/* Reset and base styles */
*, *::before, *::after {
    box-sizing: border-box;
}

* {
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

@media (prefers-reduced-motion: reduce) {
    html {
        scroll-behavior: auto;
    }

    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* CSS Custom Properties */
:root {
    /* Colors - Light theme */
    --color-primary: #007aff;
    --color-primary-hover: #0056b3;
    --color-secondary: #6c757d;
    --color-success: #28a745;
    --color-danger: #dc3545;
    --color-warning: #ffc107;
    --color-info: #17a2b8;

    /* Surface colors */
    --color-bg: #ffffff;
    --color-surface: #f8f9fa;
    --color-surface-elevated: #ffffff;
    --color-border: #e9ecef;
    --color-border-light: #f1f3f4;

    /* Text colors */
    --color-text: #212529;
    --color-text-secondary: #6c757d;
    --color-text-muted: #adb5bd;
    --color-text-inverse: #ffffff;

    /* Focus and interaction */
    --color-focus: #0056b3;
    --color-focus-ring: rgba(0, 123, 255, 0.25);

    /* Typography */
    --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    --font-family-mono: "SF Mono", Monaco, "Cascadia Code", "Roboto Mono", Consolas, "Courier New", monospace;

    /* Font sizes - fluid typography */
    --font-size-xs: clamp(0.75rem, 0.7rem + 0.25vw, 0.875rem);
    --font-size-sm: clamp(0.875rem, 0.8rem + 0.375vw, 1rem);
    --font-size-base: clamp(1rem, 0.9rem + 0.5vw, 1.125rem);
    --font-size-lg: clamp(1.125rem, 1rem + 0.625vw, 1.25rem);
    --font-size-xl: clamp(1.25rem, 1.1rem + 0.75vw, 1.5rem);
    --font-size-2xl: clamp(1.5rem, 1.3rem + 1vw, 2rem);
    --font-size-3xl: clamp(2rem, 1.7rem + 1.5vw, 3rem);

    /* Line heights */
    --line-height-tight: 1.25;
    --line-height-normal: 1.5;
    --line-height-relaxed: 1.75;

    /* Spacing - fluid spacing */
    --space-xs: clamp(0.25rem, 0.2rem + 0.25vw, 0.5rem);
    --space-sm: clamp(0.5rem, 0.4rem + 0.5vw, 0.75rem);
    --space-md: clamp(1rem, 0.8rem + 1vw, 1.5rem);
    --space-lg: clamp(1.5rem, 1.2rem + 1.5vw, 2.5rem);
    --space-xl: clamp(2rem, 1.5rem + 2.5vw, 4rem);
    --space-2xl: clamp(3rem, 2rem + 5vw, 6rem);

    /* Border radius */
    --radius-sm: 0.25rem;
    --radius-md: 0.375rem;
    --radius-lg: 0.5rem;
    --radius-xl: 0.75rem;

    /* 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);

    /* Transitions */
    --transition-fast: 150ms ease-in-out;
    --transition-normal: 250ms ease-in-out;
    --transition-slow: 350ms ease-in-out;

    /* Layout */
    --container-max-width: 1200px;
    --container-padding: var(--space-md);
}

/* Dark theme */
@media (prefers-color-scheme: dark) {
    :root {
        --color-primary: #0a84ff;
        --color-primary-hover: #409cff;
        --color-secondary: #8e8e93;

        --color-bg: #000000;
        --color-surface: #1c1c1e;
        --color-surface-elevated: #2c2c2e;
        --color-border: #38383a;
        --color-border-light: #48484a;

        --color-text: #ffffff;
        --color-text-secondary: #8e8e93;
        --color-text-muted: #636366;
        --color-text-inverse: #000000;

        --color-focus: #409cff;
        --color-focus-ring: rgba(10, 132, 255, 0.25);
    }
}

/* Base typography */
body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: var(--line-height-normal);
    color: var(--color-text);
    background-color: var(--color-bg);
    text-rendering: optimizeLegibility;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Layout components */
.container {
    width: 100%;
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding: 0 var(--container-padding);
}

/* Header */
.header {
    background-color: var(--color-surface-elevated);
    border-bottom: 1px solid var(--color-border);
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
}

.nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-md) 0;
    min-height: 60px;
    overflow: visible;
}

.logo {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 48px;
    height: 48px;
    background-color: var(--color-surface);
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border);
    text-decoration: none;
    transition: all var(--transition-fast);
    flex-shrink: 0;
    box-shadow: var(--shadow-sm);
}

.logo:hover {
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
    border-color: var(--color-border-light);
}

.logo img {
    border-radius: var(--radius-sm);
    flex-shrink: 0;
    width: 28px;
    height: 28px;
}

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

.nav-list a {
    color: var(--color-text-secondary);
    text-decoration: none;
    font-weight: 500;
    padding: var(--space-sm) 0;
    border-bottom: 2px solid transparent;
    transition: all var(--transition-fast);
}

.nav-list a:hover,
.nav-list a:focus {
    color: var(--color-primary);
    border-bottom-color: var(--color-primary);
}

.nav-list a[aria-current="page"] {
    color: var(--color-text);
    border-bottom-color: var(--color-text);
    font-weight: 600;
}

/* Mobile navigation */
@media (max-width: 768px) {
    .nav {
        flex-wrap: wrap;
        gap: var(--space-md);
        padding: var(--space-sm) 0;
    }

    .logo {
        font-size: var(--font-size-base);
    }

    .nav-list {
        gap: var(--space-md);
        flex-wrap: wrap;
        width: 100%;
        justify-content: center;
        margin-top: var(--space-sm);
    }
}

/* Hero section */
.hero {
    padding: var(--space-2xl) 0;
    text-align: center;
    background: linear-gradient(135deg, var(--color-surface) 0%, var(--color-bg) 100%);
}

.hero-content {
    max-width: 600px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
}

.hero-brand {
    display: flex;
    flex-direction: column;
    align-items: center;
    margin-bottom: var(--space-lg);
}

.hero-icon {
    border-radius: var(--radius-lg);
    margin-bottom: var(--space-md);
    box-shadow: var(--shadow-lg);
    border: 2px solid var(--color-border);
}

.hero-title {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    line-height: var(--line-height-tight);
    margin-bottom: 0;
    color: var(--color-text);
}

.hero-subtitle {
    font-size: var(--font-size-xl);
    color: var(--color-text-secondary);
    margin-bottom: var(--space-md);
    line-height: var(--line-height-relaxed);
}

.hero-mission {
    font-size: var(--font-size-lg);
    color: var(--color-text-muted);
    line-height: var(--line-height-relaxed);
    font-style: italic;
    max-width: 500px;
    margin: 0 auto var(--space-xl) auto;
    text-align: center;
}

.technology-tagline {
    color: #ffffff !important;
}

.hero-actions {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-lg);
    flex-wrap: wrap;
}

/* Buttons */
.btn-primary,
.btn-secondary {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-md) var(--space-lg);
    border-radius: var(--radius-lg);
    text-decoration: none;
    font-weight: 600;
    font-size: var(--font-size-base);
    transition: all var(--transition-fast);
    border: 2px solid transparent;
    cursor: pointer;
    min-height: 44px;
    white-space: nowrap;
    overflow: visible;
}

.btn-primary img {
    height: 40px;
    width: auto;
    max-width: none;
}

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

.btn-primary:hover,
.btn-primary:focus {
    background-color: var(--color-primary-hover);
    border-color: var(--color-primary-hover);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    background-color: transparent;
    color: var(--color-primary);
    border-color: var(--color-primary);
}

.btn-secondary:hover,
.btn-secondary:focus {
    background-color: var(--color-primary);
    color: var(--color-text-inverse);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

/* Focus states */
.btn-primary:focus,
.btn-secondary:focus,
.nav-list a:focus,
.logo:focus {
    outline: 2px solid var(--color-focus);
    outline-offset: 2px;
}

/* Sections */
.section-title {
    font-size: var(--font-size-2xl);
    font-weight: 700;
    text-align: center;
    margin-bottom: var(--space-xl);
    color: var(--color-text);
    line-height: var(--line-height-tight);
}

/* Features section */
.features {
    padding: var(--space-2xl) 0;
    background-color: var(--color-surface);
}

.feature-category {
    font-size: var(--font-size-xl);
    font-weight: 600;
    text-align: left;
    margin: var(--space-xl) 0 var(--space-lg) 0;
    color: var(--color-text);
    border-bottom: 2px solid var(--color-border);
    padding-bottom: var(--space-sm);
}

.feature-category:first-of-type {
    margin-top: 0;
}

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

.feature {
    text-align: center;
    padding: var(--space-lg);
    background-color: var(--color-surface-elevated);
    border-radius: var(--radius-xl);
    border: 1px solid var(--color-border);
    transition: all var(--transition-normal);
}

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

.feature h4 {
    font-size: var(--font-size-lg);
    font-weight: 600;
    margin-bottom: var(--space-md);
    color: var(--color-text);
}

.feature p {
    color: var(--color-text-secondary);
    line-height: var(--line-height-relaxed);
}

/* How it works section */
.how-it-works {
    padding: var(--space-2xl) 0;
    background-color: var(--color-bg);
}

.section-subtitle {
    font-size: var(--font-size-lg);
    color: var(--color-text-secondary);
    text-align: center;
    margin-bottom: var(--space-xl);
    font-weight: 500;
}

.steps {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--space-xl);
    max-width: 1000px;
    margin: 0 auto var(--space-2xl) auto;
}

.step {
    text-align: left;
    position: relative;
    padding: var(--space-xl);
    background-color: var(--color-surface-elevated);
    border-radius: var(--radius-xl);
    border: 1px solid var(--color-border);
    transition: all var(--transition-normal);
    box-shadow: var(--shadow-sm);
}

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

.step-number {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 48px;
    height: 48px;
    background-color: var(--color-primary);
    color: var(--color-text-inverse);
    border-radius: var(--radius-lg);
    font-size: var(--font-size-lg);
    font-weight: 700;
    margin-bottom: var(--space-lg);
    border: 2px solid var(--color-primary);
    box-shadow: var(--shadow-sm);
}

.step h3 {
    font-size: var(--font-size-xl);
    font-weight: 600;
    margin-bottom: var(--space-md);
    color: var(--color-text);
    line-height: var(--line-height-tight);
}

.step p {
    color: var(--color-text-secondary);
    line-height: var(--line-height-relaxed);
    font-size: var(--font-size-base);
    margin-bottom: var(--space-md);
}

.style-list {
    list-style: none;
    padding: 0;
    margin: var(--space-md) 0 0 0;
}

.style-list li {
    padding: var(--space-sm) 0;
    color: var(--color-text-secondary);
    line-height: var(--line-height-relaxed);
    border-left: 3px solid var(--color-primary);
    padding-left: var(--space-md);
    margin-bottom: var(--space-sm);
}

.style-list li strong {
    color: var(--color-primary);
    font-weight: 600;
}

/* Technology section */
.technology-section {
    background-color: var(--color-surface);
    border-radius: var(--radius-xl);
    padding: var(--space-2xl);
    margin-top: var(--space-2xl);
    border: 1px solid var(--color-border);
    box-shadow: var(--shadow-sm);
}

.technology-title {
    font-size: var(--font-size-2xl);
    font-weight: 600;
    text-align: center;
    margin-bottom: var(--space-xl);
    color: var(--color-text);
    line-height: var(--line-height-tight);
}

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

.technology-feature {
    text-align: center;
    padding: var(--space-lg);
    background-color: var(--color-surface-elevated);
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border);
    transition: all var(--transition-normal);
}

.technology-feature:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
    border-color: var(--color-primary);
}

.technology-feature h4 {
    font-size: var(--font-size-lg);
    font-weight: 600;
    margin-bottom: var(--space-md);
    color: var(--color-text);
}

.technology-feature p {
    color: var(--color-text-secondary);
    line-height: var(--line-height-relaxed);
}

.technology-tagline {
    text-align: center;
    font-size: var(--font-size-xl);
    font-weight: 600;
    color: var(--color-primary);
    margin: 0;
    padding-top: var(--space-lg);
    border-top: 2px solid var(--color-border);
}

/* Support section */
.support {
    padding: var(--space-2xl) 0;
    background-color: var(--color-surface);
    text-align: center;
}

.support p {
    font-size: var(--font-size-lg);
    color: var(--color-text-secondary);
    margin-bottom: var(--space-lg);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

/* Content pages (privacy, terms) */
.content {
    padding: var(--space-2xl) 0;
}

.policy {
    max-width: 800px;
    margin: 0 auto;
}

.policy header {
    text-align: center;
    margin-bottom: var(--space-2xl);
    padding-bottom: var(--space-xl);
    border-bottom: 2px solid var(--color-border);
}

.policy h1 {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    margin-bottom: var(--space-md);
    color: var(--color-text);
}

.updated {
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
    font-style: italic;
}

.policy section {
    margin-bottom: var(--space-2xl);
}

.policy h2 {
    font-size: var(--font-size-2xl);
    font-weight: 600;
    margin-bottom: var(--space-lg);
    color: var(--color-text);
    padding-top: var(--space-lg);
    border-top: 1px solid var(--color-border-light);
}

.policy h2:first-of-type {
    border-top: none;
    padding-top: 0;
}

.policy p {
    margin-bottom: var(--space-md);
    line-height: var(--line-height-relaxed);
    color: var(--color-text);
}

.policy ul,
.policy ol {
    margin-bottom: var(--space-md);
    padding-left: var(--space-xl);
}

.policy li {
    margin-bottom: var(--space-sm);
    line-height: var(--line-height-relaxed);
    color: var(--color-text);
}

.policy a {
    color: var(--color-primary);
    text-decoration: underline;
    transition: color var(--transition-fast);
}

.policy a:hover,
.policy a:focus {
    color: var(--color-primary-hover);
}

/* Error page */
.error-page {
    padding: var(--space-2xl) 0;
    text-align: center;
    min-height: 60vh;
    display: flex;
    align-items: center;
}

.error-content h1 {
    font-size: clamp(4rem, 8vw, 8rem);
    font-weight: 900;
    color: var(--color-primary);
    margin-bottom: var(--space-md);
    line-height: 1;
}

.error-content h2 {
    font-size: var(--font-size-2xl);
    font-weight: 600;
    margin-bottom: var(--space-lg);
    color: var(--color-text);
}

.error-content p {
    font-size: var(--font-size-lg);
    color: var(--color-text-secondary);
    margin-bottom: var(--space-xl);
    max-width: 500px;
    margin-left: auto;
    margin-right: auto;
}

.error-actions {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-lg);
    flex-wrap: wrap;
}

/* Footer */
.footer {
    background-color: var(--color-surface);
    border-top: 1px solid var(--color-border);
    padding: var(--space-xl) 0;
    margin-top: auto;
}

.footer-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: var(--space-md);
}

.footer p {
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
}

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

.footer-nav a {
    color: var(--color-text-secondary);
    text-decoration: none;
    font-size: var(--font-size-sm);
    transition: color var(--transition-fast);
}

.footer-nav a:hover,
.footer-nav a:focus {
    color: var(--color-primary);
}

/* Mobile adjustments */
@media (max-width: 768px) {
    .footer-content {
        text-align: center;
        flex-direction: column;
    }

    .footer-nav {
        flex-wrap: wrap;
        justify-content: center;
    }

    .hero-actions {
        flex-direction: column;
        align-items: center;
        gap: var(--space-md);
    }

    .hero-actions .btn-primary,
    .hero-actions .btn-secondary {
        width: auto;
        min-width: 200px;
        max-width: 300px;
    }

    .error-actions {
        flex-direction: column;
        align-items: stretch;
    }

    .hero-title {
        font-size: var(--font-size-2xl);
    }

    .hero-subtitle {
        font-size: var(--font-size-lg);
    }
}

/* Print styles */
@media print {
    .header,
    .footer,
    .hero-actions,
    .error-actions {
        display: none !important;
    }

    body {
        font-size: 12pt;
        line-height: 1.4;
        color: #000;
        background: #fff;
    }

    .policy h1 {
        font-size: 24pt;
        color: #000;
    }

    .policy h2 {
        font-size: 18pt;
        color: #000;
        page-break-after: avoid;
    }

    .policy section {
        page-break-inside: avoid;
    }

    .policy a {
        color: #000;
        text-decoration: underline;
    }

    .policy a[href]:after {
        content: " (" attr(href) ")";
        font-size: 10pt;
        color: #666;
    }
}

/* Accessibility improvements */
@media (forced-colors: active) {
    .btn-primary,
    .btn-secondary {
        border: 2px solid;
    }

    .feature:hover {
        outline: 2px solid;
    }
}

/* High contrast mode */
@media (prefers-contrast: high) {
    :root {
        --color-border: #000000;
        --color-border-light: #333333;
    }

    .feature {
        border-width: 2px;
    }
}

/* Reduce motion */
@media (prefers-reduced-motion: reduce) {
    .feature:hover,
    .btn-primary:hover,
    .btn-secondary:hover {
        transform: none;
    }
}