html {
  --s: 48px; /* control the size */
  --c1: green;
  --c2: #ffffff;
  --c3: lightgreen;
  
  --_g: var(--c3) 0 120deg,#0000 0;
  background:
    conic-gradient(from -60deg at 50% calc(100%/3),var(--_g)),
    conic-gradient(from 120deg at 50% calc(200%/3),var(--_g)),
    conic-gradient(from  60deg at calc(200%/3),var(--c3) 60deg,var(--c2) 0 120deg,#0000 0),
    conic-gradient(from 180deg at calc(100%/3),var(--c1) 60deg,var(--_g)),
    linear-gradient(90deg,var(--c1)   calc(100%/6),var(--c2) 0 50%,
                          var(--c1) 0 calc(500%/6),var(--c2) 0);
  background-size: calc(1.732*var(--s)) var(--s);
}