:root {
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --provider-color: #10b981;
    --researcher-color: #3b82f6;
    --bg: #0f172a;
    --bg-card: #1e293b;
    --text: #f8fafc;
    --text-muted: #94a3b8;
}

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

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

/* Navigation */
nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem 5%;
    max-width: 1400px;
    margin: 0 auto;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--provider-color), var(--researcher-color));
    background-clip: text;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.nav-links a {
    color: var(--text-muted);
    text-decoration: none;
    margin-left: 2rem;
    transition: color 0.2s;
}

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

/* Hero */
.hero {
    text-align: center;
    padding: 4rem 5% 6rem;
    max-width: 1200px;
    margin: 0 auto;
}

.hero h1 {
    font-size: 3.5rem;
    margin-bottom: 1rem;
    background: linear-gradient(135deg, #fff, #94a3b8);
    background-clip: text;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.tagline {
    font-size: 1.5rem;
    color: var(--text-muted);
    margin-bottom: 3rem;
}

/* CTA Cards */
.cta-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.cta-card {
    background: var(--bg-card);
    border-radius: 1rem;
    padding: 2.5rem;
    text-align: left;
    border: 1px solid transparent;
    transition: transform 0.2s, border-color 0.2s;
}

.cta-card:hover {
    transform: translateY(-4px);
}

.cta-card.provider:hover {
    border-color: var(--provider-color);
}

.cta-card.researcher:hover {
    border-color: var(--researcher-color);
}

.cta-card h2 {
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
}

.cta-card > p {
    color: var(--text-muted);
    margin-bottom: 1.5rem;
}

.cta-card ul {
    list-style: none;
    margin-bottom: 2rem;
}

.cta-card li {
    padding: 0.5rem 0;
    color: var(--text-muted);
}

.cta-card li::before {
    content: "✓ ";
    color: var(--provider-color);
}

.researcher li::before {
    color: var(--researcher-color);
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 1rem 2rem;
    border-radius: 0.5rem;
    text-decoration: none;
    font-weight: 600;
    transition: opacity 0.2s;
    width: 100%;
    text-align: center;
}

.btn:hover {
    opacity: 0.9;
}

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

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

/* Features */
.features {
    padding: 4rem 5%;
    max-width: 1200px;
    margin: 0 auto;
    text-align: center;
}

.features h2 {
    font-size: 2rem;
    margin-bottom: 3rem;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
}

.feature {
    padding: 1.5rem;
}

.feature .icon {
    font-size: 2.5rem;
    display: block;
    margin-bottom: 1rem;
}

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

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

/* Footer */
footer {
    text-align: center;
    padding: 3rem 5%;
    color: var(--text-muted);
    border-top: 1px solid var(--bg-card);
}

.footer-links {
    margin-top: 1rem;
}

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

/* Responsive */
@media (max-width: 768px) {
    .hero h1 {
        font-size: 2.5rem;
    }
    
    .tagline {
        font-size: 1.2rem;
    }
}