/*
  PREMIUM STYLESHEET - NCERT Book Store (Corrected & Improved for provided HTML)

  DESIGN PHILOSOPHY (V2):
  Retain the sophisticated, cool color palette, enhancing it with dynamic lighting and gradients.
  Create a palpable sense of depth and material quality through layered shadows, glows, and textures.
  Prioritize a fluid, responsive user experience with meaningful micro-interactions and animations.
  Ensure every interactive element provides clear, polished feedback (hover, focus, active states).

  COLOR PALETTE (Unchanged):
  Background: Midnight Blue (#0D1B2A)
  Surface/Card: Slate Blue (#1B263B)
  Border: Dark Slate (#415A77)
  Text: Off-White (#E0E1DD)
  Accent: Amber (#FFB703)
  Accent (Darker): Burnt Orange (#FB8500)

  TYPOGRAPHY (Unchanged):
  Headings: Lora (Serif)
  Body/UI: Inter (Sans-Serif)
*/

/* --- Root Variables & Global Styles --- */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&family=Lora:wght@600;700&display=swap');

:root {
  /* Colors */
  --color-bg: #0D1B2A;
  --color-surface: #1B263B;
  --color-border: #415A77;
  --color-text: #E0E1DD;
  --color-text-muted: #778DA9;
  --color-accent: #FFB703;
  --color-accent-dark: #FB8500;
  --color-accent-glow: rgba(255, 183, 3, 0.2);
  --color-accent-glow-strong: rgba(255, 183, 3, 0.4);

  /* Typography */
  --font-main: 'Inter', sans-serif;
  --font-heading: 'Lora', serif;

  /* Sizing & Spacing */
  --border-radius: 0.75rem;
  --container-padding: 2rem;
  --container-width: 1200px;

  /* Effects */
  --transition-fast: 0.2s cubic-bezier(.4, 0, .2, 1);
  --transition-std: 0.4s cubic-bezier(.4, 0, .2, 1);
  --shadow-md: 0 4px 10px rgba(0, 0, 0, 0.15);
  --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.25);
  --shadow-glow: 0 0 0 3px var(--color-accent-glow);
  --shadow-inset: inset 0 2px 4px rgba(0, 0, 0, 0.3);
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  background-color: var(--color-bg);
  background-image:
    radial-gradient(ellipse at top, rgba(65, 90, 119, 0.2), transparent 50%),
    url("data:image/svg+xml,%3Csvg viewBox='0 0 100 100' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noiseFilter'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.8' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noiseFilter)' opacity='0.02'/%3E%3C/svg%3E");
  color: var(--color-text);
  font-family: var(--font-main);
  margin: 0;
  min-height: 100vh;
  overflow-x: hidden;
}

::-webkit-scrollbar { width: 10px; }
::-webkit-scrollbar-track { background: var(--color-bg); }
::-webkit-scrollbar-thumb { background-color: var(--color-border); border-radius: 20px; border: 2px solid var(--color-bg); }
::-webkit-scrollbar-thumb:hover { background-color: var(--color-accent); }
::selection { background-color: var(--color-accent); color: var(--color-bg); }

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  color: #fff;
  letter-spacing: 0.5px;
  text-shadow: 0 1px 3px rgba(0, 0, 0, 0.2);
}

/* --- Header --- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  padding: 1rem var(--container-padding);
  background: rgba(13, 27, 42, 0.8);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid rgba(65, 90, 119, 0.3);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
}

.logo {
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--color-accent);
  text-decoration: none;
  transition: color var(--transition-fast), text-shadow var(--transition-fast);
  white-space: nowrap;
}

.logo:hover {
  color: var(--color-accent-dark);
  text-shadow: 0 0 10px var(--color-accent-glow);
}

.main-nav ul {
  list-style: none;
  display: flex;
  margin: 0;
  padding: 0;
  justify-content: center;
  gap: 1.5rem;
}

.main-nav a {
  position: relative;
  color: var(--color-text);
  text-decoration: none;
  font-weight: 500;
  font-size: 1.05rem;
  padding: 0.5rem 0.1rem;
  transition: color var(--transition-fast);
  white-space: nowrap;
}

.main-nav a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 2px;
  background-color: var(--color-accent);
  transform: scaleX(0);
  transform-origin: bottom right;
  transition: transform var(--transition-fast);
}

.main-nav a:hover,
.main-nav a:focus,
.main-nav .dropdown:hover > a {
  color: #fff;
  outline: none;
}

.main-nav a:hover::after,
.main-nav a:focus::after {
  transform: scaleX(1);
  transform-origin: bottom left;
}

/* Dropdown Menu */
.dropdown {
  position: relative;
}

.dropdown-menu {
  display: none;
  position: absolute;
  top: 100%;
  left: 0;
  z-index: 1001;
  min-width: 200px;
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius);
  padding: 0.75rem 0;
  margin-top: 0.75rem;
  list-style: none;
  box-shadow: var(--shadow-lg);
}

.dropdown:hover .dropdown-menu {
  display: block;
}

.dropdown-menu a {
  display: block;
  padding: 0.6rem 1.2rem;
  color: var(--color-text-muted);
}

.dropdown-menu a:hover,
.dropdown-menu a:focus {
  color: var(--color-accent);
  background-color: rgba(65, 90, 119, 0.2);
}



/* Search bar */
.search-bar {
  flex-grow: 1;
  max-width: 350px;
}

.search-bar input {
  width: 100%;
  padding: 0.65rem 1rem;
  font-size: 1rem;
  color: var(--color-text);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 50px;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.search-bar input::placeholder {
  color: var(--color-text-muted);
}

.search-bar input:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: var(--shadow-glow);
}

/* --- Hero Section --- */
.hero {
  text-align: center;
  padding: 6rem var(--container-padding) 7rem;
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 400px;
  overflow: hidden;
}

.hero-banner {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover; /* Ensures the image covers the area */
  object-position: center; /* Centers the image within the container */
  z-index: -1;
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: var(--container-width);
}

@keyframes shimmer {
  0% { background-position: -800px 0; }
  100% { background-position: 800px 0; }
}

.hero-content h1 {
  font-size: clamp(2.8rem, 5.5vw, 4.8rem);
  line-height: 1.1;
  margin-bottom: 1.5rem;
  color: #fff;
  background: linear-gradient(110deg, #E0E1DD 20%, #ffffff 50%, #E0E1DD 80%);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  animation: shimmer 20s linear infinite;
  background-size: 200% auto;
}

.hero-content p {
  font-size: 1.25rem;
  color: var(--color-text-muted);
  max-width: 650px;
  margin: 0 auto 2.5rem auto;
  line-height: 1.6;
}

.cta-btn {
  background-image: linear-gradient(to right, var(--color-accent) 0%, var(--color-accent-dark) 100%);
  color: var(--color-bg);
  padding: 1rem 2.5rem;
  border: none;
  border-radius: 50px;
  font-size: 1.1rem;
  font-weight: 700;
  letter-spacing: 0.5px;
  cursor: pointer;
  text-decoration: none;
  box-shadow: 0 4px 15px rgba(251, 133, 0, 0.25);
  transition: all var(--transition-fast);
  position: relative;
  top: 2rem;
  z-index: 1;
}

.cta-btn:hover {
  transform: translateY(-4px) scale(1.02);
  box-shadow: 0 10px 25px rgba(251, 133, 0, 0.4);
}

.cta-btn:focus-visible {
  outline: none;
  box-shadow: 0 0 0 4px var(--color-bg), 0 0 0 6px var(--color-accent);
}

.cta-btn:active { transform: translateY(-1px) scale(1); }

/* --- Main Content & Book Sections --- */
.featured-books,
.all-books {
  padding: 5rem var(--container-padding);
  max-width: var(--container-width);
  margin-left: auto;
  margin-right: auto;
}

.featured-books h2,
.all-books h2 {
  font-size: 2.75rem;
  text-align: center;
  margin-bottom: 3rem;
  position: relative;
  padding-bottom: 1rem;
}

.featured-books h2::after,
.all-books h2::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 80px;
  height: 3px;
  background: var(--color-accent);
  border-radius: 2px;
}

.filter-bar {
  display: flex;
  justify-content: flex-end;
  align-items: center;
  gap: 1rem;
  margin-bottom: 2.5rem;
}

.filter-bar select {
  -webkit-appearance: none;
  -moz-appearance: none;
  appearance: none;
  background-color: var(--color-surface);
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' fill='%23778DA9' class='bi bi-chevron-down' viewBox='0 0 16 16'%3E%3Cpath fill-rule='evenodd' d='M1.646 4.646a.5.5 0 0 1 .708 0L8 10.293l5.646-5.647a.5.5 0 0 1 .708.708l-6 6a.5.5 0 0 1-.708 0l-6-6a.5.5 0 0 1 0-.708z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 1rem center;
  background-size: 1em;
  padding: 0.75rem 2.5rem 0.75rem 1rem;
  border-radius: var(--border-radius);
  border: 1px solid var(--color-border);
  color: var(--color-text);
  font-size: 1rem;
  cursor: pointer;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.filter-bar select:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: var(--shadow-glow);
}

.books-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 2.5rem;
}

/* --- Premium Book Card --- */
.book-card {
  background: var(--color-surface);
  border-radius: var(--border-radius);
  border: 1px solid var(--color-border);
  display: flex;
  flex-direction: column;
  height: 100%;
  text-align: left;
  box-shadow: var(--shadow-md);
  transition: transform var(--transition-std), box-shadow var(--transition-std), border-color var(--transition-std);
  position: relative;
  overflow: hidden;
}

.book-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: radial-gradient(350px circle at var(--mouse-x, -100px) var(--mouse-y, -100px), var(--color-accent-glow), transparent 80%);
  opacity: 0;
  transition: opacity var(--transition-std);
  z-index: 0;
}

.book-card:hover {
  transform: translateY(-8px) scale(1.02);
  border-color: var(--color-accent);
  box-shadow: 0 16px 35px rgba(0, 0, 0, 0.3);
}

.book-card:hover::before {
  opacity: 1;
}

.book-cover-wrapper, .book-info {
  position: relative;
  z-index: 1;
}

.book-cover-wrapper {
  padding: 1.5rem;
  text-align: center;
  overflow: hidden;
  background-color: rgba(0,0,0,0.1);
}

.book-cover {
  width: 150px;
  height: auto;
  aspect-ratio: 2 / 3;
  object-fit: cover;
  border-radius: 0.5rem;
  box-shadow: var(--shadow-lg);
  transition: transform var(--transition-std);
}

.book-card:hover .book-cover {
  transform: scale(1.05);
}

.book-info {
  padding: 0 1.5rem 1.5rem;
  flex-grow: 1;
  display: flex;
  flex-direction: column;
}

.book-title {
  font-size: 1.2rem;
  font-weight: 600;
  color: #fff;
  line-height: 1.4;
  margin-bottom: 0.25rem;
}

.book-class, .book-subject {
  font-size: 0.95rem;
  color: var(--color-text-muted);
}

.book-footer {
  margin-top: auto;
  padding-top: 1.5rem;
  border-top: 1px solid;
  border-image-slice: 1;
  border-image-source: linear-gradient(to right, transparent, var(--color-border), transparent);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.book-price {
  font-size: 1.25rem;
  color: var(--color-accent);
  font-weight: 700;
}

.buy-btn {
  background: var(--color-accent);
  color: var(--color-bg);
  border: none;
  border-radius: 50px;
  padding: 0.6rem 1.25rem;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: background-color var(--transition-fast), transform var(--transition-fast), box-shadow var(--transition-fast);
}

.buy-btn:hover {
  background: var(--color-accent-dark);
  transform: scale(1.05);
}

.buy-btn:active {
  transform: scale(0.98);
  box-shadow: var(--shadow-inset);
}

/* --- Footer --- */
.site-footer {
  background: var(--color-bg);
  color: var(--color-text-muted);
  padding: 4rem var(--container-padding) 2rem;
  margin-top: 5rem;
  position: relative;
  border-top: 1px solid var(--color-border);
}

.site-footer::before {
  content: '';
  position: absolute;
  top: -2px;
  left: 0;
  width: 100%;
  height: 4px;
  background: linear-gradient(90deg, transparent, var(--color-accent-glow-strong), transparent);
  opacity: 0.5;
}

.footer-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 3rem;
  margin: 0 auto 3rem auto;
  max-width: var(--container-width);
}

.footer-logo {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-accent);
  margin-bottom: 1rem;
}

.footer-links, .footer-social {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.footer-links a, .footer-social a {
  color: var(--color-text-muted);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.footer-links a:hover, .footer-social a:hover {
  color: var(--color-accent);
}

.footer-copy {
  text-align: center;
  font-size: 0.9rem;
  padding-top: 2rem;
  border-top: 1px solid var(--color-border);
  max-width: var(--container-width);
  margin: 0 auto;
}

/* --- Accessibility Menu Floating Button --- */
#accessibility-menu {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 50px;
  height: 50px;
  background-color: var(--color-accent);
  border-radius: 50%;
  cursor: pointer;
  box-shadow: var(--shadow-lg);
  z-index: 1010;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: transform var(--transition-fast), background-color var(--transition-fast);
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='24' height='24' fill='%230D1B2A' viewBox='0 0 16 16'%3E%3Cpath d='M8 2a.5.5 0 0 1 .5.5v1a.5.5 0 0 1-1 0v-1A.5.5 0 0 1 8 2ZM4.226 4.226a.5.5 0 0 1 .707 0l.707.707a.5.5 0 0 1-.707.707l-.707-.707a.5.5 0 0 1 0-.707Zm1.586 8.536a.5.5 0 0 1 .707 0l.707.707a.5.5 0 0 1-.707.707l-.707-.707a.5.5 0 0 1 0-.707ZM13.5 8a.5.5 0 0 1 .5.5v1a.5.5 0 0 1-1 0v-1a.5.5 0 0 1 .5-.5ZM4.226 11.06a.5.5 0 0 1 .707.708l-.707.707a.5.5 0 0 1-.707-.707l.707-.707ZM8 12a4 4 0 1 1 0-8 4 4 0 0 1 0 8Zm0 1a5 5 0 1 0 0-10 5 5 0 0 0 0 10Z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: center;
}

#accessibility-menu:hover {
  transform: scale(1.1);
  background-color: var(--color-accent-dark);
}

#accessibility-menu:focus-visible {
  outline: none;
  box-shadow: 0 0 0 4px var(--color-bg), 0 0 0 6px var(--color-accent);
}

/* --- Responsive Styles --- */

/* Hamburger Menu Icon */
.hamburger-menu {
    display: none; /* Hidden by default on larger screens */
    font-size: 2rem;
    color: var(--color-text);
    cursor: pointer;
    z-index: 1001; /* Ensure it's above other elements */
}

/* Overlay for Mobile Navigation */
.mobile-nav-overlay {
    display: none; /* Hidden by default */
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(13, 27, 42, 0.95); /* Semi-transparent dark overlay */
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    z-index: 1000;
    align-items: center;
    justify-content: center;
    opacity: 0;
    pointer-events: none; /* Allow clicks through when hidden */
    transition: opacity var(--transition-std);
}

.mobile-nav-overlay.active {
    display: flex; /* Show when active */
    opacity: 1;
    pointer-events: all; /* Enable clicks when active */
}

.mobile-nav-overlay .main-nav ul {
    flex-direction: column;
    text-align: center;
    gap: 2rem;
}

.mobile-nav-overlay .main-nav a {
    font-size: 1.8rem;
    padding: 1rem 0;
    color: #fff;
}

.mobile-nav-overlay .main-nav a::after {
    height: 3px;
    background-color: var(--color-accent);
}

/* Adjust dropdowns for mobile */
.mobile-nav-overlay .dropdown-menu {
    position: static; /* Stack dropdown items normally */
    display: block; /* Always show dropdown items in mobile menu */
    background: transparent; /* No background for nested items */
    border: none;
    box-shadow: none;
    padding: 0;
    margin-top: 1rem;
}

.mobile-nav-overlay .dropdown-menu a {
    font-size: 1.4rem;
    padding: 0.5rem 0;
    color: var(--color-text-muted);
}

.mobile-nav-overlay .dropdown-menu a:hover,
.mobile-nav-overlay .dropdown-menu a:focus {
    color: var(--color-accent);
    background-color: transparent;
}


@media (max-width: 992px) {
  .search-bar {
    display: none;
  }
}

@media (max-width: 768px) {
  :root { --container-padding: 1.5rem; }
  
  .site-header {
    justify-content: space-between; /* Keep space between logo and hamburger */
    padding: 1rem var(--container-padding);
  }
  
  .main-nav {
    display: none; /* Hide desktop navigation */
  }

  .hamburger-menu {
      display: block; /* Show hamburger menu */
  }

  .featured-books h2, .all-books h2 {
    font-size: 2.2rem;
  }

  .filter-bar {
    flex-direction: column;
    align-items: stretch;
  }
  
  .footer-content {
      grid-template-columns: 1fr;
      text-align: center;
  }
  
  .footer-links, .footer-social {
      align-items: center;
  }

  /* Hero Banner for smaller screens */
  .hero-banner {
    /* Adjust object-position for better mobile framing if needed */
    object-position: center; /* or 'top' or 'bottom' depending on image content */
  }
}

@media (max-width: 600px) {
  :root { --container-padding: 1rem; }
  
  .hero {
    padding: 4rem var(--container-padding) 5rem;
    min-height: 300px;
  }

  .hero-content h1 {
    font-size: clamp(2rem, 8vw, 2.8rem);
  }

  .hero-content p {
    font-size: 1rem;
  }
  
  .books-grid {
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 1.5rem;
  }

  .book-card {
    text-align: center;
  }
  
  .book-cover-wrapper {
    padding: 1rem;
  }

  .book-info {
    padding: 0 1rem 1rem;
  }
  
  .book-footer {
    flex-direction: column;
    gap: 1rem;
  }

  /* Accessibility button for very small screens */
  #accessibility-menu {
    bottom: 1rem;
    right: 1rem;
    width: 45px;
    height: 45px;
  }
}

.hero-banner {
  width: 100%;
  height: auto;
  object-fit: cover;
  object-position: center;
  display: block;
}