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

:root {
    --color-primary: #2563eb;
    --color-primary-dark: #1d4ed8;
    --color-text: #1f2937;
    --color-text-light: #6b7280;
    --color-bg: #ffffff;
    --color-bg-alt: #f9fafb;
    --color-border: #e5e7eb;
    --color-accent: #0ea5e9;
    --color-surface: #ffffff;
    --color-nav-bg: rgba(255, 255, 255, 0.95);
    --color-warning-bg: #fef3c7;
    --color-warning-text: inherit;
    --color-check: #10b981;
    --color-footer-bg: #1f2937;
    --color-footer-overlay: rgba(255, 255, 255, 0.1);
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --max-width: 1200px;
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 6rem;
    --radius: 8px;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.1), 0 1px 2px 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);
}

/* Dark mode overrides */
[data-theme="dark"] {
    --color-primary: #3b82f6;
    --color-primary-dark: #2563eb;
    --color-text: #f3f4f6;
    --color-text-light: #9ca3af;
    --color-bg: #111827;
    --color-bg-alt: #1f2937;
    --color-border: #374151;
    --color-accent: #38bdf8;
    --color-surface: #1f2937;
    --color-nav-bg: rgba(17, 24, 39, 0.95);
    --color-warning-bg: #422006;
    --color-warning-text: #fde68a;
    --color-check: #34d399;
    --color-footer-bg: #0b1120;
    --color-footer-overlay: rgba(255, 255, 255, 0.08);
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.4), 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4), 0 4px 6px -2px rgba(0, 0, 0, 0.2);
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    color: var(--color-text);
    line-height: 1.6;
    background: var(--color-bg);
}

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

h1, h2, h3, h4 {
    line-height: 1.2;
    font-weight: 600;
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; margin-bottom: var(--spacing-md); }
h3 { font-size: 1.25rem; }
h4 { font-size: 1.1rem; }

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

a:hover {
    text-decoration: underline;
}

/* Navigation */
.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: var(--color-nav-bg);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--color-border);
    z-index: 100;
}

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

.nav-logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-weight: 700;
    font-size: 1.25rem;
    color: var(--color-text);
}

.nav-logo:hover {
    text-decoration: none;
}

.logo-icon {
    font-size: 1.5rem;
    vertical-align: middle;
}

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

.nav-links a {
    color: var(--color-text-light);
    font-weight: 500;
    font-size: 0.95rem;
}

.nav-links a:hover {
    color: var(--color-text);
    text-decoration: none;
}

.nav-github {
    background: var(--color-text);
    color: white !important;
    padding: 0.5rem 1rem;
    border-radius: var(--radius);
}

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

[data-theme="dark"] .nav-github {
    background: #374151;
}

/* Theme Toggle */
.theme-toggle {
    background: none;
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    cursor: pointer;
    padding: 0.4rem 0.6rem;
    font-size: 1.15rem;
    line-height: 1;
    color: var(--color-text);
    transition: background 0.2s, border-color 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
}

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

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

/* Theme transition (only on user toggle, not page load) */
body.theme-transition,
body.theme-transition *,
body.theme-transition *::before,
body.theme-transition *::after {
    transition: background-color 0.3s ease, color 0.3s ease, border-color 0.3s ease, box-shadow 0.3s ease !important;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius);
    font-weight: 600;
    font-size: 1rem;
    text-align: center;
    transition: all 0.2s;
    cursor: pointer;
    border: none;
}

.btn:hover {
    text-decoration: none;
    transform: translateY(-1px);
}

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

.btn-primary:hover {
    background: var(--color-primary-dark);
}

.btn-secondary {
    background: var(--color-surface);
    color: var(--color-text);
    border: 1px solid var(--color-border);
}

.btn-secondary:hover {
    background: var(--color-bg-alt);
}

.btn-download {
    background: var(--color-primary);
    color: white;
    width: 100%;
}

/* Hero */
.hero {
    padding: calc(var(--spacing-xl) + 60px) 0 var(--spacing-xl);
    text-align: center;
    background: linear-gradient(180deg, var(--color-bg-alt) 0%, var(--color-bg) 100%);
}

.hero h1 {
    max-width: 800px;
    margin: 0 auto var(--spacing-md);
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--color-text-light);
    max-width: 700px;
    margin: 0 auto var(--spacing-md);
}

.hero-actions {
    display: flex;
    gap: var(--spacing-sm);
    justify-content: center;
    margin-bottom: var(--spacing-lg);
}

.hero-image {
    max-width: 900px;
    margin: 0 auto;
}

.carousel {
    position: relative;
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow-lg);
    background: var(--color-bg-alt);
    user-select: none;
}

.carousel-track {
    position: relative;
}

.carousel-slide {
    display: none;
}

.carousel-slide.active {
    display: block;
}

.carousel-slide img {
    width: 100%;
    max-height: 520px;
    object-fit: contain;
    display: block;
    border-radius: var(--radius);
}

.carousel-btn {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    background: rgba(0, 0, 0, 0.45);
    color: white;
    border: none;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    font-size: 1.1rem;
    cursor: pointer;
    z-index: 10;
    transition: background 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
}

.carousel-btn:hover {
    background: rgba(0, 0, 0, 0.7);
}

.carousel-prev { left: 12px; }
.carousel-next { right: 12px; }

.carousel-caption {
    position: absolute;
    bottom: 36px;
    left: 50%;
    transform: translateX(-50%);
    background: rgba(0, 0, 0, 0.5);
    color: white;
    padding: 0.2rem 0.75rem;
    border-radius: 20px;
    font-size: 0.8rem;
    white-space: nowrap;
    pointer-events: none;
}

.carousel-dots {
    position: absolute;
    bottom: 10px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    gap: 6px;
}

.carousel-dot {
    width: 7px;
    height: 7px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.45);
    cursor: pointer;
    border: none;
    padding: 0;
    transition: background 0.2s, transform 0.2s;
}

.carousel-dot.active {
    background: white;
    transform: scale(1.3);
}

/* Problem Section */
.problem {
    padding: var(--spacing-xl) 0;
}

.problem-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-md);
}

.problem-card {
    padding: var(--spacing-md);
    background: var(--color-bg-alt);
    border-radius: var(--radius);
    text-align: center;
}

.problem-icon {
    font-size: 2.5rem;
    margin-bottom: var(--spacing-sm);
}

.problem-card h3 {
    margin-bottom: var(--spacing-xs);
}

.problem-card p {
    color: var(--color-text-light);
    font-size: 0.95rem;
}

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

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

.feature-section:last-child {
    margin-bottom: 0;
}

.feature-section-title {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-md);
    color: var(--color-primary);
}

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

.feature-card {
    background: var(--color-surface);
    padding: var(--spacing-md);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}

.feature-icon {
    font-size: 2rem;
    margin-bottom: var(--spacing-sm);
}

.feature-card h4 {
    margin-bottom: var(--spacing-xs);
}

.feature-card p {
    color: var(--color-text-light);
    font-size: 0.95rem;
}

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

.workflow {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    align-items: flex-start;
    margin-bottom: var(--spacing-lg);
    flex-wrap: wrap;
}

.workflow-column {
    flex: 1;
    min-width: 280px;
    max-width: 400px;
    background: var(--color-bg-alt);
    border-radius: var(--radius);
    padding: var(--spacing-md);
}

.workflow-column h3 {
    margin-bottom: var(--spacing-md);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.tag {
    font-size: 0.75rem;
    background: var(--color-primary);
    color: white;
    padding: 0.2rem 0.5rem;
    border-radius: 4px;
    font-weight: 500;
}

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

.workflow-step {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.step-number {
    width: 28px;
    height: 28px;
    background: var(--color-primary);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    font-size: 0.85rem;
    flex-shrink: 0;
}

.workflow-arrow {
    font-size: 2rem;
    color: var(--color-text-light);
    align-self: center;
}

.shared-storage {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-md);
    background: var(--color-bg-alt);
    padding: var(--spacing-md);
    border-radius: var(--radius);
    max-width: 500px;
    margin: 0 auto;
}

.storage-icon {
    font-size: 2.5rem;
}

.storage-text {
    display: flex;
    flex-direction: column;
}

.storage-text span {
    color: var(--color-text-light);
    font-size: 0.9rem;
}

/* Use Cases */
.use-cases {
    padding: var(--spacing-xl) 0;
    background: var(--color-bg-alt);
}

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

.use-case-card {
    background: var(--color-surface);
    padding: var(--spacing-md);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}

.use-case-card h3 {
    margin-bottom: var(--spacing-sm);
    color: var(--color-primary);
}

.use-case-card p {
    color: var(--color-text-light);
    font-size: 0.95rem;
}

/* Download */
.download {
    padding: var(--spacing-xl) 0;
}

.download-subtitle {
    text-align: center;
    color: var(--color-text-light);
    margin-bottom: var(--spacing-lg);
}

.download-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-md);
    max-width: 800px;
    margin: 0 auto var(--spacing-md);
}

.download-card {
    background: var(--color-bg-alt);
    padding: var(--spacing-md);
    border-radius: var(--radius);
    text-align: center;
}

.download-icon {
    font-size: 2.5rem;
    margin-bottom: var(--spacing-sm);
}

.download-card h3 {
    margin-bottom: var(--spacing-xs);
}

.download-card p {
    color: var(--color-text-light);
    font-size: 0.9rem;
    margin-bottom: var(--spacing-sm);
}

.download-note {
    text-align: center;
    padding: var(--spacing-md);
    background: var(--color-warning-bg);
    color: var(--color-warning-text);
    border-radius: var(--radius);
    max-width: 600px;
    margin: 0 auto;
}

/* Docs */
.docs {
    padding: var(--spacing-xl) 0;
    background: var(--color-bg-alt);
}

.docs-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: var(--spacing-md);
}

.docs-card {
    background: var(--color-surface);
    padding: var(--spacing-md);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    transition: transform 0.2s, box-shadow 0.2s;
}

.docs-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
    text-decoration: none;
}

.docs-card h3 {
    color: var(--color-text);
    margin-bottom: var(--spacing-xs);
}

.docs-card p {
    color: var(--color-text-light);
    font-size: 0.9rem;
}

/* Licensing */
.licensing {
    padding: var(--spacing-xl) 0;
}

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

.license-features {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-md);
}

.license-feature {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.check {
    color: var(--color-check);
    font-weight: bold;
}

/* Footer */
.footer {
    background: var(--color-footer-bg);
    color: white;
    padding: var(--spacing-lg) 0 var(--spacing-md);
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    flex-wrap: wrap;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-md);
    padding-bottom: var(--spacing-md);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-brand {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-weight: 700;
    font-size: 1.25rem;
}

.footer-links, .footer-legal {
    display: flex;
    gap: var(--spacing-md);
}

.footer-links a, .footer-legal a {
    color: rgba(255, 255, 255, 0.7);
    font-size: 0.9rem;
}

.footer-links a:hover, .footer-legal a:hover {
    color: white;
}

.footer-disclaimer {
    background: var(--color-footer-overlay);
    padding: var(--spacing-sm);
    border-radius: var(--radius);
    margin-bottom: var(--spacing-md);
}

.footer-disclaimer p {
    font-size: 0.85rem;
    color: rgba(255, 255, 255, 0.8);
}

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

.footer-credit p {
    font-size: 0.85rem;
    color: rgba(255, 255, 255, 0.6);
    margin-bottom: var(--spacing-xs);
}

.footer-credit a {
    color: rgba(255, 255, 255, 0.8);
}

/* Responsive */
@media (max-width: 768px) {
    h1 { font-size: 2rem; }
    h2 { font-size: 1.5rem; }

    .nav-links {
        display: none;
    }

    .hero {
        padding-top: calc(var(--spacing-lg) + 60px);
    }

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

    .workflow-arrow {
        transform: rotate(90deg);
    }

    .footer-content {
        flex-direction: column;
        align-items: center;
        text-align: center;
    }

    .footer-links, .footer-legal {
        flex-wrap: wrap;
        justify-content: center;
    }
}