解决CSS中SVG背景覆盖内容的问题：理解定位与层叠上下文

<div class="Upper-half-wrapper">
    <!-- SVG波浪形背景 -->
    <div class="custom-shape-divider-top-1655888002">
        <svg data-name="Layer 1" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1200 120" preserveAspectRatio="none">
            <path d="M0,0V46.29c47.79,22.2,103.59,32.17,158,28,70.36-5.37,136.33-33.31,206.8-37.5C438.64,32.43,512.34,53.67,583,72.05c69.27,18,138.3,24.88,209.4,13.08,36.15-6,69.85-17.84,104.45-29.34C989.49,25,1113-14.29,1200,52.47V0Z" opacity=".25" class="shape-fill"></path>
            <path d="M0,0V15.81C13,36.92,27.64,56.86,47.69,72.05,99.41,111.27,165,111,224.58,91.58c31.15-10.15,60.09-26.07,89.67-39.8,40.92-19,84.73-46,130.83-49.67,36.26-2.85,70.9,9.42,98.6,31.56,31.77,25.39,62.32,62,103.63,73,40.44,10.79,81.35-6.69,119.13-24.28s75.16-39,116.92-43.05c59.73-5.85,113.28,22.88,168.9,38.84,30.2,8.66,59,6.17,87.09-7.5,22.43-10.89,48-26.93,60.65-49.24V0Z" opacity=".5" class="shape-fill"></path>
            <path d="M0,0V5.63C149.93,59,314.09,71.32,475.83,42.57c43-7.64,84.23-20.12,127.61-26.46,59-8.63,112.48,12.24,165.56,35.4C827.93,77.22,886,95.24,951.2,90c86.53-7,172.46-45.71,248.8-84.81V0Z" class="shape-fill"></path>
        </svg>
    </div>
    <!-- 页面内容 -->
    <div class="Upper-half-content">
        <h1>欢迎来到我们的网站！</h1>
        <p>这里有一些重要的内容，我们希望它能清晰地显示在波浪形背景之上。</p>
        <button>了解更多</button>
    </div>
</div>

.Upper-half-wrapper {
    background-color: #0A2640; /* 背景颜色 */
    height: 515px; /* 容器高度 */
    position: relative; /* 关键：为子元素的绝对定位提供参考 */
    color: white; /* 确保内容文字可见 */
    padding: 20px; /* 为内容添加一些内边距 */
    display: flex; /* 使用 Flexbox 辅助内容居中 */
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
}

.custom-shape-divider-top-1655888002 {
    position: absolute; /* 关键：SVG脱离文档流，绝对定位 */
    top: 0;
    left: 0;
    width: 100%;
    overflow: hidden;
    line-height: 0;
    /* z-index: 1; /* 可选：如果需要明确设置SVG的层叠顺序，但通常默认即可 */ */
}

.custom-shape-divider-top-1655888002 svg {
    position: relative; /* SVG内部的相对定位，可能影响其子元素 */
    display: block;
    width: calc(100% + 1.3px);
    height: 266px;
    transform: rotateY(180deg); /* 示例中SVG的翻转效果 */
}

.custom-shape-divider-top-1655888002 .shape-fill {
    fill: #1B3B5D; /* SVG填充颜色 */
}

/* 解决问题的关键样式 */
.Upper-half-content {
    position: relative; /* 关键：使内容元素成为定位元素，并创建新的层叠上下文 */
    z-index: 2; /* 关键：设置一个高于SVG的z-index，确保内容在最上层 */
    /* 其他样式，例如调整位置 */
    padding-top: 50px; /* 根据SVG的高度和布局调整，避免内容被SVG顶部遮挡 */
}

.Upper-half-content h1 {
    margin-bottom: 15px;
}

.Upper-half-content p {
    margin-bottom: 25px;
    max-width: 600px;
    line-height: 1.6;
}

.Upper-half-content button {
    background-color: #61DAFB;
    color: #0A2640;
    border: none;
    padding: 10px 20px;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1em;
    transition: background-color 0.3s ease;
}

.Upper-half-content button:hover {
    background-color: #21a1f1;
}