<html lang="en"><head> <meta charset="UTF-8"> <title>欢迎来到蝴蝶教程</title></head><body> <h1>SVG 阴影效果</h1> <svg height="140" width="140"> <defs> <filter id="f4" x="0" y="0" width="200%" height="200%"> <feOffset result="offOut" in="SourceGraphic" dx="20" dy="20" /> <feColorMatrix result="matrixOut" in="offOut" type="matrix" values="0.2 0 0 0 0 0 0.2 0 0 0 0 0 0.2 0 0 0 0 0 1 0" /> <feGaussianBlur result="blurOut" in="matrixOut" stdDeviation="10" /> <feBlend in="SourceGraphic" in2="blurOut" mode="normal" /> </filter> </defs> <rect width="90" height="90" stroke="green" stroke-width="3" fill="yellow" filter="url(#f4)" /> 抱歉，您的浏览器不支持嵌入式SVG。 </svg></body></html>