textarea：有效+标签在服务器上无法正常工作

Question

我正在尝试在联系表单上创建一些标签文本，当联系表单为：focus或它是：有效时，文本移动到输入框上方并保持在那里。

在我的本地计算机上一切正常（使用括号实时预览），但是，每当我将代码放到我的网站上由于某种原因textarea标签不再移动？

有人知道为什么会这样吗？

以下是完整代码：

<div class="section">
        <div class="wrapper">
            <div class="content">
                <h2>Contact Me</h2>
                <form action="contactme.php" method="post" class="contact-form">
                    <div class="input-field">
                        <input type="text" name="name" required="">
                        <label for="">Full Name</label>
                    </div>

                    <div class="input-field">
                        <input type="text" name="cname" required="">
                        <label for="">Company Name</label>
                    </div>

                    <div class="input-field">
                        <input type="text" name="website" required="">
                        <label for="">Current Website (N/A if None)</label>
                    </div>

                    <div class="input-field">
                        <input type="email" name="mail" required="">
                        <label for="">E-Mail</label>
                    </div>

                    <div class="input-field">
                        <textarea name="message" rows="5" required=""></textarea>
                        <label for="">Message</label>
                    </div>

                    <input type="submit" name="submit" value="Submit Message" class="btn">
                </form>
            </div>
        </div>
    </div>

-

body {
    margin: 0;
    padding: 0;
    font-family: 'Roboto Condensed', sans-serif;
    width: 100%;
    height: 100vh;
    background: linear-gradient(to bottom, rgba(0, 142, 204, 5) 50%, rgba(253, 165, 15, 5) 50%);
}

.wrapper {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 600px;
    padding: 40px;
    box-sizing: border-box;
    background: #FFF;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
    animation: fadeIn 2s 0s linear;
}

.wrapper h2 {
    color: #666;
    margin: 0;
    padding: 0;
    text-align: center;
    font-size: 30px;
    text-transform: uppercase;
}

.input-field {
    position: relative;
    width: 100%;
    margin-top: 50px;
}

.input-field input,
.input-field textarea {
    font-family: 'Roboto Condensed', sans-serif;
    width: 100%;
    padding: 5px 0;
    box-sizing: border-box;
    background: transparent;
    border: none;
    outline: none;
    border-bottom: 2px solid #666;
    font-size: 16px;
    color: #666;
    font-weight: 700;
    text-transform: uppercase;
    resize: none;
}

.input-field label {
    position: absolute;
    top: 0;
    left: 0;
    padding: 5px 0;
    pointer-events: none;
    font-size: 16px;
    color: #666;
    font-weight: 700;
    transition: .5s;
}

.input-field input:focus + label,
.input-field textarea:focus + label,
.input-field input:valid + label,
.input-field textarea:valid + label {
    top: -25px;
    font-size: 14px;
    padding: 2px 5px;
    background: #FF006A;
    color: #FFF;
    border-radius: 4px;
}

.btn {
    font-family: 'Roboto Condensed', sans-serif;
    margin-top: 20px;
    background: linear-gradient(to right, #ff9966, #ff5e62);
    color: #FFF;
    padding: 15px 30px;
    border: none;
    outline: none;
    border-radius: 30px;
    font-size: 16px;
    float: right;
    transition: all .5s;
}

.btn:hover {
    cursor: pointer;
}

@media(max-width: 580px) {

    .wrapper {
        width: 250px;
        padding: 20px;
    }

    .wrapper h2 {
        font-size: 15px;
    }

    .input-field input,
    .input-field textarea {
        font-size: 12px;
    }

    .input-field label {
        font-size: 12px;
    }

    .btn {
        font-size: 12px;
    }

}