body {
    font-family: 'Roboto', sans-serif; 
    background-color: #282c34; 
    color: #ffffff; 
    text-align: center;
    margin: 0;
    padding: 0;
}
.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background-color: #36454f;
    padding: 10px 20px;
}

.logo {
    color: white;
    font-size: 24px;
}

.nav-icon {
    display: none;
    font-size: 26px;
    color: white;
    cursor: pointer;
}

.nav-links {
    list-style-type: none;
    padding: 0;
    margin: 0;
    display: flex;
}

.nav-links li {
    margin: 0 15px;
}

.nav-links a {
    color: white;
    text-decoration: none;
    font-size: 18px;
}

.nav-links a:hover {
    color: #adbac7;
    transform: scale(1.05);
}

.container {
    width: auto;
    margin: 40px auto;
    padding: 30px;
    background-color: #3c404d; 
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.25); 
    border-radius: 15px; 
}

h1 {
    color: white; 
}

.instructions {
    font-size: 20px;
    margin-bottom: 30px;
    color: #adbac7;
}

#game-board {
    display: flex;
    flex-wrap: wrap;
    gap: 20px;
    justify-content: center;
    padding: 20px;
}

.card {
    width: 250px;
    height: 250px;
    background-color: #565c6f;
    border-radius: 10px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

.card img {
    width: 100%;
    height: 100%;
    visibility: hidden; /* Hide images by default */
    display: block;
    object-fit: cover;
}

.card.show img {
    visibility: visible; /* Show image when card is flipped */
}

#start-game {
    background-color: #708090;
    color: white;
    padding: 12px 24px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 18px;
    transition: background-color 0.3s, transform 0.3s;
}

#start-game:hover {
    background-color: #333; /* Darker on hover */
    transform: scale(1.05); /* Slightly enlarges on hover */
}

@media (max-width: 600px) {
    .card {
        height: 60px;
        width: 60px;
    }
    #game-board {
        gap: 10px;
        padding: 10px;
    }
}

.back-to-top {
    position: fixed;
    bottom: 20px;
    right: 20px;
    display: none;
    font-size: 24px;
    color: #fff;
    background-color: #33788a;
    border: none;
    border-radius: 5px;
    text-decoration: none;
    text-align: center;
    padding: 10px;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.3);
    transition: background-color 0.3s;
}

.back-to-top:hover {
    background-color: #3f536b;
}

@media (max-width:768px) {
    .nav-links {
        display: none;
        flex-direction: column;
        position: absolute;
        background-color: #333;
        width: 100%;
        top: 60px;
        left: 0;
    }

    .nav-links li {
        margin: 10px 0;
    }

    .nav-icon {
        display: block;
    }
}