/* App shell, page structure and responsive grids. Breakpoints: 48rem tablet, 64rem desktop. */
@layer layout {
  .app {
    display: grid;
    grid-template: "top top" auto "banner banner" auto "nav main" 1fr / var(--sidebar-width) minmax(
        0,
        1fr
      );
    min-height: 100vh;
  }

  .topbar {
    grid-area: top;
    position: sticky;
    top: 0;
    z-index: var(--z-sticky);
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: var(--space-2) var(--space-3);
    min-height: var(--topbar-height);
    padding: var(--space-2) var(--space-4);
    background: var(--color-surface);
    border-bottom: var(--border-width) solid var(--color-border);
  }

  .topbar__brand {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    color: var(--color-brand);
    font-weight: var(--weight-bold);
    text-decoration: none;
    white-space: nowrap;
  }

  .topbar__brand img {
    height: 1.75rem;
    width: auto;
  }

  .topbar__brand .logo-dark {
    display: none;
  }

  :root[data-theme="dark"] .topbar__brand .logo-light {
    display: none;
  }

  :root[data-theme="dark"] .topbar__brand .logo-dark {
    display: block;
  }

  @media (prefers-color-scheme: dark) {
    :root:not([data-theme="light"]) .topbar__brand .logo-light {
      display: none;
    }

    :root:not([data-theme="light"]) .topbar__brand .logo-dark {
      display: block;
    }
  }

  .topbar__areas {
    display: flex;
    gap: var(--space-1);
    margin-left: var(--space-3);
  }

  .topbar__areas a {
    padding: var(--space-2) var(--space-3);
    border-radius: var(--radius-sm);
    color: var(--color-text-muted);
    font-size: var(--size-14);
    font-weight: var(--weight-medium);
    text-decoration: none;
    white-space: nowrap;
  }

  .topbar__areas a[aria-current="true"] {
    background: var(--color-brand-soft);
    color: var(--color-brand);
  }

  .topbar__controls {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: flex-end;
    gap: var(--space-2) var(--space-3);
    min-width: 0;
    margin-left: auto;
  }

  .topbar__controls label {
    display: flex;
    align-items: center;
    gap: var(--space-1);
    font-size: var(--size-12);
    color: var(--color-text-muted);
  }

  .topbar__controls select {
    max-width: 12rem;
    padding: var(--space-1) var(--space-2);
    background: var(--color-surface);
    border: var(--border-width) solid var(--color-border-strong);
    border-radius: var(--radius-sm);
    font-size: var(--size-14);
  }

  .topbar__menu {
    display: none;
  }

  .persona-chip {
    padding: var(--space-1) var(--space-2);
    border-radius: var(--radius-pill);
    background: var(--color-accent-soft);
    color: var(--color-accent-text);
    font-size: var(--size-12);
    font-weight: var(--weight-semibold);
    white-space: nowrap;
  }

  .demo-banner {
    grid-area: banner;
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-2) var(--space-4);
    justify-content: center;
    padding: var(--space-1) var(--space-4);
    background: var(--color-synthetic-bg);
    color: var(--color-synthetic-text);
    font-size: var(--size-12);
    font-weight: var(--weight-semibold);
    text-align: center;
  }

  .sidenav {
    grid-area: nav;
    position: sticky;
    top: var(--topbar-height);
    align-self: start;
    height: calc(100vh - var(--topbar-height));
    overflow-y: auto;
    padding: var(--space-4) var(--space-3);
    background: var(--color-nav-bg);
  }

  .sidenav h2 {
    margin: var(--space-4) var(--space-2) var(--space-2);
    color: var(--color-nav-text);
    font-size: var(--size-12);
    font-weight: var(--weight-semibold);
    letter-spacing: 0.06em;
    text-transform: uppercase;
  }

  .sidenav h2:first-child {
    margin-top: 0;
  }

  .sidenav ul {
    margin: 0;
    padding: 0;
    list-style: none;
  }

  .sidenav a {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    padding: var(--space-2) var(--space-3);
    border-radius: var(--radius-sm);
    color: var(--color-nav-text);
    font-size: var(--size-14);
    text-decoration: none;
  }

  .sidenav a:hover {
    background: var(--color-nav-active-bg);
    color: var(--color-nav-active-text);
  }

  .sidenav a[aria-current="page"] {
    background: var(--color-nav-active-bg);
    color: var(--color-nav-active-text);
    font-weight: var(--weight-semibold);
    box-shadow: inset 3px 0 0 var(--color-accent);
  }

  .sidenav .icon {
    flex: none;
  }

  .sidenav :focus-visible {
    outline-color: var(--color-accent);
  }

  .main {
    grid-area: main;
    min-width: 0;
    padding: var(--space-5) var(--space-5) var(--space-8);
  }

  .main > .page {
    max-width: var(--content-max);
    margin: 0 auto;
  }

  .page-header {
    display: flex;
    flex-wrap: wrap;
    align-items: flex-end;
    justify-content: space-between;
    gap: var(--space-3);
    margin-bottom: var(--space-5);
  }

  .page-header h1 {
    margin: 0;
    font-size: var(--size-30);
  }

  .page-header__subtitle {
    margin: var(--space-1) 0 0;
    color: var(--color-text-muted);
  }

  .page-header__actions {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-2);
  }

  .breadcrumb {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-1);
    margin: 0 0 var(--space-2);
    padding: 0;
    list-style: none;
    font-size: var(--size-14);
    color: var(--color-text-muted);
  }

  .breadcrumb li + li::before {
    content: "/";
    margin-right: var(--space-1);
    color: var(--color-text-subtle);
  }

  .section {
    margin-top: var(--space-6);
  }

  .section > h2 {
    font-size: var(--size-20);
  }

  .grid {
    display: grid;
    gap: var(--space-4);
  }

  .grid--2 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .grid--3 {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .grid--4 {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .grid--auto {
    grid-template-columns: repeat(auto-fill, minmax(15rem, 1fr));
  }

  .grid--wide-narrow {
    grid-template-columns: minmax(0, 2fr) minmax(0, 1fr);
  }

  .span-2 {
    grid-column: span 2;
  }

  .stack > * + * {
    margin-top: var(--space-4);
  }

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

  @media (width < 90rem) {
    .persona-chip {
      display: none;
    }

    .grid--4 {
      grid-template-columns: repeat(2, minmax(0, 1fr));
    }
  }

  @media (width < 64rem) {
    .grid--3,
    .grid--wide-narrow {
      grid-template-columns: minmax(0, 1fr);
    }

    .topbar__areas {
      display: none;
    }

    .persona-chip {
      display: none;
    }

    .topbar__controls {
      min-width: 0;
    }
  }

  @media (width < 48rem) {
    .app {
      grid-template-columns: minmax(0, 1fr);
      grid-template-areas:
        "top"
        "banner"
        "main";
    }

    .sidenav {
      position: fixed;
      inset: 0 auto 0 0;
      z-index: var(--z-drawer);
      width: min(18rem, 85vw);
      height: auto;
      transform: translateX(-100%);
      transition: transform var(--duration-base) var(--easing-standard);
      box-shadow: var(--shadow-2);
      visibility: hidden;
    }

    .app[data-nav-open="true"] .sidenav {
      transform: translateX(0);
      visibility: visible;
    }

    .topbar {
      flex-wrap: wrap;
      row-gap: var(--space-1);
    }

    .topbar__menu {
      display: inline-flex;
    }

    .topbar__controls {
      flex: 1 1 100%;
      gap: var(--space-2);
      margin-left: 0;
    }

    .topbar__controls label {
      flex: 1 1 0;
      min-width: 0;
    }

    .topbar__controls select {
      width: 100%;
      max-width: none;
    }

    .topbar__controls .control-label-text {
      position: absolute;
      width: 1px;
      height: 1px;
      overflow: hidden;
      clip-path: inset(50%);
    }

    .persona-chip {
      display: none;
    }

    .main {
      padding: var(--space-4) var(--space-3) var(--space-7);
    }

    .grid--2,
    .grid--4 {
      grid-template-columns: minmax(0, 1fr);
    }

    .span-2 {
      grid-column: auto;
    }

    .page-header h1 {
      font-size: var(--size-24);
    }
  }
}