/* CSS Reset & Base Styles */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    --primary-color: #2563eb;
    --primary-light: #eff6ff;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --bg-white: #ffffff;
    --bg-light: #f8fafc;
    --border-color: #e5e7eb;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    --radius: 8px;
    --max-width: 1200px;
    --header-height: 64px;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-white);
}

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

a:hover {
    color: #1d4ed8;
}

img {
    max-width: 100%;
    height: auto;
}

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 2rem;
}

@media (max-width: 768px) {
    .container {
        padding: 0 1rem;
    }
}

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--header-height);
    background-color: var(--bg-white);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    box-shadow: var(--shadow);
}

.navbar .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 100%;
}

.logo {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
}

.logo span {
    color: var(--primary-color);
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-links a {
    color: var(--text-primary);
    font-weight: 500;
    font-size: 0.95rem;
    padding: 0.5rem 0;
    border-bottom: 2px solid transparent;
    transition: border-color 0.2s, color 0.2s;
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--primary-color);
    border-bottom-color: var(--primary-color);
}

/* Mobile Menu Toggle */
.menu-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

.menu-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background-color: var(--text-primary);
    transition: transform 0.3s, opacity 0.3s;
}

@media (max-width: 768px) {
    .menu-toggle {
        display: flex;
    }
    
    .nav-links {
        position: fixed;
        top: var(--header-height);
        left: 0;
        right: 0;
        background-color: var(--bg-white);
        flex-direction: column;
        padding: 1rem 2rem;
        gap: 1rem;
        border-bottom: 1px solid var(--border-color);
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: transform 0.3s, opacity 0.3s, visibility 0.3s;
    }
    
    .nav-links.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }
    
    .nav-links a {
        border-bottom: none;
        padding: 0.5rem 0;
    }
}

/* Footer */
.footer {
    background-color: var(--bg-light);
    border-top: 1px solid var(--border-color);
    padding: 2rem 0;
    margin-top: 4rem;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

.footer-info {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.footer-info p {
    margin: 0.25rem 0;
}

.footer-links {
    display: flex;
    gap: 1.5rem;
}

.footer-links a {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.footer-links a:hover {
    color: var(--primary-color);
}

@media (max-width: 768px) {
    .footer-content {
        flex-direction: column;
        text-align: center;
    }
    
    .footer-links {
        justify-content: center;
    }
}

/* Page Header */
.page-header {
    background-color: var(--primary-light);
    padding: 4rem 0 2rem;
    margin-bottom: 3rem;
}

.page-header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--text-primary);
}

.page-header p {
    color: var(--text-secondary);
    margin-top: 0.5rem;
    font-size: 1.125rem;
}

@media (max-width: 768px) {
    .page-header h1 {
        font-size: 1.875rem;
    }
}

/* Cards */
.card {
    background-color: var(--bg-white);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 1.5rem;
    box-shadow: var(--shadow);
    transition: transform 0.2s, box-shadow 0.2s;
}

.card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

/* Grid Layouts */
.grid-3 {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.5rem;
}

.grid-2 {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.5rem;
}

@media (max-width: 1024px) {
    .grid-3 {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 640px) {
    .grid-3,
    .grid-2 {
        grid-template-columns: 1fr;
    }
}

/* Info Table */
.info-table {
    width: 100%;
    border-collapse: collapse;
    margin: 1.5rem 0;
}

.info-table th,
.info-table td {
    padding: 0.875rem 1rem;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

.info-table th {
    background-color: var(--bg-light);
    font-weight: 600;
    width: 30%;
}

.info-table tr:hover td {
    background-color: var(--bg-light);
}

/* Lists */
.feature-list {
    list-style: none;
    padding: 0;
}

.feature-list li {
    padding: 0.75rem 0;
    padding-left: 1.5rem;
    position: relative;
    border-bottom: 1px solid var(--border-color);
}

.feature-list li::before {
    content: "✓";
    position: absolute;
    left: 0;
    color: var(--primary-color);
    font-weight: bold;
}

/* Main Content Spacing */
main {
    padding-top: var(--header-height);
    min-height: calc(100vh - var(--header-height) - 200px);
}

.section {
    padding: 3rem 0;
}

.section-title {
    font-size: 1.875rem;
    font-weight: 700;
    margin-bottom: 2rem;
    text-align: center;
}

/* Contact Info Cards */
.contact-card {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1.5rem;
    background-color: var(--bg-white);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    margin-bottom: 1rem;
}

.contact-icon {
    width: 48px;
    height: 48px;
    background-color: var(--primary-light);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
    flex-shrink: 0;
}

.contact-details h3 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 0.25rem;
}

.contact-details p {
    color: var(--text-secondary);
    font-size: 0.875rem;
}