<style>
 
 .center-block{
  display: block;
  margin-right: auto;
  margin-left: auto;
}


.panel {
  margin-bottom: 20px;
  background-color: #fff;
  border: 1px solid transparent;
  border-radius: 4px;
  -webkit-box-shadow: 0 1px 1px rgba(0, 0, 0, .05);
          box-shadow: 0 1px 1px rgba(0, 0, 0, .05);
}
.panel-body {
  padding: 15px;
}

.panel-footer {
  padding: 10px 15px;
  background-color: #f5f5f5;
  border-top: 1px solid #ddd;
  border-bottom-right-radius: 3px;
  border-bottom-left-radius: 3px;
}

.panel-default {
  border-color: #ddd;
}
 
 </style>