src/main/resources/templates/fragment/header.html

<html xmlns:th="http://www.thymeleaf.org">
       
    <!--headerFragment 선언-->
    <div th:fragment="headerFragment" style="height: 4em;text-align: center;">
    	<div class="shadow-sm p-3 mb-5 bg-body rounded" style="height: 3.4rem;">
			<div style="text-align: left; float: left;">
			  <a th:href="@{/board/boardList?boardName=maintenance}"><button type="button" class="btn btn-outline-dark">유지보수</button></a>
			  <a th:href="@{/board/boardList?boardName=etc}"><button type="button" class="btn btn-outline-dark">기타</button></a>
			</div>
			<div style="text-align: right; float: right;">
			    <form class="d-flex" th:action="@{/logout}">
			      <button class="btn btn-outline-success" type="submit">로그아웃</button>
			    </form>
			</div>
		</div>
    </div>

</html>