.app-shell {
  min-height: 100vh;
  display: grid;
  grid-template-columns: minmax(var(--layout-sidebar-width-compact), var(--sidebar-width)) minmax(0, 1fr);
  grid-template-rows: auto 1fr auto;
  align-items: start;
}

.skip-link {
  position: fixed;
  top: var(--space-3);
  left: var(--space-3);
  z-index: 8;
  padding: var(--space-2) var(--space-3);
  border: var(--border-width-thin) var(--border-style-standard) var(--color-border);
  border-radius: var(--radius-control);
  background: var(--color-surface-secondary);
  transform: translateY(calc(-100% - var(--space-3)));
  transition: transform var(--transition-quick);
}

.skip-link:focus {
  transform: translateY(0);
}

.shell-sidebar {
  grid-row: 1 / span 3;
  position: sticky;
  top: 0;
  min-height: 100vh;
  width: min(100%, var(--sidebar-width));
  padding: var(--space-6) var(--space-4) var(--space-7);
  border-right: var(--border-width-thin) var(--border-style-standard) var(--color-border);
  background: var(--color-navigation-surface);
  color: var(--color-sidebar-text);
  box-shadow: inset -1px 0 0 color-mix(in srgb, var(--color-navigation-border) 72%, transparent);
  overflow-y: auto;
  transition:
    padding var(--transition-slow),
    background var(--transition-medium),
    box-shadow var(--transition-medium);
}

.shell-sidebar-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  margin-bottom: var(--space-5);
}

.shell-sidebar-brand {
  min-width: 0;
}

.shell-sidebar-toggle {
  min-width: 112px;
  padding-left: var(--space-3);
  padding-right: var(--space-3);
}

.shell-header,
.shell-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  padding: var(--space-4) var(--space-6);
  margin: 0 auto;
  width: min(100%, calc(var(--content-max) + var(--space-7)));
}

.shell-header {
  position: sticky;
  top: 0;
  z-index: 3;
  background: var(--color-header-surface);
  backdrop-filter: blur(18px);
  border-bottom: var(--border-width-thin) var(--border-style-standard) var(--color-border);
  box-shadow: 0 12px 32px color-mix(in srgb, var(--color-background-overlay) 14%, transparent);
}

.shell-footer {
  color: var(--color-text-secondary);
  font-size: 0.92rem;
  padding-top: var(--space-5);
  padding-bottom: var(--space-6);
  border-top: var(--border-width-thin) var(--border-style-standard) color-mix(in srgb, var(--color-border) 72%, transparent);
}

.shell-header-brand {
  display: grid;
  gap: var(--space-1);
  min-width: 0;
}

.shell-header-title {
  font-family: var(--font-display);
  font-size: 1.2rem;
}

.shell-header-subtitle {
  color: var(--color-text-secondary);
  font-size: 0.92rem;
}

.shell-header-actions {
  justify-content: flex-end;
}

.shell-footer-copy {
  max-width: 72ch;
}

.shell-main {
  min-width: 0;
  padding: var(--space-6);
  overflow: hidden;
}

.shell-content {
  max-width: min(100%, calc(var(--content-max) + var(--space-5)));
  margin: 0 auto;
  display: grid;
  gap: var(--space-6);
}

.chat-product-page {
  display: grid;
  min-height: 100vh;
  background: var(--color-background);
}

.shell-main.chat-product-main {
  min-height: 100vh;
  padding: 0;
}

.shell-content.chat-product-content {
  width: 100%;
  max-width: none;
  margin: 0;
  gap: 0;
}

.foundation-layout {
  display: grid;
  gap: var(--space-6);
  width: 100%;
}

.chat-layout {
  gap: var(--space-4);
}

.chat-product-content .chat-layout {
  min-height: 100vh;
  gap: 0;
}

.chat-stage {
  display: grid;
  grid-template-columns: minmax(0, 1.7fr) minmax(280px, 320px) minmax(200px, 240px);
  grid-template-areas: "workspace sidebar drawer";
  gap: var(--space-4);
  align-items: start;
  width: 100%;
}

.chat-stage--product-home {
  grid-template-columns: var(--layout-chat-sidebar-width) minmax(0, 1fr);
  grid-template-areas: "sidebar workspace";
  gap: 0;
  align-items: stretch;
  min-height: 100vh;
}

.chat-sidebar,
.chat-workspace,
.chat-drawer {
  display: grid;
  gap: var(--space-4);
  min-width: 0;
  align-content: start;
}

.chat-sidebar {
  grid-area: sidebar;
  position: sticky;
  top: var(--space-5);
}

.chat-stage--product-home .chat-sidebar {
  top: 0;
  min-height: 100vh;
  padding: var(--space-4);
  border-right: var(--border-width-thin) var(--border-style-standard) color-mix(in srgb, var(--color-border) 72%, transparent);
  background: var(--color-surface-secondary);
}

.chat-workspace {
  grid-area: workspace;
  grid-template-rows: minmax(0, 1fr) auto;
  align-self: start;
}

.chat-stage--product-home .chat-workspace {
  align-self: stretch;
  min-height: 100vh;
  padding: var(--space-4) var(--space-5);
  align-content: stretch;
}

.chat-stage--product-home.is-collapsed,
.chat-stage--product-home.is-sidebar-collapsed {
  grid-template-columns: var(--layout-sidebar-width-collapsed) minmax(0, 1fr);
}

.chat-stage--product-home.is-collapsed .chat-sidebar,
.chat-stage--product-home.is-sidebar-collapsed .chat-sidebar {
  overflow: hidden;
  padding-inline: var(--space-3);
}

.chat-stage--product-home.is-collapsed .chat-sidebar-section-copy span,
.chat-stage--product-home.is-collapsed .chat-sidebar-section-copy strong,
.chat-stage--product-home.is-collapsed .chat-sidebar-snapshot span,
.chat-stage--product-home.is-collapsed .chat-history-item-copy,
.chat-stage--product-home.is-sidebar-collapsed .chat-sidebar-section-copy span,
.chat-stage--product-home.is-sidebar-collapsed .chat-sidebar-section-copy strong,
.chat-stage--product-home.is-sidebar-collapsed .chat-sidebar-snapshot span,
.chat-stage--product-home.is-sidebar-collapsed .chat-history-item-copy {
  display: none;
}

.chat-drawer {
  grid-area: drawer;
  position: sticky;
  top: var(--space-5);
}

.chat-drawer--hidden {
  display: none;
}

.chat-header-host,
.chat-sidebar-host,
.chat-drawer-host,
.chat-sidebar-content,
.chat-drawer-content {
  display: grid;
  gap: var(--space-3);
}

.chat-product-nav-list,
.chat-history-list {
  display: grid;
  gap: var(--space-3);
  margin: 0;
  padding: 0;
  list-style: none;
}

.chat-product-nav-item,
.chat-history-item {
  display: grid;
  gap: var(--space-1);
  padding: var(--space-3);
  border: var(--border-width-thin) var(--border-style-standard) var(--color-border);
  border-radius: var(--radius-control);
  background: color-mix(in srgb, var(--color-surface-secondary) 72%, transparent);
}

.chat-history-item {
  padding: 0;
  border: 0;
  background: transparent;
}

.chat-history-item-button {
  width: 100%;
  min-height: 0;
  display: grid;
  justify-items: start;
  gap: var(--space-1);
  padding: var(--space-3);
  text-align: left;
  border-radius: var(--radius-control);
  border: var(--border-width-thin) var(--border-style-standard) transparent;
  background: transparent;
  transition:
    border-color var(--transition-medium),
    background var(--transition-medium);
}

.chat-history-item-button.is-active {
  border-color: color-mix(in srgb, var(--color-accent) 42%, var(--color-border));
  background: color-mix(in srgb, var(--color-accent) 12%, var(--color-surface-secondary));
}

.chat-history-item-button:hover {
  background: color-mix(in srgb, var(--color-surface) 80%, transparent);
  border-color: color-mix(in srgb, var(--color-primary) 22%, var(--color-border));
}

.chat-history-item-meta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.chat-history-item-badge {
  display: inline-flex;
  align-items: center;
  min-height: 1.6rem;
  padding: 0 var(--space-2);
  border-radius: var(--radius-pill);
  border: var(--border-width-thin) var(--border-style-standard) color-mix(in srgb, var(--color-border) 78%, transparent);
  background: color-mix(in srgb, var(--color-surface) 78%, transparent);
  font-size: 0.76rem;
}

.chat-product-nav-item strong,
.chat-history-item strong,
.chat-section-copy strong,
.chat-developer-fact strong {
  font-size: 0.86rem;
}

.chat-product-nav-item span,
.chat-history-item span,
.chat-section-copy span,
.chat-developer-fact span {
  color: var(--color-text-secondary);
  line-height: 1.45;
}

.chat-section-copy {
  display: grid;
  gap: var(--space-2);
}

.chat-sidebar-section {
  display: grid;
  gap: var(--space-2);
  padding: var(--space-3) 0;
  border-top: var(--border-width-thin) var(--border-style-standard) color-mix(in srgb, var(--color-border) 68%, transparent);
  background: transparent;
}

.chat-sidebar-section-copy {
  display: grid;
  gap: var(--space-1);
}

.chat-sidebar-section-copy strong {
  font-size: 0.96rem;
}

.chat-sidebar-section-copy span {
  color: var(--color-text-secondary);
  line-height: 1.45;
}

.chat-sidebar-section--history .chat-history-list {
  max-height: 48vh;
  overflow-y: auto;
  padding-right: var(--space-1);
  scrollbar-gutter: stable;
}

.chat-sidebar-snapshot {
  display: grid;
  gap: var(--space-2);
  padding: 0 0 0 var(--space-3);
  border-left: var(--border-width-thin) var(--border-style-standard) color-mix(in srgb, var(--color-primary) 34%, var(--color-border));
  background: transparent;
}

.chat-sidebar-snapshot strong {
  font-size: 1rem;
}

.chat-sidebar-snapshot span {
  color: var(--color-text-secondary);
  line-height: 1.45;
}

.chat-history-empty-state {
  padding: var(--space-4);
  border: var(--border-width-thin) dashed color-mix(in srgb, var(--color-border) 80%, transparent);
  border-radius: var(--radius-control);
  color: var(--color-text-secondary);
  line-height: 1.5;
  background: color-mix(in srgb, var(--color-surface) 84%, transparent);
}

.chat-sidebar-actions {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: var(--space-2);
}

.chat-sidebar-primary-action .button {
  width: 100%;
}

.chat-sidebar-actions .button {
  min-width: 0;
  padding-left: var(--space-3);
  padding-right: var(--space-3);
}

.chat-sidebar-section--navigation .chat-product-nav-list {
  grid-template-columns: 1fr;
  gap: var(--space-2);
}

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

.chat-developer-controls .button {
  min-width: 0;
}

.chat-developer-facts {
  grid-template-columns: 1fr;
}

.foundation-hero {
  display: grid;
  gap: var(--space-4);
  padding: var(--space-6);
  border: var(--border-width-thin) var(--border-style-standard) var(--color-border);
  border-radius: var(--radius-panel);
  background: var(--color-surface-secondary);
  box-shadow: var(--shadow-soft);
}

.foundation-grid {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: var(--space-5);
}

.foundation-grid > * {
  grid-column: span 4;
}

.foundation-band {
  padding: var(--space-5);
  border: var(--border-width-thin) var(--border-style-standard) var(--color-border);
  border-radius: var(--radius-panel);
  background: var(--color-surface);
  box-shadow: var(--shadow-crisp);
}

.shell-host-layer {
  position: fixed;
  inset: 0;
  pointer-events: none;
}

.notification-host,
.session-host,
.error-host {
  position: fixed;
  display: grid;
  gap: var(--space-3);
  z-index: 5;
}

.notification-host {
  top: var(--space-4);
  right: var(--space-4);
  width: min(340px, calc(100vw - 32px));
}

.session-host {
  right: var(--space-4);
  bottom: var(--space-4);
  width: min(280px, calc(100vw - 32px));
}

.error-host {
  left: var(--space-4);
  bottom: var(--space-4);
  width: min(340px, calc(100vw - 32px));
}

.dialog-host,
.loading-host {
  position: fixed;
  inset: 0;
  display: none;
  place-items: center;
  background: var(--color-background-overlay);
  backdrop-filter: blur(12px);
  opacity: 0;
  transition: opacity var(--transition-medium);
  z-index: 6;
}

.drawer-host {
  position: fixed;
  inset: 0;
  display: grid;
  justify-items: end;
  align-items: stretch;
  padding-left: var(--space-8);
  --drawer-panel-width: min(var(--layout-drawer-width-standard), calc(100vw - var(--space-4)));
  pointer-events: none;
  opacity: 0;
  transform: translateX(var(--space-2));
  transition: opacity var(--transition-medium), transform var(--transition-slow);
  z-index: 6;
}

.dialog-width-small {
  --dialog-panel-width: min(420px, calc(100vw - var(--space-4)));
}

.dialog-width-standard {
  --dialog-panel-width: min(560px, calc(100vw - var(--space-4)));
}

.dialog-width-large,
.dialog-width-full {
  --dialog-panel-width: min(760px, calc(100vw - var(--space-4)));
}

.drawer-width-narrow {
  --drawer-panel-width: min(var(--layout-drawer-width-narrow), calc(100vw - var(--space-4)));
}

.drawer-width-standard {
  --drawer-panel-width: min(var(--layout-drawer-width-standard), calc(100vw - var(--space-4)));
}

.drawer-width-wide {
  --drawer-panel-width: min(var(--layout-drawer-width-wide), calc(100vw - var(--space-4)));
}

.dialog-host.is-visible,
.loading-host.is-visible {
  display: grid;
  opacity: 1;
}

.drawer-host.is-visible {
  opacity: 1;
  transform: translateX(0);
  pointer-events: auto;
}

.app-shell.is-collapsed {
  grid-template-columns: var(--layout-sidebar-width-collapsed) minmax(0, 1fr);
}

.app-shell.is-collapsed .shell-sidebar .nav-item small,
.app-shell.is-collapsed .shell-sidebar .nav-item strong,
.app-shell.is-collapsed .shell-sidebar .brand-mark strong,
.app-shell.is-collapsed .shell-sidebar .brand-mark span {
  display: none;
}

.app-shell.is-collapsed .shell-sidebar .nav-item-copy {
  display: none;
}

.app-shell.is-collapsed .shell-sidebar .nav-item {
  justify-content: center;
  padding-left: var(--space-2);
  padding-right: var(--space-2);
}

.app-shell.is-collapsed .shell-sidebar {
  width: var(--layout-sidebar-width-collapsed);
  padding-left: var(--space-3);
  padding-right: var(--space-3);
}

.app-shell.is-collapsed .shell-sidebar-header {
  flex-direction: column;
  align-items: stretch;
}

.app-shell.is-collapsed .shell-sidebar-brand {
  justify-content: center;
}

.app-shell.is-collapsed .shell-sidebar-brand img {
  margin: 0 auto;
}

.app-shell.is-collapsed .shell-sidebar-toggle {
  min-width: 0;
  width: 100%;
}

.app-shell.is-collapsed .nav-group-label {
  text-align: center;
  padding-left: 0;
  padding-right: 0;
}

@media (max-width: 1024px) {
  .app-shell {
    grid-template-columns: 1fr;
    grid-template-rows: auto auto 1fr auto;
  }

  .shell-sidebar {
    grid-row: auto;
    position: relative;
    min-height: auto;
    width: 100%;
    border-right: 0;
    border-bottom: var(--border-width-thin) var(--border-style-standard) var(--color-navigation-border);
    padding: var(--space-5);
  }

  .drawer-host {
    padding-left: var(--space-6);
  }

  .drawer-width-narrow {
    --drawer-panel-width: min(340px, calc(100vw - var(--space-5)));
  }

  .drawer-width-standard {
    --drawer-panel-width: min(460px, calc(100vw - var(--space-5)));
  }

  .drawer-width-wide {
    --drawer-panel-width: min(560px, calc(100vw - var(--space-5)));
  }

  .dialog-width-standard {
    --dialog-panel-width: min(640px, calc(100vw - var(--space-5)));
  }

  .dialog-width-large,
  .dialog-width-full {
    --dialog-panel-width: min(760px, calc(100vw - var(--space-5)));
  }

  .shell-header,
  .shell-footer {
    width: 100%;
    padding-left: var(--space-5);
    padding-right: var(--space-5);
  }

  .shell-main {
    padding: var(--space-5);
  }

  .foundation-grid > * {
    grid-column: span 6;
  }

  .workspace-domain-grid,
  .workspace-status-grid,
  .workspace-inline-fields {
    grid-template-columns: 1fr;
  }

  .chat-stage {
    grid-template-columns: 1fr;
    grid-template-areas:
      "workspace"
      "sidebar"
      "drawer";
  }

  .chat-sidebar,
  .chat-drawer {
    position: relative;
    top: auto;
  }

  .chat-composer-controls {
    grid-template-columns: 1fr;
  }

  .chat-composer-leading-tools {
    grid-template-columns: 1fr;
  }

  .chat-composer-toolbar {
    grid-column: 1 / -1;
  }

  .chat-conversation-welcome-suggestions {
    grid-template-columns: 1fr;
  }

  .chat-conversation-empty-recent-list {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 767px) {
  .shell-main,
  .shell-sidebar,
  .shell-header,
  .shell-footer {
    padding: var(--space-4);
  }

  .shell-header,
  .shell-footer {
    flex-direction: column;
    align-items: flex-start;
  }

  .shell-header-actions {
    width: 100%;
    justify-content: flex-start;
  }

  .shell-sidebar-header {
    align-items: stretch;
  }

  .shell-sidebar-toggle {
    width: 100%;
  }

  .drawer-host {
    padding-left: var(--space-4);
  }

  .drawer-width-narrow {
    --drawer-panel-width: min(100vw - var(--space-4), 320px);
  }

  .drawer-width-standard,
  .drawer-width-wide {
    --drawer-panel-width: calc(100vw - var(--space-4));
  }

  .dialog-width-small,
  .dialog-width-standard,
  .dialog-width-large,
  .dialog-width-full {
    --dialog-panel-width: calc(100vw - var(--space-4));
  }

  .foundation-hero,
  .foundation-band {
    padding: var(--space-5);
  }

  .foundation-grid > * {
    grid-column: span 12;
  }

  .chat-composer-controls {
    grid-template-columns: 1fr;
  }

  .chat-composer-leading-tools {
    grid-template-columns: 1fr;
  }

  .chat-composer-toolbar {
    grid-column: auto;
  }

  .chat-workspace {
    gap: var(--space-3);
  }

  .chat-conversation-welcome-suggestions {
    grid-template-columns: 1fr;
  }

  .chat-conversation-empty-recent-list {
    grid-template-columns: 1fr;
  }

  .chat-message,
  .chat-message--system {
    max-width: 100%;
  }
}

@media (min-width: 1025px) and (max-width: 1439px) {
  .shell-main {
    padding-left: var(--space-6);
    padding-right: var(--space-6);
  }

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

@media (min-width: 1440px) {
  .shell-main {
    padding-left: var(--space-7);
    padding-right: var(--space-7);
  }

  .shell-content {
    max-width: min(100%, calc(var(--layout-content-wide-max) + var(--space-5)));
  }

  .shell-header,
  .shell-footer {
    width: min(100%, calc(var(--layout-content-wide-max) + var(--space-7)));
  }

  .foundation-grid > * {
    grid-column: span 3;
  }

  .shell-sidebar {
    padding-right: var(--space-5);
  }
}

@media (prefers-reduced-motion: reduce) {
  .skip-link,
  .shell-sidebar,
  .nav-item,
  .button,
  .dialog-panel,
  .dialog-host,
  .dialog-scrim,
  .loading-host,
  .drawer-host,
  .drawer-scrim {
    transition: none;
  }
}