/* CSS Variables for theming */
:root {
    /* Purple Theme Colors */
    --primary-purple: #6366f1;
    --primary-purple-light: #818cf8;
    --primary-purple-dark: #4f46e5;
    --secondary-purple: #8b5cf6;
    --accent-purple: #a855f7;
    
    /* Neutral Colors */
    --white: #ffffff;
    --gray-50: #f9fafb;
    --gray-100: #f3f4f6;
    --gray-200: #e5e7eb;
    --gray-300: #d1d5db;
    --gray-400: #9ca3af;
    --gray-500: #6b7280;
    --gray-600: #4b5563;
    --gray-700: #374151;
    --gray-800: #1f2937;
    --gray-900: #111827;
    
    /* Gradients */
    --gradient-primary: linear-gradient(135deg, var(--primary-purple) 0%, var(--secondary-purple) 100%);
    --gradient-hero: linear-gradient(135deg, var(--primary-purple-light) 0%, var(--accent-purple) 100%);
    
    /* 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;
    
    /* Spacing */
    --spacing-1: 0.25rem;
    --spacing-2: 0.5rem;
    --spacing-3: 0.75rem;
    --spacing-4: 1rem;
    --spacing-5: 1.25rem;
    --spacing-6: 1.5rem;
    --spacing-8: 2rem;
    --spacing-10: 2.5rem;
    --spacing-12: 3rem;
    --spacing-16: 4rem;
    --spacing-20: 5rem;
    --spacing-24: 6rem;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    --shadow-purple: 0 10px 15px -3px rgba(99, 102, 241, 0.1), 0 4px 6px -2px rgba(99, 102, 241, 0.05);
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-2xl: 1.5rem;
    
    /* Transitions */
    --transition-fast: 0.15s ease-in-out;
    --transition-normal: 0.3s ease-in-out;
    --transition-slow: 0.5s ease-in-out;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--gray-800);
    background-color: var(--white);
    overflow-x: hidden;
}

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-6);
}

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

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.3;
    color: var(--gray-900);
}

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

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

h3 {
    font-size: var(--font-size-2xl);
}

p {
    color: var(--gray-600);
    margin-bottom: var(--spacing-4);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-2);
    padding: var(--spacing-3) var(--spacing-6);
    border: none;
    border-radius: var(--radius-lg);
    font-weight: 500;
    font-size: var(--font-size-base);
    text-decoration: none;
    cursor: pointer;
    transition: all var(--transition-normal);
    white-space: nowrap;
}

.btn-primary {
    background: var(--gradient-primary);
    color: var(--white);
    box-shadow: var(--shadow-purple);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 20px 25px -5px rgba(99, 102, 241, 0.2), 0 10px 10px -5px rgba(99, 102, 241, 0.1);
}

.btn-secondary {
    background: var(--white);
    color: var(--primary-purple);
    border: 2px solid var(--primary-purple);
    box-shadow: var(--shadow-md);
}

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

.btn-outline {
    background: transparent;
    color: var(--gray-700);
    border: 1px solid var(--gray-300);
}

.btn-outline:hover {
    background: var(--gray-50);
    border-color: var(--primary-purple);
    color: var(--primary-purple);
}

.btn-large {
    padding: var(--spacing-4) var(--spacing-8);
    font-size: var(--font-size-lg);
}

/* Header */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--gray-200);
    z-index: 1000;
    transition: all var(--transition-normal);
}

.nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-4) var(--spacing-6);
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: var(--spacing-3);
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--primary-purple);
}

.nav-logo {
    width: 28px;
    height: 28px;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: var(--spacing-8);
}

.nav-links a {
    text-decoration: none;
    color: var(--gray-700);
    font-weight: 500;
    transition: color var(--transition-fast);
}

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

@media (max-width: 768px) {
    .nav-links {
        gap: var(--spacing-4);
    }
    
    .nav-links a:not(.btn) {
        display: none;
    }
}

/* Hero Section */
.hero {
    background: var(--gradient-hero);
    padding: var(--spacing-24) 0 var(--spacing-20);
    margin-top: 80px;
    position: relative;
    overflow: hidden;
}

.hero-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-4);
    justify-content: center;
    margin-bottom: var(--spacing-6);
}

.hero-logo-img {
    width: 80px;
    height: 80px;
    animation: float 3s ease-in-out infinite;
}

.hero-title {
    margin-bottom: 0;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.05'%3E%3Ccircle cx='30' cy='30' r='2'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E") repeat;
}

.hero .container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-16);
    align-items: center;
    position: relative;
    z-index: 1;
}

.hero-title {
    font-size: var(--font-size-5xl);
    font-weight: 700;
    color: var(--white);
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.hero-header .hero-title {
    margin-bottom: 0;
}

.hero-subtitle {
    font-size: var(--font-size-2xl);
    color: rgba(255, 255, 255, 0.95);
    margin-bottom: var(--spacing-6);
    font-weight: 400;
}

.hero-description {
    font-size: var(--font-size-lg);
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: var(--spacing-8);
    line-height: 1.7;
}

.hero-buttons {
    display: flex;
    gap: var(--spacing-4);
    flex-wrap: wrap;
}

.hero-visual {
    display: flex;
    justify-content: center;
    align-items: center;
}

.hero-illustration {
    position: relative;
    width: 300px;
    height: 300px;
}

.message-bubble {
    position: absolute;
    background: var(--white);
    padding: var(--spacing-4);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
    font-weight: 500;
    animation: float 3s ease-in-out infinite;
}

.message-bubble.deleted {
    top: 50px;
    left: 20px;
    background: var(--gray-100);
    color: var(--gray-500);
    text-decoration: line-through;
    animation-delay: 0s;
}

.message-bubble.preserved {
    bottom: 50px;
    right: 20px;
    background: var(--white);
    color: var(--primary-purple);
    border: 2px solid var(--primary-purple);
    animation-delay: 1.5s;
}

@keyframes float {
    0%, 100% { transform: translateY(0px); }
    50% { transform: translateY(-10px); }
}

@media (max-width: 768px) {
    .hero .container {
        grid-template-columns: 1fr;
        gap: var(--spacing-12);
        text-align: center;
    }
    
    .hero-header {
        flex-direction: column;
        gap: var(--spacing-3);
    }
    
    .hero-logo-img {
        width: 60px;
        height: 60px;
    }
    
    .hero-title {
        font-size: var(--font-size-4xl);
    }
    
    .hero-subtitle {
        font-size: var(--font-size-xl);
    }
    
    .hero-buttons {
        justify-content: center;
    }
    
    .hero-illustration {
        width: 250px;
        height: 250px;
    }
}

/* Section Styles */
section {
    padding: var(--spacing-20) 0;
}

.section-header {
    text-align: center;
    margin-bottom: var(--spacing-16);
}

.section-title {
    margin-bottom: var(--spacing-4);
}

.section-subtitle {
    font-size: var(--font-size-lg);
    color: var(--gray-600);
}

/* Features Section */
.features {
    background: var(--gray-50);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-8);
}

.feature-card {
    background: var(--white);
    padding: var(--spacing-8);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-md);
    text-align: center;
    transition: all var(--transition-normal);
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

.feature-icon {
    width: 80px;
    height: 80px;
    background: var(--gradient-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto var(--spacing-6);
    font-size: var(--font-size-2xl);
    color: var(--white);
}

.feature-card h3 {
    margin-bottom: var(--spacing-4);
    color: var(--gray-900);
}

.feature-card p {
    color: var(--gray-600);
    margin-bottom: 0;
}

/* Use Cases Section */
.use-cases-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: var(--spacing-10);
}

.use-case {
    text-align: center;
    padding: var(--spacing-6);
}

.use-case-icon {
    width: 100px;
    height: 100px;
    background: linear-gradient(135deg, var(--secondary-purple), var(--accent-purple));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto var(--spacing-6);
    font-size: var(--font-size-3xl);
    color: var(--white);
    box-shadow: var(--shadow-lg);
}

.use-case h3 {
    margin-bottom: var(--spacing-4);
}

.use-case p {
    font-size: var(--font-size-lg);
    font-style: italic;
    color: var(--gray-700);
    margin-bottom: 0;
}

/* Privacy Section */
.privacy {
    background: var(--gray-900);
    color: var(--white);
}

.privacy .section-title {
    color: var(--white);
}

.privacy-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: var(--spacing-16);
    align-items: center;
}

.privacy-points {
    display: grid;
    gap: var(--spacing-6);
}

.privacy-point {
    display: flex;
    gap: var(--spacing-4);
    align-items: flex-start;
}

.privacy-point i {
    font-size: var(--font-size-xl);
    color: var(--primary-purple-light);
    margin-top: var(--spacing-1);
    flex-shrink: 0;
}

.privacy-point h3 {
    color: var(--white);
    margin-bottom: var(--spacing-2);
}

.privacy-point p {
    color: var(--gray-300);
    margin-bottom: 0;
}

.privacy-visual {
    display: flex;
    justify-content: center;
    align-items: center;
}

.shield-container {
    width: 200px;
    height: 200px;
    background: var(--gradient-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 0 50px rgba(99, 102, 241, 0.3);
    animation: pulse 2s ease-in-out infinite;
}

.shield-container i {
    font-size: 4rem;
    color: var(--white);
}

@keyframes pulse {
    0%, 100% { 
        transform: scale(1);
        box-shadow: 0 0 50px rgba(99, 102, 241, 0.3);
    }
    50% { 
        transform: scale(1.05);
        box-shadow: 0 0 80px rgba(99, 102, 241, 0.5);
    }
}

@media (max-width: 768px) {
    .privacy-content {
        grid-template-columns: 1fr;
        gap: var(--spacing-12);
        text-align: center;
    }
    
    .privacy-point {
        flex-direction: column;
        text-align: center;
        align-items: center;
    }
    
    .shield-container {
        width: 150px;
        height: 150px;
    }
    
    .shield-container i {
        font-size: 3rem;
    }
}

/* Download Section */
.download {
    background: var(--gradient-primary);
    color: var(--white);
    text-align: center;
}

.download .section-title {
    color: var(--white);
}

.download .section-subtitle {
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: var(--spacing-8);
}

.download-buttons {
    display: flex;
    gap: var(--spacing-4);
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: var(--spacing-6);
}

.download-note {
    color: rgba(255, 255, 255, 0.8);
    font-size: var(--font-size-sm);
    margin-bottom: 0;
}

.download-note i {
    margin-right: var(--spacing-2);
}

/* Footer */
.footer {
    background: var(--gray-900);
    color: var(--gray-300);
    padding: var(--spacing-16) 0 var(--spacing-8);
}

.footer-content {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: var(--spacing-16);
    margin-bottom: var(--spacing-12);
}

.footer-brand {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-4);
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-3);
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--white);
}

.footer-logo-img {
    width: 24px;
    height: 24px;
}

.footer-brand p {
    color: var(--gray-400);
    margin-bottom: 0;
}

.footer-links {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-8);
}

.footer-section h4 {
    color: var(--white);
    margin-bottom: var(--spacing-4);
    font-size: var(--font-size-sm);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.footer-section {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-3);
}

.footer-section a {
    color: var(--gray-400);
    text-decoration: none;
    transition: color var(--transition-fast);
}

.footer-section a:hover {
    color: var(--primary-purple-light);
}

.footer-bottom {
    text-align: center;
    padding-top: var(--spacing-8);
    border-top: 1px solid var(--gray-800);
}

.footer-bottom p {
    color: var(--gray-500);
    font-size: var(--font-size-sm);
    margin-bottom: 0;
}

@media (max-width: 768px) {
    .footer-content {
        grid-template-columns: 1fr;
        gap: var(--spacing-12);
        text-align: center;
    }
    
    .footer-links {
        grid-template-columns: 1fr;
        gap: var(--spacing-6);
    }
}

/* Responsive Design */
@media (max-width: 480px) {
    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .download-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .use-cases-grid {
        grid-template-columns: 1fr;
    }
}

/* Smooth scrolling and performance optimizations */
html {
    scroll-behavior: smooth;
}

/* Accessibility improvements */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    
    html {
        scroll-behavior: auto;
    }
}

/* Focus styles for accessibility */
.btn:focus,
a:focus {
    outline: 2px solid var(--primary-purple);
    outline-offset: 2px;
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    :root {
        --gray-600: #000000;
        --gray-700: #000000;
        --gray-800: #000000;
    }
}