A dark CSS theme for Asana

vhx-asana-theme.css

body { 
background: #191919 !important;
 font-family: Arial !important;
 }

#project_header { background: #fff !important; }
#header { 
background: #191919 url('http://vhx.tv/images/vhx-logo-crystal.png') 25px 60px no-repeat !important; 
padding-top: 20px !important; 
height: 120px;
background-size: 200px;
}
#header #logo { display: none !important; }
#navigation_dock_main_contents { background: #191919; }
#center_pane__contents, .column-contents2, .column-contents1, #center_pane, #right_pane {  
background: #191919 !important; 
 border: 1px solid #444 !important; 
}

.grid_cell_string input { color: #eee !important; }

.grid_tags_and_date { background: #191919 !important; }

.task-row:hover td { background: #222 !important; } 
.task-row:hover td input { color: #fff !important; }
.task-row:hover .grid_tags_and_date { background: #222 !important; }

.task-row td {
border-bottom: 1px solid black !important;
border-top: 1px solid #202020 !important;
}


.task-row.grid-row-selected td { 
  background: #090909 !important;  

}
.task-row.grid-row-selected td {   
  border-top: 1px solid black !important;
  border-bottom: 1px solid #222 !important; 
}
.task-row.grid-row-selected .grid_tags_and_date  { background: #090909 !important; } 
.task-row.grid-row-selected input { color: #d81965 !important; font-weight: bold; } 

.task-row.completed { background-color: #111 !important; }
.task-row.completed .grid_tags_and_date { background: transparent !important; }

.group_header { color: #C76B43 !important; }

.bar-row .bar { background: #000 !important; border:0 !important;  }
.bar-row input { color: #C76B43 !important; }

How do you install/import this?

You can use Chrome's "Stylish" extension https://chrome.google.com/webstore/detail/stylish/fjnbnpbmkenffdnngjfgmeleoegfcffe?hl=fr

It's worth noting this is out of date. The text goes to "black on almost black" and there are white regions around a lot of UI elements.

https://userstyles.org/styles/125466/asana-dark-cobalt