好吧，我不能让这个问题悬而未决......
我无法使用您的方法解决它。制作倾斜的阴影是可行的，将其夹在圆形边框下，而不是（至少我还没有找到方法）。
替代方案：使用大量背景：
.B:before {
content:'';
position:absolute;
left: -237px;
height:135px;
width: 258px;
background-image: linear-gradient(0deg,#898481,#898481),
radial-gradient(circle at bottom right, #898481 22px, transparent 22px),
linear-gradient(0deg,#898481,#898481),
radial-gradient(circle at bottom right, #898481 22px, transparent 22px),
linear-gradient(196deg,rgba(0, 0, 0, 0.97) -21px,transparent 27px),
radial-gradient(circle at top right, #ccbcac 44px, transparent 30px),
linear-gradient(0deg,#ccbcac,#ccbcac),
linear-gradient(0deg,#898481,#898481),
radial-gradient(circle at top right, #898481 22px, transparent 22px),
linear-gradient(187deg,#B46550 2px,#f38669 24px),
radial-gradient(circle at top right, #f38669 22px, transparent 22px),
linear-gradient(196deg,rgba(60, 60, 60, 0.97) -21px,transparent 27px),
radial-gradient(circle at top right, #ccbcac 44px, transparent 30px),
linear-gradient(0deg,#ccbcac,#ccbcac),
linear-gradient(190deg,#AC6D3B -11px,#f4a668 28px),
radial-gradient(circle at top right, #f4a668 22px, transparent 22px),
linear-gradient(0deg,#ffbf7f,#ffbf7f),
radial-gradient(circle at top right, #ffbf7f 22px, transparent 22px),
radial-gradient(circle at top right, #fccda1 44px, transparent 30px),
linear-gradient(0deg,#FCCDA1,#fccda1);
background-position:
185px 110px, 163px 110px, 163px 88px, 144px 88px, 106px 88px,
41px 88px, 137px 88px,
142px 66px, 120px 66px,
142px 44px, 120px 44px,
64px 44px,42px 44px,
78px 44px, 97px 22px, 76px 22px, 65px 0px, 43px -1px, 0px 0px, 44px 0px;
background-size: 198px 22px, 22px 22px,198px 22px, 22px 22px, 76px 22px, 96px 44px, 200px 44px,198px 22px, 22px 22px,198px 22px, 22px 22px, 96px 44px, 44px 44px, 200px 44px, 198px 22px, 22px 22px, 198px 22px, 22px 22px, 44px 44px, 200px 44px;
background-repeat: no-repeat;
}
大多数背景用于重现您已经拥有的设计部分。要获得形状，您需要一个矩形背景，左侧有一个圆形背景。
对于阴影，使用了 2 种技术。
最简单的一种是当您将所有阴影都包含在一个矩形区域中时。然后你可以使用与矩形区域相同的线性渐变来获得它，只是给它一个更暗的阴影。
更难的是那些与圆圈部分重叠的部分。在这里，我需要为阴影使用另一个单独的背景图像。
我只在 Chrome 中验证了结果。
当然这种技术可以用在信中：
更新了字母的 CSS
.B {
position:absolute;
top: 200px;
left: 300px;
margin-top:-150px;
line-height:236px;
font-size:225pt;
font-weight:bold;
font-family:'Carrois Gothic SC', sans-serif;
background-image:
linear-gradient(187deg,#FFBF7F,#FFBF7F),
linear-gradient(187deg,#cc8650,#F4A668),
linear-gradient(195deg,#B46550,#F38669),
linear-gradient(187deg,#8A7668 25px,#AF9F88 35px),
linear-gradient(187deg,#af9678,#cfb698),
linear-gradient(187deg,#dcc2a1,#ecd2b1);
background-position:
0px 0px, 0px 9%, 0px 20%, 0px 30%, 0px 60%, 0px 100%;
background-size: 200px 9%, 200px 11%, 200px 10%, 200px 30%, 200px 30%, 200px 30%, 200px 40%;
background-repeat: no-repeat;
color: transparent;
-webkit-background-clip: text;
}
评论背景 CSS
background-image: linear-gradient(0deg,#898481,#898481), /* second small bar in last big bar */
radial-gradient(circle at bottom right, #898481 22px, transparent 22px),
linear-gradient(0deg,#898481,#898481), /* first small bar in last big bar */
radial-gradient(circle at bottom right, #898481 22px, transparent 22px),
linear-gradient(196deg,rgba(0, 0, 0, 0.97) -21px,transparent 27px), /* shadow */
radial-gradient(circle at top right, #ccbcac 44px, transparent 30px), /* last big bar */
linear-gradient(0deg,#ccbcac,#ccbcac),
linear-gradient(0deg,#898481,#898481), /* second small bar in second big bar */
radial-gradient(circle at top right, #898481 22px, transparent 22px),
linear-gradient(187deg,#B46550 2px,#f38669 24px), /* first small bar in 2nd big bar (shadowed) */
radial-gradient(circle at top right, #f38669 22px, transparent 22px),
linear-gradient(196deg,rgba(60, 60, 60, 0.97) -21px,transparent 27px), /* shadow on second big bar */
radial-gradient(circle at top right, #ccbcac 44px, transparent 30px), /* second big bar */
linear-gradient(0deg,#ccbcac,#ccbcac),
linear-gradient(190deg,#AC6D3B -11px,#f4a668 28px), /* second small bar on top (shadowed) */
radial-gradient(circle at top right, #f4a668 22px, transparent 22px),
linear-gradient(0deg,#ffbf7f,#ffbf7f), /* first small bar on top */
radial-gradient(circle at top right, #ffbf7f 22px, transparent 22px),
radial-gradient(circle at top right, #fccda1 44px, transparent 30px), /* big bar on top */
linear-gradient(0deg,#FCCDA1,#fccda1);
不完美，但你可以在径向渐变中再一步在圆圈中获得一些阴影：
radial-gradient(circle at top right, #fccda1 42px, #AC8D70 44px, transparent 45px)
限制是这种情况下的阴影必须与边界同心。另一种方法是设置另一个背景，可能是椭圆背景。
圆圈上的阴影
