@layer base {
  *,
  *::before,
  *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
  }

  html,
  body {
    height: 100%;
    background-color: var(--color-bg-primary);
    color: var(--color-text-primary);
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
  }

  #app {
    height: 100vh;
    overflow: hidden;
  }

  .app-layout {
    display: grid;
    grid-template-columns: var(--sidebar-width) 1fr;
    grid-template-rows: 1fr;
    height: 100vh;
    overflow: hidden;
  }

  .app-sidebar {
    grid-column: 1;
    grid-row: 1;
    background-color: var(--color-bg-secondary);
    border-right: 1px solid var(--color-border);
    display: flex;
    flex-direction: column;
    overflow: hidden;
    transition:
      transform var(--transition-slow),
      width var(--transition-slow);
    z-index: 20;
  }

  .app-content {
    grid-column: 2;
    grid-row: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    min-width: 0;
  }

  .app-header {
    height: var(--header-height);
    min-height: var(--header-height);
    background-color: var(--color-bg-secondary);
    border-bottom: 1px solid var(--color-border);
    display: flex;
    align-items: center;
    padding: 0 1rem;
    gap: 0.75rem;
    flex-shrink: 0;
    z-index: 10;
  }

  .app-main {
    flex: 1;
    overflow-y: auto;
    overflow-x: hidden;
    background-color: var(--color-bg-primary);
  }

  /* Sidebar collapsed state */
  .sidebar-collapsed .app-layout {
    grid-template-columns: 0 1fr;
  }

  .sidebar-collapsed .app-sidebar {
    width: 0;
    overflow: hidden;
  }

  /* Mobile: sidebar as drawer */
  @media (max-width: 768px) {
    .app-layout {
      grid-template-columns: 1fr;
    }
    .app-content {
      grid-column: 1;
    }
    .app-sidebar {
      position: fixed;
      top: 0;
      left: 0;
      height: 100vh;
      width: var(--sidebar-width);
      transform: translateX(-100%);
      box-shadow: var(--shadow-lg);
    }
    .sidebar-open .app-sidebar {
      transform: translateX(0);
    }
  }

  /* Scrollbar */
  ::-webkit-scrollbar {
    width: 6px;
    height: 6px;
  }
  ::-webkit-scrollbar-track {
    background: transparent;
  }
  ::-webkit-scrollbar-thumb {
    background: var(--color-border);
    border-radius: 3px;
  }
  ::-webkit-scrollbar-thumb:hover {
    background: var(--color-text-tertiary);
  }
}