@layer layout {
  .site-header {
    position: sticky;
    z-index: 50;
    top: 0.75rem;
    display: flex;
    justify-content: center;
    padding-inline: 1rem;
    pointer-events: none;
  }

  .site-header-inner {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    width: fit-content;
    max-width: min(1160px, 100%);
    padding: 0.65rem 0.85rem;
    border-radius: var(--radius-pill);
    background: #ffffff;
    pointer-events: auto;
  }

  .brand {
    display: flex;
    align-items: center;
    gap: 0.55rem;
    font-family: var(--font-sans);
    font-weight: 800;
    font-size: var(--type-callout);
    letter-spacing: -0.02em;
  }

  .brand img { border-radius: var(--radius-sm); }

  .site-header nav {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.9rem;
    font-weight: 700;
  }

  .mobile-nav { display: none; position: relative; }
  .mobile-nav summary { display: flex; align-items: center; min-height: 2.75rem; cursor: pointer; list-style: none; padding: 0.4rem 0.55rem; border-radius: var(--radius-pill); }
  .mobile-nav summary::-webkit-details-marker { display: none; }
  .mobile-nav[open] > div { position: absolute; top: calc(100% + 0.5rem); right: 0; min-width: 7rem; border: 1px solid var(--line); border-radius: var(--radius-sm); padding: 0.5rem; background: #ffffff; }
  .mobile-nav[open] a { display: block; padding: 0.4rem; }

  .site-header nav > a:not(.button),
  .site-header nav > form > .link-button {
    padding: 0.4rem 0.7rem;
    border-radius: var(--radius-pill);
    transition: background 0.2s ease;
  }

  .site-header nav > a:not(.button):hover,
  .site-header nav > form > .link-button:hover {
    background: var(--blue);
  }

  .site-header nav > form > .link-button {
    font-size: 0.9rem;
    font-weight: 700;
  }

  .site-header form { display: contents; }

  .app-layout { display: grid; grid-template-columns: 16rem minmax(0, 1fr); gap: 1rem; min-height: 100vh; padding: 1rem; transition: grid-template-columns 260ms cubic-bezier(.22, 1, .36, 1); }
  .app-layout:has(.app-sidebar.is-collapsed) { grid-template-columns: 4.5rem minmax(0, 1fr); }
  .app-shell { background: var(--app-background); }
  .app-main { min-width: 0; }
  .app-sidebar { position: sticky; top: 1rem; display: flex; flex-direction: column; justify-content: space-between; min-height: calc(100vh - 2rem); max-height: calc(100vh - 2rem); overflow-y: auto; border-radius: var(--radius-lg); background: var(--sidebar-background); padding: 1.5rem 1rem; transition: padding 260ms cubic-bezier(.22, 1, .36, 1); }
  .app-sidebar-header { display: flex; align-items: center; justify-content: space-between; gap: 0.5rem; }
  .app-sidebar .brand { min-width: 0; width: fit-content; padding-inline: 0.5rem; transition: transform 260ms cubic-bezier(.22, 1, .36, 1); }
  .app-sidebar .brand img { object-fit: contain; }
  .sidebar-toggle { display: grid; width: 2rem; height: 2rem; flex: 0 0 auto; place-items: center; border: 0; border-radius: 50%; background: transparent; color: var(--muted); font: inherit; font-size: 1.1rem; cursor: pointer; transition: background 180ms ease, color 180ms ease, transform 260ms cubic-bezier(.22, 1, .36, 1); }
  .sidebar-toggle img[hidden] { display: none; }
  .sidebar-toggle:hover { background: var(--blue); color: var(--ink); transform: scale(1.1); }
  .app-sidebar-nav { display: grid; gap: 0.5rem; margin-top: 2.5rem; }
  .app-nav-link { display: flex; align-items: center; gap: 0.75rem; min-height: 3rem; overflow: hidden; border-radius: var(--radius-sm); padding: 0.75rem; color: var(--ink); font-size: 0.9rem; font-weight: 800; transition: background 180ms cubic-bezier(.22, 1, .36, 1), gap 260ms cubic-bezier(.22, 1, .36, 1), padding 260ms cubic-bezier(.22, 1, .36, 1); }
  .app-nav-link:hover { background: var(--blue); }
  .app-nav-link.active { background: var(--progress); }
  .app-nav-link > img { width: 1.25rem; height: 1.25rem; }
  .app-sidebar-bottom { display: grid; gap: 1rem; margin-top: 2.5rem; }
  .app-sidebar-plan { display: grid; gap: 0.35rem; border-radius: var(--radius); background: var(--blue); padding: 1rem; }
  .app-sidebar-plan strong { font-size: 0.9rem; }
  .app-sidebar-plan span { color: var(--muted); font-size: var(--type-caption); }
  .app-sidebar-plan a { width: fit-content; margin-top: 0.35rem; color: var(--primary-hover); font-size: 0.8rem; font-weight: 800; text-decoration: underline; text-underline-offset: 3px; }
  .app-mobile-header { display: none; }
  .app-sidebar.is-collapsed { padding-inline: 0.75rem; }
  .app-sidebar.is-collapsed .app-sidebar-header { justify-content: center; flex-direction: column; }
  .app-sidebar.is-collapsed .brand { transform: translateX(-0.1rem); }
  .app-sidebar.is-collapsed .brand span, .app-sidebar.is-collapsed .app-nav-link span, .app-sidebar.is-collapsed .app-sidebar-plan { display: none; }
  .app-sidebar.is-collapsed .app-nav-link { justify-content: center; padding-inline: 0.5rem; }
  .app-sidebar.is-collapsed .sidebar-toggle span { display: inline-block; transform: none; }
  .user-avatar { width: 2rem; height: 2rem; border-radius: 50%; object-fit: cover; }
  .user-avatar-initials { display: grid; flex: 0 0 auto; place-items: center; background: var(--ink); color: white; font-size: 0.8125rem; font-weight: 600; }

  .site-footer {
    border-top: 1px solid var(--line);
    padding-block: 2.5rem;
  }

  .site-footer-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1.5rem;
    width: min(1160px, calc(100% - 2rem));
    margin-inline: auto;
    flex-wrap: wrap;
  }

  .footer-brand {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-family: var(--font-serif);
    font-weight: 700;
  }

  .footer-brand img { border-radius: 0.5rem; }
  .footer-links { display: flex; gap: 1.25rem; font-size: 0.9rem; color: var(--muted); }
  .footer-links a:hover { color: var(--ink); }
  .footer-copy { font-size: 0.85rem; color: var(--muted); margin-left: auto; }

  .flash {
    position: fixed;
    z-index: 60;
    top: 5.5rem;
    left: 50%;
    transform: translateX(-50%);
    border-radius: var(--radius-pill);
    padding: 0.75rem 1.25rem;
    box-shadow: var(--shadow-lg);
    font-weight: 500;
    font-size: 0.9rem;
    transition: opacity 200ms ease, transform 200ms ease;
  }

  .flash.dismissing { opacity: 0; transform: translate(-50%, -0.5rem); }
  .flash.notice { background: var(--progress); color: var(--ink); }
  .flash.alert { background: var(--danger); color: white; }

  @media (max-width: 900px) {
    .app-layout { display: block; padding: 0; }
    .app-sidebar { display: none; }
    .app-mobile-header { position: sticky; z-index: 50; top: 0; display: flex; align-items: center; justify-content: space-between; min-height: 4rem; border-bottom: 1px solid var(--line); background: #ffffff; padding: 0.5rem 1rem; }
    .app-mobile-nav { position: relative; }
    .app-mobile-nav summary { display: flex; align-items: center; gap: 0.5rem; min-height: 2.75rem; cursor: pointer; list-style: none; font-size: 0.82rem; font-weight: 800; }
    .app-mobile-nav summary::-webkit-details-marker { display: none; }
    .app-mobile-nav[open] > div { position: absolute; z-index: 51; top: calc(100% + 0.5rem); right: 0; display: grid; min-width: 12rem; border: 1px solid var(--line); border-radius: var(--radius); background: #ffffff; padding: 0.5rem; box-shadow: var(--shadow-lg); }
    .app-mobile-nav[open] a, .app-mobile-nav[open] form .link-button { display: flex; width: 100%; min-height: 2.75rem; align-items: center; border-radius: var(--radius-sm); padding: 0.65rem 0.75rem; color: var(--ink); font-size: 0.88rem; font-weight: 700; }
    .app-mobile-nav[open] a:hover, .app-mobile-nav[open] form .link-button:hover { background: var(--blue); }
  }

  @media (prefers-reduced-motion: reduce) {
    .flash, .app-layout, .app-sidebar, .app-sidebar .brand, .sidebar-toggle, .app-nav-link { transition: none; }
  }
}