<form>
  <div class="form-row">
    <label for="name">姓名：</label>
    <input type="text" id="name" name="name" required>
  </div>
  <div class="form-row">
    <label for="email">邮箱：</label>
    <input type="email" id="email" name="email" required>
  </div>
  <div class="form-row">
    <label for="message">留言：</label>
    <textarea id="message" name="message" required></textarea>
  </div>
  <div class="form-row">
    <button type="submit">提交</button>
  </div>
</form>

form {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
}

.form-row {
  display: flex;
  align-items: center;
  margin-bottom: 10px;
}

label {
  width: 100px;
  text-align: right;
  margin-right: 10px;
}

input, textarea {
  flex: 1;
}

button {
  margin-left: auto;
}