/* Google Fonts Import */
        @import url('https://fonts.googleapis.com/css2?family=Poppins:wght@300;400;600;700&display=swap');

        /* --- Root Variables for Colors --- */
        :root {
            --primary-color: #00008B; /* Dark Blue */
            --secondary-color: #0000CD; /* Medium Blue */
            --background-color: #f4f7fc;
            --text-color: #333;
            --card-bg-color: #ffffff;
            --shadow-color: rgba(0, 0, 139, 0.1);
            --header-text-color: #ffffff;
        }

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

        body {
            font-family: 'Poppins', sans-serif;
            background-color: var(--background-color);
            color: var(--text-color);
            line-height: 1.7;
        }

        /* --- Intro Animation --- */
      .intro-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100vh;

    background:
        url('images/intro2.png') top left no-repeat,
        url('images/intro1.png') center center / cover no-repeat;

    background-size:
        contain,
        cover;

    background-repeat: no-repeat, no-repeat;
    background-position: top left, center center;

    z-index: 9999;
    display: flex;
    justify-content: center;
    align-items: center;
    overflow: hidden;

    animation: slideUp 1s ease-in-out 3s forwards;
    transition: all 0.5s ease;
}

.intro-content {
    text-align: center;
    color: #ffffff;
    animation: fadeInText 1.8s ease;
    backdrop-filter: blur(4px);
    padding: 2rem;
    border-radius: 16px;
}

.intro-content h1 {
    font-size: 3.2rem;
    font-weight: 800;
    letter-spacing: 1px;
    margin-bottom: 0.5rem;
    color: #fffae3;
    text-shadow: 2px 2px 5px rgba(0, 0, 0, 0.5);
}

.intro-content p {
    font-size: 1.2rem;
    font-weight: 300;
    color: #f0f0f0;
    max-width: 700px;
    margin: 0 auto;
    line-height: 1.6;
}

/* Fade-in animation */
@keyframes fadeInText {
    0% {
        opacity: 0;
        transform: translateY(30px);
    }
    100% {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Slide up animation to hide intro */
@keyframes slideUp {
    to {
        transform: translateY(-100%);
        visibility: hidden;
    }
}

/* MEDIA QUERIES FOR RESPONSIVENESS */
@media screen and (max-width: 768px) {
    .intro-overlay {
        background:
            url('images/intro2.png') top right no-repeat,
            url('images/intro1.png') center center / cover no-repeat;

        background-size:
            120px auto,
            cover;

        background-position:
            top right,
            center center;
    }

    .intro-content h1 {
        font-size: 2.2rem;
    }

    .intro-content p {
        font-size: 1rem;
        padding: 0 1rem;
    }
}

@media screen and (max-width: 480px) {
    .intro-overlay {
        background-size:
            90px auto,
            cover;
    }

    .intro-content h1 {
        font-size: 1.8rem;
    }

    .intro-content p {
        font-size: 0.95rem;
    }
}

        /* --- Header & Navigation --- */
        header {
            box-shadow: 0 4px 12px var(--shadow-color);
        }

        nav {
            position: sticky;
            top: 0;
            left: 0;
            width: 100%;
            background-color: var(--primary-color);
            color: var(--header-text-color);
            padding: 15px 5%;
            z-index: 500;
            font-size: 1.5rem;
            font-weight: 600;
        }

        /* --- Hero Slider --- */
        .hero-slider {
            position: relative;
            width: 100%;
            height: 60vh;
            overflow: hidden;
        }

        .slide {
            position: absolute;
            width: 100%;
            height: 100%;
            background-size: cover;
            background-position: center;
            opacity: 0;
            transition: opacity 1.5s ease-in-out;
        }

        .slide.active {
            opacity: 1;
        }

        .hero-overlay {
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: rgba(0, 0, 0, 0.4);
            display: flex;
            justify-content: center;
            align-items: center;
            color: var(--header-text-color);
            text-align: center;
        }

        .hero-overlay h2 {
            font-size: 2.5rem;
            max-width: 800px;
            text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.7);
        }


        /* --- Main Content & Controls --- */
        main {
            padding: 20px 5%;
        }

        .controls-container {
            background: var(--card-bg-color);
            padding: 30px 25px;
            border-radius: 16px;
            box-shadow: 0 8px 30px rgba(0, 0, 139, 0.08);
            margin: 0 auto 50px auto;
            max-width: 700px;
            text-align: center;
        }

        .controls label {
            display: block;
            margin-bottom: 20px;
            font-size: 1.3rem;
            font-weight: 600;
            color: var(--primary-color);
        }

        .controls label i {
            margin-right: 10px;
        }

        .select-wrapper {
            position: relative;
        }

        #state-select {
            -webkit-appearance: none;
            -moz-appearance: none;
            appearance: none;
            width: 100%;
            padding: 15px 20px;
            font-size: 1.1rem;
            font-family: 'Poppins', sans-serif;
            color: var(--text-color);
            background-color: #f4f7fc;
            border: 2px solid #dde6f1;
            border-radius: 10px;
            cursor: pointer;
            transition: all 0.3s ease;
            padding-right: 50px;
            background-image: url('');
            background-repeat: no-repeat;
            background-position: right 15px center;
            background-size: 12px;
        }

        #state-select:focus {
            outline: none;
            border-color: var(--primary-color);
            box-shadow: 0 0 0 4px rgba(0, 0, 139, 0.15);
        }

        #state-select:hover {
            border-color: var(--secondary-color);
        }


        /* --- Monument Sections & Cards (UPDATED FOR FLIP) --- */
        .monument-section {
            display: none; /* Hidden by default, JS will make it active */
            grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
            gap: 30px;
        }

        .monument-section.active {
            display: grid; /* Display as grid when active */
        }
        
        .monument-card {
            background-color: transparent;
            min-height: 480px;
            perspective: 1500px;
            border-radius: 15px;
            opacity: 0;
            transform: translateY(20px);
            position: relative;
            transition: min-height 0.5s ease-in-out, z-index 0s 0.5s;
        }
        
        .card-inner {
            position: relative;
            width: 100%;
            height: 100%;
            transition: transform 0.8s;
            transform-style: preserve-3d;
            box-shadow: 0 5px 15px var(--shadow-color);
            border-radius: 15px;
        }

        .monument-section.active .monument-card {
            animation: cardFadeIn 0.5s ease-out forwards;
        }

        @keyframes cardFadeIn {
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }
        .monument-section.active .monument-card:nth-child(2) { animation-delay: 0.1s; }
        .monument-section.active .monument-card:nth-child(3) { animation-delay: 0.2s; }
        .monument-section.active .monument-card:nth-child(4) { animation-delay: 0.3s; }
        

        .monument-card.flipped {
            min-height: 85vh;
            z-index: 10;
        }
        .monument-card.flipped .card-inner {
            transform: rotateY(180deg);
        }

        .card-front,
        .card-back {
            position: absolute;
            width: 100%;
            height: 100%;
            -webkit-backface-visibility: hidden;
            backface-visibility: hidden;
            border-radius: 15px;
            background: var(--card-bg-color);
            overflow: hidden;
            display: flex;
            flex-direction: column;
        }
        
        .card-back {
            transform: rotateY(180deg);
            color: var(--text-color);
        }
        
        .card-back-content {
            padding: 25px;
            overflow-y: auto;
            display: flex;
            flex-direction: column;
            height: 100%;
        }
        
        .monument-card:not(.flipped):hover .card-inner {
            transform: translateY(-10px);
            box-shadow: 0 12px 25px rgba(0, 0, 139, 0.15);
        }

        .monument-card.flipped:hover .card-inner {
             transform: rotateY(180deg) translateY(0);
             box-shadow: 0 12px 25px rgba(0, 0, 139, 0.15);
        }
        
        .monument-card img {
            width: 100%;
            height: 220px;
            object-fit: cover;
            flex-shrink: 0;
        }

        .card-content {
            padding: 25px;
            flex-grow: 1;
            display: flex;
            flex-direction: column;
        }

        .card-content h3, .card-back-content h3 {
            color: var(--primary-color);
            font-size: 1.4rem;
            margin-bottom: 10px;
        }
        
        .card-back-content h4 {
            color: var(--secondary-color);
            margin-top: 15px;
            margin-bottom: 5px;
            font-size: 1.2rem;
            border-top: 1px solid #eee;
            padding-top: 15px;
        }
        
        .history-text {
            font-size: 0.95rem;
            line-height: 1.8;
            margin-bottom: 20px;
            text-align: left;
            flex-grow: 1;
        }
        
        .card-back-content iframe {
            width: 100%;
            height: 250px;
            border: 1px solid #ddd;
            border-radius: 8px;
            margin-bottom: 20px;
            flex-shrink: 0;
        }

        .card-content .location {
            color: #555;
            margin-bottom: 15px;
        }

        .card-content .location i {
            color: var(--secondary-color);
            margin-right: 8px;
        }

        .card-content .description {
            flex-grow: 1;
            margin-bottom: 20px;
        }

        .read-more-btn, .go-back-btn {
            align-self: flex-start;
            text-decoration: none;
            background-color: var(--primary-color);
            color: var(--header-text-color);
            padding: 10px 20px;
            border-radius: 50px;
            font-weight: 600;
            transition: background-color 0.3s ease;
            border: none;
            cursor: pointer;
            font-family: 'Poppins', sans-serif;
            font-size: 1rem;
        }

        .read-more-btn:hover {
            background-color: var(--secondary-color);
        }
        
        .go-back-btn {
            align-self: center;
            background-color: var(--secondary-color);
            padding: 12px 25px;
        }

        .go-back-btn:hover {
            background-color: var(--primary-color);
        }

        /* --- Footer --- */
        footer {
            text-align: center;
            padding: 25px;
            margin-top: 40px;
            background-color: #333;
            color: #eee;
        }

        /* --- Responsive Design --- */
        @media (max-width: 768px) {
            .intro-content h1 { font-size: 2.5rem; }
            .hero-overlay h2 { font-size: 1.8rem; padding: 0 20px; }
            nav { font-size: 1.2rem; }
            .monument-card.flipped { min-height: 95vh; }
        }

        @media (max-width: 480px) {
            .monument-section {
                grid-template-columns: 1fr;
            }
        }