:root {
    --primary-color: #3b82f6;
    --primary-hover: #2563eb;
    --accent-glow: rgba(59, 130, 246, 0.4);
    --bg-dark: #0a0d14;
    --card-bg: rgba(15, 23, 42, 0.75);
    --card-border: rgba(255, 255, 255, 0.1);
    --card-hover-border: rgba(59, 130, 246, 0.6);
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --font-kaiti: "STKaiti", "KaiTi", "Kaiti SC", "DFKai-SB", serif;
    --font-sans: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
}

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

html {
    scroll-behavior: smooth;
    font-family: var(--font-kaiti);
    background-color: var(--bg-dark);
    color: var(--text-main);
}

body {
    overflow-x: hidden;
    position: relative;
    min-height: 100vh;
    font-size: 18px;
    line-height: 1.8;
}

/* 动态网格与光彩背景 */
.bg-canvas-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    z-index: -2;
    background: radial-gradient(circle at 50% 20%, #1e1b4b 0%, #090d16 70%);
}

#bg-canvas {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

.grid-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    z-index: -1;
    background-image: linear-gradient(rgba(255, 255, 255, 0.03) 1px, transparent 1px),
                      linear-gradient(90deg, rgba(255, 255, 255, 0.03) 1px, transparent 1px);
    background-size: 50px 50px;
    pointer-events: none;
}

/* 极简导航栏 */
.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 100;
    padding: 20px 40px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    backdrop-filter: blur(16px);
    background: rgba(10, 13, 20, 0.6);
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
    transition: all 0.3s ease;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 24px;
    font-weight: 700;
    color: #fff;
    text-decoration: none;
    letter-spacing: 1px;
}

.logo span {
    background: linear-gradient(135deg, #60a5fa, #a855f7);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 32px;
    list-style: none;
}

.nav-links a {
    color: var(--text-muted);
    text-decoration: none;
    font-size: 18px;
    font-weight: 500;
    transition: color 0.3s ease;
    position: relative;
}

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

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -6px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-color);
    transition: width 0.3s ease;
}

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

.btn-login {
    background: linear-gradient(135deg, #2563eb, #3b82f6);
    color: #fff !important;
    padding: 10px 24px;
    border-radius: 30px;
    box-shadow: 0 4px 15px var(--accent-glow);
    transition: all 0.3s ease !important;
}

.btn-login:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 25px rgba(59, 130, 246, 0.6);
}

.btn-login::after {
    display: none !important;
}

/* Main Layout & Sections */
.section {
    padding: 120px 20px 80px;
    max-width: 1200px;
    margin: 0 auto;
}

.hero {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    padding-top: 140px;
}

.hero-tag {
    display: inline-block;
    padding: 6px 18px;
    background: rgba(59, 130, 246, 0.15);
    border: 1px solid rgba(59, 130, 246, 0.3);
    border-radius: 20px;
    color: #60a5fa;
    font-size: 16px;
    margin-bottom: 24px;
    backdrop-filter: blur(5px);
}

.hero h1 {
    font-size: 3.6rem;
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 24px;
    background: linear-gradient(180deg, #ffffff 0%, #94a3b8 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero p {
    font-size: 1.3rem;
    color: var(--text-muted);
    max-width: 750px;
    margin: 0 auto 40px;
}

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

.btn-primary {
    background: #2563eb;
    color: #fff;
    padding: 16px 40px;
    border-radius: 40px;
    text-decoration: none;
    font-size: 20px;
    font-weight: 600;
    box-shadow: 0 8px 25px rgba(37, 99, 235, 0.5);
    transition: all 0.3s ease;
    border: none;
    cursor: pointer;
}

.btn-primary:hover {
    background: #1d4ed8;
    transform: translateY(-3px);
    box-shadow: 0 12px 35px rgba(37, 99, 235, 0.7);
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.2);
    color: #fff;
    padding: 16px 40px;
    border-radius: 40px;
    text-decoration: none;
    font-size: 20px;
    font-weight: 600;
    backdrop-filter: blur(10px);
    transition: all 0.3s ease;
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.15);
    transform: translateY(-3px);
}

/* 关键词标签云 */
.keywords-cloud {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    justify-content: center;
    margin-top: 50px;
    max-width: 900px;
}

.keyword-badge {
    background: rgba(255, 255, 255, 0.04);
    border: 1px solid rgba(255, 255, 255, 0.08);
    padding: 8px 16px;
    border-radius: 12px;
    color: #cbd5e1;
    font-size: 15px;
    transition: all 0.3s ease;
    text-decoration: none;
}

.keyword-badge:hover {
    background: rgba(59, 130, 246, 0.2);
    border-color: rgba(59, 130, 246, 0.5);
    color: #60a5fa;
    transform: translateY(-2px);
}

/* Section Title */
.section-title {
    text-align: center;
    margin-bottom: 60px;
}

.section-title h2 {
    font-size: 2.8rem;
    color: #fff;
    margin-bottom: 16px;
}

.section-title p {
    color: var(--text-muted);
    font-size: 1.15rem;
}

/* 核心优势 Grid */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 30px;
}

.feature-card {
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    border-radius: 24px;
    padding: 40px 30px;
    backdrop-filter: blur(12px);
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    position: relative;
    overflow: hidden;
}

.feature-card:hover {
    transform: translateY(-8px);
    border-color: var(--card-hover-border);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.4);
}

.feature-icon {
    width: 60px;
    height: 60px;
    border-radius: 16px;
    background: rgba(59, 130, 246, 0.15);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 28px;
    color: #60a5fa;
    margin-bottom: 24px;
}

.feature-card h3 {
    font-size: 1.5rem;
    color: #fff;
    margin-bottom: 12px;
}

.feature-card p {
    color: var(--text-muted);
    font-size: 1rem;
    line-height: 1.6;
}

/* 套餐价格区域 (严格对照图片1) */
.pricing-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
    align-items: stretch;
}

@media (max-width: 992px) {
    .pricing-grid {
        grid-template-columns: 1fr;
    }
}

.pricing-card {
    background: #ffffff;
    border-radius: 20px;
    padding: 36px 30px;
    color: #1e293b;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    position: relative;
    transition: all 0.3s ease;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
}

.pricing-card:hover {
    transform: translateY(-6px);
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.3);
}

.pricing-card.recommended {
    border: 3px solid #2563eb;
    transform: scale(1.03);
}

.pricing-card.recommended:hover {
    transform: scale(1.03) translateY(-6px);
}

.badge-recommend {
    position: absolute;
    top: -16px;
    right: 24px;
    background: #2563eb;
    color: #fff;
    font-size: 14px;
    font-weight: 700;
    padding: 4px 16px;
    border-radius: 12px;
}

.pricing-header h3 {
    font-size: 22px;
    font-weight: 800;
    color: #0f172a;
    margin-bottom: 12px;
    font-family: var(--font-sans);
}

.pricing-price {
    font-size: 38px;
    font-weight: 800;
    color: #2563eb;
    margin-bottom: 24px;
    font-family: var(--font-sans);
}

.pricing-price span {
    font-size: 16px;
    font-weight: 400;
    color: #64748b;
}

.pricing-features {
    list-style: none;
    margin-bottom: 30px;
    font-family: var(--font-sans);
}

.pricing-features li {
    font-size: 16px;
    color: #334155;
    margin-bottom: 14px;
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 600;
}

.pricing-features li.green-check::before {
    content: "✓";
    color: #16a34a;
    font-weight: 900;
    font-size: 18px;
}

.pricing-features li.orange-flash::before {
    content: "⚡";
    color: #ea580c;
    font-size: 18px;
}

.btn-price-card {
    display: block;
    width: 100%;
    padding: 14px 0;
    text-align: center;
    border-radius: 14px;
    text-decoration: none;
    font-size: 18px;
    font-weight: 700;
    transition: all 0.3s ease;
    cursor: pointer;
    font-family: var(--font-sans);
}

.btn-price-light {
    background: #f1f5f9;
    color: #0f172a;
}

.btn-price-light:hover {
    background: #e2e8f0;
}

.btn-price-primary {
    background: #2563eb;
    color: #ffffff;
}

.btn-price-primary:hover {
    background: #1d4ed8;
}

/* 文章列表区域 */
.articles-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 30px;
}

.article-card {
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    border-radius: 20px;
    padding: 30px;
    backdrop-filter: blur(12px);
    transition: all 0.3s ease;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

.article-card:hover {
    transform: translateY(-6px);
    border-color: var(--card-hover-border);
}

.article-card h3 {
    font-size: 1.35rem;
    color: #fff;
    margin-bottom: 12px;
    line-height: 1.4;
}

.article-card p {
    color: var(--text-muted);
    font-size: 0.95rem;
    margin-bottom: 20px;
}

.article-meta {
    display: flex;
    justify-content: space-between;
    color: #64748b;
    font-size: 14px;
    border-top: 1px solid rgba(255, 255, 255, 0.08);
    padding-top: 15px;
}

.btn-read-more {
    color: #60a5fa;
    text-decoration: none;
    font-weight: 600;
    display: inline-flex;
    align-items: center;
    gap: 6px;
    transition: gap 0.2s ease;
}

.btn-read-more:hover {
    gap: 10px;
}

/* FAQ手风琴 */
.faq-list {
    max-width: 900px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.faq-item {
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    border-radius: 16px;
    overflow: hidden;
    backdrop-filter: blur(10px);
}

.faq-question {
    padding: 24px 30px;
    font-size: 1.2rem;
    font-weight: 600;
    color: #fff;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    user-select: none;
}

.faq-question::after {
    content: "+";
    font-size: 24px;
    color: #60a5fa;
    transition: transform 0.3s ease;
}

.faq-item.active .faq-question::after {
    content: "-";
    transform: rotate(180deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease, padding 0.3s ease;
    padding: 0 30px;
    color: var(--text-muted);
    font-size: 1rem;
    line-height: 1.8;
}

.faq-item.active .faq-answer {
    max-height: 300px;
    padding: 0 30px 24px;
}

/* Footer */
.footer {
    border-top: 1px solid rgba(255, 255, 255, 0.08);
    padding: 60px 20px 40px;
    text-align: center;
    color: var(--text-muted);
    background: rgba(10, 13, 20, 0.8);
    backdrop-filter: blur(12px);
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 24px;
    margin-bottom: 24px;
    flex-wrap: wrap;
}

.footer-links a {
    color: var(--text-muted);
    text-decoration: none;
}

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

/* 响应式适配 */
@media (max-width: 768px) {
    .header {
        padding: 15px 20px;
    }
    .nav-links {
        display: none;
    }
    .hero h1 {
        font-size: 2.3rem;
    }
    .hero p {
        font-size: 1.1rem;
    }
    .section {
        padding: 80px 15px 50px;
    }
}