При нажатии на button плавная прокрутка к элементу по id, не меняя на <а>.Сейчас есть переход, но рывком

$(".main__belief_d-btn").click(function() {
    $('html, body').animate({
        scrollTop: $("#main__mission").offset().top
    }, 800);
});

<section>
<div class="main__belief_d">
            <div class="container row">
                <div class="col-12  col-md-4">
                    <div class="main__belief_d-item t-a-c ">
                        <div class="c-c d-flex m-a">
                            L
                        </div>
                        <h4>
                            <span class="red">L</span>egal
                        </h4>
                        <p>
                            But I must explain to you how all this mistaken idea of denouncing pleasure and praising pain was born and I will give you a complete account of the system, and expound the actual teachings of the great explorer of the truth
                        </p>
                    </div>
                </div>
                <div class="col-12  col-md-4">
                    <div class="main__belief_d-item t-a-c">
                        <div class="c-c d-flex m-a">
                            A
                        </div>
                        <h4>
                            <span class="red">A</span>ccounting
                        </h4>
                        <p>
                            But I must explain to you how all this mistaken idea of denouncing pleasure and praising pain was born and I will give you a complete account of the system, and expound the actual teachings of the great explorer of the truth
                        </p>
                    </div>
                </div>
                <div class="col-12  col-md-4">
                    <div class="main__belief_d-item t-a-c">
                        <div class="c-c d-flex m-a">
                            B
                        </div>
                        <h4>
                            <span class="red">B</span>usiness
                        </h4>
                        <p>
                            But I must explain to you how all this mistaken idea of denouncing pleasure and praising pain was born and I will give you a complete account of the system, and expound the actual teachings of the great explorer of the truth
                        </p>
                    </div>
                </div>
                <button  type="button" class="btn-green main__belief_d-btn" >
                            Подробнее
                </button>
            </div>
        </div>
    </section>
    <section class="main__mission" id="main__mission">
        <div class="container">
            <div class="main__mission_info">
                <div class="row">
                    <div class="col-12 col-md-9">
                        <div class="main__mission_text">
                            <div class="row">
                                <div class="col-12">
                                    <h6>
                                        Миссия LAB Consulting
                                    </h6>
                                </div>
                                <div class="col-12 col-md-7">
                                    <p class="main__mission_text-t">
                                        Sed ut perspiciatis unde omnis iste natus error sit voluptatem accusantium doloremque laudantium, totam rem aperiam, eaque ipsa quae ab illo inventore veritatis et quasi architecto beatae vitae dicta sunt explicabo. Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores.
                                        <br><br>
                                        Eos qui ratione voluptatem sequi nesciunt. Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit, sed quia non numquam eius modi tempora incidunt ut labore et dolore magnam aliquam quaerat voluptatem. 
                                    </p>
                                    <button type="button" class="btn btn-outline-light main__mission_btn ">Узнать больше
                                    </button>
                                </div>
                                <div class="col-12 col-md-5">
                                    <p>
                                        Eos qui ratione voluptatem sequi nesciunt. Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit, sed quia non numquam eius modi tempora incidunt ut labore et dolore magnam aliquam quaerat voluptatem.
                                        <br><br>
                                        Ut enim ad minima veniam, quis nostrum exercitationem ullam corporis suscipit laboriosam, nisi ut aliquid ex ea commodi consequatur?
                                    </p>
                                </div>                  
                            </div>
                        </div>
                    </div>
                    <div class="col-12 col-md-3">
                        <div class="main__mission_news">
                            <h6>
                                Новости
                            </h6>
                            <div class="main__mission_news-item">
                                <p>
                                    LAB Consulting запускает новое направление в своих услугах
                                </p>
                                <span>
                                    02.12.2015
                                </span>     
                            </div>
                            <div class="main__mission_news-item">
                                <p>
                                    LAB Consulting запускает новое направление в своих услугах
                                </p>
                                <span>
                                    02.12.2015
                                </span>     
                            </div>
                            <div class="main__mission_news-item">
                                <p>
                                    LAB Consulting запускает новое направление в своих услугах
                                </p>
                                <span>
                                    02.12.2015
                                </span>     
                            </div>
                        </div>
                    </div>  
                </div>  
            </div>      
        </div>
    </section>
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