how to change mdi icon color 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

<button type="button" class="btn btn-default" aria-label="Profile">
    <i class="mdi mdi-account" aria-hidden="true"></i>
</button>
<button type="button" class="btn btn-default" aria-label="Flask">
    <i class="mdi mdi-flask" aria-hidden="true"></i>
    btn
</button>