html, body {
    width: 100%;
    height: 100%;
    margin: 0;
    padding: 0;
    overflow: hidden; /* 防止滚动条 */
}
#china-map {

    left: 0;
    top: 0;
    width: 100vw;
    height: 100vh;
    min-width: 0;
    min-height: 0;
    margin: 0;
    padding: 0;
    z-index: 1;
}