1. 1 core/modules/comment/css/comment.css
  2. 1 core/themes/basis/css/component/comment.css
#comments {
  margin-top: 15px;
}
.indented {
  margin-left: 25px; /* LTR */
}
[dir="rtl"] .indented {
  margin-left: 0;
  margin-right: 25px;
}
.comment-unpublished {
  background-color: #fff4f4;
}
.comment-preview {
  background-color: #ffffea;
}

File

core/modules/comment/css/comment.css