increase mdi icon size code example

Example 1: mdi icon size and color

<div class="alert alert-danger" role="alert">
    <span class="mdi mdi-alert-circle" aria-hidden="true"></span>
    <span class="sr-only">Error:</span>
    Enter a valid email address
</div>

Example 2: mdi icon size and color

<div class="input-group">
    <span class="input-group-addon">
        <i class="mdi mdi-tag" aria-hidden="true"></i>
    </span>
    <input type="text" class="form-control" aria-label="Tag">
</div>

Example 3: 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>