display: inline-block;
text-align: center;
width: 234px;
position: relative;
margin-left: 61px;
margin-bottom: 29px;
<form class="contact-form" name="search" method="post" action="src/php/search.php">
<input type="search" name="search_q" placeholder="Найти фильм" class="contact-form-text" maxlength="101">
<button type="submit" class="contact-form-btn">Найти</button>
</form>
<input type="search" name="search_q"/>