/* CSS Variables */
:root {
    /* Colors - Light mode */
    --color-bg: #ffffff;
    --color-bg-alt: #f8f9fa;
    --color-surface: #ffffff;
    --color-surface-alt: #f1f3f5;
    --color-text: #1a1a2e;
    --color-text-secondary: #6c757d;
    --color-primary: #5C6BC0;
    --color-primary-dark: #3F51B5;
    --color-primary-light: #7986CB;
    --color-border: #e9ecef;
    --color-gradient-start: #5C6BC0;
    --color-gradient-end: #7C4DFF;

    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;

    /* Typography */
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    --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: 2rem;
    --font-size-4xl: 2.5rem;
    --font-size-5xl: 3.5rem;

    /* Border radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 1rem;
    --radius-xl: 1.5rem;
    --radius-full: 9999px;

    /* Shadows */
    --shadow-sm: 0 1px 2px 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 25px -5px rgba(0, 0, 0, 0.1);

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

/* Dark mode */
[data-theme="dark"] {
    --color-bg: #1C1B1F;
    --color-bg-alt: #121214;
    --color-surface: #2a292e;
    --color-surface-alt: #3a393e;
    --color-text: #f8f9fa;
    --color-text-secondary: #adb5bd;
    --color-border: #3a393e;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.4);
}

/* Reset */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--color-text);
    background-color: var(--color-bg);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

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

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

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

/* Container */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    line-height: 1.2;
    font-weight: 700;
}

h1 { font-size: var(--font-size-5xl); }
h2 { font-size: var(--font-size-4xl); }
h3 { font-size: var(--font-size-2xl); }
h4 { font-size: var(--font-size-xl); }

.text-gradient {
    background: linear-gradient(135deg, var(--color-gradient-start), var(--color-gradient-end));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) var(--spacing-xl);
    font-size: var(--font-size-base);
    font-weight: 600;
    border-radius: var(--radius-md);
    border: none;
    cursor: pointer;
    transition: all var(--transition-base);
    text-decoration: none;
}

.btn-primary {
    background: linear-gradient(135deg, var(--color-gradient-start), var(--color-gradient-end));
    color: white;
}

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

.btn-sm {
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: var(--font-size-sm);
}

.btn-lg {
    padding: var(--spacing-lg) var(--spacing-2xl);
    font-size: var(--font-size-lg);
}

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
}

.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-weight: 700;
    font-size: var(--font-size-xl);
    color: var(--color-text);
}

.logo:hover {
    color: var(--color-text);
}

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

.nav-links a:not(.btn) {
    color: var(--color-text-secondary);
    font-weight: 500;
}

.nav-links a:not(.btn):hover {
    color: var(--color-primary);
}

.theme-toggle {
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--spacing-sm);
    color: var(--color-text-secondary);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
}

.theme-toggle:hover {
    background: var(--color-surface-alt);
    color: var(--color-text);
}

.sun-icon { display: block; }
.moon-icon { display: none; }

[data-theme="dark"] .sun-icon { display: none; }
[data-theme="dark"] .moon-icon { display: block; }

/* Hero Section */
.hero {
    padding-top: calc(64px + var(--spacing-3xl));
    padding-bottom: var(--spacing-3xl);
    background: var(--color-bg);
    overflow: hidden;
}

.hero-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-3xl);
    align-items: center;
}

.hero-content h1 {
    margin-bottom: var(--spacing-lg);
}

.hero-subtitle {
    font-size: var(--font-size-xl);
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-xl);
    max-width: 500px;
}

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

.hero-note {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
}

.hero-image {
    display: flex;
    justify-content: center;
}

/* Phone Carousel */
.phone-carousel {
    position: relative;
    width: 280px;
    overflow: hidden;
}

.carousel-track {
    display: flex;
    transition: transform 0.5s ease-in-out;
}

.carousel-track .phone-mockup {
    flex-shrink: 0;
}

.carousel-dots {
    display: flex;
    justify-content: center;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-lg);
}

.carousel-dot {
    width: 10px;
    height: 10px;
    border-radius: var(--radius-full);
    border: none;
    background: var(--color-border);
    cursor: pointer;
    transition: all var(--transition-fast);
    padding: 0;
}

.carousel-dot:hover {
    background: var(--color-primary-light);
}

.carousel-dot.active {
    background: var(--color-primary);
    width: 24px;
}

.phone-mockup {
    position: relative;
    width: 280px;
    height: 560px;
    background: var(--color-surface);
    border-radius: 40px;
    padding: 12px;
    box-shadow: var(--shadow-xl);
    border: 1px solid var(--color-border);
}

.phone-mockup::before {
    content: '';
    position: absolute;
    top: 16px;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 24px;
    background: var(--color-bg);
    border-radius: var(--radius-full);
}

.phone-mockup img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: 28px;
    background: var(--color-surface-alt);
}

/* Features Section */
.features {
    padding: var(--spacing-3xl) 0;
    background: var(--color-bg-alt);
}

.section-header {
    text-align: center;
    margin-bottom: var(--spacing-3xl);
}

.section-header p {
    font-size: var(--font-size-lg);
    color: var(--color-text-secondary);
    margin-top: var(--spacing-md);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-xl);
}

.feature-card {
    background: var(--color-surface);
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border);
    transition: all var(--transition-base);
}

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

.feature-icon {
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--color-gradient-start), var(--color-gradient-end));
    border-radius: var(--radius-md);
    color: white;
    margin-bottom: var(--spacing-lg);
}

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

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

/* How It Works Section */
.how-it-works {
    padding: var(--spacing-3xl) 0;
    background: var(--color-bg);
}

.steps {
    display: flex;
    align-items: flex-start;
    justify-content: center;
    gap: var(--spacing-lg);
}

.step {
    flex: 1;
    max-width: 280px;
    text-align: center;
}

.step-number {
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--color-gradient-start), var(--color-gradient-end));
    border-radius: var(--radius-full);
    color: white;
    font-weight: 700;
    font-size: var(--font-size-xl);
    margin: 0 auto var(--spacing-lg);
}

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

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

.step-arrow {
    display: flex;
    align-items: center;
    justify-content: center;
    padding-top: 10px;
    color: var(--color-text-secondary);
}

/* Download Section */
.download {
    padding: var(--spacing-3xl) 0;
    background: var(--color-bg-alt);
}

.download-card {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: linear-gradient(135deg, var(--color-gradient-start), var(--color-gradient-end));
    padding: var(--spacing-3xl);
    border-radius: var(--radius-xl);
    color: white;
}

.download-content h2 {
    margin-bottom: var(--spacing-md);
}

.download-content p {
    opacity: 0.9;
    margin-bottom: var(--spacing-xl);
    font-size: var(--font-size-lg);
}

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

.download-content .btn:hover {
    background: var(--color-bg);
    color: var(--color-primary);
}

.download-image img {
    filter: drop-shadow(0 10px 20px rgba(0, 0, 0, 0.2));
}

/* FAQ Section */
.faq {
    padding: var(--spacing-3xl) 0;
    background: var(--color-bg);
}

.faq-list {
    max-width: 700px;
    margin: 0 auto;
}

.faq-item {
    border-bottom: 1px solid var(--color-border);
}

.faq-item summary {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-lg) 0;
    cursor: pointer;
    font-weight: 600;
    font-size: var(--font-size-lg);
    list-style: none;
}

.faq-item summary::-webkit-details-marker {
    display: none;
}

.faq-item summary::after {
    content: '+';
    font-size: var(--font-size-2xl);
    color: var(--color-primary);
    transition: transform var(--transition-fast);
}

.faq-item[open] summary::after {
    transform: rotate(45deg);
}

.faq-item p {
    padding-bottom: var(--spacing-lg);
    color: var(--color-text-secondary);
}

/* Footer */
.footer {
    padding: var(--spacing-3xl) 0 var(--spacing-xl);
    background: var(--color-bg-alt);
    border-top: 1px solid var(--color-border);
}

.footer-content {
    display: flex;
    justify-content: space-between;
    gap: var(--spacing-3xl);
    margin-bottom: var(--spacing-2xl);
}

.footer-brand {
    max-width: 280px;
}

.footer-brand .logo {
    margin-bottom: var(--spacing-md);
}

.footer-brand p {
    color: var(--color-text-secondary);
}

.footer-links {
    display: flex;
    gap: var(--spacing-3xl);
}

.footer-column {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.footer-column h4 {
    font-size: var(--font-size-sm);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-sm);
}

.footer-column a {
    color: var(--color-text);
    font-size: var(--font-size-sm);
}

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

.footer-bottom {
    padding-top: var(--spacing-xl);
    border-top: 1px solid var(--color-border);
    text-align: center;
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
}

/* Responsive */
@media (max-width: 1024px) {
    h1 { font-size: var(--font-size-4xl); }
    h2 { font-size: var(--font-size-3xl); }

    .features-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    h1 { font-size: var(--font-size-3xl); }
    h2 { font-size: var(--font-size-2xl); }

    .nav-links a:not(.btn) {
        display: none;
    }

    .hero-container {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .hero-subtitle {
        margin-left: auto;
        margin-right: auto;
    }

    .hero-image {
        order: -1;
    }

    .phone-carousel {
        width: 220px;
    }

    .phone-mockup {
        width: 220px;
        height: 440px;
    }

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

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

    .step-arrow {
        transform: rotate(90deg);
        padding: var(--spacing-md) 0;
    }

    .download-card {
        flex-direction: column;
        text-align: center;
    }

    .download-image {
        order: -1;
        margin-bottom: var(--spacing-xl);
    }

    .footer-content {
        flex-direction: column;
        gap: var(--spacing-2xl);
    }

    .footer-links {
        flex-wrap: wrap;
        gap: var(--spacing-2xl);
    }
}

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

    .btn-lg {
        padding: var(--spacing-md) var(--spacing-lg);
        width: 100%;
    }
}