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

:root {
    --primary-color: #2563eb;
    --secondary-color: #7c3aed;
    --dark-bg: #1e293b;
    --light-bg: #f8fafc;
    --text-dark: #1e293b;
    --text-light: #64748b;
    --white: #ffffff;
    --border-radius: 8px;
    --transition: all 0.3s ease;
}

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

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

/* Navigation */
.navbar {
    background-color: var(--dark-bg);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    color: var(--white);
    font-size: 1.5rem;
    font-weight: 700;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 2rem;
}

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

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

.nav-links a.active {
    color: var(--primary-color);
    position: relative;
}

.nav-links a.active::after {
    content: '';
    position: absolute;
    bottom: -8px;
    left: 0;
    width: 100%;
    height: 2px;
    background-color: var(--primary-color);
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: var(--white);
    padding: 6rem 0;
    text-align: center;
}

.hero-title {
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: 1rem;
    line-height: 1.2;
}

.hero-subtitle {
    font-size: 1.25rem;
    margin-bottom: 2rem;
    opacity: 0.95;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

/* Buttons */
.btn {
    padding: 0.75rem 2rem;
    border-radius: var(--border-radius);
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition);
    display: inline-block;
    cursor: pointer;
    border: 2px solid transparent;
}

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

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
}

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

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

/* Sections */
section {
    padding: 5rem 0;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    text-align: center;
    color: var(--text-dark);
}

.section-description {
    font-size: 1.125rem;
    color: var(--text-light);
    text-align: center;
    max-width: 800px;
    margin: 0 auto 3rem;
}

/* Research Section */
.research-section {
    background-color: var(--light-bg);
}

.research-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.research-card {
    background-color: var(--white);
    padding: 2rem;
    border-radius: var(--border-radius);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    transition: var(--transition);
}

.research-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.15);
}

.research-card h3 {
    font-size: 1.5rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.research-card p {
    color: var(--text-light);
}

/* Demos Section */
.demos-section {
    background-color: var(--white);
}

.demos-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.demo-card {
    background-color: var(--light-bg);
    padding: 2rem;
    border-radius: var(--border-radius);
    border: 2px dashed var(--text-light);
    text-align: center;
}

.demo-card h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: var(--text-dark);
}

.demo-card p {
    color: var(--text-light);
}

/* About Section */
.about-section {
    background-color: var(--light-bg);
}

.about-text {
    max-width: 800px;
    margin: 0 auto 2rem;
    font-size: 1.125rem;
    color: var(--text-light);
    text-align: center;
}

.cta {
    background-color: var(--white);
    padding: 2rem;
    border-radius: var(--border-radius);
    text-align: center;
    max-width: 600px;
    margin: 0 auto;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.cta h3 {
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.cta a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
}

.cta a:hover {
    text-decoration: underline;
}

/* Footer */
footer {
    background-color: var(--dark-bg);
    color: var(--white);
    text-align: center;
    padding: 2rem 0;
}

/* Responsive Design */
@media (max-width: 768px) {
    .hero-title {
        font-size: 2rem;
    }

    .hero-subtitle {
        font-size: 1rem;
    }

    .nav-links {
        gap: 1rem;
    }

    .section-title {
        font-size: 2rem;
    }

    .research-grid,
    .demos-grid {
        grid-template-columns: 1fr;
    }
}