howto 在线编辑器 | howto代码测试

<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>.btn {
  border: 2px solid black;
  background-color: white;
  color: black;
  padding: 14px 28px;
  font-size: 16px;
  cursor: pointer;
}

/* Green */
.success {
  border-color: #4CAF50;
  color: green;
}

.success:hover {
  background-color: #4CAF50;
  color: white;
}

/* Blue */
.info {
  border-color: #2196F3;
  color: dodgerblue;
}

.info:hover {
  background: #2196F3;
  color: white;
}

/* Orange */
.warning {
  border-color: #ff9800;
  color: orange;
}

.warning:hover {
  background: #ff9800;
  color: white;
}

/* Red */
.danger {
  border-color: #f44336;
  color: red;
}

.danger:hover {
  background: #f44336;
  color: white;
}

/* Gray */
.default {
  border-color: #e7e7e7;
  color: black;
}

.default:hover {
  background: #e7e7e7;
}
</style>
</head>
<body>

</body>
</html>

报个问题: