site/_src/_assets/styles/_page-whitepaper.scss

.page-whitepaper {
    .content--page--markdown {
        > p:nth-child(1),
        > p:nth-child(2),
        > p:nth-child(3) { text-align: center; }
    }
}

.section-whitepaper-download {
    background-image: url('/assets/img/photo3.jpg')
}