改行の<br>を使用してないのに、エディタ内に入力した内容がそのままブラウザに反映されてしまいます。

改行の<br>を使用してないのに、エディタ内に入力した内容がそのままブラウザに反映されてしまいます。反映させないようにしたいのですが、どうすれば直るのでしょうか？
使用しているテキストエディタはAtomです。

html
1<!DOCTYPE html>
2<html lang="ja">
3  <head>
4    <meta charset="utf-8">
5    <title>下書き</title>
6    <link rel="stylesheet" href="style sitagaki.css">
7  </head>
8  <body>
9  <div class="header">
10    <h1>下書き</h1>
11  </div>
12  <div class="main">
13    <h2>namber</h2>
14    <img src="image/img_0.jpg" >
15    <ul>
16      <li>1ban</li>
17      <li>2ban</li>
18      <li>3ban</li>
19      <li>4ban</li>
20      <li>5ban</li>
21    </ul>
22    <p>tttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttt
23      ttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttt
24      yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
25      ttttttttttttttttttttttttttttttttttttttttttttttttttttttttttddddddddddddddddddddddddddddddddddddddddddd
26      dddddddddddddddddddddddddddddddddddddddddddddddddddd</p>
27  </div>
28    <div class="footer">
29      <h2>Q&amp;A</h2>
30    </div>
31  </body>
32</html>
33

css
1*{
2  margin: 0;
3}
4.header{
5  background-color:#0066CC ;
6  height: 200px;
7  width: 1920px;
8}
9.main{
10  background-color: #FF6633 ;
11  height: 300px;
12  width: 1920px;
13}
14.main img{
15  width: 350px;
16  height: ;
17  text-align: center;
18  float: left;
19}
20.main p{
21
22}
23.footer{
24  background-color: #669933 ;
25  height: 200px;
26}
27