.app-shell { min-height: 100vh; }
.app-header {
  position: sticky; top: 0; z-index: 100;
  min-height: var(--header-h);
  display: flex; align-items: center; gap: 1rem;
  padding: .75rem clamp(1rem, 2.5vw, 2rem);
  background: color-mix(in srgb, var(--surface) 92%, transparent);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border);
}
.brand { display: flex; align-items: center; gap: .75rem; min-width: max-content; color: var(--text); text-decoration: none; }
.brand-mark { width: 46px; height: 46px; display: grid; place-items: center; border-radius: 14px; background: linear-gradient(135deg, var(--primary), var(--purple)); color: white; font-size: 1.6rem; box-shadow: var(--shadow-sm); }
.brand strong { display: block; font-size: 1.08rem; }
.brand small { display: block; color: var(--text-soft); font-size: .75rem; }
.header-search { flex: 1; max-width: 680px; margin-inline: auto; position: relative; }
.header-search input { width: 100%; min-height: 46px; padding: .75rem 3.2rem .75rem 1rem; border: 1px solid var(--border); border-radius: var(--radius-pill); color: var(--text); background: var(--surface-2); }
.header-search button { position: absolute; right: .35rem; top: .35rem; width: 38px; height: 38px; border: 0; border-radius: 50%; background: var(--primary); color: white; cursor: pointer; }
.header-actions { display: flex; gap: .45rem; }
.app-body { position: relative; display: grid; grid-template-columns: var(--sidebar-w) minmax(0, 1fr); transition: grid-template-columns var(--transition); }
.sidebar { position: sticky; top: var(--header-h); height: calc(100vh - var(--header-h)); padding: 1rem; background: var(--surface); border-right: 1px solid var(--border); overflow-y: auto; overflow-x: hidden; transition: width var(--transition), padding var(--transition), transform var(--transition); }
.nav-list { display: grid; gap: .35rem; }
.nav-link { position: relative; display: flex; align-items: center; gap: .75rem; min-height: 44px; padding: .65rem .8rem; border-radius: .85rem; color: var(--text-soft); font-weight: 700; text-decoration: none; transition: var(--transition); white-space: nowrap; }
.nav-link:hover { background: var(--surface-2); color: var(--text); }
.nav-link[aria-current="page"] { background: var(--primary-soft); color: var(--primary-strong); }
.sidebar-section-title { margin: 1.25rem .75rem .45rem; color: var(--text-soft); font-size: .72rem; font-weight: 800; letter-spacing: .08em; text-transform: uppercase; white-space: nowrap; }
.main-content { width: 100%; max-width: var(--content); min-height: calc(100vh - var(--header-h)); padding: clamp(1rem, 3vw, 2.25rem); margin-inline: auto; }
.page-header { display: flex; align-items: flex-end; justify-content: space-between; gap: 1rem; margin-bottom: 1.5rem; }
.page-header p { max-width: 760px; color: var(--text-soft); margin: 0; }
.page-grid { display: grid; gap: 1rem; }
.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)); }
.footer { margin-top: 2rem; padding: 1.2rem; text-align: center; color: var(--text-soft); border-top: 1px solid var(--border); }
.nav-toggle { flex: 0 0 auto; }
.sidebar-backdrop { display: none; }

.app-shell.sidebar-collapsed .app-body { grid-template-columns: 78px minmax(0, 1fr); }
.app-shell.sidebar-collapsed .sidebar { padding-inline: .55rem; }
.app-shell.sidebar-collapsed .sidebar .nav-link { justify-content: center; padding-inline: .5rem; font-size: 1.1rem; }
.app-shell.sidebar-collapsed .sidebar .nav-link span:last-child,
.app-shell.sidebar-collapsed .sidebar-section-title { display: none; }