/* ===== 全局重置 & 基础 ===== */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.6;
    color: #1a1a2e;
    background: linear-gradient(135deg, #f5f7fa 0%, #e4e9f0 100%);
    min-height: 100vh;
    transition: background 0.4s, color 0.4s;
}
.container { max-width: 1200px; margin: 0 auto; padding: 0 20px; }
a { color: #2b6cb0; text-decoration: none; transition: color 0.2s; }
a:hover { color: #1a4f8a; text-decoration: underline; }
h1, h2, h3, h4 { font-weight: 600; line-height: 1.3; }
h1 { font-size: 2.4em; margin: 20px 0; }
h2 { font-size: 1.9em; margin: 30px 0 20px; border-bottom: 2px solid #2b6cb0; padding-bottom: 10px; position: relative; }
h2::after { content: ''; position: absolute; bottom: -2px; left: 0; width: 60px; height: 4px; background: #f6ad55; border-radius: 2px; }
h3 { font-size: 1.45em; margin: 25px 0 15px; }
h4 { font-size: 1.2em; margin: 20px 0 10px; }
p { margin-bottom: 15px; }
ul, ol { margin: 10px 0 20px 20px; }
li { margin-bottom: 8px; }

/* ===== 渐变Banner ===== */
.banner {
    background: linear-gradient(135deg, #2b6cb0 0%, #1a365d 50%, #2b6cb0 100%);
    padding: 80px 0;
    text-align: center;
    position: relative;
    overflow: hidden;
    box-shadow: inset 0 -8px 20px rgba(0,0,0,0.1);
}
.banner::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle at 30% 50%, rgba(255,255,255,0.08) 0%, transparent 60%);
    animation: bannerGlow 10s ease-in-out infinite alternate;
}
@keyframes bannerGlow {
    0% { transform: translate(0, 0); }
    100% { transform: translate(10%, 10%); }
}
.banner h1 { margin: 0 0 20px; color: #fff; text-shadow: 0 2px 10px rgba(0,0,0,0.3); font-size: 2.8em; }
.banner p { font-size: 1.2em; color: rgba(255,255,255,0.9); max-width: 800px; margin: 0 auto 30px; }
.banner .btn {
    display: inline-block;
    background: linear-gradient(135deg, #f6ad55, #ed8936);
    color: #fff;
    padding: 14px 36px;
    border-radius: 50px;
    font-size: 1.1em;
    font-weight: 600;
    box-shadow: 0 6px 20px rgba(237,137,54,0.4);
    transition: all 0.3s;
    border: none;
}
.banner .btn:hover { transform: translateY(-3px) scale(1.03); box-shadow: 0 10px 30px rgba(237,137,54,0.5); text-decoration: none; }

/* ===== 毛玻璃卡片 ===== */
.card {
    background: rgba(255,255,255,0.7);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid rgba(255,255,255,0.3);
    border-radius: 16px;
    padding: 24px;
    transition: all 0.4s;
    box-shadow: 0 4px 20px rgba(0,0,0,0.05);
}
.card:hover {
    background: rgba(255,255,255,0.85);
    box-shadow: 0 12px 40px rgba(0,0,0,0.12);
    transform: translateY(-5px);
    border-color: rgba(43,108,176,0.2);
}
.card h3 { margin-top: 0; color: #2b6cb0; }
.card svg { display: block; margin: 0 auto 15px; }

/* ===== 圆角卡片通用 ===== */
.section-alt .card {
    background: rgba(255,255,255,0.6);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
}

/* ===== 圆角按钮 ===== */
.btn, .search-box button {
    border-radius: 50px;
    transition: all 0.3s;
}
.search-box button:hover { background: #1a4f8a; transform: scale(1.02); }

/* ===== 响应式布局 ===== */
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 30px; }
.grid-3 { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 30px; }

/* ===== 导航毛玻璃 ===== */
.header {
    background: rgba(43,108,176,0.85);
    backdrop-filter: blur(15px);
    -webkit-backdrop-filter: blur(15px);
    color: #fff;
    padding: 15px 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 20px rgba(0,0,0,0.08);
    transition: background 0.4s;
}
.header .container { display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; }
.header .logo { font-size: 1.5em; font-weight: bold; color: #fff; text-shadow: 0 1px 4px rgba(0,0,0,0.2); }
.header nav a { color: #fff; margin-left: 20px; font-size: 0.95em; position: relative; padding: 4px 0; }
.header nav a::after { content: ''; position: absolute; bottom: 0; left: 0; width: 0; height: 2px; background: #f6ad55; transition: width 0.3s; }
.header nav a:hover::after { width: 100%; }
.header nav a:hover { text-decoration: none; }
.mobile-menu-btn { display: none; background: none; border: none; color: #fff; font-size: 1.5em; cursor: pointer; }

/* ===== 暗色模式 ===== */
.dark-mode {
    background: linear-gradient(135deg, #1a202c 0%, #2d3748 100%);
    color: #e2e8f0;
}
.dark-mode .header { background: rgba(26,32,44,0.9); backdrop-filter: blur(15px); }
.dark-mode .banner { background: linear-gradient(135deg, #1a365d 0%, #0f1f3a 50%, #1a365d 100%); }
.dark-mode .banner h1 { color: #e2e8f0; }
.dark-mode .section-alt { background: rgba(45,55,72,0.5); }
.dark-mode .card {
    background: rgba(45,55,72,0.6);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-color: rgba(255,255,255,0.1);
    color: #e2e8f0;
}
.dark-mode .card:hover { background: rgba(45,55,72,0.8); border-color: rgba(246,173,85,0.3); }
.dark-mode .card h3 { color: #f6ad55; }
.dark-mode .footer { background: #0f1a2e; }
.dark-mode .footer a { color: #a0aec0; }
.dark-mode .back-to-top { background: #f6ad55; color: #1a202c; }
.dark-mode .search-box input { background: rgba(45,55,72,0.8); color: #e2e8f0; border-color: rgba(255,255,255,0.2); }
.dark-mode .search-box button { background: #f6ad55; color: #1a202c; }
.dark-mode .faq-item { border-bottom-color: rgba(255,255,255,0.1); }
.dark-mode .article-item { border-bottom-color: rgba(255,255,255,0.1); }
.dark-mode h2 { border-bottom-color: #f6ad55; }
.dark-mode h2::after { background: #2b6cb0; }
.dark-mode .howto-step::before { background: #f6ad55; color: #1a202c; }
.dark-mode .section-alt { background: rgba(45,55,72,0.4); }

/* ===== 滚动动画 ===== */
.animate-on-scroll {
    opacity: 0;
    transform: translateY(30px) scale(0.95);
    transition: opacity 0.7s ease, transform 0.7s ease;
}
.animate-on-scroll.visible { opacity: 1; transform: translateY(0) scale(1); }

/* ===== Hover动画增强 ===== */
.card, .btn, .back-to-top, .header nav a, .faq-item, .article-item { transition: all 0.3s; }
.faq-item:hover { background: rgba(43,108,176,0.04); border-radius: 8px; }
.dark-mode .faq-item:hover { background: rgba(246,173,85,0.05); }

/* ===== 返回顶部 ===== */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    background: linear-gradient(135deg, #2b6cb0, #1a365d);
    color: #fff;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5em;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transition: all 0.4s;
    z-index: 999;
    box-shadow: 0 4px 15px rgba(43,108,176,0.4);
}
.back-to-top.show { opacity: 1; visibility: visible; }
.back-to-top:hover { transform: translateY(-5px) scale(1.1); box-shadow: 0 8px 25px rgba(43,108,176,0.5); }

/* ===== 搜索框 ===== */
.search-box { display: flex; margin: 20px 0; }
.search-box input {
    flex: 1;
    padding: 12px 18px;
    border: 1px solid rgba(0,0,0,0.1);
    border-radius: 50px 0 0 50px;
    background: rgba(255,255,255,0.8);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    font-size: 1em;
    transition: all 0.3s;
}
.search-box input:focus { outline: none; border-color: #2b6cb0; background: #fff; box-shadow: 0 0 0 3px rgba(43,108,176,0.1); }
.search-box button {
    padding: 12px 24px;
    background: linear-gradient(135deg, #2b6cb0, #1a365d);
    color: #fff;
    border: none;
    border-radius: 0 50px 50px 0;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.3s;
}

/* ===== FAQ ===== */
.faq-item { border-bottom: 1px solid rgba(0,0,0,0.08); padding: 18px 0; cursor: pointer; }
.faq-question { font-weight: 600; font-size: 1.1em; display: flex; justify-content: space-between; align-items: center; }
.faq-question span { font-size: 1.4em; transition: transform 0.3s; }
.faq-item.active .faq-question span { transform: rotate(45deg); }
.faq-answer { margin-top: 12px; display: none; padding-left: 8px; border-left: 3px solid #2b6cb0; }
.faq-item.active .faq-answer { display: block; animation: fadeSlide 0.4s ease; }
@keyframes fadeSlide { from { opacity: 0; transform: translateY(-10px); } to { opacity: 1; transform: translateY(0); } }

/* ===== 文章列表 ===== */
.article-item { margin-bottom: 30px; padding-bottom: 20px; border-bottom: 1px solid rgba(0,0,0,0.06); transition: all 0.3s; padding: 15px; border-radius: 12px; }
.article-item:hover { background: rgba(255,255,255,0.5); backdrop-filter: blur(8px); transform: translateX(5px); }
.dark-mode .article-item:hover { background: rgba(255,255,255,0.05); }
.article-item h3 { margin-bottom: 5px; }
.article-item .meta { font-size: 0.9em; color: #718096; margin-bottom: 10px; }

/* ===== HowTo步骤 ===== */
.howto-steps { counter-reset: step; }
.howto-step { margin-bottom: 24px; padding-left: 50px; position: relative; }
.howto-step::before {
    counter-increment: step;
    content: counter(step);
    position: absolute;
    left: 0;
    top: 0;
    background: linear-gradient(135deg, #2b6cb0, #1a365d);
    color: #fff;
    width: 36px;
    height: 36px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    font-size: 1em;
    box-shadow: 0 2px 10px rgba(43,108,176,0.3);
    transition: transform 0.3s;
}
.howto-step:hover::before { transform: scale(1.1); }

/* ===== Footer ===== */
.footer {
    background: linear-gradient(135deg, #1a202c, #0f1a2e);
    color: #a0aec0;
    padding: 50px 0 20px;
    font-size: 0.9em;
    margin-top: 40px;
}
.footer a { color: #a0aec0; }
.footer .container { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 30px; }
.footer h4 { color: #e2e8f0; margin-bottom: 15px; }
.footer ul { list-style: none; margin: 0; }
.footer ul li { margin-bottom: 8px; }
.footer-bottom { border-top: 1px solid rgba(255,255,255,0.1); padding: 20px 0; text-align: center; margin-top: 30px; }

/* ===== 响应式 ===== */
@media (max-width: 768px) {
    .header nav { display: none; width: 100%; margin-top: 10px; }
    .header nav a { display: block; margin: 10px 0; }
    .mobile-menu-btn { display: block; }
    .header nav.open { display: block; }
    .grid-2, .grid-3 { grid-template-columns: 1fr; }
    .footer .container { grid-template-columns: 1fr; }
    h1 { font-size: 1.9em; }
    h2 { font-size: 1.6em; }
    .banner h1 { font-size: 2em; }
    .banner { padding: 50px 0; }
    .banner .btn { padding: 12px 28px; }
    .back-to-top { width: 44px; height: 44px; font-size: 1.2em; bottom: 20px; right: 20px; }
    .search-box input { padding: 10px 14px; }
    .search-box button { padding: 10px 18px; }
}

/* ===== 其他 ===== */
.section { padding: 50px 0; }
.section-alt { background: rgba(255,255,255,0.4); backdrop-filter: blur(6px); -webkit-backdrop-filter: blur(6px); }
#sitemap ul { list-style: none; margin: 0; }
#sitemap ul li { margin-bottom: 6px; }
#links p a { margin: 0 10px; }
.footer-bottom p { margin: 0; color: #718096; }

/* ===== 暗色模式适配更多 ===== */
.dark-mode .section-alt { background: rgba(45,55,72,0.4); }
.dark-mode .footer-bottom { border-top-color: rgba(255,255,255,0.08); }
.dark-mode .footer-bottom p { color: #a0aec0; }
.dark-mode .search-box input:focus { background: rgba(45,55,72,0.9); border-color: #f6ad55; }
.dark-mode .banner .btn { background: linear-gradient(135deg, #ed8936, #dd6b20); box-shadow: 0 6px 20px rgba(237,137,54,0.3); }
.dark-mode .banner .btn:hover { box-shadow: 0 10px 30px rgba(237,137,54,0.4); }