body {
  display: flex;
  flex-direction: column;
  align-items: center;
  min-height: 98vh;
}

#grid {
  margin: auto;
}

#config {
  padding-top: 2em;
}

table {
  border-collapse: collapse;
  box-sizing: border-box;
}

td {
  border: 1px solid grey;
  font-size: 9px;
  text-align: center;
  width: 30px;
  height: 30px;
  overflow: hidden;
  color: #d7d7d7;
  user-select: none;
}

.lv {
  background-color: #080;
  border-radius: 5px 33%;
}

.rng {
  border-radius: 30%;
  background-color: #8e8;
  opacity: .1;
}

.rng_u {
  background-color: #efe;
}

.exp {
  background-color: #ccc;
  opacity: .1;
}

a:link,
a:visited {
  text-decoration: none;
  color: #080;
}

a:hover,
a:focus {
  color: #efe;
  background-color: #080;
}

button {
  font-size: 1.2em;
  padding: 0.3em 0.5em;
  margin: 0.2em;
  color: #efe;
  background-color: #080;
  border: 1px solid #040;
  border-radius: 0.1em 0.6em;
}

button:hover {
  color: #040;
  background-color: #efe;
  border: 1px solid #080;
}

#rng {
  font-size: 16px;
}

#rng_label {
  font-size: 16px;
  padding: 0.3em;
  margin-top: 0.5em;
}