页面底部出现额外空白？CSS按钮样式引发的问题求助

问题现象 #

设置按钮样式后，页面底部出现了多余的空白区域，相关触发代码及完整CSS/HTML如下：

触发问题的核心CSS代码 #

.contact-links {
    position: relative;
    bottom: 150px;
    font-size: 1.0em;
}

.linkedin-button {
    display: inline-block;
    background: url('{{ url_for('static', filename='linkedin-logo.png') }}') no-repeat;
    background-size: contain;
    width: 150px;
    height: 150px;
    text-indent: -9999px;
    overflow: hidden;
    position: relative;
    right: 50px;
}
.github-button {
    display: inline-block;
    background: url('{{ url_for('static', filename='github-logo.png') }}') no-repeat;
    background-size: contain;
    width: 150px;
    height: 150px;
    text-indent: -9999px;
    overflow: hidden;
    position: relative;
    left: 50px;
}

.email-button {
    display: inline-block;
    background: url('{{ url_for('static', filename='email.png') }}') no-repeat;
    background-size: contain;
    width: 60px;
    height: 150px;
    text-indent: -9999px;
    overflow: hidden;
}

完整CSS代码 #

@font-face {
  font-family: 'Playfair Display';
  src: url('{{ url_for('static', filename='Playfair_Display/PlayfairDisplay-VariableFont_wght.ttf') }}') format('truetype');
}

@font-face {
  font-family: 'League Spartan';
  src: url('{{ url_for('static', filename='LeagueSpartan-VariableFont_wght.ttf') }}') format('truetype');
}

body {
    color: #d3d3d3
}

a {
    color: #d3d3d3;
}

h1 {
    font: 2em 'Playfair Display', sans-serif;
    color: #d3d3d3;
    margin-bottom: 20px;
}

p {
    font: 1.5em 'League Spartan', sans-serif;
    margin-bottom: 30px;
}

.contact-links {
    position: relative;
    bottom: 150px;
    font-size: 1.0em;
}

.linkedin-button {
    display: inline-block;
    background: url('{{ url_for('static', filename='linkedin-logo.png') }}') no-repeat;
    background-size: contain;
    width: 150px;
    height: 150px;
    text-indent: -9999px;
    overflow: hidden;
    position: relative;
    right: 50px;
}
.github-button {
    display: inline-block;
    background: url('{{ url_for('static', filename='github-logo.png') }}') no-repeat;
    background-size: contain;
    width: 150px;
    height: 150px;
    text-indent: -9999px;
    overflow: hidden;
    position: relative;
    left: 50px;
}

.email-button {
  display: inline-block;
  background: url('{{ url_for('static', filename='email.png') }}') no-repeat;
  background-size: contain;
  width: 60px;
  height: 150px;
  text-indent: -9999px;
  overflow: hidden;
}

.custom-hr {
    border-top: 1px solid #d3d3d3;
    height: 250px;
    margin-top: 10px;
    margin-bottom: 20px;
}

.contact-form {
    background-color: white;
    padding: 30px;
    border-radius: 10px;
    box-shadow: none;
    width: 100%;
    max-width: 400px;
    margin: 0 auto;
    position: relative;
    bottom: 200px;
}

.contact-form label {
    display: block;
    margin-bottom: 8px;
    font-weight: bold;
    color: black;
    text-shadow: none;
    font-family: 'League Spartan', sans-serif;
}

.contact-form input,
.contact-form textarea {
    width: 100%;
    padding: 12px;
    margin-bottom: 20px;
    box-sizing: border-box;
    border: 1px solid #ced4da;
    border-radius: 4px;
    font-size: 16px;
    font-family: 'League Spartan', sans-serif;
    transition: border-color 0.3s;
}

.contact-form textarea {
    resize: vertical;
}

.contact-form input:focus,
.contact-form textarea:focus {
    border-color: #007bff;
}

.contact-form button {
    background-color: #007bff;
    color: white;
    padding: 12px 20px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 16px;
    font-family: 'League Spartan', sans-serif;
    transition: background-color 0.3s;
}

.contact-form button:hover {
    background-color: #0056b3;
}

完整HTML代码 #

<h1 style="display: flex">Contact </h1>
<div class="custom-hr"></div>

<form class="contact-form" action="/submit" method="post">
    <label for="name">Name:</label>
    <input type="text" id="name" name="name" required placeholder="Enter your name">

    <label for="email">Email:</label>
    <input type="email" id="email" name="email" required placeholder="Enter your email">

    <label for="message">Message:</label>
    <textarea id="message" name="message" rows="4" required placeholder="Enter your message"></textarea>

    <button type="submit">Submit</button>
</form>
<div class="contact-links">
    <a href="https://www.linkedin.com/in/malikmassaquoi/" target="_blank" class="linkedin-button">LinkedIn</a>
    <a href="mailto:MalikMassaquoi@outlook.com" target="_blank" class="email-button">Email</a>
    <a href="https://github.com/SirLeekster" target="_blank" class="github-button">GitHub</a>
</div>

原因分析 #

1. 相对定位的特性：.contact-form和.contact-links都用了position: relative配合bottom值向上偏移，但相对定位元素只是视觉上移动，原来占据的垂直空间会被保留，这就导致页面底部出现了它们原本位置的空白区域。
2. .custom-hr的高度设置：该元素设置了height: 250px，本身会占据大量垂直空间，进一步加剧了底部空白的问题。

修复方案 #

方案1：用负margin代替相对定位偏移 #

把相对定位的bottom属性替换为margin-top负值，这样元素会向上移动，且不会保留原占位空间：

.contact-form {
    background-color: white;
    padding: 30px;
    border-radius: 10px;
    box-shadow: none;
    width: 100%;
    max-width: 400px;
    margin: 0 auto;
    margin-top: -200px; /* 用负margin替代bottom偏移 */
}

.contact-links {
    font-size: 1.0em;
    margin-top: -150px; /* 用负margin替代bottom偏移 */
}

方案2：调整.custom-hr的垂直间距 #

如果不需要.custom-hr占据250px的高度，可改用padding控制垂直间距，避免多余空间：

.custom-hr {
    border-top: 1px solid #d3d3d3;
    margin-top: 10px;
    margin-bottom: 20px;
    padding-top: 125px; /* 用padding替代height实现垂直间距 */
    padding-bottom: 125px;
}

方案3：结合flex布局优化整体结构（推荐新手学习） #

如果希望彻底避免这类定位问题，可以用flex布局来控制元素的垂直排列和间距，示例如下：
给body添加flex布局：

body {
    color: #d3d3d3;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 20px; /* 控制元素间的统一间距 */
    min-height: 100vh;
}

然后移除.custom-hr的height、.contact-form和.contact-links的定位及偏移，通过flex的gap来控制间距，这样布局更稳定，不会出现额外空白。

内容的提问来源于stack exchange，提问作者Cycload