/* Base */
body {
  margin: 0;
  background-color: var(--color-background);
  color: var(--color-text);
  font-family: var(--font-family-body);
  font-size: 16px; /* Ensure base size 16px */
  overflow-x: hidden;
}

/* Responsive Media & Tables */
img, video, iframe {
  max-width: 100%;
  height: auto;
}

.table-wrapper {
  width: 100%;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

h1, h2, h3, .logo {
  font-family: var(--font-family-display);
  font-weight: 700;
  margin: 0;
}

/* Layout - Asymmetrical Split */
.hub-layout {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

@media (min-width: 1024px) {
  .hub-layout {
    display: grid;
    grid-template-columns: clamp(250px, 25%, 350px) 1fr;
  }
}

/* Navigation - Side Panel Layout */
.side-nav {
  background-color: var(--color-surface);
  padding: var(--spacing-sm) var(--spacing-md);
  border-bottom: 1px solid var(--color-secondary);
  display: flex;
  flex-direction: column;
  position: relative;
  height: auto;
  box-sizing: border-box;
}

.desktop-theme-btn {
  display: none;
}

.desktop-top-controls {
  display: none;
}

@media (min-width: 1024px) {
  .side-nav {
    border-right: 1px solid var(--color-secondary);
    border-bottom: none;
    padding: var(--spacing-xl) var(--spacing-lg);
    position: sticky;
    top: 0;
    height: 100vh;
  }
  .desktop-theme-btn {
    display: flex;
  }
  .desktop-top-controls {
    display: flex;
    position: absolute;
    top: var(--spacing-md);
    right: var(--spacing-md);
    align-items: center;
    gap: var(--spacing-sm);
    z-index: 100;
  }
}

.side-nav-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  width: 100%;
}

.mobile-controls {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

@media (min-width: 1024px) {
  .side-nav-header {
    flex-direction: column;
    align-items: flex-start;
  }
  .mobile-controls {
    display: none;
  }
}

.logo {
  font-size: 1.5rem;
  color: var(--color-primary);
  text-decoration: none;
  margin-bottom: 0;
}

@media (min-width: 1024px) {
  .logo {
    font-size: 2rem;
    margin-bottom: var(--spacing-xxl);
  }
}

.mobile-menu-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  background: transparent;
  color: var(--color-text);
  border: none;
  padding: 0;
  border-radius: 50%;
  font-size: 1.5rem;
  cursor: pointer;
  transition: background-color var(--duration-fast) var(--easing-standard);
}

.mobile-menu-toggle:hover {
  background-color: var(--color-surface);
}

.nav-links {
  display: none;
  flex-direction: column;
  gap: var(--spacing-md);
}

.nav-links.is-open {
  display: flex;
}

@media (min-width: 1024px) {
  .mobile-menu-toggle {
    display: none;
  }
  .nav-links {
    display: flex;
  }
}

.nav-links a, .nav-links button {
  color: var(--color-text-muted);
  text-decoration: none;
  font-size: 1.1rem;
  /* Micro-interaction 1: Link hover state */
  transition: color var(--duration-fast) var(--easing-standard), transform var(--duration-fast) var(--easing-bounce);
  display: inline-flex;
  min-height: 44px; /* Touch target */
  align-items: center;
  transform-origin: left;
}

.nav-links a:hover, .nav-links a.active, .nav-links button:hover {
  color: var(--color-text);
  transform: translateX(10px);
}

/* Main Content Area */
.hub-main {
  padding: var(--spacing-md);
}

@media (min-width: 768px) {
  .hub-main {
    padding: var(--spacing-xl);
  }
}

.hero-section {
  text-align: left; /* No centered hero */
  margin-bottom: var(--spacing-xxl);
  max-width: 800px;
}

.hero-section h1 {
  font-size: clamp(2rem, 8vw, 4rem);
  line-height: 1.1;
  color: var(--color-primary);
  margin-bottom: var(--spacing-md);
  /* Effect Animation: Entrance */
  animation: fadeSlideRight var(--duration-slow) var(--easing-smooth) forwards;
  opacity: 0;
  transform: translateX(-30px);
}

.hero-section p {
  font-size: clamp(1rem, 4vw, 1.25rem);
  color: var(--color-text-muted);
  animation: fadeSlideRight var(--duration-slow) var(--easing-smooth) forwards;
  opacity: 0;
  transform: translateX(-30px);
  animation-delay: 150ms;
}

/* Micro-interaction 2: Button Press */
.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px; /* Touch target */
  min-width: 44px;
  background-color: var(--color-accent);
  color: var(--color-background);
  padding: var(--spacing-sm) var(--spacing-lg);
  border-radius: var(--spacing-xs);
  text-decoration: none;
  font-weight: 600;
  border: none;
  cursor: pointer;
  margin-top: var(--spacing-md);
  transition: transform var(--duration-fast) var(--easing-bounce), filter var(--duration-fast) var(--easing-standard);
  animation: fadeSlideRight var(--duration-slow) var(--easing-smooth) forwards;
  opacity: 0;
  transform: translateX(-30px);
  animation-delay: 300ms;
}

.btn-primary:hover {
  filter: brightness(0.9);
}

.btn-primary:active {
  transform: scale(0.92);
}

/* Book Grid (Dynamic Responsive Layout) */
.book-masonry {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--spacing-lg);
}

/* Micro-interaction 3: Card Hover */
.book-card {
  box-sizing: border-box;
  background-color: var(--color-surface);
  padding: var(--spacing-lg);
  border-radius: var(--spacing-md);
  text-decoration: none;
  color: var(--color-text);
  border: 1px solid var(--color-secondary);
  display: flex;
  flex-direction: column;
  height: 100%;
  transition: transform var(--duration-normal) var(--easing-bounce), box-shadow var(--duration-normal) var(--easing-standard);
  /* Staggered entry */
  animation: fadeSlideUp var(--duration-slow) var(--easing-smooth) forwards;
  opacity: 0;
  transform: translateY(30px);
}

.book-card:hover {
  transform: translateY(-8px) scale(1.02);
  box-shadow: 0 15px 30px rgba(0,0,0,0.4);
  border-color: var(--color-primary);
}

.book-card h3 {
  color: var(--color-primary);
  margin-bottom: var(--spacing-sm);
  font-size: 1.5rem;
}

.book-card p {
  color: var(--color-text-muted);
}

.content-panel {
  background-color: var(--color-surface);
  padding: var(--spacing-md);
  border-radius: var(--spacing-md);
  max-width: 900px;
}

@media (min-width: 768px) {
  .content-panel {
    padding: var(--spacing-xl);
  }
}

@keyframes fadeSlideRight {
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

@keyframes fadeSlideUp {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Reduced Motion Override */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }

  .hero-section h1,
  .hero-section p,
  .btn-primary,
  .book-card {
    opacity: 1 !important;
    transform: none !important;
  }
}

/* Utilities */
.desktop-only {
  display: none;
}
@media (min-width: 768px) {
  .desktop-only {
    display: inline;
  }
}