/* 字体由 common.css 统一引入，此处不再重复引入 */

:root {
    --primary-color: #165DFF;
    --secondary-color: #FFD700;
    --dark-color: #333;
    --light-color: #f8fafc;
    --dark-bg: #000000;
    --shadow-color: rgba(109, 104, 104, 0.1);
    --accent-color: #ff5722;
    --transition: all 0.3s ease;
}

/* 基础样式 */
body {
    line-height: 1.6;
    margin: 0;
    padding: 0;
    overflow-x: hidden;
    background-color: var(--light-color);
    color: var(--dark-color);
    animation: fadeIn 1s ease-in-out;
}

@keyframes fadeIn {
    from {
        opacity: 0;
    }

    to {
        opacity: 1;
    }
}

/* 通用容器 */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 15px;
}


/* 动画定义 */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* 页脚 */
footer {
    background-color: #2c3e50;
    color: white;
    box-shadow: 0 -4px 12px rgba(0, 0, 0, 0.2);
    animation: fadeInUp 1s ease;
}

.footer-container {
    display: flex;
    justify-content: space-around;
    flex-wrap: wrap;
    max-width: 1300px;
    margin: 0 auto;
    padding: 60px 20px;
}

.footer-about,
.footer-links,
.footer-contact {
    flex: 1;
    min-width: 280px;
    margin: 0 30px;
}

.footer-about h4,
.footer-links h4,
.footer-contact h4 {
    font-size: 1.6em;
    margin-bottom: 25px;
    letter-spacing: 2px;
    border-bottom: 2px solid var(--primary-color);
    padding-bottom: 10px;
}

.footer-links ul {
    list-style-type: none;
    padding: 0;
}

.footer-links ul li {
    margin-bottom: 15px;
}

.footer-links ul li a {
    color: white;
    text-decoration: none;
    transition: var(--transition);
    font-size: 1.1em;
}

.footer-links ul li a:hover {
    color: var(--primary-color);
}

.footer-contact ul.social-icons {
    list-style-type: none;
    padding: 0;
    display: flex;
}

.footer-contact ul.social-icons li {
    margin-right: 15px;
}

.footer-contact ul.social-icons li a img {
    width: 35px;
    height: 35px;
    filter: grayscale(100%);
    transition: var(--transition);
}

.footer-contact ul.social-icons li a img:hover {
    filter: grayscale(0%);
    transform: scale(1.1);
}

/* 底部版权样式 */
.footer-bottom {
    text-align: center;
    padding: 20px 0;
    border-top: 1px solid #333;
    font-size: 0.9em;
}

/* 备案号样式（与Copyright完全一致） */
.footer-record {
    margin-top: 8px;
    font-size: inherit;
    color: inherit;
    text-align: inherit;
}

/* 备案号链接样式（优化交互） */
.footer-record a {
    color: inherit;
    /* 继承白色，和普通文字无区别 */
    text-decoration: none;
    /* 去掉默认下划线 */
    transition: var(--transition);
    /* 平滑过渡效果 */
}

/* 鼠标悬浮时的链接样式 */
.footer-record a:hover {
    color: var(--primary-color);
    /* 变主色，和其他链接风格统一 */
    text-decoration: underline;
    /* 加下划线，提示可点击 */
}

/* 返回顶端按钮 */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background-color: #2196F3;
    color: white;
    border: none;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    z-index: 999;
    opacity: 0.8;
}

.back-to-top:hover {
    background-color: #0b7dda;
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.3);
    opacity: 1;
}

@media (max-width: 768px) {
    .back-to-top {
        width: 45px;
        height: 45px;
        font-size: 18px;
        bottom: 20px;
        right: 20px;
    }
}