/* ===== 技术研发 Section ===== */
.yf_section { position: relative; width: 100%; }
.yf_bg {
    position: relative; width: 100%; min-height: 900px;
    background: url(../img/yanfa/bg.webp) no-repeat center top;
    background-size: 100% 100%;
    padding: 80px 0 100px;
}
.yf_inner { position: relative; z-index: 1; }

/* 子Tab导航 */
.yf_sub_tabs {
    display: flex; align-items: center; gap: 380px;
    justify-content: center; margin-bottom: 50px;
}
.yf_sub_tab {
    font-size: 28px; color: #777777;
    cursor: pointer; transition: all 0.3s;
    position: relative; padding-bottom: 13px;
}
.yf_sub_tab.active {
    font-size: 34px; color: #164F8F;
}
.yf_sub_tab.active::after {
    content: '';
    position: absolute; bottom: 0; left: 50%;
    transform: translateX(-50%);
    width: 48px; height: 4px;
    background: #164F8F; border-radius: 2px;
}
.yf_sub_tab:hover:not(.active) {
    color: #44403F;
}

/* 标题 + 描述 */
.yf_title {
    font-size: 42px; color: #44403F; text-align: center;
    margin-bottom: 24px; font-weight: 500;
}
.yf_desc {
    font-size: 18px; color: #44403F; line-height: 2;
    text-align: center; max-width: 1440px; margin: 0 auto 60px;
    padding: 0 40px;
}

/* ===== 轮播容器（参考 Swiper 7项方案，适配5项） ===== */
.yf_carousel {
    position: relative; margin-top: 160px;
    overflow: visible !important; width: 100%;
}
.yf_carousel .swiper-container { overflow: visible !important; }
.yf_carousel .swiper-wrapper  { overflow: visible !important; }
.yf_swiper                     { overflow: visible !important; }

.yf_carousel .swiper-slide {
    width: 240px; height: auto;
    display: flex; align-items: flex-end; justify-content: center;
    transition: 300ms;
    transform: scale(0.7); transform-origin: center bottom;
}

.yf_carousel .box_image { width: 100%; }
.yf_carousel .box_image img {
    width: 100%; height: auto; object-fit: contain;
    transform: scale(1.8); transform-origin: center center;
}

/* 左右按钮 */
.yf_prev, .yf_next {
    position: absolute; top: 50%; transform: translateY(-50%);
    width: 60px; height: 60px; background-color: #fff;
    border-radius: 50%;
    display: flex; align-items: center; justify-content: center;
    cursor: pointer; z-index: 100; transition: all 0.3s;
}
.yf_prev { left: -20%; }
.yf_next { right: -20%; }
.yf_prev svg, .yf_next svg { width: 14px; height: auto; fill: #164F8F; }
.yf_prev:hover, .yf_next:hover { background-color: #164F8F; }
.yf_prev:hover svg, .yf_next:hover svg { fill: #fff; }

/* 分页圆点 */
.yf_pagination { text-align: center; margin-top: 30px; }
.yf_pagination .swiper-pagination-bullet {
    width: 10px; height: 10px; background: #ccc;
    border-radius: 50%; display: inline-block;
    margin: 0 5px; cursor: pointer; transition: all 0.3s;
}
.yf_pagination .swiper-pagination-bullet-active {
    background-color: #164F8F; width: 24px; border-radius: 5px;
}

/* 响应式 */
@media screen and (max-width: 1440px) {
    .yf_sub_tab { font-size: 24px; }
    .yf_sub_tab.active { font-size: 28px; }
    .yf_carousel .swiper-slide { width: 300px; }
    .yf_prev { left: 2%; } .yf_next { right: 2%; }
}
@media screen and (max-width: 1024px) {
    .yf_title { font-size: 32px; }
    .yf_desc { font-size: 16px; margin-bottom: 30px; }
    .yf_sub_tab { font-size: 20px; }
    .yf_sub_tab.active { font-size: 24px; }
    .yf_carousel .swiper-slide { width: 250px; }
}
@media screen and (max-width: 768px) {
    .yf_bg { min-height: auto; padding: 60px 0 60px; }
    .yf_title { font-size: 26px; }
    .yf_desc { font-size: 14px; padding: 0 16px; }
    .yf_sub_tabs { flex-direction: column; align-items: center; gap: 16px; }
    .yf_sub_tab { font-size: 20px; }
    .yf_sub_tab.active { font-size: 24px; }
    .yf_carousel .swiper-slide { width: 200px; }
    .yf_prev, .yf_next { display: none; }
    .yf_pagination { display: block; margin-top: 15px; }
}

/* ===== 标准制定 - 三图并排 ===== */
.bz_imgs {
    display: flex; justify-content: center; gap: 80px;
    margin-top: 60px;
}
.bz_img {
    width: 320px; height: auto;
    box-shadow: 0 4px 20px rgba(0,0,0,0.08);
    transition: all .3s;
}
.bz_img img { width: 100%; height: auto; display: block; }
.bz_img:hover { transform: translateY(-6px); box-shadow: 0 8px 30px rgba(0,0,0,0.15); }

@media screen and (max-width: 1200px) {
    .bz_imgs { gap: 40px; }
    .bz_img { width: 260px; }
}
@media screen and (max-width: 768px) {
    .bz_imgs { flex-direction: column; align-items: center; gap: 30px; }
    .bz_img { width: 300px; }
}

/* ===== 技术创新 - 7图轮播（参考7项方案） ===== */
.js_carousel {
    position: relative; margin-top: 140px;
    overflow: visible !important; width: 100%;
}
.js_carousel .swiper-container { overflow: visible !important; }
.js_carousel .swiper-wrapper  { overflow: visible !important; }
.js_swiper                     { overflow: visible !important; }

.js_carousel .swiper-slide {
    width: 240px; height: auto;
    text-align: center;
    display: flex; align-items: flex-end; justify-content: center;
    transition: 300ms;
    transform: scale(0.7);
    transform-origin: center bottom;
}
.js_carousel .box_image { width: 100%; }
.js_carousel .box_image img {
    width: 100%; height: auto;
    object-fit: contain;
    transform: scale(1.8);
    transform-origin: center center;
}

.js_prev, .js_next {
    position: absolute; top: 50%; transform: translateY(-50%);
    width: 60px; height: 60px; background-color: #fff;
    border-radius: 50%;
    display: flex; align-items: center; justify-content: center;
    cursor: pointer; z-index: 100; transition: all 0.3s;
}
.js_prev { left: -20%; }
.js_next { right: -20%; }
.js_prev svg, .js_next svg { width: 14px; height: auto; fill: #164F8F; }
.js_prev:hover, .js_next:hover { background-color: #164F8F; }
.js_prev:hover svg, .js_next:hover svg { fill: #fff; }

.js_pagination { text-align: center; margin-top: 30px; }
.js_pagination .swiper-pagination-bullet {
    width: 10px; height: 10px; background: #ccc;
    border-radius: 50%; display: inline-block;
    margin: 0 5px; cursor: pointer; transition: all 0.3s;
}
.js_pagination .swiper-pagination-bullet-active {
    background-color: #164F8F; width: 24px; border-radius: 5px;
}

@media screen and (max-width: 1440px) {
    .js_carousel .swiper-slide { width: 300px; }
    .js_prev { left: 2%; } .js_next { right: 2%; }
}
@media screen and (max-width: 1024px) {
    .js_carousel .swiper-slide { width: 250px; }
}
@media screen and (max-width: 768px) {
    .js_carousel .swiper-slide { width: 200px; }
    .js_prev, .js_next { display: none; }
    .js_pagination { display: block; margin-top: 15px; }
}