JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <link rel="stylesheet" href="./index.css">
    <title>Document</title>
</head>

<body>
    <form action="/add-product" method="POST">
        <h1>E-Shopping Order</h1>
        <div id="mainblock">
            <div class="inputblock">
              <label for="">商品名稱：</label>
              <input type="text" placeholder="......">
          </div>
          <div class="inputblock">
              <label for="">價格：</label>
              <input type="text" placeholder="$$$">
          </div>
          <div class="inputblock">
              <label for="">是否免運：</label>
              <input type="checkbox">是
              <input type="checkbox">否
          </div>
          <div class="inputblock">
              <label for="">性別：</label>
              <input type="radio" name="sex" value="男">男
              <input type="radio" name="sex" value="女">女
          </div>
          <div class="inputblock">
              <label for="">類別：</label>
              <select name="" id="">
                  <option value="">上衣類</option>
                  <option value="">外套類</option>
                  <option value="">下身類</option>
                  <option value="">配件類</option>
              </select>
          </div>
          <div class="inputblock">
              <textarea name="" id="" cols="30" rows="10">商品備註：</textarea>
          </div>
          <button id="submit" type="submit">確認</button>
        </div>
    </form>
</body>

</html>

CSS

body {
    background-color: lightgray;
}

h1 {
    width: 70%;
    margin: auto;
    margin-top: 25px;
    margin-bottom: 25px;
    padding: 5px;
    border-radius: 15px;
    text-align:center;
    background-color: beige;
}

#mainblock {
    width: 70%;
    margin: auto;
    background-color: beige;
    border-radius: 15px;
    border: 1px dashed black;
  }

.inputblock{
    padding: 5px;
    margin-top: 10px;
    margin-left: 20%;
    color:darkslateblue;
    font-weight: bold;
}
#submit{
    margin-left: 20%;
    margin-bottom: 10px;
}