You can download the pattern or use the CSS3 code below (you can copy the text).
body {
/* CSS3 pattern provided by JonesPatterns.com */
background:
radial-gradient(transparent 70%,#2a9d8f 71%),
radial-gradient(transparent 70%,#2a9d8f 71%) 100px 100px,
conic-gradient(#264653 25%, #002032 0 50%, #264653 0 75%,#002032 0);
background-size: 200px 200px;
background-color: #2a9d8f;
}