:root {
            --primary-color: #ffcc00;
            --text-dark: #333;
            --text-light: #fff;
        }
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: "Microsoft YaHei", sans-serif;
        }

        body {
            background-color: #f4f4f4;
            color: var(--text-dark);
            line-height: 1.6;
        }

        /* 导航栏 */
        header {
            background: #fff;
            height: 70px;
            display: flex;
            align-items: center;
            justify-content: space-between;
            padding: 0 5%;
            position: fixed;
            width: 100%;
            top: 0;
            z-index: 1000;
            box-shadow: 0 2px 10px rgba(0,0,0,0.1);
        }

        .logo {
            display: flex;
            align-items: center;
            font-size: 24px;
            font-weight: bold;
            color: #d32f2f;
        }

        .logo img {
            height: 40px;
            margin-right: 10px;
        }

        nav a {
            margin-left: 20px;
            text-decoration: none;
            color: #666;
            transition: 0.3s;
        }

        nav a:hover {
            color: #ffcc00;
        }

        /* 首屏下载区域 */
        .hero-section {
            margin-top: 70px;
            padding: 80px 10%;
            /* 黑黄红渐变 */
            background: linear-gradient(135deg, #000000 0%, #ffcc00 50%, #d32f2f 100%);
            display: flex;
            align-items: center;
            justify-content: space-between;
            color: #fff;
            min-height: 500px;
        }

        .hero-content {
            flex: 1;
            padding-right: 50px;
        }

        .hero-content h1 {
            font-size: 3rem;
            margin-bottom: 20px;
        }

        .hero-content p {
            font-size: 1.2rem;
            margin-bottom: 30px;
            opacity: 0.9;
        }

        .download-btn {
            display: inline-block;
            padding: 15px 40px;
            background-color: #fff;
            color: #d32f2f;
            text-decoration: none;
            font-size: 1.2rem;
            font-weight: bold;
            border-radius: 50px;
            transition: transform 0.3s, box-shadow 0.3s;
        }

        .download-btn:hover {
            transform: translateY(-3px);
            box-shadow: 0 5px 15px rgba(0,0,0,0.3);
        }

        .hero-image {
            flex: 1;
            text-align: center;
        }

        .hero-image img {
            max-width: 100%;
            border-radius: 20px;
            box-shadow: 0 10px 30px rgba(0,0,0,0.5);
        }

        /* 任务列表展示区域 */
        .task-container {
            padding: 60px 10%;
            background: #fff;
        }

        .section-title {
            text-align: center;
            margin-bottom: 40px;
            font-size: 2rem;
            color: #333;
        }

        .task-list {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
            gap: 20px;
        }

        .task-item {
            border: 1px solid #eee;
            padding: 20px;
            border-radius: 12px;
            display: flex;
            align-items: center;
            transition: 0.3s;
        }

        .task-item:hover {
            border-color: #ffcc00;
            box-shadow: 0 4px 12px rgba(0,0,0,0.05);
        }

        .task-icon {
            width: 50px;
            height: 50px;
            background: #fff9c4;
            border-radius: 10px;
            margin-right: 15px;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: bold;
            color: #f57f17;
        }

        .task-info h3 {
            font-size: 1.1rem;
            margin-bottom: 5px;
        }

        .task-info p {
            font-size: 0.9rem;
            color: #888;
        }

        .task-reward {
            margin-left: auto;
            color: #d32f2f;
            font-weight: bold;
        }

        @media (max-width: 768px) {
            .hero-section {
                flex-direction: column;
                text-align: center;
            }
            .hero-content {
                padding-right: 0;
                margin-bottom: 40px;
            }
            nav {
                display: none; /* 移动端隐藏简单处理 */
            }
        }