node_modules/@covalent/core/loading/loading.component.scss

.td-loading-wrapper {
  position: relative;
  display: block;
  &.td-fullscreen {
    position: inherit;
  }
  .td-loading {
    // layout
    box-sizing: border-box;
    display: flex;
    // [layout="row"]
    flex-direction: row;
    // [layout-align="center center"]
    align-items: center;
    align-content: center;
    max-width: 100%;
    justify-content: center;
    // flex
    flex: 1;
  }
  &.td-overlay {
    .td-loading {
      position: absolute;
      margin: 0;
      top: 0;
      left: 0;
      right: 0;
      z-index: 1000;
      mat-progress-bar {
        position: absolute;
        top: 0;
        left: 0;
        right: 0;
      }
    }
  }
  &.td-overlay-circular {
    .td-loading {
      bottom: 0;
    }
  }
}