@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+SC:wght@400;500&family=Noto+Serif+SC:wght@700;900&display=swap');

/* 基础重置与变量 */
:root {
    --bg-paper: #F7F3EA;
    --text-ink: #1A1714;
    --brand-vermilion: #C8322B;
    --ochre-secondary: #9C6B30;
    --divider-hairline: #E3D9C8;
}

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

body {
    font-family: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, sans-serif;
    line-height: 1.6;
    color: var(--text-ink);
    background-color: var(--bg-paper);
}

h1, h2, h3, h4, h5, h6 {
    font-family: 'Noto Serif SC', serif;
    font-weight: 700;
}

a {
    text-decoration: none;
    color: var(--text-ink);
    transition: color 0.2s ease;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 按钮样式 - 锐利、无阴影、无渐变 */
.btn {
    display: inline-block;
    padding: 12px 32px;
    font-weight: 500;
    text-align: center;
    cursor: pointer;
    transition: all 0.2s ease;
    border-radius: 0; /* Sharp corners */
}

.btn-primary {
    background-color: var(--brand-vermilion);
    color: #fff;
    border: 1px solid var(--brand-vermilion);
}

.btn-primary:hover {
    background-color: #A62822;
    border-color: #A62822;
    color: #fff;
}

.btn-ghost {
    background-color: transparent;
    color: var(--text-ink);
    border: 1px solid var(--text-ink);
}

.btn-ghost:hover {
    background-color: var(--text-ink);
    color: var(--bg-paper);
}

.btn-large {
    padding: 16px 48px;
    font-size: 1.1rem;
}

/* 头部导航 - 粘性、极简、细线 */
.header {
    background-color: var(--bg-paper);
    border-bottom: 1px solid var(--divider-hairline);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 72px;
}

.logo-wrapper {
    display: flex;
    align-items: center;
    gap: 12px;
}

.logo-text {
    font-family: 'Noto Serif SC', serif;
    font-weight: 900;
    font-size: 1.5rem;
    color: var(--text-ink);
    letter-spacing: 2px;
}

.nav {
    display: flex;
    gap: 30px;
}

.nav a {
    font-size: 0.95rem;
    font-weight: 500;
}

.nav a:hover {
    color: var(--brand-vermilion);
}

/* 带有间距的英文小标签 */
.label-en {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.15em;
    color: var(--ochre-secondary);
    display: block;
    margin-bottom: 8px;
}

/* 主视觉区 Hero */
.hero {
    padding: 100px 0 80px;
    text-align: center;
    background-color: var(--bg-paper);
}

.hero h1 {
    font-size: 4rem;
    font-weight: 900;
    margin-bottom: 24px;
    line-height: 1.2;
    letter-spacing: 2px;
}

.hero p {
    font-size: 1.25rem;
    margin-bottom: 48px;
    color: var(--text-ink);
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
    opacity: 0.85;
}

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

/* 统计数据条 */
.stat-strip {
    border-top: 1px solid var(--divider-hairline);
    border-bottom: 1px solid var(--divider-hairline);
    padding: 30px 0;
    background-color: var(--bg-paper);
}

.stat-grid {
    display: flex;
    justify-content: space-between;
    text-align: center;
}

.stat-item {
    flex: 1;
    border-right: 1px solid var(--divider-hairline);
}

.stat-item:last-child {
    border-right: none;
}

.stat-value {
    font-family: 'Noto Serif SC', serif;
    font-size: 2rem;
    font-weight: 700;
    color: var(--brand-vermilion);
    margin-bottom: 5px;
}

.stat-label {
    font-size: 0.9rem;
    color: var(--text-ink);
    opacity: 0.8;
}

/* 通用区块与网格系统 */
.section {
    padding: 100px 0;
    border-bottom: 1px solid var(--divider-hairline);
}

.section:last-child {
    border-bottom: none;
}

.section-header {
    text-align: center;
    margin-bottom: 60px;
}

.section-title {
    font-size: 2.5rem;
    margin-bottom: 16px;
}

/* 核心特性 (3列) */
.features-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 40px;
}

.feature-card {
    padding: 20px 0;
}

.feature-icon {
    width: 48px;
    height: 48px;
    margin-bottom: 24px;
    stroke: var(--brand-vermilion);
    stroke-width: 1.5;
    fill: none;
}

.feature-card h3 {
    font-size: 1.25rem;
    margin-bottom: 16px;
}

.feature-card p {
    color: var(--text-ink);
    opacity: 0.75;
    font-size: 0.95rem;
}

/* 价格表 */
.pricing-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 0;
    border: 1px solid var(--divider-hairline);
}

.price-card {
    padding: 48px 32px;
    border-right: 1px solid var(--divider-hairline);
    text-align: center;
    background: var(--bg-paper);
}

.price-card:last-child {
    border-right: none;
}

.price-card.popular {
    background-color: #fff; /* 极轻微的提亮，维持肃穆感 */
    border-top: 4px solid var(--brand-vermilion);
}

.price-card h3 {
    font-size: 1.5rem;
    margin-bottom: 8px;
}

.price {
    font-family: 'Noto Serif SC', serif;
    font-size: 3rem;
    font-weight: 700;
    color: var(--brand-vermilion);
    margin: 24px 0;
}

.price span {
    font-size: 1rem;
    font-family: 'Noto Sans SC', sans-serif;
    color: var(--text-ink);
    font-weight: 400;
}

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

.price-features li {
    padding: 12px 0;
    border-bottom: 1px dashed var(--divider-hairline);
    font-size: 0.95rem;
}

.price-features li:last-child {
    border-bottom: none;
}

/* FAQ 与 文章区 */
.faq-list {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    border-bottom: 1px solid var(--divider-hairline);
    padding: 24px 0;
}

.faq-item:last-child {
    border-bottom: none;
}

.faq-item h4 {
    font-size: 1.15rem;
    margin-bottom: 12px;
}

.faq-item p {
    color: var(--text-ink);
    opacity: 0.8;
}

/* 页脚 */
.footer {
    background-color: var(--text-ink);
    color: var(--bg-paper);
    padding: 60px 0;
    text-align: center;
}

.footer a {
    color: var(--bg-paper);
    opacity: 0.7;
    margin: 0 20px;
    font-size: 0.9rem;
}

.footer a:hover {
    opacity: 1;
    color: var(--brand-vermilion);
}

.copyright {
    margin-top: 40px;
    font-size: 0.8rem;
    opacity: 0.5;
    letter-spacing: 1px;
}

/* 响应式 */
@media (max-width: 768px) {
    .header-container {
        flex-direction: column;
        height: auto;
        padding: 20px 0;
        gap: 20px;
    }
    
    .nav {
        flex-wrap: wrap;
        justify-content: center;
        gap: 15px;
    }
    
    .hero h1 { font-size: 2.5rem; }
    .hero-actions { flex-direction: column; }
    
    .stat-grid { flex-direction: column; }
    .stat-item { border-right: none; border-bottom: 1px solid var(--divider-hairline); padding: 20px 0; }
    .stat-item:last-child { border-bottom: none; }
    
    .features-grid, .pricing-grid { grid-template-columns: 1fr; }
    .price-card { border-right: none; border-bottom: 1px solid var(--divider-hairline); }
    .price-card:last-child { border-bottom: none; }
}

/* Smooth scrolling */
html {
    scroll-behavior: smooth;
}

/* 悬浮返回顶部按钮 */
.floating-btn {
    position: fixed;
    bottom: 40px;
    right: 40px;
    width: 50px;
    height: 50px;
    background-color: var(--brand-vermilion);
    color: var(--bg-paper);
    display: flex;
    align-items: center;
    justify-content: center;
    text-decoration: none;
    box-shadow: 0 4px 12px rgba(200, 50, 43, 0.3);
    z-index: 999;
    transition: all 0.3s ease;
    border: 1px solid var(--brand-vermilion);
}

.floating-btn:hover {
    background-color: #A62822;
    transform: translateY(-3px);
    color: #fff;
}

.floating-btn svg {
    width: 24px;
    height: 24px;
    fill: currentColor;
}

/* 下一篇文章导航 */
.next-article-nav {
    margin-top: 50px;
    padding-top: 30px;
    border-top: 1px solid var(--divider-hairline);
    text-align: right;
}

.next-article-nav a {
    display: inline-flex;
    align-items: center;
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--brand-vermilion);
    text-decoration: none;
    transition: transform 0.2s ease;
}

.next-article-nav a::after {
    content: '→';
    margin-left: 10px;
    font-family: sans-serif;
}

.next-article-nav a:hover {
    transform: translateX(5px);
}

@media (max-width: 768px) {
    .floating-btn {
        bottom: 20px;
        right: 20px;
        width: 45px;
        height: 45px;
    }
}