body {
  font-family: "Helvetica Neue", Arial, "Hiragino Kaku Gothic ProN",
    "Hiragino Sans", Meiryo, sans-serif;
}
main {
  width: 360px;
  height: 360px;
  position: relative;
  margin: 0 auto;
}

/* start */
#modal {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(31, 19, 19, 0.8);
  color: white;
}
#modal h1{
  font-size: 18px;
  text-align: center;
  color: yellowgreen;
  margin: 6px;
}
#modal p{
  padding: 3px;
  margin: 2px;
}
#selects{
  margin: 0 auto;
  display: flex;
  justify-content: space-evenly;
  flex-wrap: wrap;
  width: 350px;
}
.select{
  font-weight: bold;
  border-radius: 5px 1px;
  cursor: pointer;
  background: yellowgreen;
  color: black;
  padding: 5px;
  margin: 7px 5px;
}
.select:hover{
  background: black;
  color: yellowgreen;
}
/* game */
#board {
    width: 360px;
    height: 360px;
    border-collapse: collapse;
    background: #e6e6e6;
}
td{
    border: solid 3px white;
}
.lighton{
    background: yellowgreen;
    animation: fadein .3s;
}

@keyframes fadein{
    0%{
      opacity: 0;
    }
    100%{
      opacity: 1;
    }
}
.lightoff{
    background: yellowgreen;
    animation: fadeout .3s linear forwards;
}
@keyframes fadeout{
    0%{
      opacity: 1;
    }
    100%{
      opacity: 0;
    }
}
.hide {
  display: none;
}

/* end */
#end {
  user-select: none;
  font-weight: bold;
  position: absolute;
  top: 0;
  left: 0;
  text-align: center;
  width: 100%;
  height: 100%;
  color: white;
}
#end p {
  font-size: 34px;
  margin-top: 100px;
}
#reset{
  cursor: pointer;
}