:root {
    /* 浅色模式 */
    --page-bg: #ffffff;
    --text-primary: #1d1d1f;
    --text-secondary: #515154;
    --text-muted: #86868b;

    /* 导航栏 (半透明白) */
    --nav-bg: rgba(255, 255, 255, 0.72);
    --nav-border: rgba(0, 0, 0, 0.16);

    /* 页脚 */
    --footer-bg: #f5f5f7;
    --footer-border: #d2d2d7;

    /* 图片占位符 */
    --img-placeholder: #f5f5f7;
}

@media (prefers-color-scheme: dark) {
    :root {
        /* 深色模式 */
        --page-bg: #000000;
        --text-primary: #f5f5f7;
        --text-secondary: #a1a1a6;
        --text-muted: #6e6e73;

        /* 导航栏 */
        --nav-bg: rgba(0, 0, 0, 0.72);
        --nav-border: rgba(255, 255, 255, 0.16);

        /* 页脚 */
        --footer-bg: #1c1c1e;
        --footer-border: #424245;

        /* 图片占位符 */
        --img-placeholder: #1c1c1e;
    }
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--page-bg);
    color: var(--text-primary);
    -webkit-font-smoothing: antialiased;
    line-height: 1.47059;
    letter-spacing: -0.022em;
    transition: background-color 0.3s ease, color 0.3s ease;
}

a {
    text-decoration: none;
    color: inherit;
    transition: color 0.2s ease;
}

.global-nav {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 48px;
    background-color: var(--nav-bg);
    /* 视差模糊 */
    backdrop-filter: saturate(180%) blur(20px);
    -webkit-backdrop-filter: saturate(180%) blur(20px);
    z-index: 9999;
    border-bottom: 1px solid transparent; /* 由 JS 控制显隐 */
    transition: border-bottom-color 0.3s ease, background-color 0.3s ease;
}

.global-nav.scrolled {
    border-bottom: 1px solid var(--nav-border);
}

.nav-content {
    max-width: 1000px;
    margin: 0 auto;
    height: 100%;
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    align-items: center;
    padding: 0 20px;
}

.logo {
    font-weight: 600;
    font-size: 17px;
    letter-spacing: -0.021em;
    justify-self: start;
}

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

.nav-right-area {
    justify-self: end;
    display: flex;
    align-items: center;
    gap: 15px;
}

.nav-links a {
    font-size: 12px;
    color: var(--text-primary);
    opacity: 0.8;
}

.nav-links a:hover {
    opacity: 1;
}

.main-content {
    padding-top: 48px; /* 抵消固定导航栏的高度 */
    min-height: calc(100vh - 300px); /* 确保内容区撑开，页脚在底部 */
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    padding-bottom: 80px;
}

.hero-section {
    text-align: center;
    max-width: 800px;
    width: 100%;
    padding: 40px 20px;
}

/* 中心图片包裹器 */
.hero-image-wrapper {
    margin-top: 40px;
    margin-bottom: 40px;
}

.hero-image {
    width: 100%;
    max-width: 300px; /* 控制图片最大尺寸 */
    height: auto;
    border-radius: 20px;
    /* background-color: var(--img-placeholder); */
    /* 弥散阴影 */
    /* filter: drop-shadow(0 20px 40px rgba(0,0,0,0.1)); */
    transition: background-color 0.3s ease;
}

.hero-text h1 {
    font-size: 48px;
    font-weight: 600;
    letter-spacing: -0.003em;
    margin-bottom: 16px;
}

.hero-text p {
    font-size: 21px;
    color: var(--text-secondary);
    margin-bottom: 8px;
}

.hero-text .sub-text {
    font-size: 14px;
    color: var(--text-muted);
    font-weight: 500;
}

    .global-footer {
    background-color: var(--footer-bg);
    padding: 40px 20px 24px;
    font-size: 12px;
    color: var(--text-secondary);
    transition: background-color 0.3s ease;
}

.footer-content {
    max-width: 1000px;
    margin: 0 auto;
}

.footer-grid {
    display: flex;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 24px;
    margin-bottom: 32px;
}

.footer-column h3 {
    font-size: 12px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 12px;
}

.footer-column ul {
    list-style: none;
}

.footer-column li {
    margin-bottom: 8px;
}

.footer-column a:hover {
    color: var(--text-primary);
    text-decoration: underline;
}

.footer-divider {
    height: 1px;
    background-color: var(--footer-border);
    margin-bottom: 16px;
    transition: background-color 0.3s ease;
}

.footer-bottom {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 12px;
}

.legal-links {
    list-style: none;
    display: flex;
    gap: 16px;
}

.legal-links a:hover {
    color: var(--text-primary);
    text-decoration: underline;
}

.hover-link {
    cursor: pointer;
    color: var(--text-primary);
    text-decoration: none;
    transition: color 0.2s ease;
}

.hover-link:hover {
    text-decoration: underline;
    text-underline-offset: 4px;
    color: var(--btn-primary-bg);
}


/* 移动端简单适配 */
@media (max-width: 768px) {
    .nav-links { display: none; }
    .hero-text h1 { font-size: 32px; }
    .hero-text p { font-size: 17px; }
    .footer-grid { flex-direction: column; }
    .footer-bottom { flex-direction: column; align-items: flex-start; }
}

.main-content.item-page {
    justify-content: flex-start;
    padding-top: 80px;
}

.legal-container {
    width: 100%;
    max-width: 840px;
    margin: 0 auto;
    padding: 0 20px;
    text-align: left;
}

.legal-header {
    border-bottom: 1px solid var(--footer-border);
    padding-bottom: 24px;
    margin-bottom: 40px;
}

.legal-header h1 {
    font-size: 40px;
    font-weight: 600;
    letter-spacing: -0.015em;
    margin-bottom: 12px;
}

.legal-header .last-updated {
    font-size: 14px;
    color: var(--text-muted);
}

.legal-content h2 {
    font-size: 24px;
    font-weight: 600;
    margin: 48px 0 16px;
    letter-spacing: -0.01em;
    color: var(--text-primary);
}

.legal-content h3 {
    font-size: 18px;
    font-weight: 600;
    margin: 32px 0 12px;
    color: var(--text-primary);
}

.legal-content p {
    font-size: 15px;
    line-height: 1.6;
    color: var(--text-secondary);
    margin-bottom: 16px;
}

.legal-content ul, .legal-content ol {
    margin-bottom: 16px;
    padding-left: 24px;
    color: var(--text-secondary);
    font-size: 15px;
    line-height: 1.6;
}

.legal-content li {
    margin-bottom: 8px;
}

.legal-content a {
    color: #0066cc;
    text-decoration: none;
}

.legal-content a:hover {
    text-decoration: underline;
}

@media (prefers-color-scheme: dark) {
    .legal-content a {
        color: #2997ff;
    }
}