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

:root {
    --primary: #4CAF50; /* Green color */
    --primary-light: rgba(76, 175, 80, 0.1);
    --primary-hover: #43A047;
    --dark: #121212;
    --gray-900: #FFFFFF; /* White text for dark theme */
    --gray-600: #B0B0B0;
    --gray-500: #909090;
    --gray-400: #707070;
    --gray-200: #404040;
    --gray-100: #303030;
    --white: #1E1E1E; /* Dark background for cards */
    --bg: #121212; /* Main dark background */
}

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg);
    color: var(--gray-900);
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

@media (min-width: 768px) {
    .container {
        padding: 0 48px;
    }
}

/* Header and Navigation */
header {
    padding: 24px 0;
    border-bottom: 1px solid var(--gray-200);
    position: fixed;
    top: 0;
    width: 100%;
    background-color: var(--bg);
    z-index: 1000;
}

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

.logo {
    font-size: 1.5rem;
    font-weight: 500;
    color: var(--primary);
    text-decoration: none;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 32px;
}

.nav-link {
    color: var(--gray-400);
    text-decoration: none;
    font-size: 0.875rem;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    transition: color 0.3s ease;
    position: relative;
}

.nav-link:hover,
.nav-link.active {
    color: var(--primary);
}

.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
}

.hamburger span {
    width: 25px;
    height: 3px;
    background-color: var(--gray-400);
    margin: 3px 0;
    transition: 0.3s;
}

@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background-color: var(--bg);
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: 0 10px 27px rgba(0, 0, 0, 0.05);
        padding: 20px 0;
        gap: 0;
    }

    .nav-menu.active {
        left: 0;
    }

    .nav-link {
        display: block;
        padding: 15px;
        margin: 0;
    }

    .hamburger {
        display: flex;
    }

    .hamburger.active span:nth-child(2) {
        opacity: 0;
    }

    .hamburger.active span:nth-child(1) {
        transform: translateY(8px) rotate(45deg);
    }

    .hamburger.active span:nth-child(3) {
        transform: translateY(-8px) rotate(-45deg);
    }
}

/* Hero Section */
.hero {
    padding: 80px 0;
    text-align: center;
    padding-top: 100px;
}

.section-label {
    font-size: 0.875rem;
    color: var(--primary);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    font-weight: 500;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 300;
    margin-top: 8px;
    margin-bottom: 24px;
}

@media (min-width: 768px) {
    .section-title {
        font-size: 3rem;
    }
}

.hero-description {
    font-size: 1.125rem;
    color: var(--gray-600);
    font-weight: 300;
    max-width: 700px;
    margin: 0 auto 48px;
    line-height: 1.8;
}

/* Research Grid */
.research-grid {
    display: grid;
    gap: 48px;
    margin-top: 64px;
}

@media (min-width: 768px) {
    .research-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 64px;
    }
}

.research-category {
    background-color: var(--white);
    border: 1px solid var(--gray-100);
    padding: 32px;
    border-radius: 4px;
    transition: all 0.3s ease;
}

.research-category:hover {
    border-color: var(--primary);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

.category-icon {
    width: 56px;
    height: 56px;
    background-color: var(--primary-light);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 24px;
}

.category-icon svg {
    width: 24px;
    height: 24px;
    color: var(--primary);
}

.category-title {
    font-size: 1.5rem;
    font-weight: 500;
    margin-bottom: 16px;
       text-align: left;
}

.category-description {
    color: var(--gray-500);
    margin-bottom: 24px;
    line-height: 1.7;
    text-align: left;
}

.research-list {
    list-style: none;
}

.research-list li {
    display: flex;
    align-items: flex-start;
    gap: 12px;
    color: var(--gray-600);
    font-weight: 300;
    margin-bottom: 16px;
}

.research-list li::before {
    content: '';
    width: 6px;
    height: 6px;
    background-color: var(--primary);
    border-radius: 50%;
    margin-top: 8px;
    flex-shrink: 0;
}

/* Publications */
.publications {
    background-color: var(--white);
    padding: 64px 0;
    margin: 96px 0;
}

.publications-grid {
    display: grid;
    gap: 32px;
    margin-top: 64px;
}

@media (min-width: 768px) {
    .publications-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

.publication-card {
    border: 1px solid var(--gray-100);
    padding: 24px;
    transition: all 0.3s ease;
}

.publication-card:hover {
    border-color: var(--primary);
}

.publication-title {
    font-size: 1.125rem;
    font-weight: 500;
    margin-bottom: 12px;
}

.publication-authors {
    color: var(--gray-500);
    font-size: 0.875rem;
    margin-bottom: 12px;
}

.publication-journal {
    color: var(--primary);
    font-size: 0.875rem;
    font-weight: 500;
    margin-bottom: 8px;
}

.publication-year {
    color: var(--gray-400);
    font-size: 0.875rem;
}

/* Footer */
footer {
    border-top: 1px solid var(--gray-200);
    padding: 32px 0;
    text-align: center;
}

.copyright {
    color: var(--gray-500);
    font-size: 0.875rem;
}

.social-links {
    display: flex;
    gap: 24px;
    justify-content: center;
}

.social-link {
    color: var(--gray-400);
    transition: color 0.3s ease;
}

.social-link:hover {
    color: var(--primary);
}

.icon {
    width: 16px;
    height: 16px;
    flex-shrink: 0;
}