.shell-header {
  width: min(calc(100% - 40px), var(--content-max));
  margin: 18px auto 0;
  padding: 18px 22px;
  border-radius: var(--radius-xl);
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 18px;
  background: var(--color-surface-elevated);
  backdrop-filter: blur(16px);
  box-shadow: var(--shadow-soft);
  border: 1px solid rgba(255,255,255,.65);
  position: sticky;
  top: 12px;
  z-index: 30;
}

.shell-brand {
  display: flex;
  align-items: center;
  gap: 14px;
}

.shell-brand-logo {
  width: 52px;
  height: 52px;
  border-radius: 18px;
  overflow: hidden;
  box-shadow: var(--shadow-primary);
}

.shell-brand-home-button {
  border: 0;
  padding: 0;
  background: transparent;
  cursor: pointer;
  transition: transform var(--transition-fast), box-shadow var(--transition-fast);
}

.shell-brand-home-button:hover,
.shell-brand-home-button:focus-visible {
  transform: translateY(-1px);
  box-shadow: 0 16px 36px rgba(178, 51, 36, 0.28);
}

.shell-brand-home-button:focus-visible {
  outline: 3px solid rgba(178, 51, 36, 0.24);
  outline-offset: 4px;
}

.shell-brand-title {
  font-family: var(--font-serif);
  font-size: 1.95rem;
  font-weight: 900;
  font-style: italic;
  letter-spacing: -0.04em;
  color: var(--color-primary);
}

.shell-brand-subtitle {
  color: var(--color-muted);
  font-size: 0.75rem;
  font-weight: 800;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.shell-context {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-top: 4px;
  flex-wrap: wrap;
}

.shell-context-pill {
  display: inline-flex;
  align-items: center;
  min-height: 32px;
  padding: 0 14px;
  border-radius: 999px;
  background: var(--color-primary-soft);
  color: var(--color-primary);
  font-size: 0.75rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.shell-actions {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
  justify-content: flex-end;
}

.mobile-nav-toggle.icon-button {
  display: none;
}

.mobile-sidebar-scrim {
  display: none;
  border: 0;
  background: rgba(15, 23, 42, 0.36);
}

main.app-main {
  width: min(calc(100% - 40px), var(--content-max));
  margin: 18px auto 32px;
  display: grid;
  grid-template-columns: var(--sidebar-width) minmax(0, 1fr);
  gap: 18px;
  align-items: start;
}

.sidebar {
  position: sticky;
  top: var(--sticky-shell-offset);
  display: grid;
  gap: 16px;
  padding: 18px;
  margin-top: 0;
  align-self: start;
}

.sidebar h3 {
  font-size: 0.82rem;
  text-transform: uppercase;
  letter-spacing: 0.18em;
  color: var(--color-muted);
}

.sidebar-group {
  display: grid;
  gap: 8px;
}

.sidebar-group-title {
  font-size: 0.74rem;
  font-weight: 800;
  color: var(--color-muted);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  padding: 0 6px;
}

.stack {
  display: grid;
  gap: 18px;
}

.card {
  position: relative;
  overflow: hidden;
  border-radius: var(--radius-xl);
  background: rgba(255,255,255,.88);
  border: 1px solid rgba(255,255,255,.72);
  box-shadow: var(--shadow-card);
  backdrop-filter: blur(14px);
  padding: 24px;
}

.page-section {
  min-height: calc(100vh - 210px);
}

.section-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 16px;
  margin-bottom: 16px;
  flex-wrap: wrap;
}

.section-title {
  font-size: 0.78rem;
  font-weight: 900;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--color-muted);
  margin-bottom: 12px;
}

.inline-actions,
.filter-chip-row,
.button-row {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  align-items: center;
}

.stack-xs { display: grid; gap: 10px; }
.stack-sm { display: grid; gap: 14px; }
.stack-md { display: grid; gap: 18px; }
.stack-lg { display: grid; gap: 24px; }

.grid {
  display: grid;
  gap: 16px;
}

.two-col {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.three-col {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
}

.hero-banner {
  padding: 28px;
  border-radius: var(--radius-xl);
  background: var(--gradient-primary);
  color: white;
  box-shadow: var(--shadow-primary);
  display: grid;
  gap: 16px;
}

.hero-banner .meta,
.hero-banner p { color: rgba(255,255,255,.84); }

.hero-banner h2,
.hero-banner h3 {
  color: white;
  font-family: var(--font-serif);
  font-style: italic;
  font-size: clamp(1.8rem, 2.8vw, 2.8rem);
}

.dashboard-grid {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: 16px;
}

.dashboard-grid > * { min-width: 0; }

.span-3 { grid-column: span 3; }
.span-4 { grid-column: span 4; }
.span-5 { grid-column: span 5; }
.span-6 { grid-column: span 6; }
.span-7 { grid-column: span 7; }
.span-8 { grid-column: span 8; }
.span-12 { grid-column: span 12; }


.student-page .card,
.student-page.card {
  background: rgba(255,255,255,.9);
}

.student-page.page-section,
.teacher-overview-page.page-section,
[data-page-content="auth"].page-section {
  min-height: calc(100vh - 220px);
}


.shell-brand-subtitle {
  letter-spacing: 0.14em;
}

.shell-context {
  gap: 8px;
}

.shell-context .meta {
  max-width: 540px;
}

.sidebar {
  gap: 14px;
}

.sidebar-group {
  padding-top: 2px;
}

.sidebar-group-title {
  padding-left: 8px;
}

.sidebar-group.hidden {
  display: none !important;
}

.section-header .meta {
  max-width: 760px;
}

.inbox-shell {
  display: grid;
  gap: 14px;
}

.inbox-summary-card {
  display: grid;
  gap: 6px;
}

input::placeholder,
textarea::placeholder,
select:invalid {
  color: rgba(15,23,42,.38);
}

.sidebar {
  align-self: start;
}


input::placeholder,
textarea::placeholder {
  color: rgba(100,116,139,.55);
}

main.app-main {
  align-items: start;
}

.inbox-summary-card,
.inbox-summary-card-mixed {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 14px 16px;
  border-radius: 18px;
  background: rgba(248,250,252,.92);
  border: 1px solid var(--color-border);
}

.inbox-inline-pagination {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
}

.auth-viewport-tip {
  display: grid;
  gap: 6px;
  margin-top: 4px;
  padding: 14px 16px;
  border-radius: 18px;
  border: 1px solid rgba(178, 51, 36, .18);
  background: rgba(253, 237, 236, .62);
  color: var(--color-text-soft);
  font-size: .82rem;
  line-height: 1.45;
}

.auth-viewport-tip strong {
  color: var(--color-primary);
  font-size: .72rem;
  font-weight: 900;
  letter-spacing: .12em;
  text-transform: uppercase;
}

body:not([data-role="anonymous"]) .auth-viewport-tip {
  display: none;
}

/* Student shell baseline: keep navigation and content in separate layers. */
main.app-main > .app-content-stack,
main.app-main > .stack {
  min-width: 0;
  width: 100%;
  position: relative;
  z-index: 1;
}

.sidebar.card {
  overflow: visible;
  z-index: 42;
}

.sidebar button {
  min-width: 0;
}

.student-page.page-section,
.student-page-plain.page-section {
  width: 100%;
  min-width: 0;
}

.student-page .section-header,
.student-page-plain .section-header {
  max-width: 100%;
}

.student-page :where(.dashboard-grid, .student-kpi-grid, .student-split, .two-col, .three-col, .grid),
.student-page-plain :where(.dashboard-grid, .student-kpi-grid, .student-split, .two-col, .three-col, .grid) {
  min-width: 0;
}