@atlassian/aui/src/less/imports/aui-theme/core/layers.less

Atlassian User Interface library

@aui-z-base: 2;
@aui-z-sidebar: @aui-z-base + 1;
@aui-z-header: @aui-z-sidebar + 1;
@aui-z-skip: @aui-z-header + 1;