/* =========================================================
   core/app-shell.css
   ---------------------------------------------------------
   Teacher-side application shell: sidebar, top bar, content
   frame and responsive navigation behaviour.

   Desktop: full sidebar with labels.
   iPad landscape / narrower desktop: compact icon rail.
   Phone: off-canvas drawer opened by the top-bar menu button.
   ========================================================= */

:root {
  --nn-sidebar-full: 240px;
  --nn-sidebar-compact: 76px;
  --nn-topbar-height: 66px;
  --nn-shell-bg: #f6f7f9;
  --nn-sidebar-bg: #011528;
  --nn-sidebar-border: rgba(255, 255, 255, 0.14);
  --nn-sidebar-text: #ffffff;
  --nn-sidebar-muted: rgba(255, 255, 255, 0.78);
  --nn-sidebar-hover-bg: rgba(255, 255, 255, 0.08);
  --nn-sidebar-active-bg: color-mix(in srgb, var(--nn-color-accent) 16%, transparent);
  --nn-sidebar-active-text: var(--nn-color-accent);
}

body.nn-has-app-shell {
  background: var(--nn-shell-bg);
}

.nn-app-shell {
  display: grid;
  grid-template-columns: var(--nn-sidebar-full) minmax(0, 1fr);
  min-height: 100vh;
  background: var(--nn-shell-bg);
}

.nn-app-sidebar {
  position: sticky;
  top: 0;
  z-index: 1100;
  display: flex;
  flex-direction: column;
  width: var(--nn-sidebar-full);
  height: 100vh;
  background: var(--nn-sidebar-bg);
  border-right: 1px solid var(--nn-sidebar-border);
  box-shadow: 10px 0 30px rgba(3, 26, 40, 0.10);
  overflow: hidden;
}

.nn-app-sidebar__brand {
  display: flex;
  align-items: center;
  min-height: 52px;
  padding: 10px 14px;
  border-bottom: 1px solid var(--nn-sidebar-border);
}

.nn-app-sidebar__section-label {
  padding: 12px 12px 6px;
  color: var(--nn-sidebar-muted);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: .08em;
  text-transform: uppercase;
}

.nn-app-sidebar__logo {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  color: var(--nn-sidebar-text);
  font-size: 1.05rem;
  font-weight: 400;
  text-decoration: none;
  min-width: 0;
}

.nn-app-sidebar__logo:hover {
  color: var(--nn-sidebar-text);
  text-decoration: none;
}

.nn-app-sidebar__logo img {
  height: 36px;
  width: auto;
}

.nn-app-sidebar__nav {
  display: flex;
  flex-direction: column;
  gap: 5px;
  padding: 16px 12px;
  flex: 1;
  min-height: 0;
  overflow-y: auto;
}

.nn-app-sidebar__footer {
  padding: 12px;
  border-top: 1px solid var(--nn-sidebar-border);
  flex: 0 0 auto;
  margin-top: auto;
}

.nn-app-sidebar__profile {
  min-width: 0;
}

.nn-app-sidebar__profile .nn-avatar {
  flex: 0 0 36px;
}

.nn-app-sidebar__profile-name {
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.nn-app-sidebar__account-separator {
  height: 1px;
  margin: 10px 8px;
  background: var(--nn-sidebar-border);
}


.nn-app-sidebar__link {
  position: relative;
  display: flex;
  align-items: center;
  gap: 12px;
  min-height: 44px;
  padding: 0 12px;
  border-radius: 14px;
  color: var(--nn-sidebar-text);
  font-size: 0.98rem;
  font-weight: 600;
  text-decoration: none;
  transition: background 0.18s ease, color 0.18s ease, transform 0.18s ease;
}

.nn-app-sidebar__link i {
  width: 22px;
  text-align: center;
  color: var(--nn-sidebar-text);
  font-size: 1rem;
  line-height: 1;
  flex: 0 0 22px;
}

.nn-app-sidebar__link:hover {
  background: var(--nn-sidebar-hover-bg);
  color: var(--nn-sidebar-text);
  text-decoration: none;
}

.nn-app-sidebar__link:hover i {
  color: var(--nn-sidebar-text);
}

.nn-app-sidebar__link.is-active {
  background: var(--nn-sidebar-active-bg);
  color: var(--nn-sidebar-active-text);
}

.nn-app-sidebar__link.is-active::before {
  content: "";
  position: absolute;
  left: -12px;
  top: 10px;
  bottom: 10px;
  width: 4px;
  border-radius: 999px;
  background: var(--nn-color-accent);
}

.nn-app-sidebar__link.is-active i {
  color: var(--nn-sidebar-active-text);
}

.nn-app-sidebar__link--muted {
  color: var(--nn-sidebar-muted);
}

.nn-app-sidebar__link:focus-visible,
.nn-app-sidebar__sublink:focus-visible {
  outline: 2px solid var(--nn-color-accent);
  outline-offset: 2px;
}

.nn-app-body {
  display: flex;
  flex-direction: column;
  min-width: 0;
  min-height: 100vh;
}

.nn-app-topbar {
  display: none;
}

.nn-app-menu-button {
  display: none;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  border: 1px solid transparent;
  border-radius: 12px;
  background: transparent;
  color: inherit;
  cursor: pointer;
}

.nn-app-topbar__user {
  display: flex;
  align-items: center;
  flex: 0 0 auto;
}

.nn-app-topbar__avatar {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 999px;
  background: var(--nn-color-accent);
  color: var(--nn-sidebar-text);
  font-weight: 800;
}

.nn-app-main {
  width: 100%;
  max-width: 1480px;
  margin: 0 auto;
  padding: 24px;
}

.nn-app-footer {
  width: 100%;
  max-width: 1480px;
  margin: auto auto 0;
  padding: 18px 24px 24px;
  color: #667085;
  font-size: 0.92rem;
}

.nn-app-footer a {
  color: #475467;
  text-decoration: none;
}

.nn-app-footer a:hover {
  color: var(--accent);
  text-decoration: underline;
}

.nn-app-backdrop {
  display: none;
}

/* iPad landscape and narrower laptop views: keep navigation visible,
   but collapse labels so the dashboard/table keeps useful width. */
@media (max-width: 1180px) and (min-width: 768px) {
  .nn-app-shell {
    grid-template-columns: var(--nn-sidebar-compact) minmax(0, 1fr);
  }

  .nn-app-sidebar {
    width: var(--nn-sidebar-compact);
  }

.nn-app-sidebar__brand {
  justify-content: center;
  min-height: 58px;
  padding: 8px 0;
}

  .nn-app-sidebar__logo {
    justify-content: center;
  }

  .nn-app-sidebar__logo > span,
  .nn-app-sidebar__link > span:not(.nn-avatar) {
    position: absolute;
    width: 1px;
    height: 1px;
    overflow: hidden;
    clip: rect(0 0 0 0);
    white-space: nowrap;
  }
  
 .nn-app-sidebar__section-label {
    display: none;
  }

  .nn-app-sidebar__nav,
  .nn-app-sidebar__footer {
    padding-left: 10px;
    padding-right: 10px;
  }

  .nn-app-sidebar__link {
    justify-content: center;
    padding: 0;
  }

  .nn-app-sidebar__link i {
    width: auto;
    flex-basis: auto;
    font-size: 1.08rem;
  }

  .nn-app-sidebar__link.is-active::before {
    left: -10px;
  }

  .nn-app-main {
    padding: 20px;
  }
  
 
  .nn-app-sidebar__logo img {
    height: 32px;
  }

  .nn-app-sidebar__nav {
    gap: 3px;
    padding-top: 10px;
    padding-bottom: 10px;
  }

  .nn-app-sidebar__link {
    min-height: 46px;
  }

  .nn-app-sidebar__footer {
    padding: 8px 10px;
  }

  .nn-app-sidebar__account-separator {
    margin-right: 4px;
    margin-left: 4px;
  }
}

/* Phone: sidebar becomes an off-canvas drawer. */
@media (max-width: 767px) {
  .nn-app-shell {
    display: block;
    min-height: 100vh;
  }

  .nn-app-sidebar {
    position: fixed;
    inset: 0 auto 0 0;
    width: min(320px, 86vw);
    max-width: 86vw;
    transform: translateX(-105%);
    transition: transform 0.22s ease;
    box-shadow: 24px 0 42px rgba(15, 23, 42, 0.18);
  }

  body.nn-app-menu-open .nn-app-sidebar {
    transform: translateX(0);
  }

  .nn-app-backdrop {
    position: fixed;
    inset: 0;
    z-index: 1090;
    display: none;
    border: 0;
    background: rgba(15, 23, 42, 0.42);
    cursor: pointer;
  }

  body.nn-app-menu-open .nn-app-backdrop {
    display: block;
  }

  .nn-app-topbar {
    position: sticky;
    top: 0;
    z-index: 1000;
    display: flex;
    align-items: center;
    gap: 10px;
    width: 100%;
    min-width: 0;
    min-height: var(--nn-topbar-height);
    padding: 0 14px;
    background: var(--nn-sidebar-bg);
    border-bottom: 1px solid var(--nn-sidebar-border);
    box-shadow: 0 1px 0 rgba(255, 255, 255, 0.04);
  }

  .nn-app-topbar__brand-link {
    display: inline-flex;
    align-items: center;
    gap: 9px;
    min-width: 0;
    color: var(--nn-sidebar-text);
    font-size: 1rem;
    font-weight: 700;
    letter-spacing: -.02em;
    text-decoration: none;
    white-space: nowrap;
  }

  .nn-app-topbar__brand-link:hover,
  .nn-app-topbar__brand-link:focus-visible {
    color: var(--nn-sidebar-text);
    text-decoration: none;
  }

  .nn-app-topbar__brand-link:focus-visible,
  .nn-app-menu-button:focus-visible {
    outline: 2px solid var(--nn-color-accent);
    outline-offset: 2px;
  }

  .nn-app-topbar__brand-link img {
    width: 28px;
    height: 28px;
    object-fit: contain;
  }

  .nn-app-topbar__spacer {
    flex: 1 1 auto;
    min-width: 0;
  }

  .nn-app-menu-button {
    display: inline-flex;
    flex: 0 0 44px;
    width: 44px;
    height: 44px;
    border-color: var(--nn-sidebar-border);
    border-radius: var(--nn-radius-control, 6px);
    background: transparent;
    color: var(--nn-sidebar-text);
  }

  .nn-app-menu-button:hover {
    background: var(--nn-sidebar-hover-bg);
    color: var(--nn-sidebar-text);
  }

  .nn-app-topbar__user {
    flex: 0 0 auto;
  }

  .nn-app-topbar__avatar {
    width: 40px;
    height: 40px;
    flex-basis: 40px;
    background: var(--nn-color-accent);
    color: var(--nn-sidebar-text);
  }

  body.nn-student-view .nn-student-dashboard__intro > .nn-student-dashboard__avatar,
  body.nn-student-view .nn-student-page-heading > .nn-student-dashboard__avatar {
    display: none;
  }

  .nn-app-main {
    padding: 14px;
  }

  .nn-app-footer {
    padding: 18px 14px 24px;
  }
  
.nn-app-main {
  font-size: 0.95rem;
}

.nn-app-main p,
.nn-app-main li,
.nn-app-main label,
.nn-app-main input,
.nn-app-main select,
.nn-app-main textarea,
.nn-app-main button,
.nn-app-main table,
.nn-app-main th,
.nn-app-main td {
  font-size: 0.92rem;
}  
  
}

/* =========================================================
   Teacher app typography scale
   ---------------------------------------------------------
   Reduces teacher-facing page text without affecting sidebar.
   ========================================================= */

.nn-app-main {
  font-size: 0.92rem;
}

.nn-app-main h1,
.nn-app-main .nn-page-title,
.nn-app-main .nn-dashboard-title,
.nn-app-main .nn-invoicing__title {
  font-size: clamp(1.55rem, 2.5vw, 2.2rem);
  line-height: 1.05;
}

.nn-app-main h2,
.nn-app-main .nn-panel__title,
.nn-app-main .nn-invoicing-panel__header h2 {
  font-size: 1.05rem;
  line-height: 1.2;
}

.nn-app-main h3 {
  font-size: 0.98rem;
  line-height: 1.25;
}

.nn-app-main p,
.nn-app-main li,
.nn-app-main label,
.nn-app-main input,
.nn-app-main select,
.nn-app-main textarea,
.nn-app-main button,
.nn-app-main table,
.nn-app-main th,
.nn-app-main td {
  font-size: 0.9rem;
}

.nn-app-main small,
.nn-app-main .nn-muted,
.nn-app-main .nn-invoicing__eyebrow,
.nn-app-main .nn-invoicing-card__label,
.nn-app-main .nn-invoicing-table th {
  font-size: 0.78rem;
}

.nn-app-main .nn-invoicing-card__value,
.nn-app-main .nn-dashboard-stat__value,
.nn-app-main .nn-stat-card__value {
  font-size: 1.45rem;
  line-height: 1;
}

.nn-app-main .nn-invoicing__intro,
.nn-app-main .nn-dashboard-intro,
.nn-app-main .nn-page-intro {
  font-size: 0.9rem;
}


/* Collapsible, module-aware sidebar navigation. */
.nn-app-sidebar__separator {
  height: 1px;
  margin: 10px 8px;
  background: var(--nn-sidebar-border);
}

.nn-app-sidebar__group { min-width: 0; }
.nn-app-sidebar__toggle {
  width: 100%;
  border: 0;
  background: transparent;
  text-align: left;
  cursor: pointer;
  font-family: inherit;
}
.nn-app-sidebar__toggle .nn-app-sidebar__chevron {
  width: auto;
  margin-left: auto;
  flex: 0 0 auto;
  font-size: .72rem;
  transition: transform .2s ease;
}
.nn-app-sidebar__group.is-open .nn-app-sidebar__chevron { transform: rotate(180deg); }

.nn-app-sidebar__submenu {
  display: grid;
  grid-template-rows: 0fr;
  transition: grid-template-rows .2s ease;
}
.nn-app-sidebar__group.is-open .nn-app-sidebar__submenu { grid-template-rows: 1fr; }
.nn-app-sidebar__submenu-inner { min-height: 0; overflow: hidden; }
.nn-app-sidebar__sublink {
  display: flex;
  align-items: center;
  min-height: 36px;
  margin: 2px 0 2px 46px;
  padding: 0 12px;
  border-radius: 10px;
  color: var(--nn-sidebar-muted);
  font-size: .9rem;
  font-weight: 600;
  text-decoration: none;
  transition: background .18s ease, color .18s ease;
}
.nn-app-sidebar__sublink.nn-app-sidebar__sublink--separated {
  position: relative;
  margin-top: 26px;
}
.nn-app-sidebar__sublink--separated::before {
  position: absolute;
  top: -14px;
  right: 0;
  left: 0;
  height: 1px;
  background: var(--nn-sidebar-border);
  content: "";
  pointer-events: none;
}
.nn-app-sidebar__sublink:hover,
.nn-app-sidebar__sublink:focus-visible {
  color: var(--nn-sidebar-text);
  background: var(--nn-sidebar-hover-bg);
  text-decoration: none;
}
.nn-app-sidebar__sublink.is-active {
  color: var(--nn-sidebar-active-text);
  background: var(--nn-sidebar-active-bg);
}

@media (max-width: 1180px) and (min-width: 768px) {
  /* Tablet icon rail: submenus become touch-friendly fly-out panels. */
  .nn-app-sidebar {
    overflow: visible;
  }

  .nn-app-sidebar__group {
    position: relative;
  }

  .nn-app-sidebar__toggle .nn-app-sidebar__chevron {
    display: none;
  }

  .nn-app-sidebar__group .nn-app-sidebar__submenu {
    position: fixed;
    z-index: 1250;
    top: var(--nn-flyout-top, 80px);
    left: var(--nn-flyout-left, var(--nn-sidebar-compact));
    display: block;
    width: min(280px, calc(100vw - var(--nn-sidebar-compact) - 20px));
    grid-template-rows: 1fr;
    padding-left: 10px;
    visibility: hidden;
    opacity: 0;
    pointer-events: none;
    transform: translateX(-6px);
    transition: opacity .16s ease, transform .16s ease, visibility 0s linear .16s;
  }

  .nn-app-sidebar__group.is-open .nn-app-sidebar__submenu {
    visibility: visible;
    opacity: 1;
    pointer-events: auto;
    transform: translateX(0);
    transition-delay: 0s;
  }

  .nn-app-sidebar__submenu-inner {
    position: relative;
    min-height: auto;
    overflow: visible;
    padding: 10px;
    border: 1px solid var(--nn-sidebar-border);
    border-radius: 14px;
    background: var(--nn-sidebar-bg);
    box-shadow: 0 16px 38px rgba(15, 23, 42, .16);
  }

  .nn-app-sidebar__submenu-inner::before {
    content: "";
    position: absolute;
    top: 18px;
    left: -8px;
    width: 14px;
    height: 14px;
    background: var(--nn-sidebar-bg);
    border-left: 1px solid var(--nn-sidebar-border);
    border-bottom: 1px solid var(--nn-sidebar-border);
    transform: rotate(45deg);
  }

  .nn-app-sidebar__submenu-title {
    display: block;
    margin: 0 2px 6px;
    padding: 7px 10px 10px;
    color: var(--nn-color-accent);
    font-size: .78rem;
    font-weight: 800;
    letter-spacing: .04em;
    text-transform: uppercase;
    border-bottom: 1px solid var(--nn-sidebar-border);
  }

  .nn-app-sidebar__sublink {
    min-height: 42px;
    margin: 2px 0;
    padding: 0 12px;
    border-radius: 9px !important;
    color: var(--nn-sidebar-text);
    background: transparent;
    font-size: .9rem;
    font-weight: 500;
  }

  .nn-app-sidebar__sublink:hover,
  .nn-app-sidebar__sublink:focus-visible {
    color: var(--nn-sidebar-text);
    background: var(--nn-sidebar-hover-bg);
  }

  .nn-app-sidebar__sublink.is-active {
    color: var(--nn-sidebar-active-text);
    background: var(--nn-sidebar-active-bg);
    font-weight: 650;
  }

  .nn-app-sidebar__sublink span {
    position: static;
    width: auto;
    height: auto;
    overflow: visible;
    clip: auto;
    white-space: normal;
  }

  .nn-app-sidebar__group.is-open > .nn-app-sidebar__toggle {
    background: var(--nn-sidebar-active-bg);
    color: var(--nn-sidebar-active-text);
  }

  .nn-app-sidebar__group.is-open > .nn-app-sidebar__toggle > i:first-child {
    display: inline-block;
    visibility: visible;
    opacity: 1;
    color: var(--nn-color-accent);
  }
}

@media (min-width: 1181px), (max-width: 767px) {
  .nn-app-sidebar__submenu-title {
    display: none;
  }
}