/* 全局样式重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: "Inter", "Microsoft YaHei", sans-serif;
}

body {
    color: #333;
    background-color: #f5f5f5;
    line-height: 1.8;
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.img-fluid {
    max-width: 100%;
    height: auto;
}

/* 导航栏样式 */
.navbar {
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(8px);
    box-shadow: 0 2px 15px rgba(0, 0, 0, 0.05);
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 999;
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 80px;
}

.logo {
    display: flex;
    align-items: center;
    text-decoration: none;
}

.logo img {
    width: 45px;
    height: 45px;
    margin-right: 12px;
}

.logo span {
    font-size: 26px;
    font-weight: 700;
    color: #2c3e50;
}

.mobile-btn {
    display: none;
    background: none;
    border: none;
    font-size: 24px;
    color: #2c3e50;
    cursor: pointer;
}

/* 核心内容区（背景为“背景.png”） */
.core-section {
    margin-top: 80px;
    padding: 100px 0;
    /* 核心：设置背景图，适配显示 */
    background-image: url(../img/背景.png); /* 路径对应img目录下的“背景.png” */
    background-size: cover; /* 背景图覆盖整个区域 */
    background-position: center; /* 背景图居中 */
    background-repeat: no-repeat; /* 禁止背景图重复 */
    background-attachment: fixed; /* 滚动时背景固定（可选，按需求调整） */
    position: relative;
}

/* 背景图遮罩（提升文字可读性，若背景图过亮/过暗可调整透明度） */
.core-section::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(255, 255, 255, 0.85); /* 白色遮罩，透明度0.85 */
    z-index: 1;
}

.core-section .container {
    position: relative;
    z-index: 2; /* 确保内容在遮罩之上 */
}

/* 内容卡片样式（区分内容区块，增强层次感） */
.section-card {
    background-color: rgba(255, 255, 255, 0.9);
    border-radius: 12px;
    padding: 40px 30px;
    margin-bottom: 30px;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.08);
    transition: transform 0.3s ease;
}

.section-card:hover {
    transform: translateY(-5px);
}

.section-card h1 {
    font-size: 42px;
    color: #2c3e50;
    margin-bottom: 20px;
    line-height: 1.3;
}

.section-card h2 {
    font-size: 28px;
    color: #34495e;
    margin-bottom: 18px;
    display: flex;
    align-items: center;
    gap: 12px;
}

.section-card h2 i {
    color: #3498db; /* 图标颜色，可按需调整 */
}

.section-card p {
    font-size: 18px;
    color: #555;
    margin-bottom: 16px;
}

.section-card .intro {
    font-size: 19px;
    color: #444;
}

/* 愿景与使命并列布局 */
.vision-mission {
    display: flex;
    gap: 30px;
    flex-wrap: wrap;
}

.vision-mission .section-card {
    flex: 1;
    min-width: 300px;
}

/* 页脚样式 */
.footer {
    background-color: #2c3e50;
    color: #fff;
    padding: 40px 0;
    margin-top: 0; /* 与核心区无缝衔接 */
}

.footer-bottom {
    text-align: center;
    font-size: 16px;
    opacity: 0.9;
}

/* 响应式适配（手机/平板） */
@media (max-width: 768px) {
    .logo span {
        font-size: 22px;
    }

    .mobile-btn {
        display: block;
    }

    .core-section {
        padding: 80px 0;
        background-attachment: scroll; /* 手机端取消背景固定，避免兼容性问题 */
    }

    .section-card h1 {
        font-size: 32px;
    }

    .section-card h2 {
        font-size: 24px;
    }

    .section-card p,
    .section-card .intro {
        font-size: 16px;
    }

    .vision-mission {
        flex-direction: column;
    }
}