Letter B

I solved it on September 30, 2022. You can try to beat my record on CSSBattle!

268 chars

<body bgcolor=6592CF><p c><p b><p><style>body{padding:102 132}p{position:relative;display:inline-block;border-radius:0 40px 40px 0;margin:-30;padding:40 50;color:515DBD;background:currentcolor;box-shadow:0 60px}p[b]{color:#2E3B9F;z-index:2}p[c]{color:060F55;z-index:3}