https://html-css-js.com/css/generator/box-shadow/ Around 4th link. It's not that good looking but it absolutely has all features you need.
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box-shadow: 0px 0px 0px 3px #000000;
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/* Sample code to generate a box shadow */
.box {
box-shadow: 5px 5px 10px rgba(0, 0, 0, 0.5);
}
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I love to use tools from Code Junction, you must checkout
https://codejn.com/tool/box-shadow-generator
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box-shadow: [horizontal offset] [vertical offset] [blur radius] [spread radius] [color];