如何刪除html導航欄上的「邊距」？

Question

我想爲本網站添加頂級菜單，但它只是不斷爲topmenu添加「邊距」。

body { 
 
    background-color: #2E3058; 
 
    font-family: 'sans-sefir'; 
 
} 
 
#topMenu { 
 
    width: 100%; 
 
    height: 50px; 
 
    margin: 0; 
 
    padding: 0; 
 
    border-bottom: 1px solid #ccc; 
 
    background-color: #3A3D70; 
 
}

<div id="topMenu"> 
 
    <button class="topMenuBtn">Home</button> 
 
    <button class="topMenuBtn">Forum</button> 
 
    <button class="topMenuBtn">About</button> 
 
</div>

Answer 1

body { 
 
    background-color: #2E3058; 
 
    font-family: 'sans-sefir'; 
 
} 
 
#topMenu { 
 
    width: 100%; 
 
    margin: 0; 
 
    padding: 0; 
 
    border-bottom: 1px solid #ccc; 
 
    background-color: #3A3D70; 
 
}

<div id="topMenu"> 
 
    <button class="topMenuBtn">Home</button> 
 
    <button class="topMenuBtn">Forum</button> 
 
    <button class="topMenuBtn">About</button> 
 
</div>

從CSS文件