css去掉表单边框

* {
  border: none;
}

form, input, textarea, button {
  border: none;
}

<form class="no-border">
  <input type="text" />
  <textarea></textarea>
  <button>Submit</button>
</form>

.no-border input,
.no-border textarea,
.no-border button {
  border: none;
}

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Remove Form Border</title>
  <style>
    .no-border input,
    .no-border textarea,
    .no-border button {
      border: none;
    }
  </style>
</head>
<body>
  <form class="no-border">
    <input type="text" placeholder="Enter text here" />
    <textarea placeholder="Enter text here"></textarea>
    <button type="submit">Submit</button>
  </form>
</body>
</html>