/* 全局变量和基础设置 */
:root {
    --bg-color: #FFFACD;
    --text-color: #333333;
    --text-muted: #555555;
    --primary-color: #3b82f6;
    --accent-color: #06b6d4;
    --card-bg: rgba(0, 0, 0, 0.03);
    --card-border: rgba(0, 0, 0, 0.08);
    --hover-bg: rgba(0, 0, 0, 0.05);
    --font-main: 'Inter', system-ui, -apple-system, sans-serif;
    --font-article: 'KaiTi', 'STKaiti', '楷体', serif; /* 正楷体用于文章 */
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: var(--font-main);
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    overflow-x: hidden;
}

html {
    scroll-behavior: smooth;
}

a {
    text-decoration: none;
    color: inherit;
    transition: color 0.3s ease;
}

/* 布局容器 */
.container {
    width: 90%;
    max-width: 1200px;
    margin: 0 auto;
}

.section {
    padding: 100px 0;
}

.section-title {
    font-size: 2.5rem;
    text-align: center;
    margin-bottom: 60px;
    font-weight: 600;
    letter-spacing: 2px;
    background: linear-gradient(to right, #fff, #94a3b8);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.dark-bg {
    background-color: rgba(0, 0, 0, 0.3);
}

.grid {
    display: grid;
    gap: 30px;
}

/* 极简导航栏 */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    padding: 20px 0;
    background: rgba(10, 10, 15, 0.8);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--card-border);
    z-index: 1000;
    transition: all 0.3s ease;
}

.nav-container {
    width: 90%;
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    align-items: center;
}

.nav-container .logo {
    justify-self: start;
}

.nav-container .nav-links {
    justify-self: center;
}

.nav-container .nav-actions {
    justify-self: end;
}

.nav-container .nav-actions .btn {
    padding: 8px 20px;
    font-size: 0.9rem;
    border-radius: 6px;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    letter-spacing: 3px;
    color: #fff;
}

.nav-links {
    list-style: none;
    display: flex;
    gap: 30px;
}

.nav-links a {
    font-size: 0.95rem;
    color: #ffffff;
    font-weight: 400;
    position: relative;
}

.nav-links a:hover {
    color: #fff;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--accent-color);
    transition: width 0.3s ease;
}

.nav-links a:hover::after {
    width: 100%;
}

/* 首页 Hero */
.hero {
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    text-align: center;
}

.hero .overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: radial-gradient(circle at center, rgba(10, 10, 15, 0.4) 0%, rgba(10, 10, 15, 0.9) 100%);
}

.hero-content {
    position: relative;
    z-index: 1;
    max-width: 800px;
    padding: 0 20px;
}

.hero h1 {
    font-size: 4.5rem;
    font-weight: 700;
    margin-bottom: 20px;
    letter-spacing: 4px;
    background: linear-gradient(135deg, #fff 0%, #a5b4fc 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero p {
    font-size: 1.25rem;
    color: var(--text-muted);
    margin-bottom: 40px;
    letter-spacing: 1px;
}

/* 按钮 */
.btn {
    display: inline-block;
    padding: 15px 35px;
    border-radius: 30px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    border: none;
    text-align: center;
}

.btn-primary {
    background: linear-gradient(to right, var(--primary-color), #2563eb);
    color: #fff;
    box-shadow: 0 4px 15px rgba(59, 130, 246, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(59, 130, 246, 0.5);
    color: #fff;
}

.btn-secondary {
    background: transparent;
    color: #fff;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.05);
    border-color: rgba(255, 255, 255, 0.4);
}

.btn-accent {
    background: linear-gradient(to right, #06b6d4, #3b82f6);
    color: #fff;
    box-shadow: 0 4px 15px rgba(6, 182, 212, 0.3);
}

.btn-accent:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(6, 182, 212, 0.5);
    color: #fff;
}

.btn-block {
    display: block;
    width: 100%;
}

.hero-buttons {
    display: flex;
    gap: 20px;
    justify-content: center;
}

/* 卡片和网格悬停效果 */
.card {
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    border-radius: 16px;
    padding: 40px 30px;
    backdrop-filter: blur(5px);
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    position: relative;
    overflow: hidden;
}

.hover-effect::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: radial-gradient(circle at top right, rgba(255,255,255,0.05), transparent);
    opacity: 0;
    transition: opacity 0.4s ease;
    pointer-events: none;
}

.hover-effect:hover {
    transform: translateY(-10px);
    border-color: rgba(255, 255, 255, 0.2);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.4);
}

.hover-effect:hover::before {
    opacity: 1;
}

.features-grid {
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
}

.features-grid h3 {
    font-size: 1.25rem;
    margin-bottom: 15px;
    color: #111111;
}

.features-grid p {
    color: var(--text-muted);
    font-size: 0.95rem;
}

/* 套餐价格 */
.pricing-grid {
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    align-items: center;
}

.pricing-card {
    text-align: center;
    padding: 50px 30px;
}

.pricing-card.featured {
    border-color: rgba(6, 182, 212, 0.4);
    box-shadow: 0 0 30px rgba(6, 182, 212, 0.1);
    transform: scale(1.05);
}

.pricing-card.featured:hover {
    transform: scale(1.05) translateY(-10px);
}

.plan-title {
    font-size: 1.25rem;
    color: var(--text-muted);
    margin-bottom: 20px;
}

.price {
    font-size: 3.5rem;
    font-weight: 700;
    color: #111111;
    margin-bottom: 30px;
}

.price span {
    font-size: 1rem;
    color: var(--text-muted);
    font-weight: 400;
}

.plan-features {
    list-style: none;
    margin-bottom: 40px;
    text-align: left;
}

.plan-features li {
    margin-bottom: 15px;
    padding-left: 30px;
    position: relative;
    color: var(--text-muted);
    font-size: 0.95rem;
}

.plan-features li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--accent-color);
    font-weight: bold;
}

/* 文章列表 */
.articles-grid {
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
}

.article-card {
    padding: 30px;
    text-align: left;
    display: flex;
    flex-direction: column;
}

.article-title {
    font-size: 1.2rem;
    color: #111111;
    margin-bottom: 15px;
    line-height: 1.4;
}

.article-meta {
    color: var(--text-muted);
    font-size: 0.85rem;
    margin-bottom: 15px;
    display: flex;
    gap: 15px;
}

.article-excerpt {
    color: var(--text-muted);
    font-size: 0.9rem;
    margin-bottom: 20px;
    flex-grow: 1;
}

.read-more {
    color: var(--accent-color);
    font-weight: 600;
    font-size: 0.9rem;
    display: inline-flex;
    align-items: center;
}

.read-more::after {
    content: '→';
    margin-left: 5px;
    transition: transform 0.3s ease;
}

.article-card:hover .read-more::after {
    transform: translateX(5px);
}

/* FAQ 常见问题 */
.faq-list {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    border-bottom: 1px solid var(--card-border);
    padding: 25px 0;
}

.faq-question {
    font-size: 1.1rem;
    color: #111111;
    font-weight: 600;
    margin-bottom: 10px;
    cursor: pointer;
    position: relative;
    padding-right: 30px;
}

.faq-question::after {
    content: '+';
    position: absolute;
    right: 0;
    top: 0;
    color: var(--accent-color);
    font-size: 1.5rem;
    line-height: 1;
    transition: transform 0.3s ease;
}

.faq-item.active .faq-question::after {
    transform: rotate(45deg);
}

.faq-answer {
    color: var(--text-muted);
    font-size: 0.95rem;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease;
}

.faq-item.active .faq-answer {
    max-height: 200px;
    margin-top: 15px;
}

/* 页脚 */
footer {
    padding: 40px 0;
    text-align: center;
    border-top: 1px solid var(--card-border);
    color: var(--text-muted);
    font-size: 0.9rem;
}

/* 动画 */
.fade-in-up {
    opacity: 0;
    transform: translateY(30px);
    animation: fadeInUp 0.8s forwards;
}

.delay-1 { animation-delay: 0.2s; }
.delay-2 { animation-delay: 0.4s; }

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

/* 响应式 */
@media (max-width: 768px) {
    .hero h1 { font-size: 3rem; }
    .nav-links { display: none; } /* 移动端可以添加汉堡菜单，此处简化 */
    .hero-buttons { flex-direction: column; }
    .pricing-card.featured { transform: scale(1); }
    .pricing-card.featured:hover { transform: translateY(-10px); }
}

/* 文章详情页特殊样式 */
.article-page-body {
    font-family: var(--font-article);
    background-color: #f8f9fa; /* 文章页更适合阅读的浅色背景，或者保持深色 */
    color: #2d3748;
}
.article-page-body.dark-mode {
    background-color: var(--bg-color);
    color: #333333;
}
.article-content {
    max-width: 800px;
    margin: 120px auto 60px;
    padding: 40px;
    background: var(--card-bg);
    border-radius: 16px;
    border: 1px solid var(--card-border);
}
.article-content h1 {
    font-size: 2.5rem;
    margin-bottom: 30px;
    text-align: center;
    color: #111111;
    font-family: var(--font-main);
}
.article-content p {
    margin-bottom: 20px;
    font-size: 1.15rem;
    line-height: 1.8;
    text-indent: 2em;
}
.article-content h2, .article-content h3 {
    color: #111111;
    margin: 30px 0 15px;
    font-family: var(--font-main);
}
.article-faq {
    margin-top: 50px;
    padding-top: 30px;
    border-top: 1px solid var(--card-border);
}