how to make mdi icon bigger code example

Example 1: mdi icon size and color

<div class="input-group">
    <input type="text" class="form-control" placeholder="Search...">
    <span class="input-group-btn">
        <button class="btn btn-default" type="button" aria-label="Search">
            <i class="mdi mdi-magnify" aria-hidden="true"></i>
        </button>
    </span>
</div>

Example 2: mdi icon size and color

<div class="btn-toolbar" role="toolbar">
   <div class="btn-group">
        <button type="button"
                class="btn btn-default"
                aria-label="Left Align">
            <i class="mdi mdi-format-align-left"
               aria-hidden="true"></i>
        </button>
        ...
    </div>
</div>