JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE html>
<html lang="en">

  <head>
    <meta charset="utf-8">
    <title>Japan Connections</title>
    <link rel="stylesheet" href="styles.css" />

    <!-- viewport 読み込み -->
    <meta name="viewport" content="width=device-width, initial-scale=1" />

    <link href="https://fonts.googleapis.com/css?family=Julius+Sans+One" rel="stylesheet">
    <link href="https://fonts.googleapis.com/css?family=Source+Sans+Pro:300" rel="stylesheet">

    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/Swiper/3.4.1/css/swiper.min.css">
    <script src="https://cdnjs.cloudflare.com/ajax/libs/Swiper/3.4.1/js/swiper.min.js"></script>

    <script src="https://code.jquery.com/jquery-2.1.3.min.js"></script>
  </head>

  <body>
    <div class="container">
      <div id="globalNavi">
        <h1 class="jc">Japan <span id="sun">●</span> Connections</h1>
        <nav class="menu">
          <ul class="menulist">
            <li><a href="">HOME</a></li>
            <li><a href="">ABOUT US</a></li>
            <li><a href="">SERVICES</a></li>
            <li><a href="">CONTACT</a></li>
          </ul>
        </nav>
      </div>

      <div class="swiper-container">
        <!-- Additional required wrapper -->
        <div class="swiper-wrapper">
          <!-- Slides -->
          <div class="swiper-slide" style="background-image: url('https://placehold.jp/24/99cc99/339933/350x150.png?text=img/1.jpg');">
            Bringing the best of Japan to the World
          </div>
          <div class="swiper-slide" style="background-image: url('https://placehold.jp/24/99cc99/339933/350x150.png?text=img/2.jpg');">
            Bringing the best of Japan to the World
          </div>
          <div class="swiper-slide" style="background-image: url('https://placehold.jp/24/99cc99/339933/350x150.png?text=img/3.jpg');">
            Bringing the best of Japan to the World
          </div>
          <div class="swiper-slide" style="background-image:...

CSS

@charset "UTF-8";
body,
div,
p,
h1,
h2,
h3,
h4,
h5 {
  margin: 0;
  padding: 0;
  font-family: 'Source Sans Pro', sans-serif;
  line-height: 1.7;
  letter-spacing: 0.05em;
}

/*
* header
*/

#globalNavi {
  color: #000000;
  width: 100%;
  height: 130px;
  padding: 20px 10px 10px 50px;
  /* 変更しない */
}

#globalNavi h1 {
  font-family: 'Julius Sans One', sans-serif;
  font-size: 2.5em;
  float: left;
}

span#sun {
  color: red;
  font-size: 1.5em;
}

.menu {
  font-family: 'Julius Sans One', sans-serif;
}

.fixed {
  position: fixed;
  top: 0;
  background-color: #fff;
  width: 100%;
  height: 130px;
  z-index: 10000;
}

nav {
  text-align: center;
  position: relative;
  left: 70px;
  top: 17px;
}

ul {
  list-style: none;
  display: flex;
  flex-flow: row;
  flex-wrap: nowrap;
  padding: 0 0 10px 0;
}

ul a {
  padding: 12px 24px;
  text-decoration: none;
  padding-bottom: 5px;
  color: #000;
  display: block;
  position: relative;
}

ul a:before {
  content: '';
  width: 0;
  left: 50%;
  bottom: 0;
  transition: all 0.4s ease;
  border-bottom: 1px solid red;
  position: absolute;
  display: block;
}

ul a:hover:before {
  width: 50%;
  border-bottom: 1px solid red;
}

ul a:after {
  content: '';
  width: 0;
  right: 50%;
  bottom: 0;
  transition: all 0.4s ease;
  border-bottom: 1px solid red;
  position: absolute;
  display: block;
}

ul a:hover:after {
  width: 50%;
  border-bottom: 1px solid red;
}

/*
Swiper
*/

.swiper-container {
  width: 100%;
  height: 400px;
}

.swiper-slide {
  padding-top: 180px;
  /* 画像位置の調整用 */
  text-align: center;
  color: #fff;
  font-size: 30px;
  background-repeat: no-repeat;
  width: 1261px;
  background-size: cover;
  background-position: center center;
  "

}

/*
* main & sidebar (wrapper)
*/

.container {
  padding-left: -15px;
  padding-right: 15px;
}

.main {
  position: relative;
  top: 50px;
  left: 255px;
  width: 800px;
  margin: 0;
}

/*
Index
*/

.index-1 {
  margin: 0;
  /* デフォルトCSS打ち消し */
  font-size: 24px;
  /*...

JavaScript

var mySwiper = new Swiper('.swiper-container', {
  loop: true,
  pagination: '.swiper-pagination',
  nextButton: '.swiper-button-next',
  prevButton: '.swiper-button-prev',
  speed: 3000,

  autoplay: {
    delay: 3000, // スライドが切り替わるまでの表示時間(ミリ秒)
    stopOnLast: false, // 最後のスライドまで表示されたら自動再生を中止するか
    disableOnInteraction: true // ユーザーのスワイプ操作を検出したら自動再生を中止するか
  },

});

jQuery(function($) {
  var nav = $('#globalNavi'),
    offset = nav.offset();
  $(window).scroll(function() {
    if ($(window).scrollTop() > offset.top) {
      nav.addClass('fixed');
    } else {
      nav.removeClass('fixed');
    }
  });
});