/* ===== 全局重置 & 现代化变量 ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Inter', 'Microsoft Yahei', system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
}

html {
    scroll-behavior: smooth;
}

body {
    /* 浅蓝色背景 */
    background: 
        linear-gradient(rgba(230, 244, 255, 0.95), rgba(230, 244, 255, 0.95)),
        url('images/bg.png') no-repeat center center fixed;
    background-size: cover;
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
    min-height: 100vh;
    padding-top: 80px;
}

/* ===== 页面区块样式（正常滚动布局） ===== */
.page-section {
    position: relative;
    width: 100%;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    padding: 60px 3%;
    background: transparent;
}

/* 轮播图区块特殊处理 */
#banner {
    padding: 20px 3%;
    min-height: auto;
}

#banner .main-swiper-container {
    width: 100%;
    max-width: 1400px;
    margin: 0 auto;
    border-radius: 24px;
    overflow: hidden;
    box-shadow: 0 20px 40px rgba(52, 152, 219, 0.2);
    aspect-ratio: 16 / 9;
}

#banner .swiper-wrapper {
    height: 100%;
}

#banner .swiper-slide {
    height: 100%;
}

#banner .swiper-slide img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    background: #f0f4f8;
}

/* 合作伙伴区块特殊布局 */
#partner {
    justify-content: flex-start;
    padding: 40px 3% 40px;
}

#partner .section-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: flex-start;
    width: 100%;
    max-width: 1400px;
}

/* 新闻中心区块标题调整 */
#news {
    padding-top: 40px;
}

#news .section-title {
    margin-bottom: 0.8rem;
    margin-top: 0;
}

#news .section-content {
    justify-content: flex-start;
    padding-top: 0;
}

.page-section .section-title {
    margin-bottom: 1rem;
    flex-shrink: 0;
}

.page-section .section-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
    width: 100%;
    max-width: 1400px;
}

/* 页脚样式 */
.fp-footer {
    width: 100%;
    padding: 30px 3%;
    background: #1e3a5f;
    color: #e3f2fd;
    flex-shrink: 0;
    margin-top: auto;
}

/* ===== 导航栏 · 毛玻璃升级 ===== */
nav.navbar, .navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 80px !important;
    min-height: 80px !important;
    max-height: 80px !important;
    flex-shrink: 0;
    flex-grow: 0;
    box-sizing: border-box;
    background: rgba(230, 244, 255, 0.95);
    backdrop-filter: blur(12px) saturate(180%);
    -webkit-backdrop-filter: blur(12px) saturate(180%);
    box-shadow: 0 4px 15px rgba(52, 152, 219, 0.15);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 3%;
    z-index: 999;
    border-bottom: 1px solid rgba(52, 152, 219, 0.3);
}

.navbar-left {
    display: flex;
    align-items: center;
    cursor: pointer;
    transition: opacity 0.2s;
    position: relative;
}
.navbar-left:hover { opacity: 0.85; }

/* logo下拉菜单样式 */
.logo-dropdown {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    background: rgba(230, 244, 255, 0.98);
    backdrop-filter: blur(12px) saturate(180%);
    -webkit-backdrop-filter: blur(12px) saturate(180%);
    border-radius: 0 0 12px 12px;
    box-shadow: 0 8px 30px rgba(52, 152, 219, 0.2);
    border: 1px solid rgba(52, 152, 219, 0.3);
    border-top: none;
    min-width: 160px;
    z-index: 1000;
    overflow: hidden;
    margin-top: -1px;
}

.navbar-left:hover .logo-dropdown {
    display: block;
}

.dropdown-item {
    display: block;
    padding: 12px 20px;
    color: #1e2b3a;
    text-decoration: none;
    font-size: 0.95rem;
    font-weight: 500;
    transition: all 0.3s ease;
    border-bottom: 1px solid rgba(52, 152, 219, 0.1);
}

.dropdown-item:last-child {
    border-bottom: none;
}

.dropdown-item:hover {
    background: rgba(52, 152, 219, 0.15);
    color: #216795;
    padding-left: 25px;
}

.logo {
    width: auto;
    height: 50px;
    margin-right: 12px;
    border-radius: 6px;
    object-fit: contain;
    /* box-shadow: 0 3px 8px rgba(52, 152, 219, 0.25);
    border: 2px solid white; */
}

.brand-name {
    font-size: 20px;
    font-weight: 700;
    background: linear-gradient(135deg, #2c3e50 20%, #3498db 80%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: 0.8px;
}

.navbar-middle { display: flex; gap: 2rem; }

.nav-item {
    font-size: 1rem;
    font-weight: 500;
    color: #1e2b3a;
    text-decoration: none;
    transition: all 0.3s ease;
    position: relative;
    padding: 4px 0;
    cursor: pointer;
}

/* 菜单项分隔符 */
.nav-item:not(:last-child)::before {
    content: '';
    position: absolute;
    right: -1rem;
    top: 50%;
    transform: translateY(-50%);
    width: 1px;
    height: 16px;
    background: rgba(52, 152, 219, 0.4);
}

.nav-item::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 3px;
    background: linear-gradient(90deg, #3498db, #2ecc71);
    border-radius: 3px;
    transition: width 0.25s ease;
}

.nav-item:hover { color: #1f3a57; }
.nav-item:hover::after,
.nav-item.active::after { width: 100%; }
.nav-item.active { color: #216795; font-weight: 600; }

.login-btn {
    padding: 8px 22px;
    background: linear-gradient(145deg, #3498db, #1f6ea0);
    color: white;
    border: none;
    border-radius: 30px;
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 10px rgba(52, 152, 219, 0.35);
    letter-spacing: 0.5px;
    border: 1px solid rgba(255,255,255,0.2);
}
.login-btn:hover {
    background: linear-gradient(145deg, #1f6ea0, #0f4b73);
    transform: translateY(-2px);
    box-shadow: 0 8px 16px rgba(52, 152, 219, 0.4);
}

/* ===== 主轮播 · 优雅遮罩 ===== */
.main-swiper-container {
    width: 100%;
    height: 100%;
    margin-top: 0;
    box-shadow: 0 10px 20px -8px rgba(0,0,0,0.15);
    background: #000;
}
.swiper-slide { 
    position: relative;
    background: #000;
}
.swiper-slide::after {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(0deg, rgba(0,20,40,0.2) 0%, transparent 60%);
    pointer-events: none;
}
.swiper-slide img {
    display: block;
    width: 100%;
    height: 100%;
    object-fit: cover;
    max-width: 100%;
    max-height: 100%;
}

/* 轮播导航按钮 */
.swiper-button-next, .swiper-button-prev {
    color: #2c3e50 !important;
    width: 50px !important;
    height: 50px !important;
    background: rgba(255,255,255,0.9);
    backdrop-filter: blur(4px);
    border-radius: 50%;
    box-shadow: 0 5px 15px rgba(0, 20, 40, 0.15);
    transition: 0.25s;
    border: 1px solid rgba(255,255,255,0.6);
}
.swiper-button-next:hover, .swiper-button-prev:hover {
    background: white;
    transform: scale(1.1);
    box-shadow: 0 8px 22px rgba(52,152,219,0.4);
    color: #3498db !important;
}
.swiper-button-next::after, .swiper-button-prev::after {
    font-size: 20px !important;
    font-weight: 800;
}
.swiper-pagination-bullet {
    width: 12px;
    height: 12px;
    background: white;
    opacity: 0.7;
    box-shadow: 0 2px 6px rgba(0,0,0,0.2);
}
.swiper-pagination-bullet-active {
    background: #3498db;
    opacity: 1;
    transform: scale(1.2);
}

/* ===== 板块通用 ===== */

.section-title {
    font-size: 2.5rem;
    margin-bottom: 3rem;
    color: #1a2b3c;
    position: relative;
    padding-bottom: 20px;
    text-align: center;
    font-weight: 700;
    letter-spacing: -0.5px;
}
.section-title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 140px;
    height: 4px;
    background: linear-gradient(90deg, #3498db, #2ecc71, #f1c40f);
    border-radius: 4px;
    box-shadow: 0 2px 8px rgba(46,204,113,0.3);
}

.section-content {
    width: 100%;
    font-size: 1rem;
    color: #2c3e50;
    max-width: 1400px;
    margin: 0 auto;
}

/* 板块副标题（居中） */
.section-subtitle {
    text-align: center;
    font-size: 2rem;
    margin-bottom: 30px;
    color: #1a2b3c;
    font-weight: 600;
    background: linear-gradient(135deg, #2c3e50, #3498db);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* ===== 卡片 & 容器 美化 (浅蓝色系) ===== */

.about-container,
.split-layout,
.course-brief-layout,
.video-container,
.card {
    background: rgba(235, 248, 255, 0.9);
    backdrop-filter: blur(4px);
    border-radius: 28px;
    box-shadow: 0 16px 30px -8px rgba(52, 152, 219, 0.15), 0 0 0 1px rgba(230, 244, 255, 0.8) inset;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}
.about-container:hover,
.split-layout:hover,
.card:hover {
    transform: translateY(-6px);
    box-shadow: 0 30px 45px -12px rgba(52, 152, 219, 0.3), 0 0 0 1px rgba(230, 244, 255, 0.9) inset;
}

/* 关于引力板块 - 左右布局，含logo图片 */
.about-container {
    padding: 50px;
    display: flex;
    align-items: center;
    gap: 50px;
    max-width: 1400px;
    margin-left: auto;
    margin-right: auto;
    position: relative;
    overflow: hidden;
}
.about-container::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -20%;
    width: 400px;
    height: 400px;
    background: radial-gradient(circle, rgba(52, 152, 219, 0.1) 0%, transparent 70%);
    border-radius: 50%;
    pointer-events: none;
}
.about-logo {
    flex-shrink: 0;
    width: 200px;
    height: 200px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255, 255, 255, 0.9);
    border-radius: 24px;
    box-shadow: 0 10px 30px rgba(52, 152, 219, 0.15);
    position: relative;
    z-index: 1;
}
.about-logo img {
    width: 350px;
    height: auto;
    object-fit: contain;
}
.about-text {
    flex: 1;
    position: relative;
    z-index: 1;
}
.about-text h3 {
    font-size: 1.4rem;
    color: #216795;
    margin-bottom: 20px;
    font-weight: 600;
    text-align: center;
    background: linear-gradient(135deg, #216795, #3498db);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}
.about-text p {
    font-size: 1.2rem;
    line-height: 1.8;
    color: #2c3e50;
    text-align: justify;
    position: relative;
}

/* 新闻卡片 - 一排四个横向布局 */
.news-grid {
    display: flex;
    gap: 20px;
    width: 100%;
    max-width: 1400px;
    margin: 0 auto;
    padding: 10px 0;
}
.news-card {
    flex: 1;
    min-width: 0;
    background: rgba(235, 248, 255, 0.95);
    border-radius: 20px;
    overflow: hidden;
    box-shadow: 0 15px 25px -8px rgba(52, 152, 219, 0.15);
    padding: 40px 28px 35px;
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    text-align: left;
    border: 1px solid rgba(52, 152, 219, 0.3);
    transition: all 0.3s ease;
    position: relative;
    min-height: 450px;
}
.news-card:hover {
    box-shadow: 0 25px 45px -12px rgba(52, 152, 219, 0.4);
    border-color: rgba(52, 152, 219, 0.6);
    transform: translateY(-8px) scale(1.02);
}
.news-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 6px;
    background: linear-gradient(90deg, #3498db, #2ecc71, #3498db);
    background-size: 200% 100%;
    animation: gradientMove 3s ease infinite;
}
@keyframes gradientMove {
    0%, 100% { background-position: 0 0; }
    50% { background-position: 100% 0; }
}
.news-date {
    background: linear-gradient(145deg, #3498db, #2ecc71);
    color: white;
    padding: 8px 22px;
    border-radius: 40px;
    font-size: 0.85rem;
    font-weight: 600;
    letter-spacing: 0.5px;
    margin-bottom: 20px;
    border: 1px solid white;
    flex-shrink: 0;
}
.news-card h4 {
    font-size: 1.15rem;
    color: #2c3e50;
    margin-bottom: 15px;
    font-weight: 600;
    line-height: 1.4;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}
.news-card p {
    font-size: 0.9rem;
    color: #5a6c7d;
    line-height: 1.8;
    flex: 1;
    margin: 0;
    display: -webkit-box;
    -webkit-line-clamp: 9;
    -webkit-box-orient: vertical;
    overflow: hidden;
    text-overflow: ellipsis;
}
.news-title {
    font-size: 1.25rem;
    color: #1a2b3c;
    margin-bottom: 8px;
    font-weight: 700;
}
.news-desc {
    font-size: 1rem;
    color: #4a5a6a;
    line-height: 1.5;
}

/* ===== 项目介绍宣介视频 + 右侧按钮 ===== */
.video-wrapper {
    display: flex;
    gap: 18px;
    align-items: stretch;
    flex-wrap: wrap;
}
.video-box {
    flex: 2;
    min-width: 280px;
    aspect-ratio: 16/9;
    height: auto;
    background: linear-gradient(145deg, #e3f2fd, #f0f9ff);
    border-radius: 20px;
    display: flex;
    justify-content: center;
    align-items: center;
    color: #1e3a5f;
    font-size: 1.2rem;
    gap: 12px;
    box-shadow: inset 0 2px 10px rgba(52, 152, 219, 0.1), 0 8px 16px rgba(52, 152, 219, 0.12);
    border: 1px solid rgba(52, 152, 219, 0.3);
}
.video-box i {
    font-size: 2.5rem;
    color: #3498db;
    filter: drop-shadow(0 4px 6px #3498db60);
    transition: 0.2s;
}
.video-box:hover i { transform: scale(1.1); color: #1f6ea0; }

.video-buttons {
    flex: 1;
    min-width: 160px;
    display: flex;
    flex-direction: column;
    gap: 20px;
    justify-content: space-evenly;
    padding: 10px 0;
}
.video-btn {
    background: rgba(235, 248, 255, 0.95);
    border: none;
    padding: 16px 12px;
    border-radius: 35px;
    font-size: 1rem;
    font-weight: 600;
    color: #1e3a5f;
    box-shadow: 0 6px 12px rgba(52, 152, 219, 0.1);
    cursor: pointer;
    transition: 0.25s;
    border: 1px solid rgba(52, 152, 219, 0.3);
    text-align: center;
}
.video-btn:hover {
    background: #3498db;
    color: white;
    transform: translateY(-3px);
    box-shadow: 0 15px 25px -8px rgba(52, 152, 219, 0.4);
    border-color: transparent;
}

/* 课程简介左右排版 (两个卡片加大间距) */
.course-brief-layout {
    display: flex;
    gap: 16px;
    padding: 12px;
    margin: 8px 0;
    flex-wrap: wrap;
}
.course-brief-item {
    flex: 1 1 280px;
    background: rgba(235, 248, 255, 0.9);
    backdrop-filter: blur(2px);
    border-radius: 16px;
    padding: 16px;
    border: 1px solid rgba(52, 152, 219, 0.3);
    box-shadow: 0 4px 10px rgba(52, 152, 219, 0.1);
}
.course-brief-item h3 {
    font-size: 1.25rem;
    color: #1a2b3c;
    border-bottom: 2px solid transparent;
    border-image: linear-gradient(90deg, #3498db, #2ecc71);
    border-image-slice: 1;
    padding-bottom: 8px;
    margin-bottom: 10px;
}
.course-brief-item p {
    font-size: 0.9rem;
    line-height: 1.5;
    color: #4a5a6a;
    margin: 0;
}
/* 课程简介图片 - 2730*1535 比例 */
.course-brief-image {
    width: 100%;
    height: auto;
    aspect-ratio: 2730 / 1535;
    object-fit: cover;
    border-radius: 12px;
    margin-top: 12px;
}

/* 九域网格 3x3 (全宽容器内使用) */
.nine-domain-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 16px;
    margin: 0;
}

/* 课程详情布局 - 左右分栏 */
.course-detail-layout {
    display: grid;
    grid-template-columns: 1.4fr 0.5fr;
    gap: 25px;
    padding: 25px;
    margin-bottom: 30px;
    width: 100%;
    background: rgba(235, 248, 255, 0.9);
    backdrop-filter: blur(4px);
    border-radius: 28px;
    box-shadow: 0 20px 35px -8px rgba(52, 152, 219, 0.15), 0 0 0 1px rgba(230, 244, 255, 0.8) inset;
}

/* 左侧内容区 */
.course-content-left {
    display: flex;
    flex-direction: column;
    gap: 15px;
    text-align: center;
}

.course-detail-title {
    font-size: 1.8rem;
    color: #1a2b3c;
    font-weight: 700;
    margin: 0;
    text-align: center;
}

.course-detail-desc {
    font-size: 1.05rem;
    line-height: 1.7;
    color: #2c3e50;
    margin: 0;
    text-align: center;
}

.course-detail-image {
    width: 100%;
    aspect-ratio: 16/9;
    height: auto;
    object-fit: cover;
    border-radius: 16px;
    box-shadow: 0 8px 16px rgba(0,0,0,0.1);
}

/* 右侧卡片列表 */
.course-list-right {
    display: flex;
    flex-direction: column;
    gap: 10px;
    justify-content: center;
}

.domain-item {
    background: rgba(235, 248, 255, 0.95);
    backdrop-filter: blur(2px);
    padding: 12px 14px;
    border-radius: 12px;
    text-align: left;
    border: 1px solid rgba(52, 152, 219, 0.3);
    transition: all 0.3s ease;
    font-weight: 500;
    color: #1e3a5f;
    box-shadow: 0 4px 8px rgba(52, 152, 219, 0.1);
    word-break: break-word;
    cursor: pointer;
    font-size: 0.9rem;
    width: 100%;
}
.domain-item:hover {
    background: #3498db;
    color: white;
    transform: translateX(5px);
    border-color: transparent;
    box-shadow: 0 10px 15px -8px rgba(52, 152, 219, 0.4);
}
.domain-item.active {
    background: #3498db;
    color: white;
    border-color: transparent;
    box-shadow: 0 10px 15px -8px rgba(52, 152, 219, 0.4);
}
.domain-item.active:hover {
    transform: translateX(5px);
}

/* 全宽容器（用于九域网格和研学描述） */
.full-width-block {
    padding: 0 30px;
    margin-bottom: 40px;
    width: 100%;
}

/* 学段描述卡片 */
.course-level {
    margin-top: 15px;
    padding: 14px 18px;
    background: #eef5fa;
    border-radius: 20px;
    border-left: 6px solid #3498db;
    cursor: pointer;
    transition: all 0.3s ease;
}
.course-level:hover {
    background: #d4e8f7;
    transform: translateX(5px);
}
.course-level.active {
    background: #3498db;
    border-left: 6px solid #2ecc71;
}
.course-level.active h4 {
    color: white;
}
.course-level.active p {
    color: rgba(255,255,255,0.9);
}
.course-level h4 {
    font-size: 1.2rem;
    color: #1e3a5f;
    margin-bottom: 6px;
    transition: color 0.3s ease;
}
.course-level p {
    transition: color 0.3s ease;
}

/* 课程目标卡片样式 */
.goal-cards {
    display: flex;
    flex-direction: column;
    gap: 50px;
    margin-top: 15px;
}

.goal-card {
    background: rgba(235, 248, 255, 0.95);
    border-radius: 18px;
    padding: 12px 18px;
    border: 1px solid rgba(52, 152, 219, 0.3);
    transition: all 0.3s ease;
    cursor: pointer;
}

.goal-card:hover {
    background: rgba(52, 152, 219, 0.2);
    border-color: #3498db;
    transform: translateX(5px);
}

.goal-card.active {
    background: #3498db;
    border-color: #3498db;
    box-shadow: 0 8px 15px -5px rgba(52, 152, 219, 0.4);
}

.goal-card.active h5 {
    color: white;
    font-size: 1.05rem;
    margin-bottom: 4px;
}

.goal-card.active p {
    color: rgba(255,255,255,0.9);
    font-size: 0.9rem;
}

.goal-card h5 {
    font-size: 1rem;
    color: #1e3a5f;
    margin-bottom: 4px;
    font-weight: 600;
    transition: color 0.3s ease;
}

.goal-card p {
    font-size: 0.85rem;
    color: #4a5a6a;
    line-height: 1.4;
    transition: color 0.3s ease;
}

/* 课程目标列表美化（保留原有样式） */
.goal-list {
    list-style: none;
    padding: 0;
    margin-top: 20px;
}
.goal-list li {
    background: #f4f9ff;
    border-radius: 18px;
    padding: 16px 20px 16px 45px;
    margin-bottom: 12px;
    position: relative;
    border: 1px solid rgba(52,152,219,0.2);
    transition: 0.2s;
    font-size: 1rem;
    line-height: 1.5;
    color: #1e3a5f;
}
.goal-list li::before {
    content: "●";
    color: #3498db;
    font-size: 1.8rem;
    position: absolute;
    left: 15px;
    top: 50%;
    transform: translateY(-50%);
    line-height: 1;
}
.goal-list li:hover {
    background: #e3f0ff;
    border-color: #3498db;
    transform: translateX(5px);
}

/* 小型轮播图 */
.mini-swiper {
    width: 100%;
    aspect-ratio: 16/9;
    height: auto;
    min-height: 280px;
    border-radius: 28px;
    overflow: hidden;
    box-shadow: 0 18px 28px -12px rgba(0, 0, 0, 0.25);
    border: 1px solid rgba(255,255,255,0.5);
}
.mini-swiper .swiper-slide img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

/* 合作伙伴卡片 */
.card-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 25px;
    margin-bottom: 40px;
}
.card {
    padding: 30px 25px;
    border-left: none;
    border-top: 6px solid transparent;
    border-image: linear-gradient(90deg, #3498db, #2ecc71);
    border-image-slice: 1;
    border-radius: 28px;
}
.card-icon {
    font-size: 2.5rem;
    background: linear-gradient(145deg, #3498db20, #2ecc7120);
    width: 70px;
    height: 70px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 20px;
    color: #216795;
}

/* ===== 左右分栏布局 - 使用 Grid 避免溢出换行 ===== */
.split-layout {
    display: grid;
    grid-template-columns: 0.8fr 1.2fr;
    gap: 25px;
    padding: 25px;
    margin-bottom: 30px;
    width: 100%;
}
.split-left, .split-right {
    min-width: 0;
    width: 100%;
    display: flex;
    flex-direction: column;
}
.split-left {
    justify-content: flex-start;
}
.split-right {
    justify-content: center;
}
/* 学段课程图片容器 */
.course-level-image-container {
    width: 100%;
    aspect-ratio: 16/9;
    border-radius: 20px;
    overflow: hidden;
    box-shadow: 0 15px 30px rgba(52, 152, 219, 0.2);
    border: 2px solid rgba(52, 152, 219, 0.3);
    transition: all 0.3s ease;
}
.course-level-image-container:hover {
    transform: translateY(-5px);
    box-shadow: 0 20px 40px rgba(52, 152, 219, 0.3);
}
.course-level-image-container img {
    width: 100%;
    height: 100%;
    display: block;
    object-fit: cover;
}

/* ===== 页脚 ===== */
footer {
    background: #132231;
    color: #dee7f0;
    padding: 50px 3% 30px;
    margin-top: auto;
    width: 100%;
    border-top: 1px solid #2e4a66;
    box-shadow: 0 -10px 30px rgba(0,0,0,0.1);
}
.footer-container {
    max-width: 1400px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    margin-bottom: 30px;
}
.footer-company h3,
.footer-contact h3 {
    font-size: 1.4rem;
    color: #e3f2fd;
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 2px solid #3498db;
    display: inline-block;
}
@media (max-width: 768px) {
    .footer-company h3,
    .footer-contact h3 {
        font-size: 1.1rem;
        margin-bottom: 12px;
        padding-bottom: 8px;
    }
}
.footer-company p,
.footer-contact ul li {
    font-size: 1rem;
    color: #b8d4e6;
    margin-bottom: 12px;
    display: flex;
    align-items: center;
    gap: 12px;
}
@media (max-width: 768px) {
    .footer-company p,
    .footer-contact ul li {
        font-size: 0.85rem;
        margin-bottom: 8px;
        gap: 8px;
    }
}
.footer-contact ul li i {
    color: #3498db;
    font-size: 1.3rem;
    width: 24px;
}
@media (max-width: 768px) {
    .footer-contact ul li i {
        font-size: 1rem;
        width: 18px;
    }
}

.footer-bottom {
    max-width: 1400px;
    margin: 0 auto;
    padding-top: 25px;
    border-top: 1px solid rgba(52, 152, 219, 0.3);
    text-align: center;
}
.footer-bottom p {
    font-size: 0.95rem;
    color: #b8d4e6;
}
.footer-cert {
    display: flex;
    justify-content: center;
    gap: 20px;
    flex-wrap: wrap;
    margin-top: 15px;
}
.footer-cert span {
    font-size: 0.9rem;
    background: rgba(52, 152, 219, 0.3);
    padding: 6px 20px;
    border-radius: 40px;
    color: #e3f2fd;
    border: 1px solid rgba(52, 152, 219, 0.5);
}
@media (max-width: 768px) {
    .footer-bottom {
        padding-top: 20px;
    }
    .footer-bottom p {
        font-size: 0.8rem;
    }
    .footer-cert {
        gap: 10px;
        margin-top: 12px;
    }
    .footer-cert span {
        font-size: 0.75rem;
        padding: 4px 12px;
    }
}

/* ===== 登录模态框 ===== */
.modal {
    display: none;
    position: fixed;
    z-index: 10000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.5);
    backdrop-filter: blur(5px);
}

.modal-content {
    background: rgba(235, 248, 255, 0.95);
    backdrop-filter: blur(10px);
    margin: 15% auto;
    padding: 30px;
    border-radius: 24px;
    width: 90%;
    max-width: 400px;
    box-shadow: 0 20px 40px rgba(52, 152, 219, 0.3);
    border: 1px solid rgba(52, 152, 219, 0.3);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
    padding-bottom: 15px;
    border-bottom: 2px solid rgba(52, 152, 219, 0.3);
}

.modal-header h2 {
    color: #1e3a5f;
    font-size: 1.5rem;
    margin: 0;
}

.close {
    color: #666;
    font-size: 28px;
    font-weight: bold;
    cursor: pointer;
    transition: color 0.3s ease;
}

.close:hover {
    color: #3498db;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    color: #1e3a5f;
    font-weight: 600;
}

.form-group input {
    width: 100%;
    padding: 12px 16px;
    border: 1px solid rgba(52, 152, 219, 0.3);
    border-radius: 12px;
    font-size: 1rem;
    background: rgba(255, 255, 255, 0.8);
    transition: all 0.3s ease;
}

.form-group input:focus {
    outline: none;
    border-color: #3498db;
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.2);
}

.login-submit-btn {
    width: 100%;
    padding: 14px;
    background: linear-gradient(145deg, #3498db, #1f6ea0);
    color: white;
    border: none;
    border-radius: 12px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    margin-top: 10px;
}

.login-submit-btn:hover {
    background: linear-gradient(145deg, #1f6ea0, #0f4b73);
    transform: translateY(-2px);
    box-shadow: 0 8px 16px rgba(52, 152, 219, 0.4);
}

.login-submit-btn:active {
    transform: translateY(0);
}

/* ===== 响应式 ===== */
@media (max-width: 768px) {
    .navbar { padding: 0 4%; height: 70px; }
    .navbar-middle { gap: 1.2rem; }
    .brand-name { font-size: 1.2rem; }
    .nav-item { font-size: 0.9rem; }
    
    /* 平板下的分隔符调整 */
    .nav-item:not(:last-child)::before {
        right: -0.6rem;
        height: 14px;
    }
    
    /* 平板下拉菜单调整 */
    .logo-dropdown {
        min-width: 140px;
        margin-top: -1px;
        border-radius: 0 0 10px 10px;
    }
    .dropdown-item {
        padding: 10px 16px;
        font-size: 0.9rem;
    }
    
    /* 平板下轮播图调整 */
    #banner {
        padding: 15px 3%;
    }
    
    #banner .main-swiper-container {
        border-radius: 20px;
    }
    
    .modal-content {
        margin: 30% auto;
        padding: 25px;
    }
    
    .login-btn { padding: 6px 18px; font-size: 0.8rem; }

    .section { padding: 60px 4%; }
    .section-title { font-size: 2rem; }
    .section-subtitle { font-size: 1.6rem; }

    /* 平板下关于引力板块改为上下布局 */
    .about-container {
        flex-direction: column;
        padding: 30px;
        gap: 25px;
    }
    .about-logo {
        width: 150px;
        height: 150px;
    }
    .about-logo img {
        width: 110px;
    }
    .about-text h3 {
        font-size: 1.2rem;
        margin-bottom: 15px;
    }
    .about-text p {
        font-size: 1.1rem;
        text-align: center;
    }

    /* 平板下新闻卡片改为两行两列 */
    .news-grid {
        display: grid;
        grid-template-columns: repeat(2, 1fr);
        gap: 20px;
        max-width: 700px;
    }
    .news-card {
        padding: 30px 22px;
        min-height: 340px;
    }
    .news-card h4 {
        font-size: 1.05rem;
    }
    .news-card p {
        font-size: 0.88rem;
        -webkit-line-clamp: 7;
    }

    .split-layout {
        grid-template-columns: 1fr 1fr;
        gap: 15px;
    }
    .course-brief-layout { flex-direction: column; }
    .course-detail-layout { grid-template-columns: 1fr 1fr; gap: 20px; padding: 20px; }
    .course-detail-image { min-height: 200px; }
    .course-content-left { text-align: center; }
    .course-detail-title { text-align: center; }
    .course-detail-desc { text-align: center; }
    .course-list-right { justify-content: center; }
    .nine-domain-grid { grid-template-columns: repeat(2, 1fr); }
    .footer-container { 
        grid-template-columns: 1fr 1fr; 
        gap: 30px;
    }
    .mini-swiper { aspect-ratio: 16/9; height: auto; min-height: 200px; }
    .video-wrapper { flex-direction: column; }
    .video-box { aspect-ratio: 16/9; height: auto; min-height: 200px; }
    .video-buttons { flex-direction: row; flex-wrap: wrap; gap: 15px; padding: 10px 0; }
    .video-btn { flex: 1 1 40%; padding: 14px; font-size: 1rem; }
    .full-width-block { padding: 0 15px; }
    /* 平板下学段图片容器适配 */
    .course-level-image-container { border-radius: 16px; }
}

@media (max-width: 480px) {
    /* 手机端body顶部留白调整 */
    body { padding-top: 60px; }
    
    .main-swiper-container { height: 280px; }
    .nine-domain-grid { grid-template-columns: 1fr; }
    .video-box { height: 200px; font-size: 1rem; }
    .brand-name { font-size: 1rem; }
    
    /* 手机端导航栏简化：隐藏导航项 */
    .navbar { 
        height: 60px !important; 
        min-height: 60px !important;
        padding: 0 4%;
    }
    .navbar-middle { 
        display: none;
    }
    .logo { height: 36px; }
    .login-btn {
        padding: 6px 16px;
        font-size: 0.85rem;
    }
    
    /* 手机下拉菜单调整 */
    .logo-dropdown {
        min-width: 140px;
        margin-top: -1px;
        border-radius: 0 0 8px 8px;
    }
    .dropdown-item {
        padding: 10px 16px;
        font-size: 0.9rem;
    }
    
    /* 手机下关于引力板块适配 */
    .about-container {
        flex-direction: column;
        padding: 25px 20px;
        gap: 20px;
    }
    .about-logo {
        width: 120px;
        height: 120px;
    }
    .about-logo img {
        width: 90px;
    }
    .about-text h3 {
        font-size: 1.1rem;
        margin-bottom: 12px;
    }
    .about-text p {
        font-size: 1rem;
        text-align: center;
        line-height: 1.6;
    }
    
    /* 手机下新闻卡片改为单列 */
    .news-grid {
        display: grid;
        grid-template-columns: 1fr;
        gap: 15px;
        max-width: 350px;
    }
    .news-card {
        padding: 18px;
        min-height: 200px;
    }
    .news-card h4 {
        font-size: 0.95rem;
    }
    .news-card p {
        font-size: 0.8rem;
        -webkit-line-clamp: 3;
    }
    
    /* 手机下视频区域调整 */
    .video-container { padding: 12px !important; }
    .video-box { aspect-ratio: 16/9; height: auto; min-height: 180px; }
    .video-btn { padding: 10px; font-size: 0.95rem; }
    .course-brief-layout { padding: 12px; gap: 12px; }
    .course-brief-item { padding: 12px; }
    .course-brief-item h3 { font-size: 1.1rem; }
    .course-brief-item p { font-size: 0.85rem; }
    /* 手机下学段图片容器适配 */
    .course-level-image-container { border-radius: 12px; }
    
    /* 手机下左右分栏改为单列 */
    .split-layout { grid-template-columns: 1fr; gap: 20px; padding: 15px; }
    .mini-swiper { min-height: 180px; }
    
    /* 手机下课程详情布局 */
    .course-detail-layout { grid-template-columns: 1fr; gap: 15px; padding: 15px; }
    .course-list-right { gap: 8px; align-items: stretch; justify-content: flex-start; }
    .domain-item { padding: 12px 14px; font-size: 0.9rem; max-width: 100%; }
    .course-detail-image { min-height: 180px; }
    
    /* 手机下轮播图调整 */
    #banner {
        padding: 10px 2%;
    }
    
    #banner .main-swiper-container {
        border-radius: 16px;
    }
}