为元素设置 border-start-start-radius 边框圆角

实例代码

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <title>border-start-start-radius 示例</title>
    <style>
        body {
            font-family: 'PingFang SC', 'Microsoft YaHei', sans-serif;
            padding: 10px;
            max-width: 600px;
            margin: 0 auto;
            line-height: 1.5;
        }
        
        .box {
            width: 120px;
            height: 80px;
            margin: 20px auto;
            background-color: #a8d8ea;
            display: flex;
            align-items: center;
            justify-content: center;
            text-align: center;
            padding: 10px;
            color: #333;
        }
        
        .example {
            margin-bottom: 30px;
            border: 1px solid #e0e0e0;
            padding: 15px;
            border-radius: 8px;
            background-color: #f9f9f9;
        }
        
        h3 {
            margin-top: 0;
            color: #2c3e50;
        }
        
        .code {
            background-color: #f0f0f0;
            padding: 8px;
            border-radius: 4px;
            font-family: monospace;
            font-size: 14px;
            margin: 10px 0;
            overflow-x: auto;
        }
    </style>
</head>
<body>
    <h2>border-start-start-radius 属性示例</h2>
    
    <div class="example">
        <h3>1. 基本圆角 (50px)</h3>
        <div class="code">border-start-start-radius: 50px;</div>
        <div class="box" style="border-start-start-radius: 50px;">
            标准LTR方向
        </div>
        <p>在从左到右(LTR)的书写模式下，作用于左上角</p>
    </div>
    
    <div class="example">
        <h3>2. 椭圆圆角 (50px/20px)</h3>
        <div class="code">border-start-start-radius: 50px 20px;</div>
        <div class="box" style="border-start-start-radius: 50px 20px;">
            椭圆形圆角
        </div>
        <p>第一个值是水平半径，第二个是垂直半径</p>
    </div>
    
    <div class="example">
        <h3>3. RTL方向 (50%)</h3>
        <div class="code">border-start-start-radius: 50%;<br>direction: rtl;</div>
        <div class="box" style="border-start-start-radius: 50%; direction: rtl;">
            从右到左
        </div>
        <p>在RTL(从右到左)模式下，仍然作用于左上角(逻辑上的起始-start)</p>
    </div>
    
    <div class="example">
        <h3>4. 垂直书写模式 (50%)</h3>
        <div class="code">border-start-start-radius: 50%;<br>writing-mode: vertical-rl;</div>
        <div class="box" style="border-start-start-radius: 50%; writing-mode: vertical-rl;">
            垂直文本
        </div>
        <p>在垂直书写模式下，作用于右上角(因为起始位置变为顶部)</p>
    </div>
</body>
</html>