JSFiddle - React, Tailwind, and code Playground

HTML

<script src="//code.jquery.com/jquery-3.3.1.slim.min.js"></script>
<link rel="stylesheet" href="//stackpath.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css">
<script src="//cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.0/umd/popper.min.js"></script>
<script src="//stackpath.bootstrapcdn.com/bootstrap/4.1.0/js/bootstrap.min.js"></script>
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css">
 <header>
        <div class="container-fluid">
        <div class="row main-nav">
            <div class="col-6 nav-left">
                <a href="#"><i class="fab fa-airbnb fa-2x"></i></a>
            </div>
            <div class="col-6 nav-right">
                <p>予想月収 <i class="far fa-question-circle"></i></p>
                <h3><i class="fas fa-yen-sign"></i> 84,697</h3>
                <button type="button" class="btn btn-danger btn-ignore">はじめる</button>
            </div>
        </div>
        </div>
    </header>

CSS

header {
  background-color: aquamarine;
  width: 100%;
  height: 80px;
}

.nav-left {
  display: flex;
  align-items: center;
}
.nav-left a {
  color: #087D8A;
}

.nav-right {
  display: flex;
  align-items: center;
  justify-content: flex-end;
}

.nav-right p {
  margin-top: 15px;
  margin-right: 8px;
  font-size: .875em;
  color: #575757;
}

.nav-right h3 {
  font-size: 24px;
  color: #575757;
}

.nav-right button {
  margin-right: 40px;
  margin-left: 15px;
}

.main-nav {
  background: #ffa;
}