atom/static/editor.css

.editor {
  height: 100%;
  overflow: hidden;
  cursor: default;
  -webkit-user-select: none;
  -webkit-box-flex: 1;
  position: relative;
  z-index: 0;
}

.editor.mini {
  height: auto;
}

.editor .gutter {
  position: absolute;
  height: 100%;
  overflow: hidden;
  text-align: right;
}

.editor .gutter .line-numbers {
  position: relative;
}

.editor.mini .gutter {
  display: none;
}

.editor .vertical-scrollbar {
  position: absolute;
  right: 0;
  top: 0;
  bottom: 0;
  width: 15px;
  overflow-y: auto;
  z-index: 1;
}

.editor .scroll-view {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
  overflow-x: auto;
  overflow-y: hidden;
  -webkit-box-flex: 1;
}

.editor.mini .scroll-view {
  overflow: hidden;
}

.editor.soft-wrap .scroll-view {
  overflow-x: hidden;
}

.editor .underlayer, .editor .lines, .editor .overlayer {
  width: 100%;
  height: 100%;
}

.editor .underlayer {
  z-index: 0;
  position: absolute;
}

.editor .lines {
  position: relative;
  z-index: 1;
}

.editor .overlayer {
  z-index: 2;
  position: absolute;
}

.editor .line span {
  vertical-align: top;
}

.editor .cursor {
  position: absolute;
  border-left: 2px solid;
}

.editor:not(.focused) .cursor,
.editor.focused .cursor.blink-off {
  visibility: hidden;
}

.editor .hidden-input {
  position: absolute;
  z-index: -1;
  top: 0;
  left: 0;
  opacity: 0;
}

.editor .selection .region {
  position: absolute;
  pointer-events: none;
  z-index: -1;
}