实心圆旋转（旋转），沿着另一个实心圆的边界边缘具有渐变边界效果

Question

Image: Outer Circle static with inner circle spin with gradient effect

.outer-circle{
  width:330px;
  height:330px;
  border:35px solid #001b33;
  position:absolute;
  top:0; bottom:0; left:0;right:0;
  margin:auto;
  border-radius:50%; 
}

.spinner {
	animation: rotate 4s linear infinite;
	background: cyan;
	border-radius: 50%;
	height: 280px;
	width: 280px;
	position: relative;
}

.spinner:before,
.spinner:after {
	content: '';
	position: absolute;
}

.spinner:before {
	border-radius: 50%;
	background:
		linear-gradient(0deg,   hsla(0, 0%, 100%, 1) 50%, hsla(0, 0%, 100%, 0.9) 100%)   0%   0%,
		linear-gradient(90deg,  hsla(0, 0%, 100%, 0.9)  0%, hsla(0, 0%, 100%, 0.6) 100%) 100%   0%,
		linear-gradient(180deg, hsla(0, 0%, 100%, 0.6)  0%, hsla(0, 0%, 100%, 0.3) 100%) 100% 100%,
		linear-gradient(360deg, hsla(0, 0%, 100%, 0.3)  0%, hsla(0, 0%, 100%, 0  ) 100%)   0% 100%
	;
	background-repeat: no-repeat;
	background-size: 50% 50%;
	top: -1px;
	bottom: -1px;
	left: -1px;
	right: -1px;
}

.spinner:after {
	background: white;
	border-radius: 50%;
	top: 3%;
	bottom: 3%;
	left: 3%;
	right: 3%;
}

@keyframes rotate {
	from { transform: rotate(0deg);   }
	to   { transform: rotate(360deg); }
}

<div class="outer-circle">
<div class="spinner"></div>
</div>

我需要上传图片中显示的输出。这里有两个问题： 1）旋转圆不沿外圆边缘旋转。我需要将它精确地旋转到外圆的实心边框的中心，如图所示。旋转器的边框宽度也必须多一点。我怎样才能实现它？

2）线性渐变效果颜色代码不正确。我需要与图像中相同的颜色组合。我怎样才能用背景实现它：线性渐变语法？