如何在HTML和CSS中对齐表单输入框？

我尝试让表单中的所有输入文本框对齐，但目前它们处于未对齐状态，请问该如何处理？

原代码 #

原CSS代码 #

body{
    background-color: rgb(134, 210, 221)
}

.event{
    display: inline;
    float: left;
    clear: both;
}

.radio1{
    display: inline;
    float: left;
}

.radio2{
    float: left;
}

.gender{
    display: block;
    float: left;
    clear: both;
}

.required{
    color: red;
}

p{
    clear: both;
    
}

label{
    display: block;
    float: left;
}
#date{
    float: left;
}

.submit{
    text-align: center;
}

input{
    display: inline-block;
    margin-left: 10px;
    clear: both;
}

原HTML代码 #

<body>

<form>
    <p class="event"><span class="required">*</span>Select Event:</p> 
    <div class="radio1">
    <p><input type="radio" id="stock">Stock</p>
    <p><input type="radio" id="modified">Modified</p>
    </div>
   
        <p><span class="required">*</span>Last Name: <input type="text" name="lastname" id="lastname" />
        </p>
        <p><span class="required">*</span>First Name: <input type="text" name="firstname" id="firstname"></p>
        <p><span class="required">*</span>Address: <input type="text" name="address" id="address"></p>
        <p><span class="required">*</span>City: <input type="text" name="city" id="city"></p>

        <p><span class="required">*</span>Province: <select name="selectprovince" id="selectprovince">Select Province
        <option value="provinces">...</option>
        <option value="provinces">AB</option>
        <option value="provinces">BC</option>
        <option value="provinces">MB</option>
        <option value="provinces">NB</option>
        <option value="provinces">NL</option>
        <option value="provinces">NT</option>
        <option value="provinces">NS</option>
        <option value="provinces">NU</option>
        <option value="provinces">ON</option>
        <option value="provinces">PE</option>
        <option value="provinces">QC</option>
        <option value="provinces">SK</option>
        <option value="provinces">YT</option>
</select></p>

<p><span class="required">*</span>Postal/Zip Code: <input type="text" name="postal" id="postal"></p>
<p><span class="required">*</span>Country: <input type="text" name="country" id="country"></p>
<p><span class="required">*</span>Email: <input type="text" name="country" id="country"></p>

<label for="date"><span class="required">*</span>Date of Birth</label>
<input type="date" name="date" id="date">


<p class="gender"><span class="required">*</span>Gender: </p> 
<div class="radio2">
<p><input type="radio">Male</p>
<p><input type="radio">Female</p>
<p><input type="radio">Other</p>
</div>

<div class="bottom">
<p><span class="required">*</span>Boat Name: <input type="text" name="boat" id="boat"></p>

<p class="comments">Comments <textarea name="comments" form="form" id="comments" rows="7" cols="20"></textarea></p>
</div>

<p><span class="required">*</span>I agree to the waiver <input type="checkbox"> Yes </p>
<div class="submit">
<input type="submit" id="submit">
</div>
</form>
      
</select>

问题原因分析 #

1. 表单标签（文本描述）没有统一宽度，不同长度的文本导致输入框起始位置混乱
2. 大量使用float布局，缺少统一的表单行容器，排版逻辑失控
3. 部分表单元素（如出生日期的label和input）未放在同一容器内，破坏排版结构

解决方案（Flexbox布局） #

通过Flexbox统一表单行布局，给标签设置固定宽度并右对齐，输入元素自动填充剩余空间，确保所有输入框整齐对齐。

修改后的CSS代码 #

/* 重置默认样式，消除浏览器差异 */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body{
  background-color: rgb(134, 210, 221);
  padding: 20px; /* 给页面添加内边距，避免内容贴边 */
}

.required{
  color: red;
}

/* 统一表单行布局 */
.form-row {
  display: flex;
  align-items: center;
  margin-bottom: 15px;
  clear: both;
}

/* 标签固定宽度+右对齐，确保输入框起始位置统一 */
.form-row label, .form-row .label-text {
  width: 180px;
  text-align: right;
  margin-right: 10px;
}

/* 输入元素自适应剩余宽度 */
.form-row input, .form-row select, .form-row textarea {
  flex: 1;
  padding: 4px; /* 增加内边距提升交互体验 */
}

/* 单选框组布局 */
.radio-group {
  display: flex;
  align-items: center;
}

.radio-group .form-row {
  margin-bottom: 0;
  margin-right: 20px;
}

.radio-group .form-row label {
  width: auto;
  text-align: left;
  margin-right: 5px;
}

.submit{
  text-align: center;
  margin-top: 20px;
}

修改后的HTML代码 #

<body>
<form>
  <!-- 活动选择 -->
  <div class="form-row">
    <span class="label-text"><span class="required">*</span>Select Event:</span>
    <div class="radio-group">
      <div class="form-row">
        <input type="radio" id="stock" name="event">
        <label for="stock">Stock</label>
      </div>
      <div class="form-row">
        <input type="radio" id="modified" name="event">
        <label for="modified">Modified</label>
      </div>
    </div>
  </div>

  <!-- 姓氏 -->
  <div class="form-row">
    <span class="label-text"><span class="required">*</span>Last Name:</span>
    <input type="text" name="lastname" id="lastname" />
  </div>

  <!-- 名字 -->
  <div class="form-row">
    <span class="label-text"><span class="required">*</span>First Name:</span>
    <input type="text" name="firstname" id="firstname">
  </div>

  <!-- 地址 -->
  <div class="form-row">
    <span class="label-text"><span class="required">*</span>Address:</span>
    <input type="text" name="address" id="address">
  </div>

  <!-- 城市 -->
  <div class="form-row">
    <span class="label-text"><span class="required">*</span>City:</span>
    <input type="text" name="city" id="city">
  </div>

  <!-- 省份 -->
  <div class="form-row">
    <span class="label-text"><span class="required">*</span>Province:</span>
    <select name="selectprovince" id="selectprovince">
      <option value="provinces">...</option>
      <option value="provinces">AB</option>
      <option value="provinces">BC</option>
      <option value="provinces">MB</option>
      <option value="provinces">NB</option>
      <option value="provinces">NL</option>
      <option value="provinces">NT</option>
      <option value="provinces">NS</option>
      <option value="provinces">NU</option>
      <option value="provinces">ON</option>
      <option value="provinces">PE</option>
      <option value="provinces">QC</option>
      <option value="provinces">SK</option>
      <option value="provinces">YT</option>
    </select>
  </div>

  <!-- 邮编 -->
  <div class="form-row">
    <span class="label-text"><span class="required">*</span>Postal/Zip Code:</span>
    <input type="text" name="postal" id="postal">
  </div>

  <!-- 国家 -->
  <div class="form-row">
    <span class="label-text"><span class="required">*</span>Country:</span>
    <input type="text" name="country" id="country">
  </div>

  <!-- 邮箱 -->
  <div class="form-row">
    <span class="label-text"><span class="required">*</span>Email:</span>
    <input type="text" name="email" id="email">
  </div>

  <!-- 出生日期 -->
  <div class="form-row">
    <label for="date"><span class="required">*</span>Date of Birth</label>
    <input type="date" name="date" id="date">
  </div>

  <!-- 性别 -->
  <div class="form-row">
    <span class="label-text"><span class="required">*</span>Gender:</span>
    <div class="radio-group">
      <div class="form-row">
        <input type="radio" name="gender">
        <label>Male</label>
      </div>
      <div class="form-row">
        <input type="radio" name="gender">
        <label>Female</label>
      </div>
      <div class="form-row">
        <input type="radio" name="gender">
        <label>Other</label>
      </div>
    </div>
  </div>

  <!-- 船名 -->
  <div class="form-row">
    <span class="label-text"><span class="required">*</span>Boat Name:</span>
    <input type="text" name="boat" id="boat">
  </div>

  <!-- 评论 -->
  <div class="form-row">
    <span class="label-text">Comments</span>
    <textarea name="comments" id="comments" rows="7" cols="20"></textarea>
  </div>

  <!-- 协议勾选 -->
  <div class="form-row">
    <span class="label-text"><span class="required">*</span>I agree to the waiver</span>
    <div class="form-row" style="width: auto;">
      <input type="checkbox">
      <label style="width: auto;">Yes</label>
    </div>
  </div>

  <!-- 提交按钮 -->
  <div class="submit">
    <input type="submit" id="submit">
  </div>
</form>
</body>

补充说明 #

如果偏好CSS Grid布局，也可以将.form-row的样式替换为：

.form-row {
  display: grid;
  grid-template-columns: 180px 1fr;
  gap: 10px;
  align-items: center;
  margin-bottom: 15px;
}

效果与Flexbox方案一致，代码更简洁。

内容的提问来源于stack exchange，提问作者gl1tch