/* main */
        /* .main-before,
        .main-back {
          min-height: 75vh;
        } */
        .main-before {
            padding: 1.3vw !important;
            width: 40%;
            position: relative;
            opacity: 2;
            z-index: 2;
            margin-top: 14%;
            margin-left: 5%;
            background-color: grey;
            border-radius: 1vw;
            opacity: 0.85;
        }

        .main-before p {
            margin-bottom: 1vw;
        }

        .main {
            height: calc(800/1920*100vw);
        }

        @media (max-width: 750px) {
            .main-before {
                /* padding: 1rem !important; */
                width: 50%;
            }
        }

        @media (max-width: 500px) {
            .main-before {
                width: 90%;
            }
        }

        /* 首屏end */
        .main .main-title {
            font-size: 1.7vw;
        }

        .main .lead {
            font-size: 1vw;
        }

        .main .btn {
            font-size: 1vw;
        }