body {
    font-family: 'Roboto', sans-serif;
    margin: 0;
    padding: 0;
    background-color: #282c34;
    color: #ffffff;
    transition: background-color 0.3s, color 0.3s;
}

h1, h2, h3 {
    margin: 0;
}

a {
    text-decoration: none;
    color: #61dafb;
}


.navbar {
    display: flex;
    justify-content: center; 
    align-items: center;
    background-color: #3b3f47;
    padding: 10px 20px;
}

.nav-logo {
    font-size: 24px;
    font-weight: bold;
    margin-right: auto; 
}

.nav-links {
    list-style: none;
    display: flex;
    gap: 30px; 
}

.nav-links li {
    flex: 1; 
    text-align: center; 
}

.nav-links a {
    font-size: 22px; 
    color: #61dafb;
    transition: color 0.3s; 
}

.nav-links a:hover {
    color: #4fd3f8; 
}

.nav-user {
    display: flex;
    align-items: center;
}

.theme-toggle, .text-size-toggle {
    margin-left: 15px;
}


.hero {
    position: relative;
    height: 50vh;
    display: flex;
    justify-content: center;
    align-items: center;
    color: #ffffff;
    text-align: center;
    background-size: cover;
    background-position: center;
}

.hero-overlay {
    background: rgba(0, 0, 0, 0.5);
    padding: 20px;
}

.courses {
    padding: 20px;
}

.section-title {
    font-size: 32px;
    text-align: center;
    margin-bottom: 20px;
}

.filter-options {
    text-align: center;
    margin-bottom: 20px;
}

.filter-select {
    padding: 10px;
    border-radius: 5px;
    border: 1px solid #61dafb;
    background-color: #3b3f47;
    color: #ffffff;
}


.course-cards {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 20px;
}

.course-card {
    background-color: #444b54;
    padding: 15px;
    border-radius: 10px;
    transition: transform 0.3s, box-shadow 0.3s;
    width: 300px;
}

.course-card:hover {
    transform: scale(1.05);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

.course-title {
    font-size: 20px;
    margin: 10px 0;
}

.course-description {
    margin: 10px 0;
}

.course-links {
    display: flex;
    flex-direction: column;
    margin: 10px 0;
}

.external-link {
    margin-bottom: 5px;
    color: #61dafb;
}

.details-btn {
    background-color: #61dafb;
    color: #282c34;
    border: none;
    padding: 10px;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s;
}

.details-btn:hover {
    background-color: #21a1f1;
}

footer {
    text-align: center;
    padding: 20px;
    background-color: #3b3f47;
}


body.dark-mode {
    background-color: #181a1f;
    color: #ffffff;
}

body.dark-mode .navbar {
    background-color: #3a3f47;
}

body.dark-mode .course-card {
    background-color: #2c2f35;
}

body.dark-mode .external-link {
    color: #4fd3f8;
}

body.dark-mode .details-btn {
    background-color: #4fd3f8;
    color: #282c34;
}

body.dark-mode .details-btn:hover {
    background-color: #3ab0e5;
}


body.larger-text {
    font-size: 1.2em;
}

@media (max-width: 768px) {
    .navbar {
        flex-direction: column;
        align-items: flex-start;
    }

    .nav-links {
        display: none;
        flex-direction: column;
    }

    .nav-links.active {
        display: flex;
    }

    .hamburger {
        display: flex;
        flex-direction: column;
        cursor: pointer;
    }

    .bar {
        height: 4px;
        width: 25px;
        background-color: #61dafb;
        margin: 3px 0;
        transition: 0.3s;
    }

    .course-cards {
        flex-direction: column;
        align-items: center;
    }
}