/* Custom Scrollbar */
::-webkit-scrollbar {
    width: 10px;
    height: 10px;
}

::-webkit-scrollbar-track {
    background: var(--bg-dark);
}

::-webkit-scrollbar-thumb {
    background: rgba(255, 255, 255, 0.1);
    border-radius: 5px;
    border: 2px solid var(--bg-dark);
    transition: background 0.3s;
}

::-webkit-scrollbar-thumb:hover {
    background: rgba(255, 255, 255, 0.2);
}

/* Firefox scrollbar */
* {
    scrollbar-width: thin;
    scrollbar-color: rgba(255, 255, 255, 0.1) var(--bg-dark);
}

:root {
    --primary: #4f46e5;
    --primary-hover: #4338ca;
    --bg-dark: #0f172a;
    --glass-bg: rgba(255, 255, 255, 0.05);
    --glass-border: rgba(255, 255, 255, 0.1);
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

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

body {
    background-color: var(--bg-dark);
    color: var(--text-main);
    font-family: var(--font-sans);
    line-height: 1.5;
    overflow-x: hidden;
}

/* Background Liquid Effect */
.liquid-bg {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    overflow: hidden;
    background: radial-gradient(circle at 20% 30%, rgba(79, 70, 229, 0.15) 0%, transparent 50%),
                radial-gradient(circle at 80% 70%, rgba(139, 92, 246, 0.15) 0%, transparent 50%);
}

.liquid-blob {
    position: absolute;
    filter: blur(80px);
    opacity: 0.5;
    border-radius: 50%;
    animation: move 20s infinite alternate ease-in-out;
}

@keyframes move {
    from { transform: translate(0, 0) scale(1); }
    to { transform: translate(100px, 50px) scale(1.2); }
}

/* Header & Nav */
header {
    position: fixed;
    top: 0;
    width: 100%;
    padding: 1.5rem 2rem;
    z-index: 100;
    backdrop-filter: blur(12px);
    background: rgba(15, 23, 42, 0.7);
    border-bottom: 1px solid var(--glass-border);
}

nav {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    text-decoration: none;
    color: white;
    font-weight: 700;
    font-size: 1.5rem;
}

.logo img {
    height: 32px;
}

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

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

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

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: 0.5rem;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    cursor: pointer;
}

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

.btn-primary:hover {
    background: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 10px 15px -3px rgba(79, 70, 229, 0.4);
}

.btn-outline {
    border: 1px solid var(--glass-border);
    color: var(--text-main);
    backdrop-filter: blur(4px);
}

.btn-outline:hover {
    background: var(--glass-bg);
    border-color: var(--text-main);
}

/* Hero Section */
.hero {
    padding: 8rem 2rem 4rem;
    max-width: 1200px;
    margin: 0 auto;
    text-align: center;
}

.hero-preview {
    max-width: 1000px;
    margin: 2rem auto 4rem;
    position: relative;
    padding: 10px;
    background: rgba(255, 255, 255, 0.05);
    border-radius: 1.5rem;
    border: 1px solid rgba(255, 255, 255, 0.1);
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(10px);
    opacity: 0;
    transform: translateY(40px);
}

.hero-preview img {
    width: 100%;
    height: auto;
    display: block;
    border-radius: 1rem;
    box-shadow: 0 0 20px rgba(79, 70, 229, 0.2);
}

.hero-preview::before {
    content: '';
    position: absolute;
    top: -2px;
    left: -2px;
    right: -2px;
    bottom: -2px;
    background: linear-gradient(45deg, var(--primary), transparent, var(--primary));
    z-index: -1;
    border-radius: 1.6rem;
    opacity: 0.3;
}

.hero h1 {
    font-size: 4rem;
    font-weight: 800;
    margin-bottom: 1.5rem;
    background: linear-gradient(to right, #fff, #94a3b8);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero p {
    font-size: 1.25rem;
    color: var(--text-muted);
    max-width: 700px;
    margin: 0 auto 2.5rem;
}

/* Cards / Glass Container */
.glass-card {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    backdrop-filter: blur(12px);
    border-radius: 1rem;
    padding: 2rem;
    transition: transform 0.3s ease, border-color 0.3s ease;
}

.glass-card:hover {
    border-color: rgba(255, 255, 255, 0.2);
    transform: translateY(-5px);
}

.hero-btns {
    display: flex;
    gap: 1.5rem;
    justify-content: center;
    margin-top: 2rem;
    position: relative;
    z-index: 10;
    opacity: 0; /* 初始隐藏，由 JS 控制显示 */
}

.btn-icon {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
}

.testimonial-card {
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

.testimonial-user {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-top: 1.5rem;
}

.testimonial-avatar {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: var(--primary);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    color: white;
}

.testimonial-info h4 {
    font-size: 1rem;
    margin: 0;
}

.testimonial-info span {
    font-size: 0.875rem;
    color: var(--text-muted);
}

/* Stats Section */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
    text-align: center;
    margin: 4rem 0;
}

.stat-item h2 {
    font-size: 3rem;
    font-weight: 800;
    color: var(--primary);
    margin-bottom: 0.5rem;
}

.stat-item p {
    color: var(--text-muted);
    font-weight: 500;
}

/* FAQ Section */
.faq-container {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    margin-bottom: 1rem;
    overflow: hidden;
}

.faq-question {
    width: 100%;
    padding: 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: 0.75rem;
    color: white;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
}

.faq-question:hover {
    background: rgba(255, 255, 255, 0.1);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease, padding 0.3s ease;
    padding: 0 1.5rem;
    color: var(--text-muted);
    line-height: 1.6;
}

.faq-item.active .faq-answer {
    max-height: 200px;
    padding: 1rem 1.5rem 1.5rem;
}

.faq-item.active .faq-question {
    border-bottom-left-radius: 0;
    border-bottom-right-radius: 0;
    background: rgba(255, 255, 255, 0.08);
}

.faq-icon {
    transition: transform 0.3s ease;
}

.faq-item.active .faq-icon {
    transform: rotate(180deg);
}

/* Platform Section */
.platform-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin: 4rem 0;
}

.platform-card {
    text-align: center;
    padding: 3rem 2rem;
}

.platform-card i {
    width: 64px;
    height: 64px;
    color: var(--primary);
    margin-bottom: 1.5rem;
}

.platform-status {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    background: rgba(79, 70, 229, 0.1);
    color: var(--primary);
    border-radius: 1rem;
    font-size: 0.75rem;
    font-weight: 600;
    margin-top: 1rem;
}

/* Security Certification Section */
.security-certs {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 3rem;
    flex-wrap: wrap;
    padding: 2rem;
    background: rgba(255, 255, 255, 0.02);
    border-top: 1px solid var(--glass-border);
    border-bottom: 1px solid var(--glass-border);
    margin: 2rem 0;
}

.cert-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    color: var(--text-muted);
    font-size: 0.875rem;
    font-weight: 500;
    transition: color 0.3s ease;
}

.cert-item:hover {
    color: var(--text-main);
}

.cert-item i {
    color: #10b981; /* Success Green */
    width: 20px;
    height: 20px;
}

/* Footer */
footer {
    padding: 4rem 2rem;
    border-top: 1px solid var(--glass-border);
    margin-top: 6rem;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 3rem;
}

.footer-section h4 {
    margin-bottom: 1.5rem;
    color: white;
}

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

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

.footer-links a {
    color: var(--text-muted);
    text-decoration: none;
    transition: color 0.3s ease;
}

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

.copyright {
    text-align: center;
    padding-top: 3rem;
    color: var(--text-muted);
    font-size: 0.875rem;
}

/* Responsive */
@media (max-width: 768px) {
    .hero h1 { font-size: 2.5rem; }
    .nav-links { display: none; }
}