:root {
    --primary-color: #2c3e50;
    --secondary-color: #02a756;
    --accent-color: #e74c3c;
    --light-color: #ecf0f1;
    --dark-color: #2c3e50;
    --font-main: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

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

body {
    font-family: var(--font-main);
    line-height: 1.6;
    color: #333;
    background-color: #f9f9f9;
}

a {
    text-decoration: none;
    color: var(--secondary-color);
}

ul {
    list-style: none;
}

/* img {
    max-width: 100%;
} */

.container {
    width: 90%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 15px;
}

/* Events */
.events > .container {
    display: flex;
    justify-content: center;
    align-items: center;
    column-gap: 5rem;
    margin: 0.5rem auto;
}

.events > .container > figure {
    display: flex;
    justify-content: center;
    align-items: center;
}

.events .event-text {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    margin-bottom: 1rem;
    text-align: center;
}

.events h2 {
    color: red;
    font-size: 2.5rem;
}

.events img {
    width: 100%;
    object-fit: contain;
}

/* Header */
header {
    background-color: var(--primary-color);
    color: white;
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

header img {
    width: 32px;
}

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

.more-container {
    display: flex;
    justify-content: center;
    align-items: center;
}
.logo {
    font-size: 1.5rem;
    font-weight: bold;
    display: flex;
    column-gap: 1rem;
}

.nav-menu {
    display: flex;
}

.nav-menu li {
    margin-left: 1.5rem;
}

.nav-menu a {
    color: white;
    font-weight: 500;
    transition: color 0.3s;
}

.nav-menu a:hover {
    color: var(--secondary-color);
}

.hamburger {
    display: none;
    cursor: pointer;
    font-size: 1.5rem;
}

/* Hero Section */
.hero {
    /* background: linear-gradient(rgba(44, 62, 80, 0.8), rgba(44, 62, 80, 0.8)), url('https://source.unsplash.com/random/1600x900/?telemetry') no-repeat center center/cover; */
    background-image: linear-gradient(0deg, rgba(5, 14, 47, .65), rgba(5, 14, 47, .65)), url(../images/header-background.webp);
    background-size: cover;
    color: white;
    padding: 5rem 0;
    text-align: center;
}

.about-content .railbee_logo {
    height:300px;
    margin-bottom: 1rem;
}

.hero h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.hero p {
    font-size: 1.2rem;
    max-width: 800px;
    margin: 0 auto 2rem;
}

.btn {
    display: inline-block;
    background: var(--secondary-color);
    color: white;
    padding: 0.8rem 1.5rem;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1rem;
    transition: background 0.3s;
}

.btn:hover {
    background: #2980b9;
}

/* Sections */
.section {
    padding: 4rem 0;
}

.section-title {
    text-align: center;
    margin-bottom: 3rem;
    color: var(--primary-color);
}

.section-title h2 {
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

.section-title h3 {
    font-size: 1.2rem;
    margin-top: 2rem;
    /* margin-bottom: 0.5rem; */
}

.section-title div {
    width: 80px;
    height: 4px;
    background: var(--secondary-color);
    margin: 0 auto;
}

/* About */
.about-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 2rem;
    align-items: center;
}

/* Research Areas */
.research-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 2rem;
}

.research-card {
    background: white;
    padding: 1.5rem;
    border-radius: 5px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s;
}

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

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

/* Gallery */
.gallery {
    background: #f1f1f1;
}

.gallery-filters {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: 2rem;
}

.gallery-filter {
    padding: 0.5rem 1rem;
    margin: 0.5rem;
    background: white;
    border: 1px solid #ddd;
    border-radius: 3px;
    cursor: pointer;
    transition: all 0.3s;
}

.gallery-filter.active,
.gallery-filter:hover {
    background: var(--secondary-color);
    color: white;
    border-color: var(--secondary-color);
}

.gallery-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 1rem;
    margin-bottom: 2rem;
}

.gallery-item {
    position: relative;
    overflow: hidden;
    border-radius: 5px;
    height: 200px;
    cursor: pointer;
}

.gallery-item img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.5s;
}

.gallery-item:hover img {
    transform: scale(1.1);
}

.load-more {
    text-align: center;
    margin-top: 2rem;
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.9);
    z-index: 1000;
    justify-content: center;
    align-items: center;
}

.modal-content {
    max-width: 90%;
    max-height: 90%;
}

.modal-close {
    position: absolute;
    top: 20px;
    right: 30px;
    color: white;
    font-size: 2rem;
    cursor: pointer;
}

/* Team */

/* .team-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));    
    gap: 2rem;
    justify-content: center;
} */

.team-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, 250px);    
    justify-content: center;
    gap: 2rem;
    margin-bottom: 2rem;
}

.team-member {
    text-align: center;
    background: white;
    padding: 1.5rem;
    border-radius: 5px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

.team-member img {
    width: 150px;
    height: 150px;
    border-radius: 50%;
    object-fit: cover;
    margin-bottom: 1rem;
}

.team-member p {
    margin-bottom: 1rem;
}

.team-contacts {
    display: flex;
    align-items: center;
    justify-content: center;
    column-gap: 1rem;
}

.team-contacts .contact-icon {
    width: 23px; 
    height: 26px;    
    border-radius: 5px;
}

/* Publications */
.publication-list {
    background: white;
    border-radius: 5px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    overflow: hidden;
}

.publication-item {
    padding: 1rem 1.5rem;
    border-bottom: 1px solid #eee;
}

.publication-item:last-child {
    border-bottom: none;
}

/* Contact */
.contact-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
}

.contact-form input,
.contact-form textarea {
    width: 100%;
    padding: 0.8rem;
    margin-bottom: 1rem;
    border: 1px solid #ddd;
    border-radius: 5px;
}

.contact-form textarea {
    min-height: 150px;
}

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

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    text-align: left;
}

.footer-section h3 {
    margin-bottom: 1rem;
    font-size: 1.2rem;
}

.social-links {
    display: flex;
    gap: 1rem;
}

.social-links a {
    color: white;
    font-size: 1.5rem;
}

.copyright {
    margin-top: 2rem;
    padding-top: 1rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

/* Responsive */
@media (max-width: 768px) {
    .hamburger {
        display: block;
    }

    .nav-menu {
        position: fixed;
        top: 70px;
        left: -100%;
        background: var(--primary-color);
        width: 100%;
        height: calc(100vh - 70px);
        flex-direction: column;
        align-items: center;
        justify-content: center;
        transition: 0.3s;
    }

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

    .nav-menu li {
        margin: 1.5rem 0;
    }

    .about-content,
    .contact-content {
        grid-template-columns: 1fr;
    }

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

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

    .events > .container {
        flex-direction: column;
    }

    .events h2 {
        font-size: 2rem;
    }

}