:root {
    /* Color System */
    --primary-color: #2563eb;
    --primary-dark: #1e40af;
    --primary-light: #3b82f6;
    --accent-color: #dbeafe;
    --success-color: #10b981;
    --warning-color: #f59e0b;

    /* Background Colors */
    --bg-primary: #ffffff;
    --bg-secondary: #f9fafb;
    --bg-dark: #1f2937;
    --bg-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);

    /* Text Colors */
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --text-light: #9ca3af;
    --text-white: #ffffff;

    /* Border & Shadows */
    --border-color: #e5e7eb;
    --border-radius: 8px;
    --border-radius-lg: 16px;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 60px rgba(0, 0, 0, 0.3);

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;

    /* Typography */
    --font-family:
        "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
        sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 1.875rem;
    --font-size-4xl: 2.25rem;
    --font-size-5xl: 3rem;

    /* Transitions */
    --transition-fast: 150ms ease-in-out;
    --transition-base: 200ms ease-in-out;
    --transition-slow: 300ms ease-in-out;

    /* Layout */
    --max-width-content: 1200px;
    --max-width-text: 900px;
    --header-height: 70px;
}

/* ==================== RESET & BASE ==================== */

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

html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: var(--font-family);
    line-height: 1.7;
    color: var(--text-primary);
    background-color: var(--bg-secondary);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color var(--transition-base);
}

a:hover {
    color: var(--primary-dark);
}

/* ==================== TYPOGRAPHY ==================== */

h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    color: var(--text-primary);
    margin-bottom: var(--spacing-md);
}

h1 {
    font-size: var(--font-size-5xl);
}

h2 {
    font-size: var(--font-size-4xl);
}

h3 {
    font-size: var(--font-size-3xl);
}

h4 {
    font-size: var(--font-size-2xl);
}

h5 {
    font-size: var(--font-size-xl);
}

h6 {
    font-size: var(--font-size-lg);
}

p {
    margin-bottom: var(--spacing-sm);
    color: var(--text-secondary);
}

strong {
    font-weight: 600;
    color: var(--text-primary);
}

/* ==================== LAYOUT ==================== */

.container {
    max-width: var(--max-width-content);
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

.container-narrow {
    max-width: var(--max-width-text);
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

.section {
    padding: var(--spacing-2xl) 0;
}

.section-lg {
    padding: 4rem 0;
}

/* ==================== HEADER & NAVIGATION ==================== */

.header {
    background: var(--bg-primary);
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 1000;
    height: var(--header-height);
}

.nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: var(--header-height);
    max-width: var(--max-width-content);
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

.nav-logo {
    font-size: var(--font-size-2xl);
    font-weight: 700;
    color: var(--primary-color);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.nav-logo:hover {
    color: var(--primary-dark);
}

.nav-links {
    display: flex;
    list-style: none;
    gap: var(--spacing-lg);
    align-items: center;
}

.nav-link {
    font-weight: 500;
    color: var(--text-secondary);
    transition: color var(--transition-base);
}

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

.nav-toggle {
    display: none;
    background: none;
    border: none;
    font-size: var(--font-size-2xl);
    cursor: pointer;
    color: var(--text-primary);
}

/* ==================== BUTTONS ==================== */

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    padding: 0.75rem 1.5rem;
    font-weight: 600;
    font-size: var(--font-size-base);
    border-radius: var(--border-radius);
    border: none;
    cursor: pointer;
    transition: all var(--transition-base);
    text-decoration: none;
    white-space: nowrap;
}

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

.btn-primary:hover {
    background: var(--primary-dark);
    color: var(--text-white);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background: var(--bg-secondary);
    color: var(--text-primary);
    border: 2px solid var(--border-color);
}

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

.btn-lg {
    padding: 1rem 2rem;
    font-size: var(--font-size-lg);
}

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

/* ==================== HERO SECTION ==================== */

.hero {
    background: var(--bg-gradient);
    color: var(--text-white);
    padding: 5rem 0 4rem;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg width="100" height="100" xmlns="http://www.w3.org/2000/svg"><defs><pattern id="grid" width="100" height="100" patternUnits="userSpaceOnUse"><path d="M 100 0 L 0 0 0 100" fill="none" stroke="rgba(255,255,255,0.05)" stroke-width="1"/></pattern></defs><rect width="100%" height="100%" fill="url(%23grid)"/></svg>');
    opacity: 0.5;
}

.hero-content {
    position: relative;
    z-index: 1;
}

.hero h1 {
    color: var(--text-white);
    margin-bottom: var(--spacing-md);
    font-size: clamp(2.5rem, 5vw, 4rem);
}

.hero p {
    color: rgba(255, 255, 255, 0.95);
    font-size: var(--font-size-xl);
    margin-bottom: var(--spacing-xl);
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
}

.hero-cta {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    flex-wrap: wrap;
    margin-top: var(--spacing-xl);
}

/* ==================== FEATURES SECTION ==================== */

.features {
    background: var(--bg-primary);
    padding: var(--spacing-2xl) 0;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-xl);
    margin-top: var(--spacing-xl);
}

.feature-card {
    background: var(--bg-secondary);
    padding: var(--spacing-xl);
    border-radius: var(--border-radius-lg);
    text-align: center;
    transition: all var(--transition-base);
    border: 2px solid transparent;
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-color);
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: var(--spacing-md);
}

.feature-card h3 {
    font-size: var(--font-size-xl);
    margin-bottom: var(--spacing-sm);
}

.feature-card p {
    color: var(--text-secondary);
}

/* ==================== APP STORE BADGES ==================== */

.app-store-buttons {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    flex-wrap: wrap;
    margin-top: var(--spacing-lg);
}

.app-store-badge {
    display: inline-block;
    height: 50px;
    transition: transform var(--transition-base);
}

.app-store-badge:hover {
    transform: scale(1.05);
}

.app-store-badge img {
    height: 100%;
    width: auto;
}

/* ==================== FOOTER ==================== */

.footer {
    background: var(--bg-dark);
    color: rgba(255, 255, 255, 0.8);
    padding: var(--spacing-2xl) 0 var(--spacing-lg);
}

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

.footer-section h4 {
    color: var(--text-white);
    margin-bottom: var(--spacing-md);
}

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

.footer-links li {
    margin-bottom: var(--spacing-xs);
}

.footer-links a {
    color: rgba(255, 255, 255, 0.7);
    transition: color var(--transition-base);
}

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

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: var(--spacing-md);
    text-align: center;
    font-size: var(--font-size-sm);
    color: rgba(255, 255, 255, 0.6);
}

/* ==================== UTILITY CLASSES ==================== */

.text-center {
    text-align: center;
}

.text-white {
    color: var(--text-white);
}

.mt-sm {
    margin-top: var(--spacing-sm);
}

.mt-md {
    margin-top: var(--spacing-md);
}

.mt-lg {
    margin-top: var(--spacing-lg);
}

.mb-sm {
    margin-bottom: var(--spacing-sm);
}

.mb-md {
    margin-bottom: var(--spacing-md);
}

.mb-lg {
    margin-bottom: var(--spacing-lg);
}

/* ==================== RESPONSIVE DESIGN ==================== */

@media (max-width: 768px) {
    :root {
        --font-size-5xl: 2.5rem;
        --font-size-4xl: 2rem;
        --font-size-3xl: 1.5rem;
        --spacing-xl: 2rem;
        --spacing-2xl: 3rem;
    }

    .nav-links {
        position: fixed;
        top: var(--header-height);
        left: 0;
        right: 0;
        background: var(--bg-primary);
        flex-direction: column;
        padding: var(--spacing-lg);
        box-shadow: var(--shadow-lg);
        opacity: 0;
        visibility: hidden;
        transform: translateY(-20px);
        transition: all var(--transition-base);
        gap: var(--spacing-md);
    }

    .nav-links.active {
        opacity: 1;
        visibility: visible;
        transform: translateY(0);
    }

    .nav-toggle {
        display: block;
    }

    .hero {
        padding: 3rem 0 2rem;
    }

    .hero-cta {
        flex-direction: column;
        align-items: center;
    }

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

    .footer-content {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
    }
}

@media (max-width: 480px) {
    .container,
    .container-narrow {
        padding: 0 var(--spacing-sm);
    }

    .section {
        padding: var(--spacing-xl) 0;
    }
}