边框样式

.border-xs-black {
  border: 1px solid #000;
}
.border-sm-black {
  border: 2px solid #000;
}
.border-md-black {
  border: 3px solid #000;
}
.border-lg-black {
  border: 5px solid #000;
}

.border-xs-gray {
  border: 1px solid #9c9c9c;
}
.border-sm-gray {
  border: 2px solid #9c9c9c;
}
.border-md-gray {
  border: 3px solid #9c9c9c;
}
.border-lg-gray {
  border: 5px solid #9c9c9c;
}