:root {
    --primary: #007aff;
    --primary-dark: #0056b3;
    --text: #333;
    --light-bg: #f5f5f7;
    --white: #ffffff;
    --border: #e1e1e1;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    color: var(--text);
    line-height: 1.6;
    background-color: var(--white);
    scroll-behavior: smooth;
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Navbar */
header {
    background: var(--white);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.navbar {
    height: 70px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    text-decoration: none;
    display: flex;
    flex-direction: column;
}

.brand {
    font-size: 24px;
    font-weight: 800;
    color: var(--primary);
    line-height: 1;
}

.tagline {
    font-size: 12px;
    color: #999;
}

.nav-links {
    list-style: none;
    display: flex;
    gap: 30px;
}

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

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

/* Hero Section */
.hero {
    padding: 80px 0;
    background: linear-gradient(135deg, #f0f7ff 0%, #ffffff 100%);
    overflow: hidden;
}

.hero .container {
    display: flex;
    align-items: center;
    gap: 50px;
}

.hero-content {
    flex: 1;
}

.hero-content h1 {
    font-size: 42px;
    font-weight: 800;
    margin-bottom: 20px;
    line-height: 1.2;
    color: #1d1d1f;
}

.subtitle {
    font-size: 20px;
    color: #666;
    margin-bottom: 40px;
}

.cta-group {
    display: flex;
    gap: 20px;
    margin-bottom: 25px;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 15px 30px;
    border-radius: 50px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s;
}

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

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

.btn-sub {
    border: 2px solid var(--primary);
    color: var(--primary);
}

.btn-sub:hover {
    background: #f0f7ff;
    transform: translateY(-2px);
}

.version-info {
    font-size: 14px;
    color: #999;
}

.hero-image {
    flex: 1;
}

.hero-image img {
    max-width: 100%;
    border-radius: 20px;
    box-shadow: 0 20px 40px rgba(0,0,0,0.1);
}

/* Section Common */
.section-title {
    text-align: center;
    font-size: 32px;
    margin-bottom: 50px;
    font-weight: 700;
}

/* Features */
.features {
    padding: 100px 0;
    background: var(--light-bg);
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 30px;
}

.feature-card {
    background: var(--white);
    padding: 40px 30px;
    border-radius: 20px;
    text-align: center;
    transition: transform 0.3s;
}

.feature-card:hover {
    transform: translateY(-10px);
}

.f-icon {
    font-size: 48px;
    margin-bottom: 20px;
}

.feature-card h3 {
    font-size: 20px;
    margin-bottom: 15px;
}

.feature-card p {
    color: #666;
    font-size: 15px;
}

/* Guide */
.guide {
    padding: 100px 0;
}

.guide-steps {
    display: flex;
    justify-content: space-between;
    gap: 30px;
}

.step {
    flex: 1;
    text-align: center;
    position: relative;
}

.step-num {
    font-size: 64px;
    font-weight: 900;
    color: #f0f0f0;
    display: block;
    margin-bottom: -30px;
}

.step h4 {
    font-size: 20px;
    position: relative;
    z-index: 1;
    margin-bottom: 15px;
}

/* FAQ */
.faq {
    padding: 100px 0;
    background: var(--light-bg);
}

.faq-list {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    margin-bottom: 30px;
    background: var(--white);
    padding: 25px;
    border-radius: 15px;
}

.faq-item h4 {
    margin-bottom: 10px;
    color: var(--primary);
}

/* Footer */
footer {
    padding: 60px 0;
    background: #1d1d1f;
    color: #888;
    text-align: center;
}

.footer-bottom p {
    margin-bottom: 10px;
}

.links a {
    color: #888;
    text-decoration: none;
    margin: 0 10px;
}

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

/* Responsive */
@media (max-width: 768px) {
    .hero .container {
        flex-direction: column;
        text-align: center;
    }
    .cta-group {
        justify-content: center;
        flex-direction: column;
    }
    .guide-steps {
        flex-direction: column;
    }
    .nav-links {
        display: none;
    }
    .hero-content h1 {
        font-size: 32px;
    }
}