gap-md { gap: var(--space-md); }
.gap-lg { gap: var(--space-lg); }

.header-actions { margin-left: auto; flex-shrink: 0; }
.header-breadcrumb { overflow: hidden; }
.breadcrumb-current { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
@media (max-width: 600px) {
  .app-header { height: auto; min-height: var(--header-height); padding: 8px 16px; }
  .header-inner { flex-wrap: wrap; gap: 4px 12px; }
  .header-breadcrumb:not(:empty) { order: 3; flex-basis: 100%; padding: 4px 0; }
  .header-breadcrumb:empty { display: none; }
  .header-actions { gap: 0; }
  .app-main { padding: 24px 16px; }
  .toast-container { left: 16px; right: 16px; }
  .toast { max-width: 100%; }
}
@media (max-width: 600px) {
  .header-actions { flex-wrap: wrap; }
  .header-actions .btn-sm { padding-left: 8px; padding-right: 8px; }
}