p span {
  position: relative;
  /* background: linear-gradient(transparent 40%, yellow 40%); */ /* default */
  /* background: linear-gradient(transparent 55%, rgb(154, 255, 230) 40%); */
  /* background: linear-gradient(transparent 55%, #aa8f7b 110%); */
  /* background: linear-gradient(transparent 55%, #caa588 110%); */
  background: linear-gradient(transparent 55%, #dbb293 120%);
  /* background: linear-gradient(transparent 55%, #e7bd9c 110%); */

}

/****** Base style. ******/
/*
body {
  display: flex;
  height: 100vh;
  justify-content: center;
  align-items: center;
  margin: 0;
  font-family: YuMincho, "游明朝体", "YuMincho", "游明朝", "Yu Mincho", "Hiragino Mincho ProN", "ヒラギノ明朝 Pro W3";
}

p {
  width: 80%;
}