swiperを使用しスライダーを設置しているのですが、数回更新しないとスライダーが正しく表示されません。PCで表示枚数を設定しボタンもつけているのですが、1枚表示やボタンが作動しない事があります。

スライダーをこう表示したいのですが、
真ん中のひとつしか表示されず、矢印も作動しません。
何度か更新すれば、正しく表示されることもあるのですが、
どこか修正点があれば教えてください。


<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html lang="ja">
<head>

<meta http-equiv="Content-Type" content="text/html; charset=euc-jp">
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<meta name="viewport" content="width=device-width,user-scalable=yes,initial-scale=1.0,minimum-scale=1.0">

<meta name="description" content="">

<title></title>



<style type="text/css">
p {
color:#666666;
}
p.ifont { font-family: YuGothic,'Yu Gothic',monospace;  line-height:120%;  }




.btn-flat-border {
  display: inline-block;
  padding: 1em 1.5em;
  text-decoration: none;
  color: #666666;
  border: solid 2px #f3d3b8;
  border-radius: 3px;
  transition: .4s;
}

.btn-flat-border:hover {
  background: #f3d3b8;
  color: #666666;
}


.sample-text1 {
    animation: fadeIn 4s ease 0s 1 normal;
    -webkit-animation: fadeIn 4s ease 0s 1 normal;
}


@media screen and (max-width:639px) {

img {
  width: auto;
  max-width: 100%;
  height: auto;
}

table {
width: 100%;
}

h1 {
font-size:16px;
}

h2 {
font-size:14px;
}


span {
font-size:12px;
line-height:1.9em;
letter-spacing:0.1em;
}

div p {
    display: inline-block;
    text-align: left;
    width: 95% 
    }



/* swiperのサイズ　*/

.swiper-container {
    width: 100%;
    height: auto;
}



}


@media screen and (min-width:1024px) {

span {
line-height:2em;
letter-spacing:0.1em;
}





/* swiperのサイズ　*/

.swiper-container {
    width: 1000px;
    height: 150px;
}







}




.container {
  font-family: "Yu Gothic", YuGothic, Verdana, 'Hiragino Kaku Gothic ProN','Hiragino Kaku Gothic Pro', 'ヒラギノ角ゴ Pro W3', 'メイリオ', Meiryo, sans-serif;
  text-align: center;
  padding-top: 40px;
}



</style>











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<script>
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<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/Swiper/5.4.3/css/swiper.min.css">


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</head>



<body bgcolor="#ffffff">



<div class="swiper-container">
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   <div class="swiper-button-prev swiper-button-black"></div>
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</div>



</div>




<div class="animation">
<p class="ifont" align="center" >
<span style= 'font-size:3'>



</div>




</td></tr></table>
</td></tr></table>
</div>


<!-- スクロール　ふわっと表示 -->
<script>

$(function(){
    $(window).scroll(function (){
        $('.fadein').each(function(){
            var elemPos = $(this).offset().top;
            var scroll = $(window).scrollTop();
            var windowHeight = $(window).height();
            if (scroll > elemPos - windowHeight + 200){
                $(this).addClass('scrollin');
            }
        });
    });
});

</script>


<!-- ふわっと切り替え -->
 <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script>
    <script>
        jQuery(function($){
            $('body').fadeIn(1000);
            $(window).on("beforeunload",function(e){
                $('body').fadeOut();
            });
        });
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    <script>document.body.style.display = 'none';</script>


<script>

$(function() {
    var topBtn = $('#page-top');    
    topBtn.hide();
    //スクロールが100に達したらボタン表示
    $(window).scroll(function () {
        if ($(this).scrollTop() > 100) {
            topBtn.fadeIn();
        } else {
            topBtn.fadeOut();
        }
    });
});

</script>



<style type="text/css">
<!--
#page-top {
    position: fixed;
    bottom: 10px;
    right: 10px;
    opacity:0.8; 
    font-size: 40%;
    z-index: 100;
}
#page-top a {
    background: #666;
    text-decoration: none;
    color: #fff;
    width: 100px;
    padding: 15px 0;
    text-align: center;
    display: block;
    border-radius: 5px;
}
#page-top a:hover {
    text-decoration: none;
    background: #999;
}
-->

</style>

<p id="page-top" align="right"><a href=""><font size="3">TOPへ戻る</font></a></p>

<script src="https://code.jquery.com/jquery-3.3.1.min.js"></script>

<style>
.fadeInDown {
-webkit-animation-fill-mode:both;
-ms-animation-fill-mode:both;
animation-fill-mode:both;
-webkit-animation-duration:1.5s;
-ms-animation-duration:1.5s;
animation-duration:1.5s;
-webkit-animation-name: fadeInDown;
animation-name: fadeInDown;
visibility: visible !important;
}
@-webkit-keyframes fadeInDown {
0% { opacity: 0; -webkit-transform: translateY(50px); }
100% { opacity: 1; -webkit-transform: translateY(0); }
}
@keyframes fadeInDown {
0% { opacity: 0; -webkit-transform: translateY(50px); -ms-transform: translateY(50px); transform: translateY(50px); }
100% { opacity: 1; -webkit-transform: translateY(0); -ms-transform: translateY(0); transform: translateY(0); }
}
</style>


  <script>

$(function(){
$('.animation').css('visibility','hidden');
$(window).scroll(function(){
var windowHeight = jQuery(window).height(),
     topWindow = jQuery(window).scrollTop();
$('.animation').each(function(){
  var targetPosition = jQuery(this).offset().top;
  if(topWindow > targetPosition - windowHeight + 70 ){
   jQuery(this).addClass("fadeInDown");
  }
});
});
});</script> 















<script src="https://cdnjs.cloudflare.com/ajax/libs/Swiper/5.4.3/js/swiper.min.js"></script>




<script src="swiper.js"></script>
<script>
      









var myswiper = new Swiper('.swiper-container', {
　loop: true,
  centeredSlides:true,
  slidesPerView: 1.7,

  
  
  navigation: {
      nextEl: '.swiper-button-next',
      prevEl: '.swiper-button-prev',
      
  
  
  },



  breakpoints: {
  640: {
　　　slidesPerView: 3.7,
　　
　　　
　　　
　　　　}
　　　
　　　
　　　
}


  
});






</script>



</body>
</html>