How to center align button with an icon for materialize css?
<p>I have this login form and I want to center align the button but I can't seem to align it perfectly. What's the best way to center align it? </p>

<pre><code>&lt;form class="col s12"&gt;
    &lt;div class="row"&gt;
        &lt;div class="input-field col s10 offset-s1"&gt;
            &lt;input id="last_name" type="text" class="validate"&gt;
            &lt;label for="last_name"&gt;Username&lt;/label&gt;
        &lt;/div&gt;
    &lt;/div&gt;
    &lt;div class="row"&gt;
        &lt;div class="input-field col s10 offset-s1"&gt;
            &lt;input id="password" type="password" class="validate"&gt;
            &lt;label for="password"&gt;Password&lt;/label&gt;
        &lt;/div&gt;
    &lt;/div&gt;
    &lt;div class="row"&gt;
        &lt;div class="col s6 offset-s4"&gt;
            &lt;button class="btn waves-effect waves-light" type="submit" name="action"&gt;
                Submit
                &lt;i class="material-icons right"&gt;send&lt;/i&gt;
            &lt;/button&gt;
        &lt;/div&gt;
    &lt;/div&gt;
&lt;/form&gt;
</code></pre>

<p>Please help. Thank you!</p>