/* =========================================================================
   APP SHELL — sidebar + main area flex layout
   ========================================================================= */
.app-shell {
  display: flex;
  min-height: 100vh;
}
.app-main {
  flex: 1;
  min-width: 0;
  display: flex;
  flex-direction: column;
}
/* Editor page: sidebar starts collapsed, togglable via body class */
.editor-page .sidebar {
  margin-left: -260px;
  transition: margin-left 0.25s ease;
}
.editor-page.sidebar-open .sidebar {
  margin-left: 0;
}
.editor-page .sidebar-toggle {
  display: block;
}
.editor-page .container {
  max-width: none !important;
  padding: 0;
}
.editor-page.sidebar-open .editor-float-statusbar,
.editor-page.sidebar-open .editor-float-toolbar {
  left: 260px;
}

/* =========================================================================
   SIDEBAR — persistent left-edge nav (desktop), hidden (mobile)
   ========================================================================= */
.sidebar {
  width: 260px;
  flex-shrink: 0;
  background: var(--md-sys-color-surface-container-low);
  display: flex;
  flex-direction: column;
  padding: 1.25rem 0.75rem;
  gap: 0.5rem;
  height: 100vh;
  position: sticky;
  top: 0;
  overflow-y: auto;
}
.sidebar__brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.5rem 0.75rem;
  margin-bottom: 1.5rem;
}
.sidebar__brand-mark {
  width: 36px;
  height: 36px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  text-decoration: none;
  flex-shrink: 0;
}
.sidebar__brand-mark svg {
  width: 36px;
  height: 36px;
  border-radius: var(--md-sys-shape-corner-medium);
}
.sidebar__brand-name {
  font: 800 1.125rem/1.2 var(--md-sys-typescale-font-shell);
  color: var(--md-sys-color-primary);
  text-decoration: none;
  text-transform: uppercase;
  letter-spacing: -0.01em;
  display: block;
}
.sidebar__brand-tagline {
  font: 600 0.5625rem/1.3 var(--md-sys-typescale-font-label);
  color: var(--md-sys-color-on-surface-variant);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  display: block;
  margin-top: 0.125rem;
}
.sidebar__nav {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}
.sidebar__link {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.625rem 0.875rem;
  border-radius: var(--md-sys-shape-corner-large);
  color: var(--md-sys-color-on-surface-variant);
  font: 600 0.75rem/1.4 var(--md-sys-typescale-font-label);
  letter-spacing: 0.04em;
  text-transform: uppercase;
  text-decoration: none;
  transition:
    background-color var(--md-sys-motion-duration-short) var(--md-sys-motion-easing-standard),
    color var(--md-sys-motion-duration-short) var(--md-sys-motion-easing-standard),
    transform var(--md-sys-motion-duration-short) var(--md-sys-motion-easing-standard);
}
.sidebar__link:hover {
  background: color-mix(in srgb, var(--md-sys-color-on-surface) 5%, transparent);
  transform: translateX(2px);
  text-decoration: none;
}
.sidebar__link.is-active {
  background: var(--md-sys-color-surface-container-lowest);
  color: var(--md-sys-color-primary);
  font-weight: 700;
  box-shadow: var(--md-sys-elevation-1);
}
.sidebar__footer {
  padding-top: 0.75rem;
  margin-top: auto;
  box-shadow: inset 0 1px 0 0 var(--md-sys-color-ghost-stroke);
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.app-footer {
  padding: 1rem 1.5rem 1.25rem;
  margin-top: auto;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.625rem 1.25rem;
  border-top: 1px solid var(--md-sys-color-ghost-stroke, rgba(0, 0, 0, 0.08));
}

.app-footer a {
  font-size: 0.75rem;
  text-decoration: none;
  color: var(--md-sys-color-outline, #76767a);
}

.app-footer a:hover {
  color: var(--md-sys-color-primary, #231f73);
}

/* Mobile hamburger toggle */
.sidebar-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 1.5rem;
  color: var(--md-sys-color-on-surface);
  cursor: pointer;
  padding: 0.25rem;
}

@media (max-width: 768px) {
  .sidebar {
    position: fixed;
    left: 0;
    top: 0;
    z-index: 60;
    transform: translateX(-100%);
    transition: transform var(--md-sys-motion-duration-medium) var(--md-sys-motion-easing-standard);
    box-shadow: var(--md-sys-elevation-3);
  }
  body.sidebar-open .sidebar {
    transform: translateX(0);
  }
  .sidebar-toggle {
    display: block;
  }
}

/* =========================================================================
   TOP APP BAR — streamlined: hamburger (mobile) + spacer + user actions
   ========================================================================= */
.md-top-app-bar {
  position: sticky;
  top: 0;
  z-index: 10;
  background: var(--md-sys-color-surface-container-low);
  color: var(--md-sys-color-on-surface);
  height: 72px;
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 0 2rem;
  transition:
    background-color var(--md-sys-motion-duration-medium) var(--md-sys-motion-easing-standard),
    backdrop-filter var(--md-sys-motion-duration-medium) var(--md-sys-motion-easing-standard);
}
/* Glassmorphic lift on scroll — a floating header that recedes behind
   the content instead of casting a hard shadow. 85% opacity + 20px
   backdrop blur is the Glass & Gradient rule. */
body.is-scrolled .md-top-app-bar {
  background: color-mix(in srgb, var(--md-sys-color-surface-container-lowest) 85%, transparent);
  backdrop-filter: blur(20px) saturate(140%);
  -webkit-backdrop-filter: blur(20px) saturate(140%);
}

/* Leading circular mark — abstract "G" in the primary-fixed-dim tint.
   Uses the fixed-dim token so the mark reads consistently across light
   and dark schemes without needing a per-scheme override. */
.md-top-app-bar__mark {
  width: 40px;
  height: 40px;
  border-radius: var(--md-sys-shape-corner-full);
  background: var(--md-sys-gradient-primary);
  color: var(--md-sys-color-on-primary);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font: 800 1.125rem/1 var(--md-sys-typescale-font-shell);
  letter-spacing: -0.02em;
  flex-shrink: 0;
  text-decoration: none;
}

.md-top-app-bar__brand {
  font: 800 1.25rem/1.2 var(--md-sys-typescale-font-shell);
  color: var(--md-sys-color-on-surface);
  text-decoration: none;
  letter-spacing: -0.01em;
  text-transform: uppercase;
}
.md-top-app-bar__brand:hover {
  text-decoration: none;
  color: var(--md-sys-color-primary);
}
.md-top-app-bar__tagline {
  color: var(--md-sys-color-on-surface-variant);
  margin-left: 0.25rem;
  font: 500 0.6875rem/1.4 var(--md-sys-typescale-font-label);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

/* Pushes trailing content to the right edge. */
.md-top-app-bar__spacer {
  flex: 1;
}

/* Trailing nav — label-voice links with a subtle active underline
   in the primary color. The previous pill-background is out; the
   Scholarly Lens spec calls for more restrained chrome. */
.md-top-app-bar__nav {
  display: flex;
  gap: 0.5rem;
  align-items: center;
}
.md-top-app-bar__link {
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  height: 40px;
  padding: 0 0.875rem;
  border-radius: var(--md-sys-shape-corner-medium);
  color: var(--md-sys-color-on-surface-variant);
  font: 600 0.8125rem/1.4 var(--md-sys-typescale-font-label);
  letter-spacing: 0.005em;
  text-decoration: none;
  transition:
    color var(--md-sys-motion-duration-short) var(--md-sys-motion-easing-standard),
    background-color var(--md-sys-motion-duration-short) var(--md-sys-motion-easing-standard);
}
.md-top-app-bar__link:hover {
  color: var(--md-sys-color-on-surface);
  background: var(--md-sys-color-surface-container-high);
  text-decoration: none;
}
.md-top-app-bar__link.is-active {
  color: var(--md-sys-color-primary);
  background: transparent;
  position: relative;
}
.md-top-app-bar__link.is-active::after {
  content: "";
  position: absolute;
  left: 0.875rem;
  right: 0.875rem;
  bottom: 6px;
  height: 2px;
  background: var(--md-sys-gradient-primary);
  border-radius: var(--md-sys-shape-corner-full);
}

/* Responsive: hide tagline on narrow screens so the brand wins. */
@media (max-width: 720px) {
  .md-top-app-bar {
    padding: 0 1rem;
    gap: 0.5rem;
  }
  .md-top-app-bar__tagline {
    display: none;
  }
  .md-top-app-bar__link {
    padding: 0 12px;
  }
}

/* =========================================================================
   BREADCRUMBS
   =========================================================================
   Breadcrumbs aren't a native Material component (M3 recommends top-app-bar
   navigation for most flows), but the pattern is a standard web convention
   and useful for this app's 3-level nesting: assignment -> submission ->
   {editor|replay|diff}. Built on M3 tokens for color and type so it feels
   of-a-piece with the rest of the UI.

   Markup is `<nav aria-label="Breadcrumb"><ol>...<li aria-current="page">`,
   generated by the `breadcrumbs` ApplicationHelper. The current page item
   renders without an <a> and is visually emphasized. */
.md-breadcrumbs {
  margin: 0 0 1.25rem;
  font: 500 0.6875rem/1.4 var(--md-sys-typescale-font-label);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}
.md-breadcrumbs__list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0;
}
.md-breadcrumbs__item {
  display: inline-flex;
  align-items: center;
  color: var(--md-sys-color-on-surface-variant);
}
.md-breadcrumbs__item + .md-breadcrumbs__item::before {
  content: "";
  display: inline-block;
  width: 6px;
  height: 6px;
  margin: 0 0.75rem;
  border-top: 1.5px solid var(--md-sys-color-outline-variant);
  border-right: 1.5px solid var(--md-sys-color-outline-variant);
  transform: rotate(45deg);
}
.md-breadcrumbs__item a {
  color: var(--md-sys-color-on-surface-variant);
  text-decoration: none;
  padding: 4px 8px;
  border-radius: var(--md-sys-shape-corner-extra-small);
  transition:
    background-color var(--md-sys-motion-duration-short) var(--md-sys-motion-easing-standard),
    color var(--md-sys-motion-duration-short) var(--md-sys-motion-easing-standard);
}
.md-breadcrumbs__item a:hover {
  background: color-mix(in srgb, var(--md-sys-color-primary) 8%, transparent);
  color: var(--md-sys-color-on-surface);
  text-decoration: none;
}
.md-breadcrumbs__item[aria-current="page"] {
  color: var(--md-sys-color-on-surface);
  font-weight: 500;
}