c9-core/plugins/c9.ide.tree/style.css

.filetree.ace_tree {
    background: transparent;
    border: none;
    font: 11px Tahoma, Arial;
    .font-smoothing(@tree-font-smoothing)
}

.filetree .tree-row {
    background : transparent;
    color : @color;
    border-radius: 3px;
    margin: 1px 0px 0px 10px;
    padding-left: 6px;
    height: @tree-row-height;
}

.filetree .tree-row.selected {
    background: @selected-background;
    border-color: transparent;
    color : @selected-color;
}

.filetree .tree-row.projectRoot, .filetree .tree-row:first-child {
    margin-right: @tree-first-row-margin-right;
}

.filetree.ace_tree_focus .tree-row.selected {
    background: @selected-focus-background;
    color: @selected-focus-color;
}
.filetree.ace_tree_focus.alternative .tree-row.selected {
    background: @tree-selected-background-alternative;
    color : @tree-selected-color-alternative;
}

.filetree .message {
    border : 0;
    padding : 3px;
    text-align : center;
    background : transparent;
    font-size: 11px;
    
    margin: 20px 10px 0 10px;
    word-wrap: break-word;
    white-space: normal;
    color: #BBB;
    line-height: 1.5em;
}

.filetree .tree-row .toggler{
    .image-2x("@{tree-arrow}", 20px, 10px);
    margin: 0 1px 0 0;
}

.filetree.ace_tree_focus .tree-row.selected .toggler{
    .image-2x("@{tree-arrow-focus-selected}", 20px, 10px);
}

.filetree .tree-row > span {    
    vertical-align: middle;
    padding: @tree-row-padding;
    line-height: 20px;
    display: inline-block;
}

.filetree .filetree-icon {
    width: 16px;
    height: 16px;
    padding: 0px;
    margin: 0px 1px;
    background-repeat: no-repeat;
}

.filetree-icon.folder {
    .image-2x("@{icon-path}/@{tree-folder-icon}", @tree-folder-icon-width, @tree-folder-icon-height);
}
.filetree.alternative .filetree-icon.folder {
    .image-2x("@{icon-path}/@{tree-folder-icon-alternative}", @tree-folder-icon-width, @tree-folder-icon-height);
}

.filetree .loading .filetree-icon,
.filetree .loading.filetree-icon {
    .image-2x("@{tree-spinner}", @tree-spinner-width, @tree-spinner-height);
}

.filetree .loading.selected .filetree-icon,
.filetree .selected .loading.filetree-icon {
    .image-2x("@{tree-focus-spinner}", @tree-spinner-width, @tree-spinner-height);
}
        
.filetree.ace_tree_focus .loading.selected .filetree-icon,
.filetree.ace_tree_focus .selected .loading.filetree-icon {
    .image-2x("@{tree-selected-focus-spinner}", @tree-spinner-width, @tree-spinner-height);
}

.filetree .symlink>.filetree-icon:after, .filetree .favorite>.filetree-icon:after {
    content: "";
    display: block;
    background: url("@{icon-path}/@{tree-symlink}") no-repeat;
    position: relative;
    width: 12px;
    height: 12px;
    top: @tree-symlink-y;
    left: @tree-symlink-x;
}

.filetree .favorite{
    opacity : 0.5;
}
.filetree .extrainfo{
    color : rgb(92, 92, 92);
}
.filetree.ace_tree_focus .selected .extrainfo{
    color : #CCCCCC;
}

.filetree .tree-row.dragAppendUpload .filetree-icon {
    background-image : url("@{image-path}/@{tree-upload}");
    background-position: -5px -1px;
}

.filetree.dragImage.copy:after {
    content: "+";
    background: fade(@selected-focus-background, 92%);
    border: 1px @selected-focus-background solid;
    position: absolute;
    right: -6px;
    bottom: -6px;
    color: @selected-focus-color;
    font-size: 14px;
    border-radius: 8px;
    width: 14px;
    height: 13px;
    text-align: center;
    line-height: 13px;
    font-weight: bold;
    font-family: monospace;
    background: -webkit-radial-gradient(5px 5px, circle, rgb(126, 143, 28), rgb(76, 93, 0));
    background: radial-gradient(5px 5px, circle,  rgb(126, 143, 28), rgb(76, 93, 0));
    box-shadow: 0px 0px 7px 0px #000;
}
.filetree.dragImage .toggler {
    pointer-events: none;
}

.dragOver.filetree .tree-row.selected {
    background: fade(@selected-background, 60%);
}
.dragOver.filetree .tree-row.dropTarget {
    background: @selected-focus-background;
    box-shadow: 1px 1px fade(@selected-focus-background, 60%) inset;
    color: @selected-color;
    border-radius: 3px;
    .box-sizing(border-box);
    margin-right: 5px;
}

.filetree .dragHighlight {
    position: absolute;
    border: solid 1px fade(@selected-focus-background, 60%);    
    border-right: rgba(0, 0, 0, 0);
    border-top: rgba(0, 0, 0, 0);
    background: fade(@selected-focus-background, 10%);
}


.filetree .dragArrow {
    position: absolute;
    border: 1px solid @selected-focus-background;
    margin-top: 2px;
}
.filetree .dragArrow::before {
    content:"";
    background: @selected-focus-background;
    position: absolute;
    top: -3px;
    left: -3px;
    width: 6px;
    height: 6px;
    border-radius: 4px;
}

.ace_tree-editor {
    color: @tree-editor-color;
    background-color: @tree-editor-background;
    border: 1px solid @tree-editor-border-color;
    height: @tree-editor-height !important;
    margin-top: @tree-editor-margin-top !important;
}

.workspace_files{
    display: -webkit-flex;
    display: flex;
    flex-direction: column;
    -webkit-flex-direction: column;
}

.workspace_files .filetree.real{
    flex : 1;
    -webkit-flex: 1;
}

.filetree .heading{
    font-variant: small-caps;
    font-size: 16px;
    margin-top: 0px;
    margin-bottom: 3px;
    color: @tree-heading-color;
    text-shadow: @tree-heading-text-shadow;
    line-height: 0;
}
.filetree .heading .toggler{
    display : none;
}
.filetree .heading .filetree-icon{
    display : none;
}