*, *::before, *::after { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
}

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

.app-header {
  height: var(--header-height);
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--spacing-lg);
  flex-shrink: 0;
  z-index: 100;
}

.app-header__brand {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.app-header__logo {
  width: 28px;
  height: 28px;
  background: var(--color-primary);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-weight: 700;
  font-size: var(--font-size-sm);
}

.app-header__title {
  font-size: var(--font-size-md);
  font-weight: 600;
  color: var(--color-text);
  margin: 0;
}

.app-header__subtitle {
  font-size: var(--font-size-xs);
  color: var(--color-text-secondary);
  margin-left: var(--spacing-xs);
}

.app-header__auth {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.app-body {
  display: flex;
  flex: 1;
  overflow: hidden;
}

.app-sidebar {
  width: var(--sidebar-width);
  background: var(--color-surface);
  border-right: 1px solid var(--color-border);
  display: flex;
  flex-direction: column;
  flex-shrink: 0;
  overflow-y: auto;
}

.app-sidebar__nav {
  padding: var(--spacing-sm) 0;
}

.nav-group__label {
  padding: var(--spacing-sm) var(--spacing-lg) var(--spacing-xs);
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  font-weight: 500;
}

.nav-item {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: 7px var(--spacing-lg);
  margin: 1px var(--spacing-sm);
  border-radius: var(--radius-md);
  color: var(--color-text-secondary);
  text-decoration: none;
  font-size: var(--font-size-base);
  cursor: pointer;
  transition: all var(--transition);
  border: none;
  background: none;
  width: calc(100% - var(--spacing-md));
  text-align: left;
}

.nav-item:hover {
  background: var(--color-surface-hover);
  color: var(--color-text);
}

.nav-item.active {
  background: var(--color-primary-light);
  color: var(--color-primary);
  font-weight: 500;
}

.nav-item__icon {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
  opacity: 0.7;
}

.nav-item.active .nav-item__icon {
  opacity: 1;
}

.app-main {
  flex: 1;
  overflow-y: auto;
  padding: var(--spacing-md) var(--spacing-lg);
}

.page-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--spacing-md);
  min-height: 32px;
}

.page-header__title {
  font-size: var(--font-size-lg);
  font-weight: 600;
  margin: 0;
  color: var(--color-text);
}

.page-header__desc {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  margin: 2px 0 0;
}

.page-header__actions {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.page-content {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.app-main--no-scroll {
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

.page-viewport-fill {
  flex: 1;
  min-height: 0;
  display: flex;
  flex-direction: column;
}

.page-viewport-fill .page-content {
  flex: 1;
  min-height: 0;
  display: flex;
  flex-direction: column;
}

@media (max-width: 768px) {
  .app-sidebar {
    position: fixed;
    left: -100%;
    top: var(--header-height);
    bottom: 0;
    z-index: 200;
    transition: left var(--transition);
    box-shadow: var(--shadow-md);
  }
  .app-sidebar.open { left: 0; }
  .app-main { padding: var(--spacing-sm); }
  .page-content > [style*="grid-template-columns:1fr 1fr"] {
    grid-template-columns: 1fr !important;
  }
}