/* App shell per Catalog Home wireframe.
 * The whole app sits in a rounded frame floating on a neutral canvas. TopNav
 * spans the top inside the frame; below it a 3-column grid: floating SideNav
 * card | main | right rail. Desktop only in M1 per 12.01 §3; mobile deferred
 * to Phase 3b.
 */

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

html,
body {
  margin: 0;
  padding: 0;
  background: var(--color-canvas);
  color: var(--color-text);
  font-family: var(--font-sans);
  font-size: var(--text-md);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a { color: inherit; text-decoration: none; }

button {
  font-family: inherit;
  color: inherit;
  background: none;
  border: 0;
  padding: 0;
  cursor: pointer;
}

#top-nav {
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
}

.app-shell {
  display: grid;
  grid-template-columns: var(--sidenav-w) 1fr var(--rightrail-w);
  gap: var(--space-4);
  align-items: start;
  padding: var(--space-5) var(--space-5) var(--space-5);
  background: var(--color-bg);
  min-height: calc(100vh - var(--topnav-h));
}

.app-shell--nav-collapsed {
  grid-template-columns: var(--sidenav-collapsed-w) 1fr var(--rightrail-w);
}

.app-shell:has(#right-rail:empty) {
  grid-template-columns: var(--sidenav-w) 1fr 0;
}
.app-shell:has(#right-rail:empty) #right-rail { display: none; }
.app-shell--nav-collapsed:has(#right-rail:empty) {
  grid-template-columns: var(--sidenav-collapsed-w) 1fr 0;
}

#side-nav {
  position: sticky;
  top: var(--space-4);
  height: calc(100vh - var(--topnav-h) - var(--space-5));
}

#main {
  min-width: 0;
  padding-top: var(--space-2);
}

#right-rail {
  position: sticky;
  top: var(--space-4);
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  padding-top: var(--space-2);
}

/* Portal layers */
#toast-container {
  position: fixed;
  top: var(--space-4);
  right: var(--space-4);
  z-index: 1000;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  pointer-events: none;
}
#toast-container > * { pointer-events: auto; }

#modal-container {
  position: fixed;
  inset: 0;
  z-index: 500;
  display: none;
}
#modal-container:not(:empty) {
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(12, 17, 36, 0.45);
}

/* Page-level error state */
.page-error {
  padding: var(--space-7) var(--space-5);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  text-align: center;
  color: var(--color-text-muted);
}
.page-error__retry {
  margin-top: var(--space-3);
}