SVG data image not working as a background-image in a pseudo element

I'm setting a SVG as background-image for a pseudo element:

content: '';
position: absolute;
 right: 0;
bottom: 0;
  left: 0;
width: 100%;
height: 12px;
background-image: url('data:image/svg+xml;utf8,<svg version="1.1" id="Layer_1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px" viewBox="0 0 620 12" enable-background="new 0 0 620 12" xml:space="preserve"><g><polygon fill="#D11A3C" points="48.8,12 0,12 0,0 54.1,0"/><polygon fill="#952592" points="93.8,12 44,12 49.3,0 99.1,0"/><polygon fill="#1E65AF" points="133.5,12 83.7,12 89,0 138.8,0"/><polygon fill="#D11A3C" points="156.3,12 106.5,12 111.8,0 161.6,0"/><polygon fill="#40BFC2" points="201,12 151.3,12 156.5,0 206.3,0"/><polygon fill="#1E65AF" points="216.4,12 166.6,12 171.9,0 221.7,0"/><polygon fill="#952592" points="226.5,12 176.7,12 182,0 231.7,0"/><polygon fill="#1E65AF" points="241.3,12 191.5,12 196.8,0 246.6,0"/><polygon fill="#40BFC2" points="260.9,12 211.1,12 216.4,0 266.2,0"/><polygon fill="#952592" points="282.6,12 232.9,12 238.1,0 287.9,0"/><polygon fill="#952592" points="282.6,12 232.9,12 238.1,0 287.9,0"/><polygon fill="#D11A3C" points="318.6,12 268.9,12 274.2,0 323.9,0"/><polygon fill="#D11A3C" points="318.6,12 268.9,12 274.2,0 323.9,0"/><polygon fill="#40BFC2" points="364.2,12 314.4,12 319.7,0 369.5,0"/><polygon fill="#1E65AF" points="368.1,12 318.3,12 323.6,0 373.4,0"/><polygon fill="#1E65AF" points="368.1,12 318.3,12 323.6,0 373.4,0"/><polygon fill="#D11A3C" points="378.5,12 328.7,12 334,0 383.8,0"/><polygon fill="#D11A3C" points="378.5,12 328.7,12 334,0 383.8,0"/><polygon fill="#40BFC2" points="424.8,12 375,12 380.3,0 430.1,0"/><polygon fill="#40BFC2" points="424.8,12 375,12 380.3,0 430.1,0"/><polygon fill="#952592" points="430.1,12 380.3,12 385.6,0 435.4,0"/><polygon fill="#1E65AF" points="465.6,12 415.8,12 421.1,0 470.9,0"/><polygon fill="#D11A3C" points="488.3,12 438.5,12 443.8,0 493.6,0"/><polygon fill="#D11A3C" points="620,12 613.4,12 618.7,0 620,0"/><polygon fill="#40BFC2" points="534.2,12 484.5,12 489.8,0 539.5,0"/><polygon fill="#1E65AF" points="548,12 498.2,12 503.5,0 553.3,0"/><polygon fill="#952592" points="556.5,12 506.7,12 512,0 561.8,0"/><polygon fill="#1E65AF" points="573.8,12 524.1,12 529.4,0 579.1,0"/><polygon fill="#40BFC2" points="592.5,12 542.8,12 548.1,0 597.8,0"/><polygon fill="#952592" points="614.4,12 564.6,12 569.9,0 619.7,0"/></g></svg>');
background-repeat: repeat-x;
background-position: bottom;

but for some reason it does not show up on Firefox. I do not wanna use a base64 data-url. Isn't this possible at all in Firefox?

The # character in a URL is reserved to indicate the start of a fragment identifier.

You must URL encode the data URL contents, which means converting any hash characters in the data URL to %23

You can use the encodeURIComponent(uri) function of JS.

This function encodes special characters and can encodes also the following characters: , / ? : @ & = + $ #

Reference: https://www.w3schools.com/jsref/jsref_encodeuricomponent.asp

For anyone having this encoding issue when trying to use url with sass variables (for fills, for instance), the following is quite useful: https://gist.github.com/JacobDB/0ffffaf8e772c12acf7102edb8a302be

Note, you may need to edit the output url from inline-svg depending on your needs (in my case, I was using data:image/svg+xml;utf8 instead)

A related question " svg fill color not working with hex colors"
https://stackoverflow.com/questions/61099149/svg-fill-color-not-working-with-hex-colors
was referred here. The example given was:

OK:

I encountered a similar problem trying to export an svg using XMLSerializer. The exported svg was truncated following the # character. In my case, the %23 substitution for # did not work.

I was able to work around the problem by replacing the hex constant with the rgb() function and decimal values. For example, fill ="#FF0000" becomes fill = "rgb(255,0,0)"