vikunja-frontend/src/styles/theme/background.scss

.app-container.has-background,
.link-share-container.has-background {
  position: relative;

  &, .app-container-background {
    background-position: center;
    background-size: cover;
    background-repeat: no-repeat;
    background-attachment: fixed;
    min-height: 100vh;
  }

  // FIXME: move to pagination component
  .pagination-link:not(.is-current) {
    background: var(--grey-100);
  }

  .box,
  .card,
  .switch-view,
  .list-table .button,
  .filter-container .button,
  .search .button {
    box-shadow: none;
  }

  .task-view {
    border-radius: $radius;
    margin: 0 1rem;
  }

  .kanban .tasks {
    background: transparent;

    .task {
      border-radius: $radius !important;
    }
  }
}

.app-container-background {
  width: 100vw;
  height: 100vh;
  position: fixed;
  z-index: 0;
}

.background-fade-in {
  opacity: 0;
  transition: opacity $transition;
  transition-delay: $transition-duration * 2; // To fake an appearing background

  &.is-visible {
    opacity: 1;
  }
}