/* Root Colors - Clean Professional Black & White */
:root {
    --black: #000000;
    --dark-gray: #1a1a1a;
    --medium-gray: #666666;
    --light-gray: #f5f5f5;
    --white: #ffffff;
    --accent: #d4af37;
}

/* General Styles */
body {
    font-family: 'Calibri', 'Segoe UI', sans-serif;
    color: var(--black);
    line-height: 1.7;
    background-color: var(--white);
}

a {
    color: var(--black);
    text-decoration: none;
    transition: color 0.3s ease;
}

a:hover {
    color: var(--medium-gray);
}

/* Navigation */
.navbar-custom {
    background-color: var(--black);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    padding: 1.2rem 0;
}

.navbar-brand {
    font-size: 1.6rem;
    color: var(--white) !important;
    letter-spacing: 1px;
    font-weight: 700;
    font-family: 'Calibri', sans-serif;
}

.navbar-custom .nav-link {
    color: var(--white) !important;
    margin-left: 2.5rem;
    font-weight: 400;
    letter-spacing: 0.3px;
    transition: opacity 0.3s ease;
    font-family: 'Calibri', sans-serif;
}

.navbar-custom .nav-link:hover,
.navbar-custom .nav-link.active {
    opacity: 0.7;
}

/* Hero Section */
.hero-section {
    background: var(--white);
    padding: 6rem 0;
    border-bottom: 1px solid var(--light-gray);
}

.hero-section h1 {
    color: var(--black);
    font-family: 'Calibri', sans-serif;
    font-size: 3.2rem;
    font-weight: 700;
    letter-spacing: -0.5px;
}

.hero-section .lead {
    font-size: 1.2rem;
    color: var(--medium-gray);
    font-weight: 300;
    letter-spacing: 0.3px;
}

.btn-primary {
    background-color: var(--black);
    border-color: var(--black);
    font-weight: 500;
    padding: 0.75rem 2rem;
    transition: all 0.3s ease;
    border-radius: 2px;
    letter-spacing: 0.3px;
    font-family: 'Calibri', sans-serif;
}

.btn-primary:hover {
    background-color: var(--dark-gray);
    border-color: var(--dark-gray);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

.btn-outline-primary {
    color: var(--black);
    border-color: var(--black);
    font-weight: 500;
    border-width: 1.5px;
}

.btn-outline-primary:hover {
    background-color: var(--black);
    border-color: var(--black);
    color: var(--white);
    transform: translateY(-2px);
}

/* Projects Section */
.projects-section {
    padding: 5rem 0;
    background-color: var(--white);
}

.projects-section h2 {
    color: var(--black);
    font-size: 2.8rem;
    margin-bottom: 3rem;
    font-family: 'Calibri', sans-serif;
    font-weight: 700;
    letter-spacing: -0.5px;
}

/* Project Card */
.project-card {
    background: var(--white);
    border-radius: 0;
    overflow: hidden;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
    transition: all 0.3s ease;
    height: 100%;
    display: flex;
    flex-direction: column;
    border: 1px solid var(--light-gray);
}

.project-card:hover {
    transform: translateY(-6px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.12);
}

.project-header {
    padding: 2rem;
    color: var(--white);
    font-weight: 600;
    background-color: var(--black);
}

.game-header {
    background-color: var(--dark-gray);
}

.paper-header {
    background-color: var(--black);
}

.project-header h3 {
    font-size: 1.5rem;
    margin: 0;
    font-family: 'Calibri', sans-serif;
}

.project-body {
    padding: 2rem;
    flex-grow: 1;
    display: flex;
    flex-direction: column;
}

.project-body p {
    color: var(--medium-gray);
    margin-bottom: 1.5rem;
    flex-grow: 1;
    line-height: 1.8;
}

.project-features {
    list-style: none;
    padding: 0;
    margin: 1.5rem 0;
}

.project-features li {
    padding: 0.5rem 0;
    color: var(--medium-gray);
    display: flex;
    align-items: center;
}

.project-features li:before {
    content: "•";
    color: var(--black);
    font-weight: bold;
    margin-right: 0.75rem;
    font-size: 1rem;
}

/* About Section */
.about-section {
    padding: 5rem 0;
    background: var(--light-gray);
}

.about-section h2 {
    color: var(--black);
    font-size: 2.5rem;
    font-family: 'Calibri', sans-serif;
    font-weight: 700;
    letter-spacing: -0.5px;
    margin-bottom: 2rem;
}

.about-section p {
    font-size: 1.05rem;
    line-height: 1.9;
    color: var(--medium-gray);
}

.about-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.5rem;
    margin-top: 2.5rem;
}

.stat-box {
    background: var(--white);
    padding: 2rem;
    border-radius: 0;
    text-align: center;
    box-shadow: 0 2px 6px rgba(0, 0, 0, 0.06);
    border: 1px solid var(--light-gray);
    transition: all 0.3s ease;
}

.stat-box:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 15px rgba(0, 0, 0, 0.1);
}

.stat-box h4 {
    font-size: 2.5rem;
    color: var(--black);
    margin-bottom: 0.5rem;
    font-family: 'Calibri', sans-serif;
    font-weight: 700;
}

.stat-box p {
    color: var(--medium-gray);
    margin: 0;
    font-weight: 400;
    letter-spacing: 0.3px;
}

/* CTA Section */
.cta-section {
    background: var(--black);
    color: var(--white);
    padding: 4rem 0;
}

.cta-section h2 {
    font-size: 2.5rem;
    margin-bottom: 1.5rem;
    font-family: 'Calibri', sans-serif;
    font-weight: 700;
}

.cta-section .lead {
    font-size: 1.15rem;
    font-weight: 300;
}

.btn-outline-light {
    font-weight: 500;
    padding: 0.75rem 2rem;
    border-width: 1.5px;
    border-color: var(--white);
    color: var(--white);
}

.btn-outline-light:hover {
    background-color: var(--white);
    color: var(--black);
    border-color: var(--white);
}

/* Footer */
.footer {
    background-color: var(--black);
    color: var(--white);
    margin-top: 0;
    padding: 2.5rem 0;
    border-top: 1px solid var(--dark-gray);
}

.footer p {
    font-size: 0.9rem;
    letter-spacing: 0.3px;
}

.footer-link {
    color: var(--white);
    transition: opacity 0.3s ease;
    font-weight: 400;
}

.footer-link:hover {
    opacity: 0.7;
}

/* Responsive Design */
@media (max-width: 768px) {
    .hero-section {
        padding: 3rem 0;
    }

    .hero-section h1 {
        font-size: 2rem;
    }

    .projects-section h2 {
        font-size: 1.8rem;
    }

    .about-stats {
        grid-template-columns: 1fr;
        gap: 1rem;
    }

    .navbar-custom .nav-link {
        margin-left: 1.5rem;
    }
}

@media (max-width: 576px) {
    .hero-section h1 {
        font-size: 1.6rem;
    }

    .hero-section .lead {
        font-size: 1rem;
    }

    .hero-buttons {
        display: flex;
        flex-direction: column;
    }

    .hero-buttons .btn {
        margin-bottom: 0.75rem;
        margin-right: 0 !important;
    }

    .navbar-brand {
        font-size: 1.3rem;
    }

    .navbar-custom .nav-link {
        margin-left: 1rem;
    }
}

/* Placeholder styles for game and arxiv pages */
.container-placeholder {
    min-height: 60vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
}

.container-placeholder h1 {
    color: var(--black);
    margin-bottom: 1rem;
    font-family: 'Calibri', sans-serif;
    font-size: 2.3rem;
}

.container-placeholder p {
    color: var(--medium-gray);
    font-size: 1rem;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-family: 'Calibri', sans-serif;
}

/* Game panel difficulty display - smaller text */
#difficultyDisplay {
    font-size: 0.9rem !important;
}