css woody back

CSSで木目調背景と畳調背景 - Qiita
https://qiita.com/nakyos/items/c71dbd723b1df3492b9a

.dark-wood {
  background:
    repeating-radial-gradient(
      circle at -1000% 0%,
      rgba(116, 77, 48, 0.7),
      #573216 7.5%,
      rgba(116, 77, 48, 0.9) 10%
    ),
    repeating-radial-gradient(
      circle at -1000% 0%,
      #573216,
      #573216 0.1%,
      #744d30 0.4%,
      #744d30 0.5%
    );
}

.wood {
  background:
    linear-gradient(
      90deg,
      rgba(208, 147, 82, 0.6),
      rgba(192, 134, 70, 0.6) 60%,
      rgba(208, 147, 82, 0.6)
    ),
    repeating-radial-gradient(
      ellipse at 60% 500%,
      #c08646,
      #c08646 0.2%,
      #d09352 0.6%,
      #d09352 1%
    );
}