html {
  --s: 80px; /* control the size */
  --c: #542437;
  
  --_g: 
    #0000 calc(-650%/13) calc(50%/13),var(--c) 0 calc(100%/13),
    #0000 0 calc(150%/13),var(--c) 0 calc(200%/13),
    #0000 0 calc(250%/13),var(--c) 0 calc(300%/13);
  --_g0: repeating-linear-gradient( 45deg,var(--_g));
  --_g1: repeating-linear-gradient(-45deg,var(--_g));
  background:
    var(--_g0),var(--_g0) var(--s) var(--s),
    var(--_g1),var(--_g1) var(--s) var(--s) #C02942;
  background-size: calc(2*var(--s)) calc(2*var(--s));
}

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