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HTML 

              
                <div class="ruler"></div>
!

CSS 

              
                @import url('https://fonts.googleapis.com/css?family=Kaushan+Script');

html, body { height: 100%; }
body {
  margin: 0;
  display: flex;
  font-size: 10px;
  background: linear-gradient(to bottom right, dodgerblue 50%, darken(dodgerblue, 5%) 50%);
}

$yellow: mix(yellow, orange, 50%);

.ruler {
  position: relative;
  margin: auto;
  border-radius: 0.5em;
  border: black solid 0.25em;
  width: 25em;
  height: 8em;
  box-shadow:
    inset 0 0.25em rgba(white, 0.7),
    inset 0 1.5em rgba(white, 0.3),
    inset 0 -1.5em rgba(black, 0.1),
    inset 0 -0.25em rgba(black, 0.1)
  ;
  background:
    linear-gradient(to bottom, $yellow 4em, rgba($yellow, 0) 4em) no-repeat,
    linear-gradient(
      to right,
      rgba(black, 0) 5em, black 5em, black calc(5em + 1px), rgba(black, 0) calc(5em + 1px),
      rgba(black, 0) 10em, black 10em, black calc(10em + 1px), rgba(black, 0) calc(10em + 1px),
      rgba(black, 0) 15em, black 15em, black calc(15em + 1px), rgba(black, 0) calc(15em + 1px),
      rgba(black, 0) 20em, black 20em, black calc(20em + 1px), rgba(black, 0) calc(20em + 1px)
    ) no-repeat,
    linear-gradient(to bottom, $yellow 6em, rgba($yellow, 0) 6em) no-repeat,
    linear-gradient(
      to right,
      rgba(black, 0) 2.5em, black 2.5em, black calc(2.5em + 1px), rgba(black, 0) calc(2.5em + 1px),
      rgba(black, 0) 7.5em, black 7.5em, black calc(7.5em + 1px), rgba(black, 0) calc(7.5em + 1px),
      rgba(black, 0) 12.5em, black 12.5em, black calc(12.5em + 1px), rgba(black, 0) calc(12.5em + 1px),
      rgba(black, 0) 17.5em, black 17.5em, black calc(17.5em + 1px), rgba(black, 0) calc(17.5em + 1px),
      rgba(black, 0) 22.5em, black 22.5em, black calc(22.5em + 1px), rgba(black, 0) calc(22.5em + 1px)
    ) no-repeat,
    $yellow;
}

.ruler::before,
.ruler::after {
  display: block;
  position: absolute;
  text-align: center;
  left: 0;
  right: 0;
  color: white;
  font-size: 3em;
  font-family: 'Kaushan Script', cursive;
}

.ruler::before {
  content: 'Need a ruler?';
  bottom: calc(100% + 2rem);
}

.ruler::after {
  content: 'Print this page!';
  top: calc(100% + 2rem);
}

@function unit($val) {
  @return ($val * 72) * 1px;
}

@media print {
  body {
    -webkit-print-color-adjust: exact;
    print-color-adjust: exact;
    font-size: 10pt;
    background: transparent none;
    zoom: 1;
  }

  .ruler {
    overflow: hidden;
    text-indent: -9999999em;
    position: absolute;
    display: block;
    top: calc(50% - #{unit(3)});
    left: calc(50% - #{unit(0.75)});
    height: unit(6);
    width: unit(1.5);
    border-radius: 0;
    box-shadow: 0 0 0 4px black;
    background:
      linear-gradient(to left, white unit(0.75), rgba(white, 0) unit(0.75)) no-repeat center left,
      linear-gradient(
        to bottom,
        rgba(black, 0) unit(1), black unit(1), black calc(#{unit(1)} + 1px), rgba(black, 0) calc(#{unit(1)} + 1px),
        rgba(black, 0) unit(2), black unit(2), black calc(#{unit(2)} + 1px), rgba(black, 0) calc(#{unit(2)} + 1px),
        rgba(black, 0) unit(3), black unit(3), black calc(#{unit(3)} + 1px), rgba(black, 0) calc(#{unit(3)} + 1px),
        rgba(black, 0) unit(4), black unit(4), black calc(#{unit(4)} + 1px), rgba(black, 0) calc(#{unit(4)} + 1px),
        rgba(black, 0) unit(5), black unit(5), black calc(#{unit(5)} + 1px), rgba(black, 0) calc(#{unit(5)} + 1px)
      ) no-repeat center left,
      linear-gradient(to left, white unit(1), rgba(white, 0) unit(1)) no-repeat center left,
      linear-gradient(
        to bottom,
        rgba(black, 0) unit(0.5), black unit(0.5), black calc(#{unit(0.5)} + 1px), rgba(black, 0) calc(#{unit(0.5)} + 1px),
        rgba(black, 0) unit(1.5), black unit(1.5), black calc(#{unit(1.5)} + 1px), rgba(black, 0) calc(#{unit(1.5)} + 1px),
        rgba(black, 0) unit(2.5), black unit(2.5), black calc(#{unit(2.5)} + 1px), rgba(black, 0) calc(#{unit(2.5)} + 1px),
        rgba(black, 0) unit(3.5), black unit(3.5), black calc(#{unit(3.5)} + 1px), rgba(black, 0) calc(#{unit(3.5)} + 1px),
        rgba(black, 0) unit(4.5), black unit(4.5), black calc(#{unit(4.5)} + 1px), rgba(black, 0) calc(#{unit(4.5)} + 1px),
        rgba(black, 0) unit(5.5), black unit(5.5), black calc(#{unit(5.5)} + 1px), rgba(black, 0) calc(#{unit(5.5)} + 1px)
      ) no-repeat center left,
      linear-gradient(to left, white unit(1.25), rgba(white, 0) unit(1.25)) no-repeat center left,
      linear-gradient(
        to bottom,
        rgba(black, 0) unit(0.25), black unit(0.25), black calc(#{unit(0.25)} + 1px), rgba(black, 0) calc(#{unit(0.25)} + 1px),
        rgba(black, 0) unit(0.75), black unit(0.75), black calc(#{unit(0.75)} + 1px), rgba(black, 0) calc(#{unit(0.75)} + 1px),
        rgba(black, 0) unit(1.25), black unit(1.25), black calc(#{unit(1.25)} + 1px), rgba(black, 0) calc(#{unit(1.25)} + 1px),
        rgba(black, 0) unit(1.75), black unit(1.75), black calc(#{unit(1.75)} + 1px), rgba(black, 0) calc(#{unit(1.75)} + 1px),
        rgba(black, 0) unit(2.25), black unit(2.25), black calc(#{unit(2.25)} + 1px), rgba(black, 0) calc(#{unit(2.25)} + 1px),
        rgba(black, 0) unit(2.75), black unit(2.75), black calc(#{unit(2.75)} + 1px), rgba(black, 0) calc(#{unit(2.75)} + 1px),
        rgba(black, 0) unit(3.25), black unit(3.25), black calc(#{unit(3.25)} + 1px), rgba(black, 0) calc(#{unit(3.25)} + 1px),
        rgba(black, 0) unit(3.75), black unit(3.75), black calc(#{unit(3.75)} + 1px), rgba(black, 0) calc(#{unit(3.75)} + 1px),
        rgba(black, 0) unit(4.25), black unit(4.25), black calc(#{unit(4.25)} + 1px), rgba(black, 0) calc(#{unit(4.25)} + 1px),
        rgba(black, 0) unit(4.75), black unit(4.75), black calc(#{unit(4.75)} + 1px), rgba(black, 0) calc(#{unit(4.75)} + 1px),
        rgba(black, 0) unit(5.25), black unit(5.25), black calc(#{unit(5.25)} + 1px), rgba(black, 0) calc(#{unit(5.25)} + 1px),
        rgba(black, 0) unit(5.75), black unit(5.75), black calc(#{unit(5.75)} + 1px), rgba(black, 0) calc(#{unit(5.75)} + 1px)
      ) no-repeat center left,
      linear-gradient(to left, white unit(1.325), rgba(white, 0) unit(1.325)) no-repeat center left,
      linear-gradient(
        to bottom,
        rgba(black, 0) unit(0.125), black unit(0.125), black calc(#{unit(0.125)} + 1px), rgba(black, 0) calc(#{unit(0.125)} + 1px),
        rgba(black, 0) unit(0.375), black unit(0.375), black calc(#{unit(0.375)} + 1px), rgba(black, 0) calc(#{unit(0.375)} + 1px),
        rgba(black, 0) unit(0.625), black unit(0.625), black calc(#{unit(0.625)} + 1px), rgba(black, 0) calc(#{unit(0.625)} + 1px),
        rgba(black, 0) unit(0.875), black unit(0.875), black calc(#{unit(0.875)} + 1px), rgba(black, 0) calc(#{unit(0.875)} + 1px),
        
        rgba(black, 0) unit(1.125), black unit(1.125), black calc(#{unit(1.125)} + 1px), rgba(black, 0) calc(#{unit(1.125)} + 1px),
        rgba(black, 0) unit(1.375), black unit(1.375), black calc(#{unit(1.375)} + 1px), rgba(black, 0) calc(#{unit(1.375)} + 1px),
        rgba(black, 0) unit(1.625), black unit(1.625), black calc(#{unit(1.625)} + 1px), rgba(black, 0) calc(#{unit(1.625)} + 1px),
        rgba(black, 0) unit(1.875), black unit(1.875), black calc(#{unit(1.875)} + 1px), rgba(black, 0) calc(#{unit(1.875)} + 1px),
        
        rgba(black, 0) unit(2.125), black unit(2.125), black calc(#{unit(2.125)} + 1px), rgba(black, 0) calc(#{unit(2.125)} + 1px),
        rgba(black, 0) unit(2.375), black unit(2.375), black calc(#{unit(2.375)} + 1px), rgba(black, 0) calc(#{unit(2.375)} + 1px),
        rgba(black, 0) unit(2.625), black unit(2.625), black calc(#{unit(2.625)} + 1px), rgba(black, 0) calc(#{unit(2.625)} + 1px),
        rgba(black, 0) unit(2.875), black unit(2.875), black calc(#{unit(2.875)} + 1px), rgba(black, 0) calc(#{unit(2.875)} + 1px),
        
        rgba(black, 0) unit(3.125), black unit(3.125), black calc(#{unit(3.125)} + 1px), rgba(black, 0) calc(#{unit(3.125)} + 1px),
        rgba(black, 0) unit(3.375), black unit(3.375), black calc(#{unit(3.375)} + 1px), rgba(black, 0) calc(#{unit(3.375)} + 1px),
        rgba(black, 0) unit(3.625), black unit(3.625), black calc(#{unit(3.625)} + 1px), rgba(black, 0) calc(#{unit(3.625)} + 1px),
        rgba(black, 0) unit(3.875), black unit(3.875), black calc(#{unit(3.875)} + 1px), rgba(black, 0) calc(#{unit(3.875)} + 1px),
        
        rgba(black, 0) unit(4.125), black unit(4.125), black calc(#{unit(4.125)} + 1px), rgba(black, 0) calc(#{unit(4.125)} + 1px),
        rgba(black, 0) unit(4.375), black unit(4.375), black calc(#{unit(4.375)} + 1px), rgba(black, 0) calc(#{unit(4.375)} + 1px),
        rgba(black, 0) unit(4.625), black unit(4.625), black calc(#{unit(4.625)} + 1px), rgba(black, 0) calc(#{unit(4.625)} + 1px),
        rgba(black, 0) unit(4.875), black unit(4.875), black calc(#{unit(4.875)} + 1px), rgba(black, 0) calc(#{unit(4.875)} + 1px),
        
        rgba(black, 0) unit(5.125), black unit(5.125), black calc(#{unit(5.125)} + 1px), rgba(black, 0) calc(#{unit(5.125)} + 1px),
        rgba(black, 0) unit(5.375), black unit(5.375), black calc(#{unit(5.375)} + 1px), rgba(black, 0) calc(#{unit(5.375)} + 1px),
        rgba(black, 0) unit(5.625), black unit(5.625), black calc(#{unit(5.625)} + 1px), rgba(black, 0) calc(#{unit(5.625)} + 1px),
        rgba(black, 0) unit(5.875), black unit(5.875), black calc(#{unit(5.875)} + 1px), rgba(black, 0) calc(#{unit(5.875)} + 1px)
      ) no-repeat center left,
      white
    ;
  }
  
  .ruler::before,
  .ruler::after {
    display: none;
  }
}
!

JS
!
999px

Console