amis2/scss/components/_chart.scss

.#{$ns}Chart {
  min-width: 300px;
  min-height: 300px;
  position: relative;

  &-placeholder {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
  }

  &-content {
    position: absolute;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
  }
}