:root {
    --bg-color: #1a1a1a; /* Dark background to make the book pop */
    --book-cover: #5d4037; /* Leather brown */
    --book-cover-accent: #3e2723; /* Darker leather */
    --page-bg: #f4e4bc; /* Aged parchment */
    --text-color: #2c1810; /* Dark brown ink */
    --accent-color: #8d6e63; /* Soft brown accent */
    --gold-accent: #ffd700;
}

body {
    margin: 0;
    padding: 0;
    font-family: 'Cormorant Garamond', serif;
    background-color: var(--bg-color);
    background-image: radial-gradient(circle at center, #2a2a2a 0%, #000000 100%);
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    overflow: hidden;
}

/* Login Screen */
#login-screen {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.85);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    transition: opacity 0.5s ease;
}

.login-container {
    text-align: center;
    background: #f4e4bc;
    padding: 3rem;
    border-radius: 2px;
    box-shadow: 0 0 50px rgba(0,0,0,0.5), inset 0 0 60px rgba(0,0,0,0.1);
    border: 1px solid #d7ccc8;
    max-width: 400px;
    position: relative;
}

/* Add a border effect to login */
.login-container::before {
    content: '';
    position: absolute;
    top: 10px; left: 10px; right: 10px; bottom: 10px;
    border: 2px solid var(--text-color);
    pointer-events: none;
}

h1 {
    font-family: 'Cinzel', serif;
    color: var(--text-color);
    font-size: 2.5rem;
    margin-bottom: 1rem;
    text-transform: uppercase;
    letter-spacing: 2px;
}

input {
    padding: 12px;
    border: none;
    border-bottom: 2px solid var(--text-color);
    background: transparent;
    font-family: 'Cormorant Garamond', serif;
    font-size: 1.2rem;
    outline: none;
    color: var(--text-color);
    text-align: center;
    width: 80%;
    margin-bottom: 20px;
}

input::placeholder {
    color: rgba(44, 24, 16, 0.5);
}

button {
    padding: 12px 30px;
    background-color: var(--text-color);
    color: var(--page-bg);
    border: none;
    border-radius: 2px;
    cursor: pointer;
    font-size: 1.1rem;
    transition: all 0.3s;
    font-family: 'Cinzel', serif;
    letter-spacing: 1px;
    text-transform: uppercase;
}

button:hover {
    background-color: var(--book-cover);
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.3);
}

.hidden {
    display: none !important;
}

#error-msg {
    color: red;
    margin-top: 10px;
    font-size: 0.9rem;
}

/* Book Styles */
#book-container {
    perspective: 2000px; /* Increased perspective for better mobile view */
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    width: 100%;
    height: 100%;
    position: relative;
    z-index: 10;
}

.book {
    position: relative;
    width: 45vw; /* Adjusted for mobile to fit open state */
    height: 65vw;
    max-width: 400px;
    max-height: 600px;
    transform-style: preserve-3d;
    transition: transform 1s ease-in-out; /* Smooth centering */
}

.book.open {
    transform: translateX(50%);
}

.book.view-back {
    transform: translateX(100%);
}

@media (min-width: 768px) {
    .book {
        width: 400px;
        height: 600px;
    }
}

/* Background Scene */
#background-scene {
    position: fixed;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 1;
    display: flex;
    justify-content: center;
    align-items: flex-end;
    opacity: 0.6; /* Subtle background */
}

#scene-svg {
    height: 100%;
    width: 100%;
    filter: drop-shadow(0 0 10px rgba(255, 215, 0, 0.3));
}

#grass {
    transform-origin: bottom;
    transition: transform 1s ease-out;
}

#small-sunflowers {
    transform-origin: bottom;
    transition: transform 1s ease-out;
}

.stem {
    transition: stroke-dashoffset 1s ease-out;
}

.leaves {
    transition: transform 1s cubic-bezier(0.34, 1.56, 0.64, 1);
    transform-box: fill-box;
    transform-origin: center bottom;
}

.head {
    /* No transition here, we handle children */
}

.flower-center {
    transition: transform 1s cubic-bezier(0.34, 1.56, 0.64, 1);
    transform-origin: center;
    transform-box: fill-box;
}

.flower-petals {
    transition: transform 1s cubic-bezier(0.34, 1.56, 0.64, 1);
    transform-origin: center;
    transform-box: fill-box;
}

.page {
    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    transform-origin: left center;
    transform-style: preserve-3d;
    transition: transform 1.2s cubic-bezier(0.645, 0.045, 0.355, 1); /* Slower, smoother flip */
    background-color: var(--page-bg);
    /* Realistic paper texture and shadow */
    background-image: linear-gradient(to right, rgba(0,0,0,0.15) 0%, rgba(0,0,0,0) 5%, rgba(0,0,0,0) 95%, rgba(0,0,0,0.15) 100%);
    box-shadow: inset 0 0 30px rgba(139, 69, 19, 0.1), 5px 0 15px rgba(0,0,0,0.2);
    border-radius: 0 3px 3px 0;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    padding: 20px;
    box-sizing: border-box;
    text-align: center;
    cursor: pointer;
}

.page.flipped {
    transform: rotateY(-180deg);
    box-shadow: inset 0 0 30px rgba(139, 69, 19, 0.1), -5px 0 15px rgba(0,0,0,0.2);
}

/* Z-Index helper class for animation */
.page.flipping {
    z-index: 100 !important;
}

/* Front of the page */
.front, .back {
    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    backface-visibility: hidden;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    padding: 3rem 2rem;
    box-sizing: border-box;
}

.front {
    z-index: 2;
}

.back {
    transform: rotateY(180deg);
    z-index: 1;
    background-color: var(--page-bg);
    background-image: linear-gradient(to left, rgba(0,0,0,0.15) 0%, rgba(0,0,0,0) 5%, rgba(0,0,0,0) 95%, rgba(0,0,0,0.15) 100%);
}

/* Cover */
.page:first-child {
    background-color: var(--book-cover);
    /* Leather texture effect */
    background-image: url("data:image/svg+xml,%3Csvg width='100' height='100' viewBox='0 0 100 100' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noise'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.8' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noise)' opacity='0.15'/%3E%3C/svg%3E");
    color: var(--gold-accent);
    border-radius: 3px 5px 5px 3px;
    box-shadow: inset 4px 0 10px rgba(0,0,0,0.5), 10px 10px 30px rgba(0,0,0,0.6);
    border-left: 5px solid #3e2723; /* Spine */
}

.page:first-child .front {
    border: 3px double var(--gold-accent);
    margin: 15px;
    width: calc(100% - 30px);
    height: calc(100% - 30px);
    box-shadow: inset 0 0 20px rgba(0,0,0,0.5);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}

.page:first-child .front h2 {
    font-family: 'Cinzel', serif;
    font-size: 3.5rem;
    color: transparent;
    background: linear-gradient(45deg, #ffd700, #f0e68c, #ffd700);
    -webkit-background-clip: text;
    background-clip: text;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.5);
    margin: 0;
    line-height: 1.2;
}

.page:first-child .front p {
    color: #d7ccc8;
    font-style: italic;
    margin-top: 20px;
}

/* Back Cover */
.back-cover-face {
    background-color: var(--book-cover);
    background-image: url("data:image/svg+xml,%3Csvg width='100' height='100' viewBox='0 0 100 100' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noise'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.8' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noise)' opacity='0.15'/%3E%3C/svg%3E");
    color: var(--gold-accent);
    border: 3px double var(--gold-accent);
    margin: 15px;
    width: calc(100% - 30px);
    height: calc(100% - 30px);
    box-shadow: inset 0 0 20px rgba(0,0,0,0.5);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    /* Ensure it covers the page background */
    position: absolute;
    top: 0;
    left: 0;
    z-index: 2;
}

.back-cover-face h2 {
    font-family: 'Cinzel', serif;
    font-size: 1.5rem;
    color: var(--gold-accent);
    opacity: 0.8;
}

.end-paper {
    display: flex;
    justify-content: center;
    align-items: center;
    font-style: italic;
    color: rgba(44, 24, 16, 0.5);
}

/* Content Styling */
.page h2 {
    font-family: 'Cinzel', serif;
    color: var(--text-color);
    font-size: 2rem;
    margin-bottom: 1.5rem;
    border-bottom: 1px solid rgba(44, 24, 16, 0.3);
    padding-bottom: 10px;
    width: 80%;
}

.page p {
    font-size: 1.2rem;
    line-height: 1.8;
    color: var(--text-color);
    font-weight: 500;
}

.page img {
    max-width: 85%;
    max-height: 45%;
    border: 8px solid white;
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
    transform: rotate(-2deg);
    margin-bottom: 1.5rem;
    filter: sepia(30%) contrast(90%); /* Vintage photo effect */
    transition: transform 0.3s;
}

.page img:hover {
    transform: rotate(0deg) scale(1.02);
}

/* Controls */
.controls {
    margin-top: 40px;
    z-index: 10;
    display: flex;
    gap: 40px;
}

.nav-btn {
    background: transparent;
    color: #d7ccc8; /* Light brown/parchment color */
    border: none;
    font-family: 'Cinzel', serif;
    font-size: 3rem;
    font-weight: 700;
    letter-spacing: 2px;
    cursor: pointer;
    padding: 10px;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 10px;
    text-shadow: 0 2px 4px rgba(0,0,0,0.5);
    opacity: 0.7;
}

.nav-btn:hover {
    color: var(--gold-accent);
    transform: scale(1.1);
    opacity: 1;
    text-shadow: 0 0 10px rgba(255, 215, 0, 0.5);
    background: transparent; /* Ensure no background on hover */
    box-shadow: none; /* Remove box shadow from previous style */
}

.arrow {
    font-size: 1.5rem;
    display: inline-block;
    transition: transform 0.3s ease;
}

#prev-btn:hover .arrow {
    transform: translateX(-5px);
}

#next-btn:hover .arrow {
    transform: translateX(5px);
}

/* Hearts Animation */
#hearts-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 5; /* Behind book (10) but above background (1) */
    overflow: hidden;
}

.heart {
    position: absolute;
    top: -50px;
    color: #e91e63; /* Pink/Red */
    opacity: 0.8;
    animation: fall linear forwards;
    text-shadow: 0 0 5px rgba(233, 30, 99, 0.5);
    font-size: 20px; /* Default size */
}

@keyframes fall {
    to {
        transform: translateY(110vh) rotate(360deg);
    }
}