/* ===== 全局重置与基础 ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans SC", sans-serif;
    line-height: 1.6;
    color: #222;
    background: #f8f9fa;
    transition: background 0.3s, color 0.3s;
}
a {
    color: #1a5c8a;
    text-decoration: none;
}
a:hover {
    text-decoration: underline;
}
img, svg {
    max-width: 100%;
    height: auto;
    display: block;
}
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}
/* ===== 暗黑模式 ===== */
body.dark {
    background: #1a1a2e;
    color: #e0e0e0;
}
body.dark a {
    color: #8ab4f8;
}
body.dark header,
body.dark footer,
body.dark .card,
body.dark .article-item,
body.dark .faq-item,
body.dark .howto-step {
    background: #16213e;
    color: #e0e0e0;
}
body.dark .nav-menu {
    background: #0f3460;
}
/* ===== 导航吸顶 ===== */
header {
    background: #ffffff;
    border-bottom: 2px solid #e9ecef;
    position: sticky;
    top: 0;
    z-index: 1000;
    transition: box-shadow 0.3s;
}
body.dark header {
    border-bottom-color: #2a3a5c;
}
.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 10px 20px;
    max-width: 1200px;
    margin: 0 auto;
}
.logo svg {
    height: 50px;
    width: auto;
}
.nav-menu {
    display: flex;
    gap: 20px;
    list-style: none;
}
.nav-menu li a {
    padding: 8px 12px;
    border-radius: 6px;
    transition: background 0.2s;
    font-weight: 500;
}
.nav-menu li a:hover {
    background: #e9ecef;
}
body.dark .nav-menu li a:hover {
    background: #2a3a5c;
}
.menu-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 28px;
    cursor: pointer;
    color: #1a3a5c;
}
body.dark .menu-toggle {
    color: #e0e0e0;
}
/* ===== 移动菜单 ===== */
@media (max-width: 768px) {
    .nav-menu {
        display: none;
        flex-direction: column;
        background: #fff;
        position: absolute;
        top: 70px;
        left: 0;
        right: 0;
        padding: 20px;
        box-shadow: 0 4px 12px rgba(0,0,0,0.1);
        z-index: 999;
    }
    body.dark .nav-menu {
        background: #0f3460;
    }
    .nav-menu.active {
        display: flex;
    }
    .menu-toggle {
        display: block;
    }
}
/* ===== 面包屑 ===== */
.breadcrumb {
    padding: 12px 0;
    font-size: 14px;
    color: #666;
}
body.dark .breadcrumb {
    color: #aaa;
}
.breadcrumb a {
    color: #1a5c8a;
}
/* ===== 返回顶部 ===== */
.back-to-top {
    position: fixed;
    bottom: 40px;
    right: 40px;
    background: #1a5c8a;
    color: #fff;
    border: none;
    border-radius: 50%;
    width: 50px;
    height: 50px;
    font-size: 24px;
    cursor: pointer;
    opacity: 0;
    transition: opacity 0.3s, transform 0.3s;
    z-index: 999;
    box-shadow: 0 4px 12px rgba(0,0,0,0.2);
}
.back-to-top.visible {
    opacity: 1;
}
.back-to-top:hover {
    transform: scale(1.1);
}
/* ===== Banner轮播 ===== */
.banner {
    position: relative;
    overflow: hidden;
    height: 400px;
    background: #1a3a5c;
}
.banner-slide {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: opacity 1s ease;
    color: #fff;
    text-align: center;
    padding: 40px;
}
.banner-slide.active {
    opacity: 1;
}
.banner-slide h2 {
    font-size: 2.5rem;
    margin-bottom: 20px;
    text-shadow: 0 2px 8px rgba(0,0,0,0.3);
}
.banner-slide p {
    font-size: 1.2rem;
    max-width: 700px;
    margin: 0 auto;
}
.banner-dots {
    position: absolute;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    gap: 12px;
}
.banner-dots span {
    width: 14px;
    height: 14px;
    border-radius: 50%;
    background: rgba(255,255,255,0.5);
    cursor: pointer;
    transition: background 0.3s;
}
.banner-dots span.active {
    background: #fff;
}
/* ===== 通用区块 ===== */
section {
    padding: 60px 0;
}
.section-title {
    font-size: 2rem;
    margin-bottom: 40px;
    text-align: center;
    position: relative;
}
.section-title::after {
    content: "";
    display: block;
    width: 60px;
    height: 4px;
    background: #1a5c8a;
    margin: 12px auto 0;
    border-radius: 2px;
}
body.dark .section-title::after {
    background: #8ab4f8;
}
.grid-2 {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 30px;
}
.grid-3 {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    gap: 30px;
}
.grid-4 {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
}
@media (max-width: 768px) {
    .grid-2, .grid-3, .grid-4 {
        grid-template-columns: 1fr;
    }
}
.card {
    background: #fff;
    border-radius: 12px;
    padding: 24px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.06);
    transition: transform 0.2s;
}
.card:hover {
    transform: translateY(-4px);
}
body.dark .card {
    background: #16213e;
}
/* ===== 文章列表 ===== */
.article-item {
    background: #fff;
    padding: 20px;
    border-radius: 10px;
    margin-bottom: 20px;
    box-shadow: 0 1px 4px rgba(0,0,0,0.05);
}
.article-item h4 {
    font-size: 1.2rem;
    margin-bottom: 8px;
}
.article-item .meta {
    font-size: 0.9rem;
    color: #888;
    margin-bottom: 10px;
}
.article-item p {
    margin-bottom: 12px;
}
.article-item a {
    font-weight: 600;
}
/* ===== FAQ ===== */
.faq-item {
    background: #fff;
    border-radius: 10px;
    margin-bottom: 16px;
    padding: 18px 24px;
    cursor: pointer;
    box-shadow: 0 1px 4px rgba(0,0,0,0.05);
    transition: background 0.2s;
}
.faq-item:hover {
    background: #f1f3f5;
}
body.dark .faq-item {
    background: #16213e;
}
.faq-question {
    font-weight: 600;
    font-size: 1.1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.faq-question::after {
    content: "+";
    font-size: 1.5rem;
    transition: transform 0.3s;
}
.faq-item.open .faq-question::after {
    content: "−";
    transform: rotate(180deg);
}
.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease, padding 0.3s;
    padding-top: 0;
}
.faq-item.open .faq-answer {
    max-height: 600px;
    padding-top: 16px;
}
/* ===== HowTo ===== */
.howto-step {
    background: #fff;
    padding: 20px;
    border-radius: 10px;
    margin-bottom: 20px;
    border-left: 4px solid #1a5c8a;
}
body.dark .howto-step {
    background: #16213e;
    border-left-color: #8ab4f8;
}
.howto-step h4 {
    margin-bottom: 8px;
}
/* ===== 页脚 ===== */
footer {
    background: #1a3a5c;
    color: #ccc;
    padding: 40px 0 20px;
}
footer a {
    color: #8ab4f8;
}
.footer-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 30px;
    margin-bottom: 30px;
}
@media (max-width: 768px) {
    .footer-grid {
        grid-template-columns: 1fr 1fr;
    }
}
footer h4 {
    color: #fff;
    margin-bottom: 16px;
}
footer ul {
    list-style: none;
}
footer ul li {
    margin-bottom: 8px;
}
.copyright {
    text-align: center;
    border-top: 1px solid #2a4a6c;
    padding-top: 20px;
    font-size: 0.9rem;
}
/* ===== 站内搜索 ===== */
.search-box {
    display: flex;
    gap: 8px;
    max-width: 400px;
    margin: 0 auto 40px;
}
.search-box input {
    flex: 1;
    padding: 10px 16px;
    border: 2px solid #ddd;
    border-radius: 30px;
    font-size: 1rem;
    outline: none;
}
.search-box input:focus {
    border-color: #1a5c8a;
}
.search-box button {
    padding: 10px 20px;
    background: #1a5c8a;
    color: #fff;
    border: none;
    border-radius: 30px;
    cursor: pointer;
}
/* ===== 数字动画 ===== */
.stat-number {
    font-size: 2.5rem;
    font-weight: 700;
    color: #1a5c8a;
}
body.dark .stat-number {
    color: #8ab4f8;
}
/* ===== 滚动动画 ===== */
.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}
.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}
/* ===== 图片占位 ===== */
.svg-placeholder {
    background: #e9ecef;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 180px;
    color: #6c757d;
    font-size: 0.9rem;
}
body.dark .svg-placeholder {
    background: #2a3a5c;
    color: #aaa;
}
/* ===== 其他 ===== */
.contact-info p {
    margin-bottom: 8px;
}
.highlight {
    color: #1a5c8a;
    font-weight: 600;
}
body.dark .highlight {
    color: #8ab4f8;
}
.btn {
    display: inline-block;
    padding: 10px 24px;
    background: #1a5c8a;
    color: #fff;
    border-radius: 30px;
    font-weight: 600;
    transition: background 0.2s;
}
.btn:hover {
    background: #134a6f;
}
/* ===== 暗黑切换按钮 ===== */
.dark-toggle {
    background: none;
    border: 2px solid #1a5c8a;
    border-radius: 30px;
    padding: 6px 14px;
    cursor: pointer;
    font-size: 0.9rem;
    color: #1a5c8a;
    transition: background 0.2s, color 0.2s;
}
body.dark .dark-toggle {
    border-color: #8ab4f8;
    color: #8ab4f8;
}
.dark-toggle:hover {
    background: #1a5c8a;
    color: #fff;
}
body.dark .dark-toggle:hover {
    background: #8ab4f8;
    color: #1a1a2e;
}