📅  最后修改于: 2022-03-11 14:47:33.884000             🧑  作者: Mango
/* If input is not empty */
input:not(:placeholder-shown) {
/* You need to add a placeholder to your fields. For example: */
border-color: green;
}
/* If input is empty */
input:placeholder-shown {
border-color: red;
}