style.css

/**
 * @license
 * Copyright 2019 Google LLC. All Rights Reserved.
 * SPDX-License-Identifier: Apache-2.0
 */
/* [START maps_control_custom_state] */
/* 
 * Always set the map height explicitly to define the size of the div element
 * that contains the map. 
 */
#map {
  height: 100%;
}

/* 
 * Optional: Makes the sample page fill the window. 
 */
html,
body {
  height: 100%;
  margin: 0;
  padding: 0;
}

#goCenterUI,
#setCenterUI {
  background-color: #fff;
  border: 2px solid #fff;
  border-radius: 3px;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.3);
  cursor: pointer;
  float: left;
  margin-bottom: 22px;
  text-align: center;
}

#goCenterText,
#setCenterText {
  color: rgb(25, 25, 25);
  font-family: Roboto, Arial, sans-serif;
  font-size: 15px;
  line-height: 25px;
  padding-left: 5px;
  padding-right: 5px;
}

#setCenterUI {
  margin-left: 12px;
}

/* [END maps_control_custom_state] */