css　画面の一部の横幅が画面一杯に広がりません

写真のBicycleから下の右側がなぜか空白になってしまいます。なぜでしょうか？

html
1コード
2    <!DOCTYPE html>
3<html>
4  <head>
5    <meta charset="utf-8">
6    <title>Profile</title>
7    <link rel="stylesheet" href="../css/level1.css">
8  </head>
9<body>
10  <div class="header">
11    <div class="header-contents">
12    <p class="header-left">Profile</p>
13    <div class="header-right">
14     <a href="#" class="btn-About" href="#index">About</a>
15     <a href="#" class="btn Bicycle" href="#index2">Bicycle </a>
16    </div>
17    </div>
18  </div>
19  </div>
20  <div class="main">
21    <div class="main-contents">
22      <div class="main-photo">
23    <img src="https://code-step.com/demo/html/profile/img/mainvisual.jpg" alt="bike-image" class="main-image">
24      </div>
25    <h3 id="index">About</h3>
26    <div class="main-icon">
27    <img src="https://code-step.com/demo/html/profile/img/about.jpg" alt="icon-image">
28    <h4>KAKERU MIYAICHI</h4><br><p>テキストmain</p>
29    </div>
30   <div class="option">
31    <div class="main-intro">
32      <p id="index2" class="bicycle">Bicycle</p>
33      <div class="intro-image">
34        <img src="https://code-step.com/demo/html/profile/img/bicycle1.jpg" alt="intro-image">
35        <p>タイトルタイトル</p>
36        <p>テキスト</p>
37      </div>
38      <div class="intro-image">
39        <img src="https://code-step.com/demo/html/profile/img/bicycle2.jpg" alt="intro-image">
40        <p>タイトルタイトル</p>
41        <p>テキスト</p>
42      </div>
43      <div class="intro-image">
44        <img src="https://code-step.com/demo/html/profile/img/bicycle3.jpg" alt="intro-image">
45        <p>タイトルタイトル</p>
46        <p>テキスト</p>
47      </div>
48    </div>
49  </div>
50</div>
51  </div>
52  <div class="last">
53<div class="footer-last">
54  <p>© 2020 Profile</p>
55</div>
56  </div>
57</body>
58</html>
59

css
1コード
2.header-contents p btn{
3  float: left;
4}
5.header-left{
6  padding: 4px 24px;
7  background-color: black;
8  color: white;
9  font-size: 24px;
10  float: left;
11}
12.header-right{
13  font-size: 16px;
14  padding: 32px 16px 0 0;
15  display: inline-block;
16  float:right;
17  color: black;
18}
19.header-right a{
20  color: black;
21  text-decoration: none;
22  padding: 24px 8px 0 0;
23}
24.main-photo img{
25  display: block;
26  width:100%;
27}   
28.main-contents h3{
29    text-align: center;
30    font-size: 32px;
31    padding: 8px 0 8px 0;
32  text-decoration:underline;
33  text-decoration-thickness: 3px
34  }
35  .main-icon{
36  
37  }
38.main-icon img{
39  height:80px;
40  width: 80px;
41  border-radius: 50%;
42  float: left;
43  margin-left: 80px;
44}
45.main-icon h4{
46  margin:40px  0 0 184px;
47}
48.main-icon p{
49  margin: 0 0 0 184px
50}
51.last{
52  width: 100%;
53}
54.bicycle{
55  font-size: 32px;
56  text-align: center;
57  border-bottom: 3px solid black ;
58  font-weight: bold;
59  margin-bottom: 24px;
60}
61.intro-image{
62  float: left;
63  width : calc(100% / 3) ;
64  padding: 16px 24px;
65box-sizing: border-box;
66}
67.intro-image img{
68  height: 200px;
69  width:100%;
70}
71.main-intro{
72  height: 64px;
73  box-sizing: border-box;
74}
75.footer-last{
76  position: relative;
77  top: 496px;
78  text-align: center;
79  padding-bottom: 32px;
80  font-size: 16px;
81}
82.option{
83  position:absolute
84}