Change HTML and CSS per Matrix row
When looping through Matrix rows, you can use {{ loop.index }} or {{ loop.index0 }} to see which row you're at.

With loop.index, you could create html for each row number, or (for instance) create different html for even/uneven:

{% for row in entry.matrixFieldHandle %}
    {% if loop.index is divisible by(2) %}
        &lt;p class="even"&gt;{{ row.text }}&lt;/p&gt;
    {% else %}
        &lt;p class="uneven"&gt;{{ row.text }}&lt;/p&gt;
    {% endif %}
{% endfor %}