/* Basic styling for Game Theory Explorer */
:root {
    --primary-color: #1e3a8a;
    --secondary-color: #3b82f6;
    --dark-bg: #0f172a;
    --light-bg: #1e293b;
    --text-color: #f8fafc;
    --accent-color: #38bdf8;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background: var(--dark-bg);
}

.container {
    width: 90%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header */
header {
    background-color: var(--light-bg);
    padding: 1rem 0;
    border-bottom: 1px solid var(--primary-color);
}

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

header h1 {
    color: var(--accent-color);
    font-size: 1.8rem;
}

nav ul {
    display: flex;
    list-style: none;
}

nav ul li {
    margin-left: 1.5rem;
}

nav a {
    color: var(--text-color);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
}

nav a:hover {
    color: var(--accent-color);
}

/* Hero Section */
.hero {
    text-align: center;
    padding: 3rem 0;
    background-color: var(--primary-color);
    border-radius: 8px;
    margin: 2rem 0;
}

.hero h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

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

.card {
    background-color: var(--light-bg);
    border-radius: 8px;
    padding: 1.5rem;
    transition: transform 0.3s ease;
}

.card:hover {
    transform: translateY(-5px);
}

.card h3 {
    color: var(--accent-color);
    margin-bottom: 1rem;
}

.btn {
    display: inline-block;
    background-color: var(--secondary-color);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 4px;
    text-decoration: none;
    margin-top: 1rem;
    transition: background-color 0.3s ease;
}

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

/* Footer */
footer {
    text-align: center;
    padding: 2rem 0;
    margin-top: 3rem;
    background-color: var(--light-bg);
    border-top: 1px solid var(--primary-color);
}

/* Responsive Design */
@media (max-width: 768px) {
    header .container {
        flex-direction: column;
    }
    
    nav ul {
        margin-top: 1rem;
    }
    
    nav ul li {
        margin: 0 0.75rem;
    }
}