* {
    padding: 0;
    margin: 0;
    box-sizing: border-box;
}

html,
body {
    width: 100%;
}

/* ========== 字体引入 ========== */
@font-face {
    font-family: '方正大标宋';
    src: url('../font/方正大标宋_GBK.TTF') format('truetype');
}

@font-face {
    font-family: '方正大标宋2';
    src: url('../font/方正大标宋_GBK.TTF') format('truetype');
    font-weight: bold;
}

/* 注：以下所有尺寸均基于 1920 设计稿，px → vw（1px = 100/1920 vw ≈ 0.05208vw） */

.container {
    width: 100%;
    overflow-x: hidden;
    background: url(../img/大背景.png) no-repeat center / cover;
}

.banner {
    width: 100%;
    position: relative;
}

.banner-img {
    width: 100%;
}

.banner-img1 {
    position: absolute;
    top: 11.25vw;
    left: 9.90vw;
    width: 80.36vw;
    height: 13.23vw;
}

.banner-img2 {
    position: absolute;
    top: 26.04vw;
    right: 20vw;
    width: 53.80vw;
    height: 4.06vw;
}


.banner-img3 {
    position: absolute;
    top: 32.81vw;
    right: 20.42vw;
    width: 27.03vw;
    height: 3.75vw;
}

.preface {
    width: 100%;
    height: 55.83vw;
    position: relative;
    background: url(../img/4-前言背景.png) no-repeat top / cover;
    margin-top: -5.73vw;
    z-index: 1;
}

.preface-content {
    width: 80%;
    margin: 0 auto;
}

.preface-img {
    position: absolute;
    width: 13.8541vw;
    height: 4.5312vw;
    top: 8.33vw;
    left: 50%;
    transform: translateX(-50%);
}

.preface-title {
    font-family: '方正大标宋';
    font-weight: 500;
    font-size: 0.9375vw;
    color: #1a1a1a;
    text-indent: 2em;
    line-height: 1.8;
}

.preface-title-item {
    width: 100%;
    padding-top: 15.10vw;
}

.long-march-spirit {
    display: flex;
    align-items: center;
    flex-direction: column;
    margin-bottom: 0.9vw;

}

.long-march-spirit-title {
    margin: 0;
    font-family: '方正大标宋';
    font-size: 1.875vw;
    color: #8d2722;
    margin-top: 4.17vw;
}

.long-march-spirit-title span {
    margin: 0 0.26vw;
}

.long-march-spirit>img {
    width: 11.67vw;
    height: 1.20vw;
    margin-top: 0.52vw;
}

.long-march-spirit-content {
    display: flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
    font-family: '方正大标宋';
    font-weight: 500;
    font-size: 1.25vw;
    color: #8d2722;
    text-indent: 2em;
    line-height: 1.8;
}

.video {
    width: 100%;
    margin-top: 2.60vw;
}

.video-content {
    width: 80%;
    margin: 0 auto;
}

.video-item {
    width: 100%;
    padding: 1.04vw;
    border: 1px solid #b67552;
    display: flex;
    align-items: center;
    justify-content: center;
}

.video-item video {
    width: 100%;
}

.video-item-img {
    width: 100%;
    height: 17.29vw;
    position: relative;
    margin-top: 4.17vw;
    cursor: pointer;
}

.video-item-img>img {
    width: 100%;
}

.video-item-img-title {
    position: absolute;
    right: 5.47vw;
    top: 47%;
    display: flex;
    align-items: center;
    flex-direction: column;
    justify-content: center;
}

.video-item-img-title p {
    margin: 0;
    font-family: '方正大标宋';
    font-weight: 500;
    font-size: 2.71vw;
    color: #fde7c3;
}

.video-item-btn {
    margin-top: 0.52vw;
}

.box-1 {
    width: 100%;
    height: 26.61vw;
    display: flex;
    align-items: center;
    flex-direction: column;
    justify-content: center;
    background: url(../img/10-1背景.png) no-repeat top / cover;
    margin-top: 2.08vw;
}

.box-content {
    width: 80%;
    margin: 0 auto;
}

.box-title {
    font-family: '方正大标宋';
    font-size: 1.875vw;
    color: #8d2722;
}

.box-content-text {
    width: 52.08vw;
    font-family: '方正大标宋';
    font-weight: 500;
    font-size: 0.9375vw;
    color: #1a1a1a;
    text-indent: 2em;
    line-height: 1.8;
    margin-top: 0.52vw;
}

.box-2 {
    width: 100%;
    height: 29.69vw;
    margin-top: 4.17vw;
}

.box2-content {
    width: 80%;
    height: 100%;
    margin: 0 auto;
    display: flex;
    align-items: center;
    gap: 1.04vw;
}

.box2-left>img {
    width: 60.9375vw;
    height: 22.6562vw;
}

.box2-left {
    height: 100%;
    display: flex;
    align-items: center;
    flex-direction: column;
    justify-content: flex-end;
    padding: 1.04vw 0.52vw;
    border: 1px solid #b67552;
}

.box2-right {
    display: flex;
    align-items: center;
    flex-direction: column;
    gap: 1.04vw;
}

.box2-title {
    font-family: '方正大标宋';
    font-weight: 500;
    font-size: 0.83vw;
    color: #f5f6f3;
    display: flex;
    align-items: center;
    flex-direction: column;
    margin-top: 0.26vw;
}

.box2-right-item {
    width: 16.67vw;
    height: 14.32vw;
    line-height: 1.2;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-direction: column;
    border: 1px solid #b67552;
}

.box2-title-left {
    margin-top: 1.04vw;
}

.box-3 {
    width: 100%;
    height: 26.61vw;
    display: flex;
    align-items: center;
    flex-direction: column;
    justify-content: center;
    background: url(../img/11-1背景.png) no-repeat top / cover;
    margin-top: 2.08vw;
}

.box2-right-item>img {
    width: 14.8958vw;
    height: 10.9375vw;
}

.box-content-3 {
    display: flex;
    align-items: flex-end;
    flex-direction: column;
}

/* ========== 四、文物（四宫格） ========== */
.box-4 {
    width: 100%;
    margin-top: 4.17vw;
}

.box-4-content {
    display: flex;
    align-items: flex-start;
    gap: 1.04vw;
}

.box-4-left {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 1.04vw;
}

.box-4-right {
    width: 58%;
    display: flex;
    flex-direction: column;
    gap: 1.04vw;
}

.box-4-item {
    position: relative;
    border: 1px solid #d9a882;
}

.box-4-item-lg {
    height: 24.64vw;
}

.box-4-item-sm {
    height: 19.06vw;
}

.box-4-item img {
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    max-width: 100%;
    height: auto;
}

.box-4-left .box-4-item-lg img {
    top: 0.83vw;
}

.box-4-right .box-4-item-lg img {
    top: 1.30vw;
}

.box-4-left .box-4-item-sm img {
    top: -2.55vw;
}

.box-4-right .box-4-item-sm img {
    top: -3.18vw;
}

.box-4-item-title {
    position: absolute;
    left: 0;
    right: 0;
    bottom: 1.56vw;
    text-align: center;
    font-family: '方正大标宋';
    font-weight: 500;
    font-size: 0.83vw;
    line-height: 1.20vw;
    color: #f7ecdc;
}

.box-4-item-title p {
    margin: 0;
}

.box-5 {
    width: 100%;
    height: 26.61vw;
    display: flex;
    align-items: center;
    flex-direction: column;
    justify-content: center;
    background: url(../img/12-1背景.png) no-repeat top / cover;
    margin-top: 2.08vw;

}

/* ========== 五、文物（三宫格） ========== */
.box-6 {
    width: 100%;
    margin-top: 4.17vw;
}

.box-6-content {
    display: flex;
    align-items: flex-start;
    gap: 1.04vw;
}

.box-6-item {
    position: relative;
    flex: 1;
    height: 29.17vw;
    border: 1px solid #d9a882;
}

.box-6-item img {
    position: absolute;
    top: 2.14vw;
    left: 50%;
    transform: translateX(-50%);
    max-width: 100%;
    height: auto;
}

.box-6-item-title {
    position: absolute;
    top: 25.57vw;
    left: 0;
    right: 0;
    text-align: center;
    font-family: '方正大标宋';
    font-weight: 500;
    font-size: 0.83vw;
    line-height: 1.20vw;
    color: #f7ecdc;
}

.box-6-item-title p {
    margin: 0;
}

.box-4-item-img>img {
    width: 29.1145vw;
    height: 18.5416vw;
}

.box-4-item-img1>img {
    width: 39.6875vw;
    height: 18.5416vw;
}

.box-7 {
    width: 100%;
    height: 26.61vw;
    display: flex;
    align-items: center;
    flex-direction: column;
    justify-content: center;
    background: url(../img/13-1背景.png) no-repeat top / cover;
    margin-top: 1.04vw;
}

/* ========== 六、文物（三宫格） ========== */
.box-8 {
    width: 100%;
    margin-top: 4.17vw;
}

.box-6-item>img {
    width: 15vw;
    height: 21.1458vw;
}

.box-8-content {
    display: flex;
    align-items: flex-start;
    gap: 1.04vw;
}

.box-8-item {
    position: relative;
    flex: 1;
    height: 20.36vw;
    border: 1px solid #d9a882;
}

.box-8-item img {
    position: absolute;
    top: 1.56vw;
    left: 50%;
    transform: translateX(-50%);
    max-width: 100%;
    height: auto;
}

.box-8-item-title {
    position: absolute;
    left: 0;
    right: 0;
    bottom: 1.15vw;
    text-align: center;
    font-family: '方正大标宋';
    font-weight: 500;
    font-size: 0.83vw;
    line-height: 1.20vw;
    color: #f7ecdc;
}

.box-8-item>img {
    width: 21.4583vw;
    height: 12.8125vw;
}

.box-8-item-title p {
    margin: 0;
}

.box-9 {
    width: 100%;
    height: 26.61vw;
    display: flex;
    align-items: center;
    flex-direction: column;
    justify-content: center;
    background: url(../img/14-1背景.png) no-repeat top / cover;
    margin-top: 2.08vw;
}

/* ========== 七、会师合影 + 下一专题 ========== */
.box-10 {
    width: 100%;
    margin-top: 4.17vw;
}

.box-10-content {
    display: flex;
    align-items: flex-start;
    margin-bottom: 4.95vw;
    gap: 1.04vw;
}

.box-10-item {
    position: relative;
    height: 31.25vw;
    border: 1px solid #d9a882;
}

.box-10-photo {
    width: 55.94vw;
}

.box-10-doc {
    width: 22.24vw;
}

.box-10-photo>img {
    width: 54.1145vw;
    height: 25.8854vw;
}

.box-10-doc>img {
    width: 20.4166vw;
    height: 25.8854vw;
}

.box-10-item img {
    position: absolute;
    top: 0.83vw;
    left: 50%;
    transform: translateX(-50%);
}

.box-10-item-title {
    position: absolute;
    top: 27.86vw;
    left: 0;
    right: 0;
    text-align: center;
    font-family: '方正大标宋';
    font-weight: 500;
    font-size: 0.83vw;
    line-height: 1.20vw;
    color: #f7ecdc;
}

.box-10-item-title p {
    margin: 0;
}

/* 底部下一专题横幅（与内容区左对齐） */
.box-10-banner {
    position: relative;
    width: 80%;
    height: 9.375vw;
    margin: 0 auto;
    cursor: pointer;
}

.box-10-banner-bg {
    position: absolute;
    top: 0;
    left: 0;
    width: 81.67vw;
    height: 10.21vw;

}

.box-10-banner-sub {
    position: absolute;
    top: 0.52vw;
    left: 3.18vw;
    width: 20.83vw;
    height: 4.69vw;
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: '方正大标宋';
    font-weight: 500;
    font-size: 2.08vw;
    color: #8d2722;
    white-space: nowrap;
}

.box-10-banner-main {
    position: absolute;
    top: 2.60vw;
    left: 31.56vw;
    height: 6.61vw;
    display: flex;
    align-items: center;
    font-family: '方正大标宋';
    font-weight: 500;
    font-size: 3.125vw;
    color: #fde7c3;
}

.box-10-banner-arrow {
    display: flex;
    margin-left: 1.56vw;
}

.box-footer {
    width: 100%;
    height: 20.83vw;
    padding-top: 2.92vw;
    box-sizing: border-box;
    background: url(../img/16-背景.png) no-repeat top / cover;
    margin-top: 4.17vw;
}

.footer-block {
    text-align: center;
    margin-bottom: 1.35vw;
}

.footer-title {
    font-family: '方正大标宋';
    font-weight: 500;
    font-size: 1.25vw;
    line-height: 1.875vw;
    color: #fde7c3;
    padding-right: 2.5vw;
}

.footer-list {
    font-family: '方正大标宋';
    font-size: 0.9375vw;
    line-height: 1.875vw;
    font-weight: 500;
    color: #fde7c3;
}

/* ========== 移动端适配（≤768px 单列堆叠 + 可读性字号） ========== */
@media (max-width: 768px) {

    /* 统一图片自适应，防止溢出 */
    img {
        max-width: 100%;
        height: auto;
    }

    .banner-img {
        height: 60vw;
    }

    .box2-content {
        width: 90%;
    }

    /* 各内容区统一留白 */
    .preface-content,
    .video-content,
    .box-content,
    .box-10-banner {
        width: 90%;
    }

    /* ---------- 前言 ---------- */
    .preface {
        height: auto;
        margin-top: -100px;
        padding: 80px 0 200px;
    }

    .preface-img {
        position: static;
        transform: none;
        display: block;
        width: auto;
        width: 133px;
        height: 43.5px;
        margin: 30px auto 0;
    }

    .preface-title-item {
        padding-top: 6vw;
    }

    .preface-title {
        font-size: 16px;
        margin: 0 auto;
    }

    .long-march-spirit {
        margin-bottom: 2vw;
    }

    .long-march-spirit-title {
        font-size: 22px;
        margin-top: 26px;
    }

    .long-march-spirit>img {
        width: 116px;
        height: auto;
    }

    .long-march-spirit-content {
        font-size: 18px;
    }

    /* ---------- 视频 ---------- */
    .video {
        margin-top: -50px;
        position: relative;
        z-index: 1;
    }

    .video-item {
        padding: 3vw;
    }

    .video-item-img {
        height: auto;
        margin-top: 26px;
    }

    .video-item-img>img {
        display: block;
    }

    .video-item-btn {
        width: 50%;
    }

    .video-item-img-title p {
        font-size: 16px;
    }

    /* ---------- 章节大背景块（box-1/3/5/7/9） ---------- */
    .box-1,
    .box-3,
    .box-5,
    .box-7,
    .box-9 {
        height: auto;
        background-size: cover;
        padding: 40vw 0;
        margin: -20px 0;
    }

    .box-content-3 {
        align-items: flex-start;
    }

    .box-title {
        font-size: 22px;
    }

    .box-content-text {
        width: 100%;
        font-size: 16px;
        margin-top: 14px;
        line-height: 1.9;
    }

    .box2-left>img {
        width: 100%;
        height: 100%;
    }

    .box2-right-item>img {
        width: 100%;
        height: 100%;
    }


    .box-2 {
        height: auto;
    }

    /* 列布局必须拉伸，否则卡片会塌缩成内容宽度 */
    .box2-content,
    .box-4-content,
    .box-4-left,
    .box-4-right,
    .box-6-content,
    .box-8-content,
    .box-10-content {
        flex-direction: column;
        align-items: stretch;
    }

    .box2-content,
    .box-4-content,
    .box-6-content,
    .box-8-content,
    .box-10-content {
        gap: 20px;
    }

    /* box-2：左大图 + 右侧两小图 */
    .box2-left,
    .box2-right,
    .box2-right-item {
        width: 100%;
    }

    .box2-left {
        padding: 4vw 3vw;
        justify-content: center;
    }

    .box2-right {
        gap: 4vw;
    }

    .box2-right-item {
        height: auto;
        padding: 4vw 3vw;
    }

    .box2-title {
        font-size: 14px;
        margin-top: 8px;
    }

    /* box-4/6/8/10：文物网格转单列卡片 */
    .box-4-left,
    .box-4-right,
    .box-4-item,
    .box-6-item,
    .box-8-item,
    .box-10-item {
        width: 100%;
        gap: 20px;
    }

    .box-4-item,
    .box-6-item,
    .box-8-item,
    .box-10-item {
        height: auto;
        padding: 5vw 4vw 5vw;
        border: 1px solid #d9a882;
        border-radius: 4px;
    }

    .box-4-item img,
    .box-6-item img,
    .box-8-item img,
    .box-10-item img {
        position: static !important;
        transform: none !important;
        left: auto !important;
        top: auto !important;
        width: 100%;
        height: 100%;
        display: block;
        margin: 0 auto;
    }

    .box-4-item-title,
    .box-6-item-title,
    .box-8-item-title,
    .box-10-item-title {
        position: static;
        margin-top: 12px;
        font-size: 16px;
        line-height: 1.6;
    }

    .box-10-photo,
    .box-10-doc {
        width: 100%;
    }

    .box-10-content {
        margin-bottom: 5vw;
    }

    /* ---------- 底部「下一专题」横幅 ---------- */
    .box-10-banner {
        height: auto;
        padding: 6vw 4vw;
        display: flex;
        flex-direction: column;
        align-items: center;
        /* border: 1px solid #8d2722;
        border-radius: 6px;
        background: linear-gradient(135deg, #8d2722, #b67552); */
    }

    .box-10-banner-bg {
        width: 100%;
        height: auto;
    }


    .box-10-banner-arrow {
        margin-left: 8px;
    }

    .box-10-banner-arrow img {
        width: 26px;
    }

    /* ---------- 页脚 ---------- */
    .box-footer {
        height: auto;
        padding: 9vw 5vw;
        margin-top: 26px;
        background-size: cover;
    }

    .footer-block {
        margin-bottom: 5vw;
    }

    .footer-title {
        font-size: 20px;
        line-height: 1.6;
        padding-right: 0;
        margin-bottom: 4px;
    }

    .footer-list {
        font-size: 16px;
        line-height: 1.9;
        word-break: normal;
    }

    .box-10-banner-sub {
        left: 4.5vw;
    }

    .box-10-banner-main {
        height: 7.61vw;
        left: 35.56vw;
    }
}

@media (max-width: 500px) {
    .video-item-img-title {
        right: 10px;
    }

    .video-item-img-title p {
        font-size: 14px;
    }
}

/* ========== 滚动入场动画（顺滑） ========== */
/* 三种方向：reveal-up 从下往上 / reveal-left 从左往右 / reveal-right 从右往左 */
.js .reveal-up,
.js .reveal-left,
.js .reveal-right {
    opacity: 0;
    transition: opacity .9s cubic-bezier(.22, .61, .36, 1),
        transform .9s cubic-bezier(.22, .61, .36, 1);
    will-change: opacity, transform;
}

.js .reveal-up {
    transform: translateY(50px);
}

.js .reveal-left {
    transform: translateX(-60px);
}

.js .reveal-right {
    transform: translateX(60px);
}

.js .reveal-up.is-visible,
.js .reveal-left.is-visible,
.js .reveal-right.is-visible {
    opacity: 1;
    transform: translate(0, 0);
}

/* preface-img 桌面端靠 translateX(-50%) 居中，动画需保留水平居中 */
.js .preface-img.reveal-up {
    transform: translateX(-50%) translateY(50px);
}

.js .preface-img.reveal-up.is-visible {
    transform: translateX(-50%) translateY(0);
}

/* 移动端 preface-img 为静态流，去掉水平位移避免偏移 */
@media (max-width: 768px) {

    .js .preface-img.reveal-up,
    .js .preface-img.reveal-up.is-visible {
        transform: translateY(50px);
    }

    .js .preface-img.reveal-up.is-visible {
        transform: translateY(0);
    }

    /* 移动端取消左右滑动，统一为从下往上淡入 */
    .js .reveal-left,
    .js .reveal-right {
        transform: translateY(50px);
    }
}

/* ---------- 鼠标悬停放大 ---------- */

.video-content .video-item-img:hover {
    transform: scale(1.05);
    transition: transform .4s ease;
}

.js .box-10-banner:hover {
    transform: scale(1.03);
    transition: transform .4s ease;
}

.box-4-item img,
.box-6-item img,
.box-8-item img,
.box-10-item img,
.box2-left img,
.box2-right-item img {
    transition: transform .4s ease;
}

.box-4-item img:hover,
.box-6-item img:hover,
.box-8-item img:hover,
.box-10-item img:hover {
    transform: translateX(-50%) scale(1.06);
}

.box-10-photo img:hover {
    transform: translateX(-50%) scale(1.02);
}

.box2-left img:hover {
    transform: scale(1.01);
}

.box2-right-item img:hover {
    transform: scale(1.06);
}

/* 尊重系统的「减少动态效果」偏好 */
@media (prefers-reduced-motion: reduce) {

    .js .reveal-up,
    .js .reveal-left,
    .js .reveal-right {
        opacity: 1;
        transform: none;
        transition: none;
    }

    .video-item-img>img,
    .box-10-banner,
    .box-4-item img,
    .box-6-item img,
    .box-8-item img,
    .box-10-item img,
    .box2-left img,
    .box2-right-item img {
        transition: none;
    }
}


/* ========== 文物图片查看器（Lightbox） ========== */
.box-4-item img,
.box-6-item img,
.box-8-item img,
.box-10-item img,
.box2-left img,
.box2-right-item img {
    cursor: zoom-in;
}

.artifact-lightbox {
    position: fixed;
    inset: 0;
    z-index: 100;
    display: none;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

.artifact-lightbox.is-open {
    display: flex;
}

.lightbox-backdrop {
    position: absolute;
    inset: 0;
    background: rgba(0, 0, 0, 0.7);
    cursor: zoom-out;
}

.lightbox-stage {
    position: relative;
    z-index: 2;
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    touch-action: none;
    pointer-events: none;
}

.lightbox-img {
    max-width: 85vw;
    max-height: 85vh;
    object-fit: contain;
    user-select: none;
    -webkit-user-drag: none;
    will-change: transform;
    transition: transform 0.15s ease-out;
    pointer-events: auto;
}

.lightbox-img.is-dragging {
    transition: none;
}

.overview-section-line {
    position: absolute;
    left: -9vw;
    bottom: 5vw;
    width: 16vw;
}

.lightbox-toolbar {
    position: fixed;
    top: 2vw;
    right: 2vw;
    z-index: 3;
    display: flex;
    flex-direction: column;
    gap: 0.4167vw;
    padding: 2px;
    background: black;
    border-radius: 0.5208vw;
    box-shadow: 0 0.2083vw 0.8333vw rgba(0, 0, 0, 0.4);
}

.lightbox-btn {
    width: 3vw;
    height: 3vw;
    min-width: 32px;
    min-height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: none;
    border-radius: 0.2604vw;
    background: black;
    color: #fff;
    font-size: 20px;
    line-height: 1;
    cursor: pointer;
    transition: background 0.2s ease;
}

.lightbox-btn:hover {
    background: rgba(255, 255, 255, 0.25);
}

.lightbox-btn img {
    width: 25px;
}

.lightbox-btn svg {
    width: 55%;
    height: 55%;
    pointer-events: none;
}

@media (max-width: 768px) {
    .lightbox-toolbar {
        right: 10px;
        padding: 8px;
        gap: 8px;
        border-radius: 8px;
    }

    .lightbox-btn img {
        width: 20px;
    }

    .lightbox-btn {
        width: 36px;
        height: 36px;
        border-radius: 6px;
        font-size: 18px;
    }

    .lightbox-img {
        max-width: 92vw;
        max-height: 80vh;
    }
}