:root {
    --primary: #1A2B4C;
    --blue: #1E6FFF;
    --blue-dark: #0052D9;
    --blue-light: #E8F4FD;
    --sidebar-bg: #F5F7FA;
    --text-dark: #1A2B4C;
    --text-gray: #5A6B7D;
    --text-light: #8C9BAB;
    --border: #E2E8F0;
    --white: #ffffff;
    --radius: 10px;
    --radius-lg: 14px;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    color: var(--text-dark);
    line-height: 1.6;
    background: #f8fafc;
    -webkit-font-smoothing: antialiased;
}

a { text-decoration: none; color: inherit; }

.page-header {
    background: linear-gradient(135deg, #1E6FFF 0%, #0052D9 100%);
    color: white;
    padding: 48px 24px;
    text-align: center;
}

.page-header h1 { font-size: 1.75rem; font-weight: 700; }
.page-header p { font-size: 14px; opacity: 0.9; margin-top: 8px; }

.page-container {
    max-width: 900px;
    margin: 32px auto;
    padding: 0 24px;
}

.page-content {
    background: var(--white);
    border-radius: var(--radius-lg);
    padding: 36px 32px;
    border: 1px solid var(--border);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.04);
}

.page-content h2 {
    color: var(--primary);
    font-size: 1.15rem;
    margin: 28px 0 12px;
}

.page-content h2:first-child { margin-top: 0; }

.page-content p {
    color: var(--text-gray);
    margin-bottom: 12px;
    line-height: 1.85;
}

.page-content .indent { text-indent: 2em; }

.intro-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 20px;
    margin-top: 20px;
}

.intro-card {
    background: #F8FBFF;
    border: 1px solid var(--border);
    border-left: 3px solid var(--blue);
    border-radius: var(--radius);
    padding: 24px 20px;
}

.intro-card h3 {
    color: var(--primary);
    font-size: 16px;
    margin-bottom: 10px;
}

.intro-card p {
    font-size: 14px;
    text-indent: 0;
}

.why-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
    margin-top: 20px;
}

.why-card {
    background: linear-gradient(135deg, var(--primary) 0%, #2a4365 100%);
    color: white;
    border-radius: var(--radius);
    padding: 20px 16px;
    text-align: center;
}

.why-card strong {
    display: block;
    color: #fbd38d;
    margin-bottom: 6px;
}

.why-card span { font-size: 13px; opacity: 0.85; }

.doc-cards {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
    margin-top: 20px;
}

.doc-card {
    flex: 1;
    min-width: 200px;
    background: #F8FBFF;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 24px 20px;
    text-align: center;
    transition: box-shadow 0.2s, transform 0.2s;
}

.doc-card:hover {
    box-shadow: 0 8px 24px rgba(30, 111, 255, 0.1);
    transform: translateY(-2px);
}

.doc-card img {
    width: 44px;
    height: 44px;
    object-fit: contain;
    margin: 0 auto 12px;
    display: block;
}

.doc-card h3 { color: var(--primary); font-size: 16px; margin-bottom: 6px; }
.doc-card p { font-size: 13px; color: var(--text-light); text-indent: 0; }

.back-link {
    display: inline-block;
    margin-top: 24px;
    color: var(--blue);
    font-size: 14px;
}

.back-link:hover { color: var(--blue-dark); }

.site-footer {
    background: transparent;
    color: var(--text-light);
    text-align: center;
    padding: 20px;
    font-size: 12px;
    margin-top: 48px;
}

.site-footer a { color: var(--text-gray); }
.site-footer a:hover { color: var(--blue); }

.top-nav {
    background: var(--white);
    border-bottom: 1px solid var(--border);
    padding: 0 24px;
    height: 56px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.top-nav .brand {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 700;
    color: var(--primary);
}

.top-nav .brand img { width: 32px; height: 32px; }

.top-nav-links a {
    font-size: 14px;
    color: var(--text-gray);
    margin-left: 24px;
}

.top-nav-links a:hover { color: var(--blue); }

@media (max-width: 640px) {
    .why-grid { grid-template-columns: 1fr; }
    .page-content { padding: 24px 20px; }
}