/*------------------------header------------------------*/
header {
    position: relative;
}
.header-bg {
    position: absolute;
    left: 0px;
    top: 0px;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0, 0.7);
    z-index: 1;
}
/*------------------------sec-3------------------------*/
.sec-3 {
    padding-top: 80px;
}
.sec-3 .title {
    text-align: center;
}
/*------------------------sec-4------------------------*/
.sec-4 {
    background-attachment: fixed;
}
/*------------------------introduce------------------------*/
.introduce {
    padding: 80px 0;
}
.introduce .title {
    padding-right: 45px;
}
.introduce .title .st-span {
    margin-bottom: 15px;
}
.introduce .title .st-h2 {
    margin-bottom: 35px;
}
.introduce .title p {
    font-size: 17px;
    color: var(--color-4);
}

.introduce .box img {
    padding: 10px 20px;
}
.introduce .box img {
    width: 100%;
    height: auto;
    max-width: 530px;
}