/* Skip link: the first thing a keyboard user reaches, hidden until it has focus. */

.skip-link {
  position: fixed;
  inset-block-start: var(--space-sm);
  inset-inline-start: var(--space-sm);
  z-index: var(--z-skip-link);
  padding-block: var(--space-xs);
  padding-inline: var(--space-md);
  background-color: var(--color-surface);
  color: var(--color-text);
  border: var(--border-width) solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-md);
  text-decoration: none;
}

.skip-link:not(:focus) {
  box-shadow: none;
}

/* Signed-in shell: a floating sidebar pane on the left, a floating page capsule above the content. */

.app-shell {
  --page-inset: var(--space-lg);
  --shell-inset: var(--space-md);
  --topbar-offset: calc(var(--shell-inset) + var(--topbar-height));

  display: grid;
  grid-template-columns: calc(var(--sidebar-width) + var(--shell-inset)) minmax(0, var(--content-width));
  grid-template-rows: auto minmax(0, 1fr);
  grid-template-areas:
    "sidebar topbar"
    "sidebar main";
  justify-content: center;
  min-block-size: 100dvh;
}

.app-shell__backdrop {
  --backdrop-fade: calc(var(--shell-inset) + var(--page-inset) + var(--space-xl));
  --backdrop-shell-inline-start: max(
    0px,
    calc(50% - (var(--shell-inset) + var(--sidebar-width) + var(--content-width)) / 2)
  );
  --backdrop-hold-inline: calc(
    var(--backdrop-shell-inline-start) + var(--shell-inset) + var(--sidebar-width)
  );
  --backdrop-shell-inline-end: calc(var(--backdrop-hold-inline) + var(--content-width));
  --backdrop-hold-block: var(--topbar-offset);
  --icon-grid-opacity: 12%;

  position: fixed;
  inset: 0;
  z-index: var(--z-behind);
  overflow: clip;
  isolation: isolate;
  pointer-events: none;
  mask-image:
    linear-gradient(
      to right,
      transparent calc(var(--backdrop-shell-inline-start) - var(--backdrop-fade)),
      #000 var(--backdrop-shell-inline-start),
      #000 var(--backdrop-shell-inline-end),
      transparent calc(var(--backdrop-shell-inline-end) + var(--backdrop-fade))
    ),
    linear-gradient(
      to right,
      #000 var(--backdrop-hold-inline),
      transparent calc(var(--backdrop-hold-inline) + var(--backdrop-fade))
    ),
    linear-gradient(
      to bottom,
      #000 var(--backdrop-hold-block),
      transparent calc(var(--backdrop-hold-block) + var(--backdrop-fade))
    );
  mask-composite: intersect, add;
}

.app-sidebar,
.app-topbar,
.app-navbar {
  border: var(--border-width) solid var(--color-border);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-md);
}

.app-sidebar {
  --sidebar-inset: var(--space-sm);

  grid-area: sidebar;
  position: sticky;
  inset-block-start: var(--shell-inset);
  align-self: start;
  block-size: calc(100dvh - 2 * var(--shell-inset));
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  margin-block: var(--shell-inset);
  margin-inline-start: var(--shell-inset);
  padding: var(--sidebar-inset);
}

.app-sidebar__brand {
  display: block;
  padding: var(--space-xs);
  font-size: var(--font-size-heading-2);
  color: var(--color-text);
  text-decoration: none;
}

@property --nav-fade-start {
  syntax: "<length>";
  inherits: false;
  initial-value: 0px;
}

@property --nav-fade-end {
  syntax: "<length>";
  inherits: false;
  initial-value: 0px;
}

.app-sidebar__nav {
  --nav-fade-size: var(--space-xl);
  --nav-ring-space: calc(var(--focus-ring-width) + var(--focus-ring-offset));

  display: flex;
  flex-direction: column;
  gap: var(--space-2xs);
  min-block-size: 0;
  overflow-y: auto;
  overscroll-behavior: contain;
  margin-block: calc(-1 * var(--nav-ring-space));
  margin-inline: calc(-1 * var(--sidebar-inset));
  padding-block: var(--nav-ring-space);
  padding-inline: var(--sidebar-inset);
  mask-image: linear-gradient(
    to bottom,
    transparent 0,
    #000 var(--nav-fade-start),
    #000 calc(100% - var(--nav-fade-end)),
    transparent 100%
  );
}

@supports (animation-timeline: scroll()) {
  .app-sidebar__nav {
    scroll-timeline-name: --sidebar-nav;
    scroll-timeline-axis: block;
    animation-name: sidebar-nav-fade-start, sidebar-nav-fade-end;
    animation-timeline: --sidebar-nav, --sidebar-nav;
    animation-range: 0 var(--nav-fade-size), calc(100% - var(--nav-fade-size)) 100%;
    animation-fill-mode: both;
    animation-timing-function: linear;
  }
}

@keyframes sidebar-nav-fade-start {
  from { --nav-fade-start: 0px; }
  to { --nav-fade-start: var(--nav-fade-size); }
}

@keyframes sidebar-nav-fade-end {
  from { --nav-fade-end: var(--nav-fade-size); }
  to { --nav-fade-end: 0px; }
}

.app-sidebar__divider {
  block-size: 0;
  margin-block: var(--space-2xs);
  border-block-start: var(--border-width) solid var(--color-border);
}

.app-sidebar__household {
  margin-block-start: auto;
}

@property --topbar-overhang {
  syntax: "<length>";
  inherits: false;
  initial-value: 0px;
}

.app-topbar {
  --topbar-overhang: var(--space-xs);
  --topbar-margin-inline: calc(var(--page-inset) - var(--topbar-overhang));
  --control-radius: var(--radius-pill);
  --topbar-padding-inline: calc((var(--topbar-height) - var(--control-block-size)) / 2);

  grid-area: topbar;
  position: sticky;
  inset-block-start: var(--shell-inset);
  z-index: var(--z-sticky);
  min-block-size: var(--topbar-height);
  max-inline-size: calc(var(--content-width) - 2 * var(--topbar-margin-inline));
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: center;
  gap: var(--space-md);
  margin-block-start: var(--shell-inset);
  margin-inline: var(--topbar-margin-inline);
  padding-inline: var(--topbar-padding-inline);
}

@supports (animation-timeline: scroll()) {
  .app-topbar {
    --topbar-overhang: 0px;

    animation-name: topbar-overhang;
    animation-timeline: scroll(root block);
    animation-range: var(--page-inset) calc(2 * var(--page-inset) + var(--topbar-height));
    animation-fill-mode: both;
    animation-timing-function: linear;
  }
}

@keyframes topbar-overhang {
  from { --topbar-overhang: 0px; }
  to { --topbar-overhang: var(--space-sm); }
}

.app-topbar .page-header__title:first-child {
  margin-inline-start: calc(var(--radius-xl) - var(--topbar-padding-inline));
}

.app-topbar__avatar {
  --icon-size: var(--icon-size-md);
}

.app-navbar {
  position: fixed;
  inset-block-end: var(--dock-inset-block-end);
  inset-inline: var(--shell-inset);
  z-index: var(--z-sticky);
  display: none;
}

.app-navbar .nav-link {
  border-radius: calc(var(--radius-xl) - var(--space-2xs));
}

.app-navbar__nav {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  align-items: stretch;
  gap: var(--space-2xs);
  min-block-size: var(--navbar-height);
  padding: var(--space-2xs);
}

.app-navbar__nav > li {
  display: grid;
}

.preview-main,
.app-main {
  container: page / inline-size;
  grid-area: main;
  inline-size: 100%;
  max-inline-size: var(--content-width);
  padding-block: var(--page-inset) var(--space-3xl);
  padding-inline: var(--page-inset);
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
}

.auth-shell {
  --auth-shell-inset-block-start: 10dvh;

  min-block-size: 100dvh;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-lg);
  padding: var(--space-lg);
  padding-block-start: var(--auth-shell-inset-block-start);
}

.auth-shell__brand {
  font-size: var(--font-size-display);
}

.auth-shell__panel {
  --auth-panel-inline-size: 24rem;

  inline-size: 100%;
  max-inline-size: var(--auth-panel-inline-size);
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

@media (width <= 48rem) {
  .app-main {
    --card-bleed: calc(-1 * var(--page-inset));
    --card-padding-inline: var(--space-sm);
    --card-padding-block: var(--space-sm);
    --card-border-width: 0;
    --card-radius: 0;

    padding-block: var(--space-lg) calc(var(--dock-height) + var(--dock-inset-block-end));
  }

  .app-shell {
    --page-inset: var(--space-md);
    --topbar-gap: var(--space-xs);
    --dock-inset-block-end: 4px;
    --dock-height: calc(
      var(--dock-inset-block-end) + var(--navbar-height) + var(--topbar-gap) + var(--topbar-height)
    );

    grid-template-columns: minmax(0, 1fr);
    grid-template-rows: minmax(0, 1fr);
    grid-template-areas: "main";
  }

  @media (display-mode: standalone) {
    .app-shell {
      --dock-inset-block-end: var(--space-lg);
    }
  }

  .app-shell__backdrop {
    --backdrop-hold-block: var(--dock-height);

    mask-image: linear-gradient(
      to top,
      #000 var(--backdrop-hold-block),
      transparent calc(var(--backdrop-hold-block) + var(--backdrop-fade))
    );
  }

  .app-shell .app-sidebar,
  .app-shell .app-topbar__user {
    display: none;
  }

  .app-topbar {
    position: fixed;
    inset-block: auto calc(var(--dock-inset-block-end) + var(--navbar-height) + var(--topbar-gap));
    inset-inline: var(--shell-inset);
    max-inline-size: none;
    grid-template-columns: minmax(0, 1fr);
    margin: 0;
  }

  .app-topbar .page-header__title {
    margin-inline-start: calc(var(--radius-xl) - var(--topbar-padding-inline));
  }

  .app-topbar:not(:has(.page-header__back)) .page-header__title {
    position: absolute;
    inline-size: 1px;
    block-size: 1px;
    clip-path: inset(50%);
  }

  .app-shell:not(:has(.app-topbar :is(.page-header__back, .page-header__actions))) {
    --topbar-height: 0px;
    --topbar-gap: 0px;
  }

  .app-topbar:not(:has(.page-header__back, .page-header__actions)) {
    background-color: transparent;
    backdrop-filter: none;
    border: 0;
    box-shadow: none;
  }

  .app-topbar:not(:has(.page-header__back, .page-header__actions)) .page-header {
    min-block-size: 0;
  }

  .app-navbar {
    display: block;
  }
}