discourse/app/assets/stylesheets/common/components/site-skeleton.scss

.site-skeleton {
  // Derived from the active color scheme so the skeleton matches any theme.
  --site-skeleton-accent: var(--tertiary);
  --site-skeleton-accent-soft: var(--tertiary-hover);
  --site-skeleton-bg: var(--tertiary-low);
  --site-skeleton-content-bg: var(--secondary);
  --site-skeleton-muted: var(--primary-medium);
  --site-skeleton-border: var(--primary-low);
  --site-skeleton-sidebar-border: var(--primary-low);
  --site-skeleton-sidebar-active: var(--tertiary-medium);
  --site-skeleton-search-bg: var(--secondary);

  // Fixed lavender-grey placeholder tone (reads as neutral "text", so it
  // intentionally doesn't track the theme accent). Light/dark variants keep the
  // bars legible against the surface in either color mode.
  --site-skeleton-line: light-dark(#c3cbe0, #7b7f88);
  --site-skeleton-line-strong: light-dark(#aab4d2, #969aa3);
  --site-skeleton-scrim: rgb(var(--secondary-rgb), 0.18);
  --site-skeleton-sweep: rgb(var(--primary-rgb), 0.06);
  position: fixed;
  inset: 0;
  z-index: 0;
  background: var(--site-skeleton-bg);
  filter: saturate(0.72);
  opacity: 0.78;
  pointer-events: none;
  user-select: none;
}

.site-skeleton::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 2;
  background: var(--site-skeleton-scrim);
  backdrop-filter: blur(1.5px);
}

// Sweeping highlight that gives every placeholder bar its shimmer.
.site-skeleton::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 1;
  background: linear-gradient(
    110deg,
    transparent 0%,
    transparent 28%,
    var(--site-skeleton-sweep) 45%,
    transparent 62%,
    transparent 100%
  );
  animation: siteSkeletonSweep 3.8s ease-in-out infinite;
}

// Generic placeholder bar that stands in for any line of text.
.site-skeleton__bar {
  display: block;
  width: 55%;
  height: 0.62rem;
  border-radius: 999px;
  background: var(--site-skeleton-line);

  &.--xs {
    width: 22%;
  }

  &.--sm {
    width: 38%;
  }

  &.--md {
    width: 55%;
  }

  &.--lg {
    width: 78%;
  }

  &.--full {
    width: 100%;
  }

  &.--title {
    width: 34%;
    height: 0.46rem;
  }

  &.--strong {
    height: 0.85rem;
    background: var(--site-skeleton-line-strong);
  }

  &.--heading {
    height: 1rem;
    border-radius: 6px;
    background: var(--site-skeleton-line-strong);
  }

  &.--brand {
    width: 92px;
    height: 0.7rem;
  }

  &.--accent {
    background: var(--site-skeleton-accent);
    opacity: 0.85;
  }
}

.site-skeleton__header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1;
  display: grid;
  grid-template-columns: 300px minmax(0, 1fr) max-content max-content;
  column-gap: 0.85rem;
  align-items: center;
  height: 48px;
  background: var(--site-skeleton-bg);
}

.site-skeleton__brand {
  display: flex;
  align-items: center;
  gap: 1.25rem;
  padding: 0 1.65rem;
}

.site-skeleton__menu {
  display: flex;
  align-items: center;
  color: var(--site-skeleton-accent-soft);
  font-size: 1.35rem;
  line-height: 1;
}

.site-skeleton__chat {
  display: flex;
  align-items: center;
  grid-column: 3;
  justify-self: end;
  color: var(--site-skeleton-accent-soft);
  font-size: 1.35rem;
  line-height: 1;
}

.site-skeleton__avatar {
  grid-column: 4;
  width: 2.25rem;
  height: 2.25rem;
  border-radius: 50%;
  margin-right: 1.25rem;
  background: var(--site-skeleton-line-strong);
}

.site-skeleton__body {
  display: grid;
  grid-template-columns: 300px minmax(720px, 1fr);
  min-height: 100%;
  padding-top: 48px;
  background: var(--site-skeleton-bg);
}

.site-skeleton__sidebar,
.site-skeleton__content {
  min-width: 0;
}

.site-skeleton__sidebar {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  padding: 0.25rem 1.3rem 1rem;
}

.site-skeleton__new-topic {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 36px;
  margin: 0.1rem 0 1.45rem;
  border-radius: 999px;
  background: var(--site-skeleton-accent);
}

.site-skeleton__nav-item,
.site-skeleton__category {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  min-height: 2rem;
  padding: 0.3rem 0.55rem;
  border-radius: 7px;
  line-height: 1.2;
}

.site-skeleton__nav-item.--active {
  background: var(--site-skeleton-sidebar-active);
}

.site-skeleton__nav-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 1rem;
  color: var(--site-skeleton-muted);
  flex: 0 0 auto;
  font-size: 0.95rem;
  line-height: 1;
}

.site-skeleton__sidebar-section {
  margin-top: 1rem;
  padding-top: 0.65rem;
  border-top: 1px solid var(--site-skeleton-sidebar-border);
}

.site-skeleton__sidebar-title {
  padding: 0 0.55rem 0.7rem;
}

.site-skeleton__category-dot {
  width: 0.75rem;
  height: 0.75rem;
  border-radius: 50%;
  flex: 0 0 auto;
}

// Fixed swatches standing in for real category/channel colors (these mimic
// arbitrary per-category colors, not the theme palette).
.site-skeleton__category-dot.--blue {
  background: #2da8e8;
}

.site-skeleton__category-dot.--light-blue {
  background: #bfe8fb;
}

.site-skeleton__category-dot.--staff {
  background: linear-gradient(90deg, #2c95d3 0 50%, #4961bf 50% 100%);
}

.site-skeleton__channel {
  width: 14px;
  height: 12px;
  border-radius: 999px;
  flex: 0 0 auto;
}

.site-skeleton__channel.--blue {
  background: #2ca8e0;
}

.site-skeleton__channel.--red {
  background: #df4a32;
}

.site-skeleton__content {
  padding: 0 1rem 1rem 0;
}

.site-skeleton__card {
  min-height: calc(100vh - 7rem);
  padding: 1.05rem 0 3rem;
  border-radius: 14px;
  background: var(--site-skeleton-content-bg);
}

.site-skeleton__welcome-row {
  display: grid;
  grid-template-columns: 1fr 1.25fr;
  align-items: center;
  gap: 3rem;
  width: min(72%, 954px);
  margin: 0 auto 3.35rem;
  padding-bottom: 2rem;
  border-bottom: 1px solid var(--site-skeleton-border);
}

.site-skeleton__welcome-greeting {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.7rem;
}

.site-skeleton__search {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  width: min(42vw, 600px);
  height: 38px;
  box-sizing: border-box;
  padding: 0 0.95rem;
  border: 1px solid var(--site-skeleton-border);
  border-radius: 7px;
  background: var(--site-skeleton-search-bg);
}

.site-skeleton__search-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 1rem;
  color: var(--site-skeleton-muted);
  flex: 0 0 auto;
  font-size: 0.95rem;
  line-height: 1;
}

.site-skeleton__search-icon.--filters {
  margin-left: auto;
}

.site-skeleton__tabs {
  display: flex;
  align-items: center;
  gap: 1.55rem;
  width: min(72%, 954px);
  margin: 0 auto 1.2rem;
}

.site-skeleton__tabs > span {
  padding: 0.8rem 0;
}

.site-skeleton__tabs > .--active {
  border-bottom: 2px solid var(--site-skeleton-accent-soft);
}

.site-skeleton__tabs button {
  width: 6rem;
  height: 2.1rem;
  margin-left: auto;
  border: 1px solid var(--site-skeleton-border);
  border-radius: 7px;
  background: var(--site-skeleton-content-bg);
}

.site-skeleton__topic-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  width: min(72%, 954px);
  margin: 0 auto;
}

.site-skeleton__topic {
  position: relative;
  display: grid;
  grid-template-columns: 2.4rem minmax(0, 1fr) auto;
  gap: 0.85rem;
  min-height: 9.5rem;
  padding: 1.25rem 1rem 1rem;
  border: 1px solid var(--site-skeleton-border);
  border-radius: 18px;
  background: var(--site-skeleton-content-bg);
}

.site-skeleton__topic-avatar {
  width: 2rem;
  height: 2rem;
  border-radius: 50%;
  background: var(--site-skeleton-line-strong);
}

.site-skeleton__topic-avatar.--system {
  position: relative;
  background:
    radial-gradient(
      circle at 50% 50%,
      transparent 0 38%,
      var(--site-skeleton-line-strong) 39% 60%,
      transparent 61%
    ),
    conic-gradient(
      from 0deg,
      var(--site-skeleton-line-strong) 0deg 20deg,
      transparent 20deg 40deg,
      var(--site-skeleton-line-strong) 40deg 60deg,
      transparent 60deg 80deg,
      var(--site-skeleton-line-strong) 80deg 100deg,
      transparent 100deg 120deg,
      var(--site-skeleton-line-strong) 120deg 140deg,
      transparent 140deg 160deg,
      var(--site-skeleton-line-strong) 160deg 180deg,
      transparent 180deg 200deg,
      var(--site-skeleton-line-strong) 200deg 220deg,
      transparent 220deg 240deg,
      var(--site-skeleton-line-strong) 240deg 260deg,
      transparent 260deg 280deg,
      var(--site-skeleton-line-strong) 280deg 300deg,
      transparent 300deg 320deg,
      var(--site-skeleton-line-strong) 320deg 340deg,
      transparent 340deg 360deg
    );
}

.site-skeleton__topic-main {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  min-width: 0;
}

.site-skeleton__topic-excerpt {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  margin: 0.7rem 0 0;
  padding-bottom: 0.85rem;
  border-bottom: 1px solid var(--site-skeleton-border);
}

.site-skeleton__topic-tag {
  align-self: flex-start;
  width: 3.4rem;
  height: 1.15rem;
  margin-top: 0.65rem;
  border-radius: 4px;
  background: var(--tertiary-low);
}

.site-skeleton__topic-tag.--staff {
  background: var(--danger-low);
}

.site-skeleton__topic-pin {
  align-self: start;
  width: 3.2rem;
  height: 1.5rem;
  border: 1px solid var(--site-skeleton-border);
  border-radius: 7px;
}

@keyframes siteSkeletonSweep {
  0% {
    transform: translateX(-100%);
  }

  100% {
    transform: translateX(100%);
  }
}

@media screen and (prefers-reduced-motion: reduce) {
  .site-skeleton::before {
    animation: none;
  }
}

@media screen and (width <= 40rem) {
  .site-skeleton__header {
    padding: 0 1rem;
  }

  .site-skeleton__body {
    grid-template-columns: 1fr;
    margin-top: 1rem;
    padding: 0 1rem;
  }

  .site-skeleton__sidebar,
  .site-skeleton__search {
    display: none;
  }

  .site-skeleton__brand {
    min-width: 0;
  }

  .site-skeleton__tabs {
    gap: 0.9rem;
  }

  .site-skeleton__tabs button {
    display: none;
  }

  .site-skeleton__topic {
    grid-template-columns: 2rem minmax(8rem, 1fr) 2.5rem;
    gap: 0.75rem;
    min-height: 4rem;
    padding: 0.65rem 0.75rem;
  }

  .site-skeleton__topic-avatar {
    width: 2rem;
    height: 2rem;
  }
}