default/nvd/style.css

table#vgListTable td.cvss span {
    background-color: #CCC;
    display: inline-block;
    min-width: 2.4em;
    padding: 0.3em 0.5em;
    color: #fff;
    line-height: normal;
    text-align: center;
    border-radius: 0.5em;
    font-weight: 700;
  }
  
  #vgListTable .cvss span[title^="8"],
  #vgListTable .cvss span[title^="7"]
  {
  background-color: salmon;
  }
  
  #vgListTable .cvss span[title^="6"],
  #vgListTable .cvss span[title^="5"],
  #vgListTable .cvss span[title^="4"]
  {
  background-color: orange;
  }
  
  #vgListTable .cvss span[title^="3"],
  #vgListTable .cvss span[title^="2"],
  #vgListTable .cvss span[title^="1."],
  #vgListTable .cvss span[title^="0."]
  {
  background-color: gold;
  color: #000;
  }
  
  #vgListTable .cvss span[title="0"],
  #vgListTable .cvss span[title="0.0"]
  {
  background-color:rgb(162, 213, 114);
  }
  
  #vgListTable .cvss span[title^="10"],
  #vgListTable .cvss span[title^="9"]
  {
  background-color: orangered;
  }