:root {
    --bg: #0a0a0a;
    --fg: #e5e5e5;
    --muted: #737373;
    --accent: #3b82f6;
    --accent-hover: #2563eb;
    --card-bg: #141414;
    --border: #262626;
    --max-width: 1100px;
}

@media (prefers-color-scheme: light) {
    :root {
        --bg: #fafafa;
        --fg: #171717;
        --muted: #737373;
        --card-bg: #ffffff;
        --border: #e5e5e5;
    }
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg);
    color: var(--fg);
    line-height: 1.6;
    min-height: 100vh;
}

/* Header */
header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(10, 10, 10, 0.8);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border);
    z-index: 100;
}

@media (prefers-color-scheme: light) {
    header {
        background: rgba(250, 250, 250, 0.8);
    }
}

nav {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--fg);
    text-decoration: none;
    letter-spacing: -0.02em;
}

.nav-links {
    display: flex;
    gap: 1.5rem;
}

.nav-links a {
    color: var(--muted);
    text-decoration: none;
    font-size: 0.9rem;
    transition: color 0.2s;
}

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

/* Main content */
main {
    padding-top: 80px;
}

section {
    padding: 4rem 2rem;
    max-width: var(--max-width);
    margin: 0 auto;
}

/* Hero */
.hero {
    text-align: center;
    padding: 6rem 2rem;
}

.badge {
    display: inline-block;
    background: var(--accent);
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 9999px;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 1.5rem;
}

.hero h1 {
    font-size: clamp(2rem, 5vw, 3.5rem);
    font-weight: 700;
    letter-spacing: -0.03em;
    margin-bottom: 1rem;
    line-height: 1.1;
}

.tagline {
    font-size: 1.1rem;
    color: var(--muted);
    max-width: 600px;
    margin: 0 auto 2rem;
}

.cta-group {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    font-size: 0.9rem;
    font-weight: 500;
    text-decoration: none;
    transition: all 0.2s;
}

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

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

.btn.secondary {
    background: var(--card-bg);
    color: var(--fg);
    border: 1px solid var(--border);
}

.btn.secondary:hover {
    border-color: var(--muted);
}

/* Features */
.features h2 {
    text-align: center;
    font-size: 1.75rem;
    margin-bottom: 3rem;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 1.5rem;
}

.feature {
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 1.5rem;
}

.feature-icon {
    width: 40px;
    height: 40px;
    background: var(--accent);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1rem;
}

.feature-icon svg {
    width: 20px;
    height: 20px;
    color: white;
}

.feature h3 {
    font-size: 1rem;
    margin-bottom: 0.5rem;
}

.feature p {
    font-size: 0.9rem;
    color: var(--muted);
}

/* Demo */
.demo {
    text-align: center;
}

.demo h2 {
    font-size: 1.75rem;
    margin-bottom: 2rem;
}

.demo-placeholder {
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 4rem 2rem;
    color: var(--muted);
}

/* Signup */
.signup {
    text-align: center;
    background: var(--card-bg);
    border-radius: 16px;
    border: 1px solid var(--border);
    margin: 2rem auto;
    max-width: calc(var(--max-width) - 4rem);
}

.signup h2 {
    font-size: 1.75rem;
    margin-bottom: 1rem;
}

.signup > p {
    color: var(--muted);
    margin-bottom: 0.5rem;
}

.notice {
    font-size: 0.85rem;
    color: var(--muted);
    font-style: italic;
    margin-bottom: 2rem;
}

.signup-form {
    margin-top: 1.5rem;
}

.signup-form p {
    margin-bottom: 1rem;
    color: var(--muted);
}

/* Footer */
footer {
    border-top: 1px solid var(--border);
    padding: 2rem;
    margin-top: 4rem;
}

.footer-content {
    max-width: var(--max-width);
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

.footer-content p {
    color: var(--muted);
    font-size: 0.85rem;
}

.footer-links {
    display: flex;
    gap: 1.5rem;
}

.footer-links a {
    color: var(--muted);
    text-decoration: none;
    font-size: 0.85rem;
}

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

/* Responsive */
@media (max-width: 600px) {
    .hero {
        padding: 4rem 1.5rem;
    }

    section {
        padding: 3rem 1.5rem;
    }

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