metamask-extension/ui/app/components/gas-customization/gas-price-chart/index.scss

.gas-price-chart {
  display: flex;
  position: relative;

  .tick text, .c3-axis-x-label, .c3-axis-y-label {
    font-family: Roboto;
    font-style: normal;
    font-weight: bold;
    line-height: normal;
    font-size: 8px;
    text-align: center;
    fill: #9A9CA6 !important;
  }

  .custom-tooltip {
    background: rgba(0, 0, 0, 1);
  box-shadow: 0px 4px 4px rgba(0, 0, 0, 0.25);
  border-radius: 3px;
    transform: translate(-41px, -50px);
    opacity: 1 !important;
    width: 44px;
    height: 21px;
    z-index: 1;
  }

  .tooltip-arrow {
      background: rgba(0, 0, 0, 1);
  box-shadow: 0px 4px 4px rgba(0, 0, 0, 0.5);
    top: -35px;
    left: -23px;
    transform: rotate(45deg);
    opacity: 1 !important;
    width: 9px;
    height: 9px;
    position: absolute;
    display: inline-block;
  }

  .custom-tooltip th {
    font-family: Roboto;
  font-style: normal;
  font-weight: 500;
  line-height: normal;
  font-size: 10px;
  text-align: center;

  color: #FFFFFF;
  }

  .c3-circle._expanded_ {
    fill: #FFFFFF !important;
    stroke-width: 2.4px !important;
    stroke: #2d9fd9 !important;
  }

  .c3-axis-x-label, .c3-axis-y-label {
    font-weight: normal;
  }

  .tick text tspan {
    visibility: hidden;
  }

  .c3-circle {
    fill: #2d9fd9 !important;
  }

  .c3-line-data1 {
    stroke: #2d9fd9 !important;
    background: rgba(0,0,0,0) !important;
    color: rgba(0,0,0,0) !important;
  }

  .c3 path {
    fill: none;
  }

  .c3 path.c3-area-data1 {
    opacity: 1;
    fill: #e9edf1 !important;
  }

  .c3-xgrid-line line {
    stroke: #B8B8B8 !important;
  }

  .c3-axis .tick line {display: none;}

  .c3-axis-x .domain {
    fill: none;
    stroke: none;
  }

  .c3-axis-y .domain {
    fill: none;
    stroke: #C8CCD6;
  }
}

@import url(//fonts.googleapis.com/css?family=Roboto:400,700,300);

#chart {
  background: #F8F9FB
}