.page_main iframe {
    height: 100vh;
}
.page_main {
   margin-top: 0 !important;
}
.ebook-sec {
    height: 600px;
    background-color: #303030;
}
.ebook-sec .ebookwrap {
    width: 100%;
    height: 750px;
}
.ebook-sec .ebookwrap iframe {
    margin: 50px auto;
    width: 100%;
    height: 500px;
    
} 
/*CSS ends*/