* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: "Microsoft Yahei", sans-serif;
        }

        /* ========== 视频背景容器 ========== */
        .banner {
            width: 100%;
            height: 100vh;
            position: relative;
            overflow: hidden;
        }
        .bg-video {
            position: absolute;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            min-width: 100%;
            min-height: 100%;
            z-index: 1;
            object-fit: cover;
        }
        .banner-mask {
            position: absolute;
            width:100%;
            height:100%;
            background: rgba(0,0,0,0.25);
            z-index: 2;
        }

        /* ========== 顶部导航 ========== */
        .nav-bar {
            position: absolute;
            top:0;
            width:100%;
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 18px 24px;
            color: #ffffff;
            z-index: 3;
        }
        /* 左上角登录按钮 */
        .login-btn {
            background-color: #5c74f0;
            padding: 7px 14px;
            border-radius: 14px;
            text-decoration: none;
            color: #fff;
            font-size: 14px;
        }
        .nav-right a {
            color: #fff;
            text-decoration: none;
            margin-left: 16px;
            font-size: 15px;
            cursor: pointer;
        }
        .nav-right a:hover {
            text-decoration: underline;
        }

        /* 首屏居中文字 */
        .banner-text {
            position: absolute;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            text-align: center;
            color: white;
            z-index:3;
        }
        .banner-text h1 {
            font-size: 46px;
            margin-bottom: 12px;
            font-weight: 600;
        }
        .banner-text p {
            font-size: 22px;
            opacity: 0.92;
        }

        /* ===== 大标题：单字波浪 + 打字放大缩小 ===== */
        .banner-text h1 span {
            display: inline-block;
            transform-origin: bottom center;
            will-change: transform, opacity;
            animation: charWave 3s ease-in-out infinite;
            animation-delay: calc(var(--i) * 0.12s);
        }
        .banner-text h1 span.space {
            animation: none;
        }
        @keyframes charWave {
            0%   { opacity: 0; transform: translateY(16px) scale(2.2); }
            12%  { opacity: 1; transform: translateY(0) scale(1.12); }
            24%  { transform: translateY(-6px) scale(1); }
            55%  { transform: translateY(6px) scale(1); }
            70%  { transform: translateY(0) scale(1); }
            100% { opacity: 1; transform: translateY(0) scale(1); }
        }

        /* ===== 小标题：打字机光标 ===== */
        .banner-text .typing {
            min-height: 30px;
        }
        .banner-text .typing::after {
            content: "▍";
            margin-left: 2px;
            animation: cursorBlink 0.9s step-end infinite;
        }
        @keyframes cursorBlink {
            0%, 100% { opacity: 1; }
            50% { opacity: 0; }
        }

        /* 尊重系统“减少动态效果”设置 */
        @media (prefers-reduced-motion: reduce) {
            .banner-text h1 span { animation: none; }
            .banner-text .typing::after { animation: none; }
        }

        /* ========== 悬浮磨砂搜索框（箭头触发，自动收起） ========== */
        .float-search-wrap{
            position: fixed;
            top: 120px;
            left: 50%;
            transform: translateX(-50%);
            z-index:9998;
            display:flex;
            align-items:center;
        }
        /* 箭头按钮 */
        .search-arrow{
            width:44px;
            height:44px;
            border-radius:50%;
            background: rgba(255,255,255,0.15);
            backdrop-filter: blur(12px);
            border:1px solid rgba(255,255,255,0.3);
            color:#fff;
            font-size:20px;
            display:flex;
            align-items:center;
            justify-content:center;
            cursor:pointer;
            transition: all 0.3s ease;
        }
        /* 搜索输入框容器，默认隐藏，展开显示 */
        .search-box{
            overflow:hidden;
            width:0px;
            transition: width 0.3s ease;
            background: rgba(255,255,255,0.15);
            backdrop-filter: blur(12px);
            border:1px solid rgba(255,255,255,0.3);
            border-radius:99px;
            height:44px;
            display:flex;
            align-items:center;
        }
        .search-box.open{
            width:320px;
            padding:0 16px;
            margin-left:8px;
        }
        #search-input{
            border:none;
            background:transparent;
            outline:none;
            color:#fff;
            font-size:16px;
            width:100%;
        }
        #search-input::placeholder{
            color:rgba(255,255,255,0.7);
        }
        .search-result{
            position:absolute;
            top:52px;
            left:44px;
            width:320px;
            background: rgba(0,0,0,0.45);
            backdrop-filter: blur(10px);
            border:1px solid rgba(255,255,255,0.2);
            border-radius:12px;
            padding:14px;
            max-height:280px;
            overflow-y:auto;
            color:#fff;
            display:none;
        }
        .result-item {
            padding:10px 8px;
            border-bottom:1px solid #444;
            cursor:pointer;
        }
        .result-item:hover {
            background: rgba(255,255,255,0.1);
        }
        .result-item h4{
            margin-bottom:4px;
        }

        /* ========== 底部提示文字：点击任意位置进入首页 ========== */
        .bottom-tip-area{
            position:absolute;
            bottom:40px;
            left:50%;
            transform:translateX(-50%);
            z-index:3;
            color:#fff;
            font-size:16px;
            opacity:0.85;
        }

        /* ========== 知识库文章列表 ========== */
        .kb-section{
            max-width:1100px;
            margin:0 auto;
            padding:50px 24px 70px;
        }
        .kb-title{
            text-align:center;
            font-size:28px;
            margin-bottom:30px;
            color:#222;
        }
        .kb-list{
            display:grid;
            grid-template-columns:repeat(3,1fr);
            gap:20px;
        }
        .kb-card{
            display:block;
            background:#fff;
            border-radius:12px;
            padding:22px;
            text-decoration:none;
            color:inherit;
            box-shadow:0 2px 12px rgba(0,0,0,.08);
            transition:transform .2s ease, box-shadow .2s ease;
        }
        .kb-card:hover{
            transform:translateY(-4px);
            box-shadow:0 8px 20px rgba(0,0,0,.15);
        }
        .kb-card h3{
            font-size:18px;
            margin-bottom:10px;
            color:#2b3a8f;
        }
        .kb-card p{
            font-size:14px;
            color:#666;
            line-height:1.7;
            display:-webkit-box;
            -webkit-line-clamp:3;
            -webkit-box-orient:vertical;
            overflow:hidden;
        }
        .kb-empty{
            grid-column:1/-1;
            text-align:center;
            color:#888;
            padding:20px 0;
        }
        @media (max-width:900px){
            .kb-list{ grid-template-columns:repeat(2,1fr); }
        }
        @media (max-width:600px){
            .kb-list{ grid-template-columns:1fr; }
        }