[div] Colored note boxes inside Jupyter Notebooks

<div class="alert alert-block alert-info"> <b>NOTE</b> Use blue boxes for Tips and notes. </div>

<div class="alert alert-block alert-success"> Use green boxes sparingly, and only for some specific purpose that the other boxes can't cover. For example, if you have a lot of related content to link to, maybe you decide to use green boxes for related links from each section of a notebook. </div>

<div class="alert alert-block alert-warning"> Use yellow boxes for examples that are not inside code cells, or use for mathematical formulas if needed. </div>

<div class="alert alert-block alert-danger"> In general, just avoid the red boxes. </div>