<!DOCTYPE html>
<html lang="ko">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>인라인 블럭라인</title>
<style>
h1, div, a, span {
border: 2px solid black;
}
</style>
</head>
<body>
<h1>hello wodld</h1>
<div>hello world</div>
<br>
<a href="">Inline element</a>
<span>인라인 요소</span>
</body>
</html>
직접 작성을 통해 확인해 본다면 더 쉽게 이해할 수 있습니다.