body {
  background-color: SkyBlue;
}

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

.center_table {
  margin-left: auto;
  margin-right: auto;
  text-align: left;
}


.button {
  background-color: #4CAF50; /* Green */
  border: none;
  color: white;
  padding: 10px 35px;
  text-align: center;
  text-decoration: none;
  display: inline-block;
  font-size: 16px;
  margin: 4px 2px;
  transition-duration: 0.4s;
  cursor: pointer;
}
.button_black {
  background-color: white;
  color: black;
  border: 2px solid #555555;
}

.button_black:hover {
  background-color: #555555;
  color: white;
}