/* Shared Agent-upgrade shell and cross-study-set home. */
.app { grid-template-columns: var(--sidebar-width) minmax(0, 1fr); }
.sidebar { z-index: 20; gap: 14px; padding: 18px 12px; border-right: 0; background: var(--sidebar); color: #fff; }
.brand { min-width: 0; padding: 0 8px 20px; }
.brand-avatar { margin-right: var(--space-3); }
.brand h1 { color: #fff; }
.brand p { color: #b6b3ad; font: 12px/1.4 var(--font-ui); }
.nav { display: flex; flex-direction: column; min-height: 0; overflow: hidden; }
.nav-main { min-height: 0; flex: 1 1 auto; overflow-y: auto; scrollbar-width: thin; }
.nav-global, .nav-study-set, .nav-footer { display: grid; gap: 4px; }
.nav-global { padding-bottom: 12px; border-bottom: 1px solid #3d3b38; }
.nav-study-set { margin-top: 12px; }
.nav-study-set[hidden] { display: none; }
.nav-footer { flex: none; padding-top: 12px; border-top: 1px solid #3d3b38; }
.nav-group-label { padding: 12px 12px 5px; color: #a9a6a0; font-size: 12px; }
.nav .sidebar-set-card { display: flex; min-height: 52px; margin-bottom: 8px; padding: 8px 10px; background: var(--sidebar-active); color: #fff; }
.sidebar-set-icon { width: 34px; height: 34px; display: inline-grid; flex: none; place-items: center; border-radius: 8px; color: var(--ink); font-size: 19px; }
.sidebar-set-icon .icon { width: 21px; height: 21px; }
.sidebar-set-name { min-width: 0; flex: 1; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; font-weight: 650; }
.nav button { min-height: 40px; gap: 10px; padding: 0 10px; border-radius: var(--radius-sm); color: #d1cec8; font: 14px/1.4 var(--font-ui); }
.nav button:hover, .nav button.active { background: var(--sidebar-active); color: #fff; box-shadow: none; }
.nav .sidebar-set-card.active { box-shadow: inset 0 0 0 1px #77736d; }
.nav button:focus-visible { outline-color: #fff; }
.main { position: relative; padding: 0; }
.topbar { flex: 0 0 56px; min-height: 56px; padding: 0 24px; border-bottom: 0; background: var(--canvas); }
.page-title { display: flex; align-items: center; min-width: 0; gap: 10px; }
.page-title h2 { min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; font-size: 14px; font-weight: 550; }
.topbar-study-set-link { overflow: hidden; max-width: 30vw; padding: 0; border: 0; color: #6e6b65; background: transparent; text-decoration: underline; text-overflow: ellipsis; white-space: nowrap; cursor: pointer; font-size: 14px; }
.topbar-path-separator { color: #9d9a92; font-size: 20px; }
.topbar-actions { position: absolute; top: 11px; right: 24px; z-index: 25; }
.account-menu-toggle { padding: 0; border: 0; background: transparent; cursor: pointer; }
.account-menu-toggle:focus-visible, .topbar-study-set-link:focus-visible { outline: 2px solid #292929; outline-offset: 3px; }
.account-menu-toggle .status-line { color: #6e6b65; font-family: var(--font-ui); font-size: 13px; }
.account-menu { position: absolute; top: 42px; right: 0; z-index: 35; min-width: 145px; padding: 6px; border: 1px solid #dedbd3; border-radius: 10px; background: #fff; box-shadow: 0 12px 30px #0002; }
.account-menu button { width: 100%; padding: 10px 12px; border: 0; border-radius: 6px; background: transparent; color: #292929; cursor: pointer; text-align: left; }
.account-menu button:hover { background: #f3f2ed; }
.account-menu[hidden], .topbar-study-set-link[hidden], .topbar-path-separator[hidden] { display: none; }
.nav-toggle, .nav-backdrop { display: none; }
.tab-panel.active { background: var(--canvas); }
body[data-active-tab="sets"] .topbar,
body[data-active-tab="workspace"] .topbar,
#sets.tab-panel.active,
#workspace.tab-panel.active { background: var(--canvas); color: var(--ink); }

#home.tab-panel.active { padding: 0; }
.home-layout { display: grid; grid-template-columns: minmax(0, 1fr); min-height: 100%; }
.home-main { min-width: 0; width: min(100%, 1160px); margin-inline: auto; padding: var(--space-8) clamp(20px, 3vw, 48px) var(--space-12); }
.home-heading { margin-bottom: var(--space-8); }
.home-heading h3 { font: 400 32px/1.25 var(--font-reading); overflow-wrap: anywhere; }
.home-heading p { margin-top: var(--space-2); color: var(--muted); font-size: 14px; }
.home-section { min-width: 0; padding: var(--space-6) 0; border-bottom: 1px solid var(--line); }
.home-section h4 { margin-bottom: var(--space-4); font: 600 20px/1.4 var(--font-reading); }
.home-section-heading { display: flex; align-items: center; justify-content: space-between; gap: var(--space-3); }
.home-section-heading h4 { margin-bottom: var(--space-4); }
.home-section-body { min-width: 0; color: var(--ink); }
.home-section-body .home-empty, .home-section-body .home-loading { color: var(--muted); line-height: 1.7; }
.home-recommendation { padding-top: 0; }
.home-recommendation .home-card { background: var(--lavender); border-color: transparent; }
.home-card, .home-row, .home-action-grid button { min-width: 0; width: 100%; border: 1px solid var(--line); border-radius: var(--radius-md); color: var(--ink); background: var(--surface); text-align: left; }
.home-card, .home-row { display: grid; gap: var(--space-2); padding: var(--space-4); }
button.home-card, button.home-row, .home-action-grid button:not(:disabled) { cursor: pointer; }
button.home-card:hover, button.home-row:hover, .home-action-grid button:not(:disabled):hover { border-color: var(--ink); }
button.home-card:focus-visible, button.home-row:focus-visible, .home-action-grid button:focus-visible, .home-text-link:focus-visible { outline: 2px solid var(--ink); outline-offset: 3px; box-shadow: 0 0 0 5px var(--lavender); }
.home-card strong, .home-row strong { font-size: 16px; overflow-wrap: anywhere; }
.home-card span, .home-row span { color: var(--muted); font-size: 13px; line-height: 1.5; overflow-wrap: anywhere; }
.home-study-sets { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: var(--space-4); }
.home-study-sets .home-card { min-height: 190px; align-content: space-between; }
.home-study-sets .home-create { border-style: dashed; background: transparent; }
.home-list { display: grid; gap: var(--space-2); }
.home-text-link { border: 0; color: var(--ink); background: transparent; text-decoration: underline; cursor: pointer; }
.home-action-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: var(--space-3); }
.home-action-grid button { min-height: 80px; display: flex; flex-wrap: wrap; align-content: center; align-items: center; gap: var(--space-2); padding: var(--space-4); font-weight: 600; }
.home-action-grid button:disabled { color: var(--muted); background: var(--surface-soft); cursor: not-allowed; }
.home-action-grid .icon { width: 20px; height: 20px; }
.home-action-note { flex-basis: 100%; color: var(--muted); font-size: 12px; font-weight: 400; }
.home-error { display: flex; flex-wrap: wrap; align-items: center; gap: var(--space-3); color: var(--danger); }
.home-error button { padding: var(--space-2) var(--space-3); border: 1px solid var(--danger); border-radius: var(--radius-sm); color: var(--danger); background: var(--surface); cursor: pointer; }

@media (max-width: 1240px) {
  .app, body[data-active-tab="study"] .app { grid-template-columns: 84px minmax(0, 1fr); }
  .home-layout { grid-template-columns: minmax(0, 1fr); }
  .sidebar { position: relative; height: 100vh; padding: var(--space-3) var(--space-2); border: 0; }
  .sidebar .brand { padding: 0; text-align: center; }
  .sidebar .brand-avatar { margin: 0; }
  .sidebar .brand h1, .sidebar .brand p, .sidebar .nav-label, .sidebar-new-chat { display: none !important; }
  .sidebar-set-name { display: none; }
  .nav .sidebar-set-card { justify-content: center; padding: 4px; }
  .nav-group-label { font-size: 0; padding-block: 5px; }
  .nav button { justify-content: center; padding: var(--space-2); }
  .nav .icon { width: 22px; height: 22px; }
}
@media (max-width: 960px) {
  .app, body[data-active-tab="study"] .app { grid-template-columns: 76px minmax(0, 1fr); }
  .home-layout { grid-template-columns: minmax(0, 1fr); }
}
@media (max-width: 700px) {
  .app, body[data-active-tab="study"] .app { grid-template-columns: minmax(0, 1fr); }
  .sidebar { position: fixed; inset: 0 auto 0 0; z-index: 31; width: min(280px, 84vw); height: 100vh; padding: var(--space-4); transform: translateX(-100%); transition: transform .18s ease; }
  body.nav-open .sidebar { transform: translateX(0); }
  .sidebar .brand { text-align: left; }
  .sidebar .brand-avatar { margin-right: var(--space-3); }
  .sidebar .brand h1 { display: inline-block; }
  .sidebar .brand p { display: block; }
  .sidebar .nav-label { display: inline !important; }
  .sidebar-set-name { display: inline; }
  .nav-group-label { font-size: 12px; padding: 12px 12px 5px; }
  .nav .sidebar-set-card { justify-content: flex-start; padding: 8px 10px; }
  .nav button { justify-content: flex-start; padding: 10px 12px; }
  .nav-toggle { display: inline-flex; flex: none; }
  .nav-backdrop:not([hidden]) { position: fixed; inset: 0; z-index: 30; display: block; width: 100%; border: 0; background: rgb(0 0 0 / 45%); }
  .topbar { flex: 0 0 56px; flex-direction: row; align-items: center; gap: var(--space-3); padding-inline: var(--space-3); }
  .page-title { min-width: 0; }
  .page-title h2 { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
  .topbar-actions { top: 11px; right: 12px; }
  .topbar-actions .btn { padding: var(--space-2); white-space: nowrap; }
  .account-menu-toggle .status-line #systemStatus { display: none; }
  .home-main { padding: var(--space-6) var(--space-4) var(--space-8); }
  .home-heading h3 { font-size: 26px; }
  .home-study-sets, .home-action-grid { grid-template-columns: minmax(0, 1fr); }
}