/* --- 基本重置和全局设置 --- */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', 'Noto Sans SC', sans-serif;
    background: linear-gradient(135deg, #f5f7fa 0%, #e9ecef 100%); /* 全局渐变背景 */
    color: #343a40;
    line-height: 1.75;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.container {
    width: 90%;
    max-width: 1140px;
    margin: 0 auto;
    padding: 80px 15px;
}

/* --- 通用区块标题 --- */
.section-title {
    text-align: center;
    font-size: 2.4rem;
    font-weight: 700;
    color: #212529;
    margin-bottom: 60px;
    position: relative;
    padding-bottom: 15px;
}

.section-title::after {
    content: '';
    position: absolute;
    display: block;
    width: 60px;
    height: 3px;
    background: #0d6efd;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    border-radius: 2px;
}

/* --- 交替背景色 --- */
.section-bg-alt {
    background-color: #f8f9fa; /* 非常浅的灰色 */
}


/* --- 链接和按钮 (微调) --- */
a {
    color: #0d6efd; /* Bootstrap 5 蓝色 */
    text-decoration: none;
    transition: color 0.3s ease;
}

a:hover {
    color: #0a58ca;
}

.cta-button {
    display: inline-block;
    padding: 14px 35px; /* 稍微增大按钮 */
    border-radius: 50px; /* 全圆角 */
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    text-align: center;
    transition: all 0.3s ease; /* 统一过渡效果 */
    margin: 10px 5px;
    border: 1px solid transparent;
    letter-spacing: 0.5px; /* 增加字间距 */
}

.cta-button.primary {
    background-color: #0d6efd;
    color: #ffffff;
    border-color: #0d6efd;
}

.cta-button.primary:hover {
    background-color: #0a58ca;
    border-color: #0a58ca;
    transform: translateY(-3px);
    box-shadow: 0 6px 18px rgba(13, 110, 253, 0.3);
}

.cta-button.secondary {
    background-color: transparent;
    border: 1px solid #adb5bd;
    color: #495057;
}

.cta-button.secondary:hover {
    background-color: #f8f9fa;
    color: #212529;
    border-color: #6c757d;
    transform: translateY(-3px);
    box-shadow: 0 6px 18px rgba(108, 117, 125, 0.15);
}

/* --- 按钮脉冲动画 --- */
.pulse {
    animation: pulse-animation 2s infinite;
}

@keyframes pulse-animation {
    0% { box-shadow: 0 0 0 0 rgba(13, 110, 253, 0.4); }
    70% { box-shadow: 0 0 0 10px rgba(13, 110, 253, 0); }
    100% { box-shadow: 0 0 0 0 rgba(13, 110, 253, 0); }
}


/* --- 1. 首屏 Hero Section (使用 CSS 背景纹理) --- */
.hero-section {
    position: relative;
    min-height: 90vh;
    display: flex;
    align-items: center;
    text-align: center;
    padding: 100px 0;
    overflow: hidden;
    /* 优化背景：柔和蓝色渐变 + 微妙纹理 */
    background: linear-gradient(120deg, #e6f0ff 0%, #f0f6ff 100%);
    background-image: repeating-linear-gradient(
            45deg,
            transparent,
            transparent 20px,
            rgba(13, 110, 253, 0.06) 20px,
            rgba(13, 110, 253, 0.06) 22px
    );
}

/* 背景图层 (不再使用图片) */
/* .hero-background-image { ... } */

/* 蒙版层 (可以调整透明度或移除，取决于背景效果) */
.hero-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(255, 255, 255, 0.7); /* 略透明蒙版 */
    z-index: 1;
}

.hero-content {
    position: relative;
    z-index: 2;
    max-width: 800px;
    margin: 0 auto;
}

.hero-section h1 {
    font-size: clamp(3rem, 7vw, 4.5rem);
    color: #212529;
    margin-bottom: 0.5em;
    font-weight: 700;
    line-height: 1.2;
}

.hero-section h2 {
    font-size: clamp(1.2rem, 3vw, 1.7rem);
    color: #495057;
    margin-bottom: 1.2em;
    font-weight: 400;
}

.hero-section .intro-text {
    font-size: 1.15rem;
    color: #6c757d;
    margin-bottom: 1.8em;
}

.hero-section .mission {
    font-size: 1.4em;
    color: #0d6efd; /* 主蓝色 */
    margin-bottom: 3em;
    font-weight: 700; /* 加粗 */
}

/* --- 2. 核心功能 / 平台工具 (卡片优化) --- */
.features-showcase {
    background: #f8f9fa; /* 浅灰色背景 */
    position: relative;
    /* 添加微妙装饰线条 */
    background-image: linear-gradient(
            to right,
            rgba(13, 110, 253, 0.1) 1px,
            transparent 1px
    );
    background-size: 40px 100%;
}

.features-showcase .section-title {
    /* 通用样式 */
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(270px, 1fr));
    gap: 35px;
}

.feature-card {
    background-color: #ffffff;
    border: 1px solid #e9ecef;
    padding: 40px 30px;
    border-radius: 10px;
    display: flex;
    flex-direction: column;
    min-height: 240px;
    transition: all 0.35s cubic-bezier(0.25, 0.8, 0.25, 1);
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.06);
}

.feature-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.1);
    border-color: #0d6efd;
}

.feature-card h3 {
    color: #343a40;
    font-size: 1.4rem;
    margin-bottom: 18px;
    font-weight: 700;
}

.feature-card p {
    font-size: 1rem;
    color: #6c757d;
    margin-bottom: 25px;
    flex-grow: 1;
}

.feature-card .learn-more {
    font-size: 0.95rem;
    font-weight: 700;
    color: #0d6efd;
    margin-top: auto;
    align-self: flex-start;
}
.feature-card .learn-more:hover {
    color: #0a58ca;
    text-decoration: none;
}
.feature-card .learn-more::after {
    content: ' \2192'; /* 右箭头 */
    display: inline-block;
    transition: transform 0.3s ease;
    margin-left: 4px;
}
.feature-card:hover .learn-more::after {
    transform: translateX(5px);
}


/* --- 3. 使命与社区理念 (微调) --- */
.mission-philosophy {
    background: linear-gradient(to bottom, #ffffff 0%, #f5f7fa 100%);
    text-align: center; /* 确保文本居中 */
}

.mission-philosophy .container {
    display: flex;
    flex-direction: column;
    align-items: center; /* 确保容器内容居中 */
}

.mission-philosophy .mission-statement {
    font-size: clamp(1.6rem, 4.5vw, 2.2rem);
    color: #198754; /* 使用柔和的绿色作为次要强调色 */
    font-style: normal;
    font-weight: 700;
    margin-bottom: 1.5em;
    line-height: 1.4;
}
.mission-philosophy .philosophy-text {
    font-size: 1.2rem;
    max-width: 850px;
    margin: 0 auto;
    color: #495057;
    line-height: 1.9;
}

/* --- 4. 加入我们 / 行动号召 --- */
.final-cta {
    background: linear-gradient(135deg, #e6f0ff 0%, #f0f6ff 100%);
    text-align: center;
}
.final-cta .section-title {
    /* 通用样式 */
}

.final-cta p {
    margin-bottom: 35px;
    color: #495057;
    font-size: 1.15rem;
    max-width: 650px;
    margin-left: auto;
    margin-right: auto;
}
.cta-buttons {
    display: flex;
    justify-content: center; /* 水平居中 */
    align-items: center; /* 垂直居中 */
    gap: 20px; /* 按钮之间的间距 */
    flex-wrap: wrap; /* 响应式时允许换行 */
}

/* --- 5. 页脚 --- */
.footer {
    background: linear-gradient(to top, #dee2e6 0%, #e9ecef 100%); /* 灰色渐变 */
    color: #6c757d;
    text-align: center;
    padding: 40px 0;
    font-size: 0.9em;
    border-top: 1px solid #dee2e6;
}

.footer nav {
    margin-top: 15px;
}

.footer nav a {
    color: #6c757d;
    margin: 0 15px;
    transition: color 0.3s ease;
}
.footer nav a:hover {
    color: #0d6efd;
}

/* --- 响应式调整 --- */
@media (max-width: 992px) {
    .container {
        max-width: 960px;
    }
    .section-title {
        font-size: 2.2rem;
    }
}

@media (max-width: 768px) {
    .container {
        padding: 60px 15px;
    }
    .hero-section h1 {
        font-size: 2.8rem;
    }
    .hero-section h2 {
        font-size: 1.4rem;
    }
    .section-title {
        font-size: 2rem;
        margin-bottom: 40px;
    }
    .features-grid {
        grid-template-columns: 1fr;
        gap: 30px;
    }
    .feature-card {
        padding: 30px 25px;
        min-height: auto;
    }
    .final-cta h2 { /* 修正选择器 */
        font-size: 2rem;
    }
    .mission-philosophy .philosophy-text {
        font-size: 1.1rem;
    }
}

@media (max-width: 576px) {
    .hero-section h1 {
        font-size: 2.4rem;
    }
    .hero-section h2 {
        font-size: 1.2rem;
    }
    .cta-button {
        display: inline-block;
        padding: 14px 35px;
        border-radius: 50px;
        font-size: 1rem;
        font-weight: 500;
        cursor: pointer;
        text-align: center;
        transition: all 0.3s ease;
        margin: 10px 5px;
        border: 1px solid transparent;
        letter-spacing: 0.5px;
    }
    .section-title {
        font-size: 1.8rem;
    }
    .mission-philosophy .mission-statement {
        font-size: 1.5rem;
    }
    .mission-philosophy .philosophy-text {
        font-size: 1rem;
    }
    .footer nav a {
        margin: 0 10px;
    }
}

.about-us {
    background: #ffffff; /* 纯白背景 */
    position: relative;
    /* 添加微妙绿色渐变装饰 */
    background-image: linear-gradient(
            to bottom,
            rgba(25, 135, 84, 0.05),
            transparent 50%
    );
}

.about-content {
    max-width: 900px;
    margin: 0 auto;
}

.about-details {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
    margin-top: 40px;
}

.detail-item h3 {
    font-size: 1.3rem;
    color: #343a40;
    margin-bottom: 15px;
    font-weight: 700;
}

.detail-item p {
    font-size: 1rem;
    color: #6c757d;
}

/* --- 联系方式 --- */
.contact-us {
    background: #f8f9fa;
    background-image: repeating-linear-gradient(
            0deg,
            transparent,
            transparent 15px,
            rgba(108, 117, 125, 0.05) 15px,
            rgba(108, 117, 125, 0.05) 16px
    );
    text-align: center; /* 确保文本居中 */
}

.contact-us .container {
    display: flex;
    flex-direction: column;
    align-items: center; /* 确保容器内容居中 */
}

.contact-content {
    max-width: 900px;
    margin: 0 auto;
    width: 100%; /* 确保内容占满容器 */
}

.contact-methods {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 30px;
    margin-top: 40px;
    justify-items: center; /* 确保网格项居中 */
    width: 100%; /* 确保网格占满容器 */
}

.contact-item h3 {
    font-size: 1.3rem;
    color: #343a40;
    margin-bottom: 15px;
    font-weight: 700;
}

.contact-item p {
    font-size: 1rem;
    color: #6c757d;
}

.qr-placeholder {
    width: 120px;
    height: 120px;
    background-color: #e9ecef;
    margin: 15px auto;
    line-height: 120px;
    color: #6c757d;
    font-size: 0.9rem;
}

/* --- 响应式调整 --- */
@media (max-width: 768px) {
    .about-details, .contact-methods {
        grid-template-columns: 1fr;
        gap: 25px;
    }

    .detail-item h3, .contact-item h3 {
        font-size: 1.2rem;
    }

    .qr-placeholder {
        width: 100px;
        height: 100px;
        line-height: 100px;
    }
}

@media (max-width: 576px) {
    .about-content, .contact-content {
        padding: 0 10px;
    }

    .detail-item p, .contact-item p {
        font-size: 0.95rem;
    }
}

@media (max-width: 576px) {
    .cta-buttons {
        flex-direction: column; /* 小屏幕时垂直排列 */
        gap: 15px;
    }

    .cta-button {
        padding: 12px 25px;
        font-size: 0.9rem;
        width: 100%; /* 小屏幕时按钮占满一行 */
        max-width: 250px; /* 限制最大宽度 */
    }
}