/* ========================================
           3. 视频背景通用样式
           ======================================== */
html {
            scroll-snap-type: y mandatory;
            scroll-behavior: smooth;
        }
        .video-background {
            position: absolute;
            top: 50%;
            left: 50%;
            min-width: 100%;
            min-height: 100%;
            width: auto;
            height: auto;
            z-index: -1;
            transform: translate(-50%, -50%);
            object-fit: cover;
        }

        /* ========================================
           4. 英雄视口区域 (Hero Section)
           ======================================== */
        .hero-section {
            height: 100vh;
            width: 100%;
            position: relative;
            scroll-snap-align: start;
            overflow: hidden;
        }

        .slide {
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            opacity: 0;
            transition: opacity 1.2s ease-in-out;
        }

        .slide.active { opacity: 1; }

        .carousel-overlay {
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background-color: transparent;
            z-index: 1;
        }

        .carousel-content {
            position: absolute;
            top: 55%;
            left: 50%;
            transform: translate(-50%, -40%);
            text-align: center;
            z-index: 2;
            width: 80%;
            opacity: 0;
            transition: all 1.2s cubic-bezier(0.22, 1, 0.36, 1);
        }

        .hero-section.is-visible .carousel-content {
            opacity: 1;
            transform: translate(-50%, -50%);
        }

        .carousel-content h1 {
            font-size: 4em;
            margin-bottom: 20px;
            color: #fff;
            text-shadow: 0 2px 10px rgba(0, 0, 0, 0.5);
        }

        .carousel-content p {
            color: #fff;
            font-size: 1.3em;
            margin-bottom: 30px;
            text-shadow: 0 1px 5px rgba(0, 0, 0, 0.5);
        }

        .btn-main {
            padding: 12px 40px;
            background-color: #1771FF;
            color: white;
            border: none;
            border-radius: 5px;
            font-size: 1.1em;
            cursor: pointer;
            transition: 0.3s;
        }

        .btn-main:hover { background-color: #0d5cce; transform: scale(1.05); }

        .carousel-controls button {
            position: absolute;
            top: 50%;
            transform: translateY(-50%);
            background: rgba(255, 255, 255, 0.2);
            border: none;
            color: white;
            padding: 20px 15px;
            cursor: pointer;
            z-index: 10;
            transition: background 0.3s;
        }
        .prev-button { left: 20px; }
        .next-button { right: 20px; }
        .carousel-controls button:hover { background: rgba(255, 255, 255, 0.4); }

        /* ========================================
           5. 分段内容样式 (Section)
           ======================================== */
        .section {
            height: 100vh;
            width: 100%;
            background-size: cover;
            background-position: center;
            position: relative;
            scroll-snap-align: start;
            overflow: hidden;
            display: block;
        }

        .side-mask {
            position: absolute;
            top: 0;
            width: 40%;
            height: 100%;
            background-color: rgba(0, 0, 0, 0.5);
            display: flex;
            align-items: center;
            padding: 0 60px;
            box-sizing: border-box;
            backdrop-filter: blur(8px);
            color: white;
            z-index: 5;
        }

        .side-mask.left { left: 0; border-right: 1px solid rgba(255,255,255,0.1); }
        .side-mask.right { right: 0; border-left: 1px solid rgba(255,255,255,0.1); }

        .content-box {
            opacity: 0;
            transform: translateY(40px);
            transition: all 1.2s cubic-bezier(0.22, 1, 0.36, 1);
        }

        .section.is-visible .content-box {
            opacity: 1;
            transform: translateY(0);
        }

        .section-title {
            font-size: 2.8em;
            color: #fff;
            margin-bottom: 25px;
            position: relative;
        }

        .section-title::after {
            content: '';
            position: absolute;
            bottom: -10px;
            left: 0;
            width: 60px;
            height: 4px;
            background: #1771FF;
        }

        .side-mask p {
            font-size: 1.1em;
            line-height: 1.8;
            color: rgba(255, 255, 255, 0.9);
            margin-bottom: 30px;
        }

        @media (max-width: 991px) {
            .side-mask { width: 100%; padding: 40px; }
        }
.footer-area {

            scroll-snap-align: end;

        }