/* 全局重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: "Quicksand", "Noto Sans SC", "Microsoft Yahei", sans-serif;
}

:root {
    --primary-color: #0066cc;
    --secondary-color: #0099ff;
    --accent-color: #00ccff;
    --text-color: #333333;
    --light-text: #666666;
    --bg-color: #f8f9fa;
    --card-bg: #ffffff;
    --border-color: #e0e0e0;
    --shadow: 0 4px 20px rgba(0, 102, 204, 0.08);
    --hover-shadow: 0 8px 30px rgba(0, 102, 204, 0.15);
    --transition: all 0.3s ease;
}

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    overflow-x: hidden;
}

.container {
    width: 90%;
    max-width: 1200px;
    margin: 0 auto;
}

.section {
    padding: 100px 0;
    scroll-margin-top: 80px;
    position: relative;
}

.section::before {
    content: "";
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-color), var(--accent-color));
    border-radius: 2px;
}

.section-title {
    text-align: center;
    margin-bottom: 60px;
}

.section-title h2 {
    font-size: 2.2rem;
    color: var(--text-color);
    margin-bottom: 15px;
    letter-spacing: 1px;
    font-weight: 700;
}

.section-title h2 span {
    color: var(--primary-color);
    margin: 0 10px;
}

.section-title .subtitle {
    color: var(--light-text);
    font-size: 1rem;
}

.btn {
    display: inline-block;
    padding: 12px 30px;
    border: none;
    border-radius: 6px;
    font-size: 1rem;
    font-weight: 600;
    text-decoration: none;
    cursor: pointer;
    transition: var(--transition);
    text-align: center;
    position: relative;
    overflow: hidden;
    letter-spacing: 0.5px;
}

.primary-btn {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: #ffffff;
    box-shadow: var(--shadow);
}

.secondary-btn {
    background: transparent;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
}

.btn:hover {
    transform: translateY(-3px);
    box-shadow: var(--hover-shadow);
}

.primary-btn:hover {
    background: linear-gradient(135deg, var(--secondary-color), var(--primary-color));
}

.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background: var(--card-bg);
    box-shadow: 0 2px 15px rgba(0, 0, 0, 0.05);
    z-index: 999;
    padding: 15px 0;
    border-bottom: 1px solid var(--border-color);
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
}

.logo img {
    width: 60px;
    height: 60px;
    object-fit: contain;
}

.logo .slogan-sm {
    font-size: 1.1rem;
    color: var(--primary-color);
    font-weight: 700;
    letter-spacing: 2px;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 35px;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 600;
    transition: var(--transition);
    position: relative;
    letter-spacing: 0.5px;
}

.nav-links a::after {
    content: "";
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-color);
    transition: var(--transition);
}

.nav-links a:hover::after, .nav-links a.active::after {
    width: 100%;
}

.nav-links a:hover, .nav-links a.active {
    color: var(--primary-color);
}

.hamburger {
    display: none;
    font-size: 1.6rem;
    color: var(--primary-color);
    cursor: pointer;
}

.mobile-nav {
    position: fixed;
    top: 80px;
    left: -100%;
    width: 100%;
    height: calc(100vh - 80px);
    background: var(--card-bg);
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 40px;
    transition: var(--transition);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

.mobile-nav.active {
    left: 0;
}

.banner {
    height: 100vh;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    background: linear-gradient(135deg, #e6f0fa 0%, #f0f6fc 100%);
}

#particles-js {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 0;
}

.banner-content {
    text-align: center;
    z-index: 1;
    padding: 0 20px;
}

.banner-text h1 {
    font-size: 3.5rem;
    margin-bottom: 20px;
    color: var(--text-color);
    letter-spacing: 2px;
    font-weight: 800;
}

.banner-slogan {
    font-size: 1.2rem;
    margin-bottom: 40px;
    color: var(--light-text);
    letter-spacing: 1px;
}

.banner-buttons {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin-bottom: 60px;
}

.cooperate-units {
    background: var(--card-bg);
    padding: 25px;
    border-radius: 12px;
    box-shadow: var(--shadow);
    max-width: 800px;
    margin: 0 auto;
    border: 1px solid var(--border-color);
}

.cooperate-units h3 {
    margin-bottom: 15px;
    font-size: 1.2rem;
    color: var(--primary-color);
}

.units-list {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 25px;
}

.unit-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    transition: var(--transition);
}

.unit-item:hover {
    transform: translateY(-5px);
}

.logo-placeholder {
    width: 90px;
    height: 90px;
    background: var(--bg-color);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--primary-color);
    font-size: 0.85rem;
    text-align: center;
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.logo-placeholder:hover {
    box-shadow: var(--hover-shadow);
    border-color: var(--primary-color);
}

.unit-item span {
    color: var(--text-color);
    font-size: 0.9rem;
}

.training {
    background: var(--bg-color);
}

.training-content {
    max-width: 1100px;
    margin: 0 auto;
}

.training-stage {
    display: flex;
    align-items: flex-start;
    gap: 25px;
    background: var(--card-bg);
    padding: 35px;
    border-radius: 12px;
    margin-bottom: 30px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.training-stage:hover {
    transform: translateY(-5px);
    box-shadow: var(--hover-shadow);
}

.stage-icon {
    width: 70px;
    height: 70px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #ffffff;
    font-size: 1.8rem;
    flex-shrink: 0;
}

.stage-info h3 {
    color: var(--primary-color);
    margin-bottom: 15px;
    font-size: 1.4rem;
    font-weight: 700;
}

.stage-info ul {
    list-style: none;
    gap: 12px;
    display: flex;
    flex-direction: column;
}

.stage-info li {
    color: var(--text-color);
    line-height: 1.7;
    font-size: 1rem;
    position: relative;
    padding-left: 20px;
}

.stage-info li::before {
    content: "";
    position: absolute;
    left: 0;
    top: 8px;
    width: 6px;
    height: 6px;
    background: var(--primary-color);
    border-radius: 50%;
}

.training-benefits {
    background: linear-gradient(135deg, rgba(0, 102, 204, 0.05), rgba(0, 153, 255, 0.05));
    color: var(--text-color);
    padding: 25px;
    border-radius: 12px;
    margin-bottom: 40px;
    border-left: 4px solid var(--primary-color);
}

.training-benefits h3 {
    margin-bottom: 10px;
    font-size: 1.2rem;
    color: var(--primary-color);
}

.trainers {
    margin-bottom: 40px;
}

.trainers h3 {
    text-align: center;
    margin-bottom: 30px;
    color: var(--text-color);
    font-size: 1.3rem;
}

.trainers-list {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 35px;
}

.trainer-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 12px;
    width: 180px;
    transition: var(--transition);
}

.trainer-item:hover {
    transform: translateY(-8px);
}

.avatar-placeholder {
    width: 110px;
    height: 110px;
    background: var(--bg-color);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--primary-color);
    font-weight: 700;
    font-size: 1.1rem;
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

/* 适配img标签的讲师头像样式 */
img.avatar-placeholder {
    display: block;
    object-fit: cover;
    object-position: center;
}

.avatar-placeholder:hover {
    box-shadow: var(--hover-shadow);
    border-color: var(--primary-color);
}

.trainer-item p {
    text-align: center;
    font-size: 0.95rem;
    color: var(--light-text);
    line-height: 1.5;
}

.training-btn {
    display: block;
    width: 200px;
    margin: 0 auto;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: #ffffff;
}

/* 研学板块核心样式：恢复PC端2行3列 + 手机端适配 */
.study {
    background: #ffffff;
}

/* PC端：2行3列布局（核心） */
.study-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
    margin-bottom: 50px;
    max-width: 100%;
    margin-left: auto;
    margin-right: auto;
}

.study-item {
    background: var(--bg-color);
    padding: 25px;
    border-radius: 12px;
    transition: var(--transition);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow);
}

.study-item:hover {
    transform: translateY(-8px);
    box-shadow: var(--hover-shadow);
}

.item-img {
    margin-bottom: 15px;
    border-radius: 8px;
    overflow: hidden;
    width: 100%;
    height: 200px; /* 适配3列的图片高度 */
    max-width: 100%;
}

.img-placeholder {
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: center;
    display: block;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

/* 兼容div占位符的样式 */
div.img-placeholder {
    background: var(--card-bg);
    color: var(--primary-color);
    font-size: 0.95rem;
    display: flex;
    align-items: center;
    justify-content: center;
}

.study-item h3 {
    color: var(--primary-color);
    margin-bottom: 15px;
    font-size: 1.2rem;
    font-weight: 700;
}

.study-item ul {
    list-style: disc inside;
    color: var(--text-color);
    line-height: 1.7;
    font-size: 0.95rem;
}

.study-btn {
    display: block;
    width: 200px;
    margin: 0 auto;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: #ffffff;
}

.community {
    background: var(--bg-color);
}

.community-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    margin-bottom: 50px;
}

.community-item {
    background: var(--card-bg);
    padding: 30px;
    border-radius: 12px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.community-item:hover {
    transform: translateY(-5px);
    box-shadow: var(--hover-shadow);
}

.community-item h3 {
    color: var(--primary-color);
    margin-bottom: 15px;
    font-size: 1.2rem;
    font-weight: 700;
}

.community-item p {
    color: var(--text-color);
    line-height: 1.7;
    font-size: 0.95rem;
}

.community-item ul {
    list-style: disc inside;
    color: var(--text-color);
    line-height: 1.7;
    font-size: 0.95rem;
}

.community-btn {
    display: block;
    width: 200px;
    margin: 0 auto;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: #ffffff;
}

.courses {
    background: #ffffff;
    text-align: center;
}

.courses-content {
    max-width: 800px;
    margin: 0 auto;
    background: var(--bg-color);
    padding: 40px;
    border-radius: 12px;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow);
}

.courses-desc {
    font-size: 1.2rem;
    color: var(--primary-color);
    font-weight: 700;
    margin-bottom: 20px;
}

.courses-content p {
    color: var(--text-color);
    line-height: 1.8;
    margin-bottom: 40px;
    font-size: 1rem;
}

.courses-btn {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: #ffffff;
}

.cooperation {
    background: var(--bg-color);
    padding: 80px 0;
}

.cooperation-title, .links-title {
    text-align: center;
    margin-bottom: 30px;
    color: var(--text-color);
    font-size: 1.5rem;
    font-weight: 700;
}

.cooperation-units {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 40px;
    margin-bottom: 60px;
}

.coop-unit {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
    transition: var(--transition);
}

.coop-unit:hover {
    transform: scale(1.05);
}

.friend-links {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    list-style: none;
    gap: 20px;
}

.friend-links a {
    text-decoration: none;
    color: var(--light-text);
    transition: var(--transition);
    padding: 8px 15px;
    border-radius: 6px;
    border: 1px solid transparent;
}

.friend-links a:hover {
    color: var(--primary-color);
    background: rgba(0, 102, 204, 0.05);
    border-color: var(--primary-color);
    transform: translateY(-2px);
}

.footer {
    background: var(--card-bg);
    color: var(--light-text);
    padding: 70px 0 20px;
    border-top: 1px solid var(--border-color);
}

.footer-top {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
    margin-bottom: 50px;
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 15px;
}

.footer-logo img {
    width: 80px;
    height: 80px;
}

.footer-logo-text {
    font-size: 1.3rem;
    color: var(--primary-color);
    font-weight: 700;
    letter-spacing: 3px;
}

.contact-info h3, .footer-nav h3 {
    color: var(--text-color);
    margin-bottom: 20px;
    font-size: 1.2rem;
    font-weight: 700;
}

.contact-info ul {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.contact-info li {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 1rem;
}

.contact-info li i {
    color: var(--primary-color);
    font-size: 1.1rem;
}

.qrcode {
    width: 120px;
    height: 120px;
    object-fit: contain;
    border: 1px solid var(--border-color);
    border-radius: 8px;
}

.footer-nav ul {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.footer-nav a {
    text-decoration: none;
    color: var(--light-text);
    transition: var(--transition);
    font-size: 1rem;
}

.footer-nav a:hover {
    color: var(--primary-color);
    transform: translateX(5px);
}

.footer-bottom {
    text-align: center;
    padding-top: 20px;
    border-top: 1px solid var(--border-color);
    font-size: 0.9rem;
}

/* 响应式适配：768px以下（平板/手机） */
@media (max-width: 768px) {
    .desktop-nav {
        display: none;
    }

    .hamburger {
        display: block;
    }
    .navbar {
    padding: 8px 0 !important; /* 手机端导航更矮 */
    }
    /* 修复banner文字溢出核心样式 */
    .banner-text h1 {
        font-size: 1.8rem !important;
        word-wrap: break-word;
        line-height: 1.2;
        margin-bottom: 10px;
        padding: 0 15px;
        white-space: normal;
    }

    .banner-slogan {
        font-size: 0.9rem !important;
        word-wrap: break-word;
        line-height: 1.3;
        padding: 0 15px;
        margin-bottom: 25px;
        white-space: normal;
    }

    .section-title h2 {
        font-size: 1.8rem;
    }

    .training-stage {
        flex-direction: column;
        align-items: center;
        text-align: center;
    }

    /* 合作单位2行2列布局 */
    .units-list {
        display: grid;
        grid-template-columns: repeat(2, 1fr);
        gap: 10px;
        max-width: 320px;
        margin: 0 auto;
    }

    .courses-content {
        padding: 30px;
    }

    /* 研学图片手机端适配 */
    .item-img {
        width: 100%;
        height: auto;
        aspect-ratio: 640/400;
    }

    /* 合作单位item适配 */
    .unit-item {
        gap: 4px;
    }

    .unit-item span {
        font-size: 0.75rem;
    }

    .logo-placeholder {
        width: 65px;
        height: 65px;
        font-size: 0.65rem;
    }

    /* banner高度自适应，避免内容遮挡 */
    .banner {
        height: auto !important;
        padding: 120px 0 60px;
    }

    .banner-content {
        padding: 0 10px;
    }
}

/* 超小屏适配（480px以下，如iPhone SE） */
@media (max-width: 480px) {
    .banner-text h1 {
        font-size: 1.5rem !important;
    }

    .banner-slogan {
        font-size: 0.85rem !important;
    }

    .banner-buttons {
        flex-direction: column;
        align-items: center;
        gap: 15px;
    }

    .btn {
        width: 100%;
        max-width: 250px;
    }

    .logo .slogan-sm {
        font-size: 1rem;
        letter-spacing: 1px;
    }

    .footer-logo-text {
        font-size: 1.1rem;
    }

    /* 合作单位进一步适配 */
    .units-list {
        max-width: 280px;
    }

    .logo-placeholder {
        width: 60px;
        height: 60px;
    }
}