css fontweight numaralandırma

yazının kalınlık unsurlarını 100’den 900’e kadar numaralandırmaya yarayan koddur.
html

<p class="light">This is a font with a "lighter" weight.</p>
<p class="thick">This is a font with a "bold" weight.</p>
<p class="thicker">This is a font with a "700" weight.</p>

css

p.light {
   font-weight: lighter;
}
p.thick {
   font-weight: bold;
}
p.thicker {
   font-weight: 700;
}

(bkz: http://www.mastersozluk.com/css-fontweight)