font-weight: lighter; (細め)
font-weight: normal; (通常)
font-weight: bold; (太字)
font-weight: bolder; (太め)
font-weight: 100;
font-weight: 200;
font-weight: 300;
font-weight: 400;
font-weight: 500;
font-weight: 600;
font-weight: 700;
font-weight: 800;
font-weight: 900;
<p style='font-weight: lighter;'>font-weight: lighter; (細め)</p>
<p style='font-weight: normal;'>font-weight: normal; (通常)</p>
<p style='font-weight: bold;'>font-weight: bold; (太字)</p>
<p style='font-weight: bolder;'>font-weight: bolder; (太め)</p>
<p style='font-weight: 100;'>font-weight: 100;</p>
<p style='font-weight: 200;'>font-weight: 200;</p>
<p style='font-weight: 300;'>font-weight: 300;</p>
<p style='font-weight: 400;'>font-weight: 400;</p>
<p style='font-weight: 500;'>font-weight: 500;</p>
<p style='font-weight: 600;'>font-weight: 600;</p>
<p style='font-weight: 700;'>font-weight: 700;</p>
<p style='font-weight: 800;'>font-weight: 800;</p>
<p style='font-weight: 900;'>font-weight: 900;</p>