form input{
    padding: 10px;
}
.pop-close{
    position: absolute;
    top:10px;
    right: 15px;
    cursor: pointer;
}
.pop-close:hover{
    color: red;
}
canvas#techBackground {
    position: fixed;
    top: 0;
    left: 0;
    z-index: -1;
    background: #0a0a1a; /* 深蓝色背景，科技感 */
}