Horizontal and vertical alignment in materialize framework

Question

How can I center the login box both horizontal and vertical?

Here is my structure:

<div class="container">
<div class="row">
<div class="col s12 m6">
    <div class="card">
        <div class="card-content">
            <span class="card-title black-text">Sign In</span>
            <form>
                <div class="row">
                    <div class="input-field col s12">
                        <input placeholder="Placeholder" id="firstname" type="text" class="validate">
                        <label for="firstname" class="active">First Name</label>
                    </div>
                </div>
                <div class="row">
                    <div class="input-field col s12">
                        <input placeholder="Placeholder" id="lastname" type="text" class="validate">
                        <label for="lastname" class="active">Last Name</label>
                    </div>
                </div>
            </form>
        </div>
        <div class="card-action">
            <input type="submit" class="btn" value="Sign In">
        </div>
    </div>
</div>

I tried using valign-wrapper and valign class but it does not work.

Answer 1

Here is the proper (materializecss) way to do it and without messy css:

<div class="valign-wrapper" style="width:100%;height:100%;position: absolute;">
    <div class="valign" style="width:100%;">
        <div class="container">
           <div class="row">
              <div class="col s12 m6 offset-m3">
                 <div class="card">
                    <div class="card-content">
                       <span class="card-title black-text">Sign In</span>
                       <form>
                          <div class="row">
                             <div class="input-field col s12">
                                <input placeholder="Placeholder" id="firstname" type="text" class="validate">
                                <label for="firstname" class="active">First Name</label>
                             </div>
                          </div>
                          <div class="row">
                             <div class="input-field col s12">
                                <input placeholder="Placeholder" id="lastname" type="text" class="validate">
                                <label for="lastname" class="active">Last Name</label>
                             </div>
                          </div>
                       </form>
                    </div>
                    <div class="card-action">
                       <input type="submit" class="btn" value="Sign In">
                    </div>
                 </div>
              </div>
           </div>
        </div>
    </div>
</div>