/* Base Styles & Typography */
:root {
    --primary-color: #2563eb;
    --secondary-color: #1e40af;
    --text-color: #334155;
    --text-light: #64748b;
    --bg-color: #f8fafc;
    --white: #ffffff;
    --border-color: #e2e8f0;
    --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
}

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

body {
    font-family: var(--font-family);
    color: var(--text-color);
    background-color: var(--bg-color);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

/* Language Toggle Logic */
.lang-en .zh { display: none !important; }
.lang-zh .en { display: none !important; }

/* Layout */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

/* Header & Nav */
header {
    background: var(--white);
    box-shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
    position: sticky;
    top: 0;
    z-index: 1000;
}

nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 80px;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 10px;
}

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

.nav-links a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    transition: color 0.3s;
}

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

.lang-switch {
    background: var(--bg-color);
    border: 1px solid var(--border-color);
    padding: 0.5rem 1rem;
    border-radius: 4px;
    cursor: pointer;
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text-color);
    transition: all 0.3s;
}

.lang-switch:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, #1e3a8a 0%, #2563eb 100%);
    color: var(--white);
    padding: 6rem 0;
    text-align: center;
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 1.5rem;
    font-weight: 800;
}

.hero p {
    font-size: 1.25rem;
    max-width: 800px;
    margin: 0 auto 2rem;
    opacity: 0.9;
}

.btn {
    display: inline-block;
    padding: 0.75rem 2rem;
    border-radius: 4px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s;
    cursor: pointer;
    border: none;
}

.btn-primary {
    background: var(--white);
    color: var(--primary-color);
}

.btn-primary:hover {
    background: var(--bg-color);
    transform: translateY(-2px);
}

/* Sections */
.section {
    padding: 5rem 0;
}

.section-title {
    text-align: center;
    font-size: 2.25rem;
    margin-bottom: 3rem;
    color: #0f172a;
}

/* Features/Services */
.grid-3 {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.card {
    background: var(--white);
    padding: 2.5rem;
    border-radius: 8px;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    transition: transform 0.3s;
}

.card:hover {
    transform: translateY(-5px);
}

.card-icon {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 1.5rem;
}

.card h3 {
    font-size: 1.25rem;
    margin-bottom: 1rem;
    color: #0f172a;
}

/* Content Pages */
.page-header {
    background: var(--white);
    padding: 4rem 0;
    border-bottom: 1px solid var(--border-color);
    margin-bottom: 3rem;
}

.page-header h1 {
    font-size: 2.5rem;
    color: #0f172a;
}

.content-box {
    background: var(--white);
    padding: 3rem;
    border-radius: 8px;
    box-shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1);
    margin-bottom: 4rem;
}

.content-box h2 {
    margin-top: 2rem;
    margin-bottom: 1rem;
    color: #0f172a;
}

.content-box p {
    margin-bottom: 1rem;
    color: var(--text-color);
}

.content-box ul {
    margin-bottom: 1rem;
    padding-left: 2rem;
}

.content-box li {
    margin-bottom: 0.5rem;
}

/* Footer */
footer {
    background: #0f172a;
    color: #94a3b8;
    padding: 4rem 0 2rem;
    margin-top: auto;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 3rem;
    margin-bottom: 3rem;
}

.footer-col h4 {
    color: var(--white);
    font-size: 1.125rem;
    margin-bottom: 1.5rem;
}

.footer-col p {
    margin-bottom: 0.75rem;
}

.footer-links {
    list-style: none;
}

.footer-links li {
    margin-bottom: 0.75rem;
}

.footer-links a {
    color: #94a3b8;
    text-decoration: none;
    transition: color 0.3s;
}

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

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid #1e293b;
    font-size: 0.875rem;
}

/* Responsive */
@media (max-width: 768px) {
    .nav-links {
        display: none; /* simple mobile nav approach for static */
    }
    .hero h1 {
        font-size: 2rem;
    }
    .grid-3 {
        grid-template-columns: 1fr;
    }
}