style.css

html,body {
  height: 98%;
}

body {
  font-family: 'Open Sans', sans-serif;
  background-color: #4f5b66;
  color: #eff1f5;
}

li {
  list-style: none;
  color: #eff1f5;
}

a {
  text-decoration: none;
  color: #a3be8c;
}

a:hover {
  text-decoration: underline;
}

input {
  color: #2b303b;
}

::selection {
  background: #c0c5ce; /* WebKit/Blink Browsers */
}
::-moz-selection {
  background: #c0c5ce; /* Gecko Browsers */
}

.box {
  background-color: #c0c5ce;
  height: 50px;
  width: 50px;
}

.pointer {
  cursor: pointer;
}

.button {
  width: 81px;
  height: 42px;
  margin: 20px;
  line-height: 42px;
}

.buttonSimple {
  width: 140px;
  height: 42px;
  margin: 20px;
  line-height: 42px;
  border: 1px solid #2b303b;
  background-color: #4f5b66;
  color: #eff1f5;
}

.buttonSimple:hover {
  background-color: #c0c5ce;
}

.invisible {
  display: none;
}

.inline-block {
  display: inline-block;
}

.centerText{
  text-align: center;
}

.rightText {
  text-align: right;
}

.center {
  margin-left: auto;
  margin-right: auto;
}

.hint {
  color: #c0c5ce;
  margin-top: 5px;
  font-size: 12px;
}

.underline:hover {
  text-decoration: underline;
}

.leaderboard th {
  border: 1px solid #2b303b;
  padding-left: 20px;
  padding-right: 20px;
}

.leaderboard tr:nth-child(even) {
  background-color: rgba(192, 197, 206, 0.6);
}

.parent {
  height: 100%;
}

.element {
  position: relative;
  top: 50%;
  transform: translateY(-50%);
}

#feld {
  background-color: #4f5b66;
}