/* Reset & Base */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Light mode */
    --bg: #F1F2F4;
    --surface: #FFFFFF;
    --fg: #1E293B;
    --fg-muted: #64748B;
    --accent: #FF6B4A;
    --button: #C83D1B;
    --border: #E2E8F0;
    --shadow: rgba(0, 0, 0, 0.08);
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg: #0C0C0E;
        --surface: #1C1C1E;
        --fg: #F8FAFC;
        --fg-muted: #94A3B8;
        --accent: #FF8F6B;
        --button: #C83D1B;
        --border: #2D2D30;
        --shadow: rgba(0, 0, 0, 0.3);
    }
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Inter', 'SF Pro Text', 'Segoe UI', sans-serif;
    background: var(--bg);
    color: var(--fg);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Navigation */
.nav {
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(10px);
    background: rgba(255, 255, 255, 0.9);
}

@media (prefers-color-scheme: dark) {
    .nav {
        background: rgba(28, 28, 30, 0.9);
    }
}

.nav-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 600;
    font-size: 1.125rem;
}

.nav-logo {
    font-size: 1.5rem;
}

.nav-title {
    color: var(--fg);
}

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

.nav-link {
    color: var(--fg-muted);
    text-decoration: none;
    font-size: 0.9375rem;
    font-weight: 500;
    transition: color 0.2s;
}

.nav-link:hover {
    color: var(--accent);
}

.nav-link.active {
    color: var(--accent);
}

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 3rem 1.5rem;
}

/* Hero */
.hero {
    text-align: center;
    padding: 4rem 0 3rem;
}

.hero-title {
    font-size: clamp(2rem, 5vw, 3rem);
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 1rem;
    letter-spacing: -0.02em;
}

.hero-subtitle {
    font-size: clamp(1rem, 2.5vw, 1.25rem);
    color: var(--fg-muted);
    margin-bottom: 2rem;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
    line-height: 1.6;
}

/* CTA Button */
.cta-button {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: var(--button);
    color: #FFFFFF;
    padding: 0.875rem 1.75rem;
    border-radius: 12px;
    text-decoration: none;
    font-weight: 600;
    font-size: 1rem;
    transition: all 0.2s;
    box-shadow: 0 2px 8px var(--shadow);
}

.cta-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px var(--shadow);
}

.cta-button:active {
    transform: translateY(0);
}

.cta-button.secondary {
    background: var(--surface);
    color: var(--accent);
    border: 1px solid var(--border);
}

.cta-icon {
    font-size: 1.25rem;
}

/* Features */
.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
    margin: 4rem 0;
}

.feature-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 16px;
    padding: 2rem;
    transition: all 0.2s;
}

.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 16px var(--shadow);
}

.feature-icon {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.feature-title {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
    color: var(--fg);
}

.feature-description {
    color: var(--fg-muted);
    font-size: 0.9375rem;
    line-height: 1.7;
}

/* App Info Section */
.app-info {
    text-align: center;
    padding: 4rem 0;
    background: var(--surface);
    border-radius: 20px;
    margin: 3rem 0;
    border: 1px solid var(--border);
}

.section-title {
    font-size: clamp(1.75rem, 4vw, 2.25rem);
    font-weight: 700;
    margin-bottom: 1rem;
}

.section-description {
    color: var(--fg-muted);
    font-size: 1.125rem;
    margin-bottom: 2rem;
    max-width: 500px;
    margin-left: auto;
    margin-right: auto;
}

/* Document Pages */
.document {
    max-width: 800px;
}

.document h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    letter-spacing: -0.02em;
}

.last-updated {
    color: var(--fg-muted);
    font-size: 0.875rem;
    margin-bottom: 3rem;
}

.policy-section,
.faq-section,
.contact-section,
.feedback-section {
    margin-bottom: 3rem;
}

.document h2 {
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    color: var(--fg);
}

.document h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin: 2rem 0 1rem;
    color: var(--fg);
}

.document p {
    margin-bottom: 1rem;
    color: var(--fg-muted);
    line-height: 1.7;
}

.document ul {
    margin: 1rem 0 1rem 1.5rem;
    color: var(--fg-muted);
}

.document li {
    margin-bottom: 0.5rem;
    line-height: 1.7;
}

.document a {
    color: var(--accent);
    text-decoration: none;
    transition: opacity 0.2s;
}

.document a:hover {
    opacity: 0.8;
}

.document strong {
    color: var(--fg);
    font-weight: 600;
}

/* FAQ */
.faq-item {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 1.5rem;
    margin-bottom: 1rem;
}

.faq-item h3 {
    margin-top: 0;
    font-size: 1.125rem;
}

.faq-item ul {
    margin-top: 0.5rem;
}

/* Contact */
.contact-email {
    font-size: 1.25rem;
    font-weight: 600;
    margin: 1.5rem 0;
}

.contact-email a {
    color: var(--accent);
}

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

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
    text-align: center;
}

.footer-content p {
    color: var(--fg-muted);
    font-size: 0.875rem;
    margin-bottom: 0.75rem;
}

.footer-links {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 0.75rem;
    flex-wrap: wrap;
}

.footer-links a {
    color: var(--fg-muted);
    text-decoration: none;
    font-size: 0.875rem;
    transition: color 0.2s;
}

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

.separator {
    color: var(--fg-muted);
    font-size: 0.875rem;
}

/* Responsive */
@media (max-width: 768px) {
    .nav-content {
        flex-direction: column;
        gap: 1rem;
    }

    .nav-links {
        gap: 1rem;
    }

    .hero {
        padding: 2rem 0;
    }

    .features {
        grid-template-columns: 1fr;
    }

    .app-info {
        padding: 2rem 1.5rem;
    }
}