discourse/app/assets/stylesheets/desktop/topic-timeline.scss

.timeline-loading {
  width: 900px;
}

.fixed-gutter {
  width: 100%;
  box-sizing: border-box;
  z-index: 1;
  margin-left: 757px;
  position: fixed;
  top: 140px;

  .topic-timeline {
    margin-left: 3em;
    width: 200px;

    .timeline-controls {
      margin-bottom: 2em;
    }

    .start-date {
      color: dark-light-choose(scale-color($primary, $lightness: 50%), scale-color($secondary, $lightness: 50%));
    }

    .timeline-scrollarea {
      margin-top: 0.5em;
      margin-left: 0.5em;
      border-left: 1px solid;
      border-color: dark-light-choose(scale-color($tertiary, $lightness: 80%), scale-color($tertiary, $lightness: 20%));
      position: relative;
    }

    .timeline-padding {
      transition: height 0.15s ease-out;
      cursor: pointer;
      .widget-dragging & {
        transition: none;
      }
    }

    .timeline-handle {
      @include border-radius-all(0.8em);
      width: 0.35em;
      background-color: $tertiary;
      height: 100%;
      float: left;
    }

    .timeline-scroller-content {
      padding-left: 1em;
    }

    .timeline-scroller {
      @include unselectable;
      margin-left: -0.18em;
      cursor: move;
      display: flex;
      align-items: center;
    }

    .timeline-replies {
      font-weight: bold;
    }

    .timeline-last-read {
      position: absolute;
      margin-left: -0.18em;

      i.progress {
        font-size: 0.5em;
        color: $tertiary;
        margin-right: 1em;
      }
    }

    .now-date {
      display: inline-block;
      color: dark-light-choose(scale-color($primary, $lightness: 50%), scale-color($secondary, $lightness: 50%));
      margin-top: 0.5em;
      i {
        margin-left: 0.15em;
      }
    }
  }
}