twitter bootstrap - how can i Get proportional gray color? -

here list have:

      $gray-base:          #000 !default;       $gray-darker:        lighten($gray-base, 13.5%) !default; // #222                           $gray:               lighten($gray-base, 46.7%) !default; // #777       $gray-light:         lighten($gray-base, 65%) !default;   // #a6a6a6       $gray-lighter:       lighten($gray-base, 93.5%) !default; // #eee 

but want make #dddddd in proportional style above other color are.how can done.thanks

$gray-medium:        lighten($gray-base, 86.5%) !default; // #dddddd   

you can test here: http://fiddlesalad.com/less/

html:

<div style="width:100px; height:100px;" class="graymedium"></div> 

less:

@gray-base:          #000; @gray-medium:        lighten(@gray-base, 86.5%);  .graymedium{     background: @gray-medium; } 

in source css window should see:

.graymedium {     background: #dddddd; }