$main-color: #5dbc8e; // minty green
$neutral-color: #dfdfdf; // light gray
$secondary-color: #9EC7B3; // lighter minty
$darker: #303C36;

body {
  font-family: "Arvo";
}

small {
  display: block;
  width: 700px;
  margin: 10px auto;
  text-align: center;
  color: $secondary-color;
}

a {
  color: $secondary-color;
  &:hover {
    color: $main-color;
  }
}

span {
  display: inline-block;
  width: 130px;
  text-align: center;
  border-radius: 2px;
}

button {
  display: inline-block;
  width: 140px;
  height: 40px;
  margin-top: 10px;
  padding: 10px;
  text-align: center;
  font-family: "Arvo";
  font-weight: 400;
  font-size: 120%;
  color: #fff;
  border: none;
  outline: none;
  border-radius: 2px;
  background-color: $secondary-color;
  &:hover {
    background-color: $main-color;
    cursor: pointer;
  }
}

.container {
  width: 700px;
  height: 540px;
  margin: 0 auto;
  padding: 20px;
  background-color: $neutral-color;
  border-radius: 2px;
}

.right {
  width: 150px;
  height: 528px;
  float: right;
  text-align: center;
}

.sum-display {
  height: 70px;
  padding: 5px;
  font-weight: 700;
  font-size: 3.5em;
  color: #fff;
  background-color: $darker;
}

.score-display {
  height: 40px;
  margin-top: 10px;
  padding: 15px 5px 0 5px;
  background-color: #fff;
  color: $darker;
  &::before {
    content: "Score: ";
    font-weight: 700;
  }
}

.board {
  width: 528px;
  height: 528px;
  float: left;
  padding: 5px;
  background-color: $main-color;
  border-radius: 2px;
  &:hover {
    cursor: pointer;
  }
}

.board div {
  display: block;
  height: 40px;
  width: 40px;
  float: left;
  margin: 2px;
  padding: 15px 10px 5px 10px;
  text-align: center;
  font-size: 150%;
  font-weight: 700;
  color: $main-color;
  border: 1px solid $main-color;
  border-radius: 2px;
  background-color: #fff;
  &:hover {
    background-color: $neutral-color;
  }
}

.board .selected {
  background-color: $darker;
  &:hover {
    background-color: $darker;
  }
}

.board .dead {
  background-color: $secondary-color;
  &:hover {
    cursor: default;
    background-color: $secondary-color;
  }
}

div.how-to-play {
  display: none;
  position: absolute;
  width: 700px;
  height: 540px;
  margin: 0 auto;
  padding: 10px;
  background-color: rgba(255, 255, 255, 0.8);
  color: $darker;
  z-index: 2;
  &.displayed {
    display: block;
  }
  p {
    width: 60%;
  }
}

a.how-to-play {
  display: block;
  margin-top: 10px;
}