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

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    color: #0a0a0a;
    line-height: 1.6;
    background: #ffffff;
}

/* ============================================
   DESIGN TOKENS
   ============================================ */
:root {
    --space-1: 8px;
    --space-2: 16px;
    --space-3: 24px;
    --space-4: 32px;
    --space-5: 40px;
    --space-6: 48px;
    --space-8: 64px;
    --space-10: 80px;
    --space-12: 96px;
    --space-16: 128px;
    
    --color-text-primary: #0a0a0a;
    --color-text-secondary: #525252;
    --color-bg-light: #fafafa;
    --color-border: rgba(0, 0, 0, 0.08);
}

/* ============================================
   CONTAINER
   ============================================ */
.container {
    max-width: 680px;
    margin: 0 auto;
    padding: 0 var(--space-2);
}

@media (min-width: 480px) {
    .container {
        padding: 0 var(--space-3);
    }
}

@media (min-width: 768px) {
    .container {
        padding: 0 var(--space-4);
    }
}

/* ============================================
   NAVIGATION
   ============================================ */
.nav {
    position: sticky;
    top: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--color-border);
    z-index: 100;
    width: 100%;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--space-2) var(--space-2);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

@media (min-width: 768px) {
    .nav-container {
        padding: var(--space-3) var(--space-4);
    }
}

.nav-brand {
    font-size: 16px;
    font-weight: 500;
    color: var(--color-text-primary);
    text-decoration: none;
    letter-spacing: -0.01em;
    transition: opacity 200ms ease;
}

.nav-brand:hover {
    opacity: 0.7;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: var(--space-3);
}

.nav-link {
    font-size: 15px;
    color: var(--color-text-secondary);
    text-decoration: none;
    transition: color 200ms ease;
}

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

/* ============================================
   HERO SECTION
   ============================================ */
.hero {
    padding: var(--space-10) 0 var(--space-8);
    text-align: center;
    width: 100%;
}

.hero-title {
    font-size: 48px;
    font-weight: 600;
    color: var(--color-text-primary);
    letter-spacing: -0.03em;
    line-height: 1.1;
    margin-bottom: var(--space-4);
}

.hero-subtitle {
    font-size: 18px;
    color: var(--color-text-secondary);
    letter-spacing: -0.01em;
    line-height: 1.7;
    max-width: 600px;
    margin: 0 auto;
}

@media (min-width: 768px) {
    .hero {
        padding: var(--space-12) 0 var(--space-10);
    }
    
    .hero-title {
        font-size: 64px;
        margin-bottom: var(--space-4);
    }
    
    .hero-subtitle {
        font-size: 24px;
    }
}

/* ============================================
   CONTENT SECTIONS
   ============================================ */
.section {
    padding: var(--space-6) 0;
}

.section-title {
    font-size: 32px;
    font-weight: 600;
    color: var(--color-text-primary);
    letter-spacing: -0.025em;
    line-height: 1.25;
    margin-bottom: var(--space-3);
}

.section-text {
    font-size: 18px;
    color: var(--color-text-secondary);
    line-height: 1.8;
    margin-bottom: var(--space-6);
    letter-spacing: -0.01em;
}

.section-highlight {
    font-size: 20px;
    font-weight: 500;
    color: var(--color-text-primary);
    text-align: center;
    margin-top: var(--space-6);
    letter-spacing: -0.015em;
}

@media (min-width: 768px) {
    .section {
        padding: var(--space-8) 0;
    }
    
    .section-title {
        font-size: 40px;
        margin-bottom: var(--space-3);
    }
    
    .section-text {
        font-size: 20px;
        margin-bottom: var(--space-6);
    }
    
    .section-highlight {
        font-size: 24px;
        margin-top: var(--space-6);
    }
}

/* ============================================
   FEATURE LISTS
   ============================================ */
.feature-list {
    list-style: none;
    margin: var(--space-6) 0;
    padding: 0;
}

.feature-item {
    font-size: 18px;
    color: var(--color-text-secondary);
    padding: var(--space-2) 0;
    letter-spacing: -0.01em;
    line-height: 1.7;
}

@media (min-width: 768px) {
    .feature-list {
        margin: var(--space-8) 0;
    }
    
    .feature-item {
        font-size: 20px;
        padding: var(--space-2) 0;
    }
}

/* ============================================
   SECTION DIVIDERS
   ============================================ */
.section-divider {
    border: none;
    height: 0;
    margin: var(--space-6) 0;
    width: 100%;
}

@media (min-width: 768px) {
    .section-divider {
        margin: var(--space-8) 0;
    }
}

/* ============================================
   CTA SECTION
   ============================================ */
.cta {
    padding: var(--space-10) 0;
    text-align: center;
    margin: var(--space-5) 0 var(--space-16) 0;
}

.cta-title {
    font-size: 32px;
    font-weight: 600;
    color: var(--color-text-primary);
    letter-spacing: -0.025em;
    line-height: 1.25;
    margin-bottom: var(--space-3);
}

.cta-text {
    font-size: 18px;
    color: var(--color-text-secondary);
    line-height: 1.8;
    margin-bottom: var(--space-5);
    letter-spacing: -0.01em;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.cta-highlight {
    font-size: 20px;
    font-weight: 500;
    color: var(--color-text-primary);
    letter-spacing: -0.015em;
}

@media (min-width: 768px) {
    .cta {
        padding: var(--space-10) 0;
        margin: var(--space-8) 0 var(--space-16) 0;
    }
    
    .cta-title {
        font-size: 40px;
        margin-bottom: var(--space-3);
    }
    
    .cta-text {
        font-size: 20px;
        margin-bottom: var(--space-6);
    }
    
    .cta-highlight {
        font-size: 24px;
    }
}

/* ============================================
   FOOTER
   ============================================ */
.footer {
    border-top: 1px solid var(--color-border);
    padding: var(--space-6) 0;
    width: 100%;
    margin-top: var(--space-12);
}

.footer-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-2);
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--space-2);
    font-size: 14px;
    color: var(--color-text-secondary);
}

.footer-container a {
    color: var(--color-text-secondary);
    text-decoration: none;
    transition: color 200ms ease;
}

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

@media (min-width: 480px) {
    .footer-container {
        padding: 0 var(--space-3);
    }
}

@media (min-width: 768px) {
    .footer {
        margin-top: var(--space-16);
    }
    
    .footer-container {
        padding: 0 var(--space-4);
    }
}