<html lang="en"><head> <meta charset="UTF-8"> <title>欢迎来到蝴蝶教程</title></head><body><h1>SVG 矩形不透明度</h1><svg width="400" height="180"> <rect x="50" y="20" width="150" height="150" style="fill:blue;stroke:pink;stroke-width:5;opacity:0.5" />抱歉，您的浏览器不支持嵌入式SVG。</svg></body></html>