Subscribe form: email field not aligned with button

Good evening,

Thank you for your awesome plugin. Just a little issue (due to my incompetence?): I used an html custom subscribe form, but the email field is not aligned with the “GO” button.

Here is my html code:

<div class="tnp tnp-subscription">
<form method="post" action="https://test.librairiedamase.com/?na=s">

<input class="tnp-email" type="email" autocomplete="on" min="1" id="tnp-1" value placeholder="Email" style placeholder="color:#B9B9B9" required></div>
<div class="tnp-field tnp-field-button"><input class="tnp-submit" type="submit" value="S’abonner" >
</div>
</form>
</div>

And here is my CSS:

input#tnp-1.tnp-email {
    border-top-left-radius: 25px;
    border-bottom-left-radius: 25px;
	padding-left: 10px;
	width: 66%;
}

input#tnp-1.tnp-email:focus {
  	outline: none;
	border-width: 1px;
	border-color: #6B6B6BFF;
	border-style: solid;
}

input.tnp-submit {
	border-top-right-radius: 25px;
    border-bottom-right-radius: 25px;
	width: 33%;
	padding-right: 10px;
}

input.tnp-submit:hover {
	background: #FFFFFF;
}

button, input, optgroup, select, textarea {
    font-size: 100%;
    line-height: 30px;
    font-family: inherit;
    border: none;
}

And the worst part is that the registration don’t run. Message:

Registration failed. Text below only visibile [sic] to administrators
Wrong email address

Thank you by forehand.

The page I need help with: [log in to see the link]