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

:root {
  --primary-color: #2c5f8d;
  --secondary-color: #4a90a4;
  --accent-color: #6bb6ff;
  --text-color: #333;
  --bg-color: #f5f5f5;
  --white: #ffffff;
  --border-color: #ddd;
  --success-color: #28a745;
  --error-color: #dc3545;
  --warning-color: #ffc107;
}

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  color: var(--text-color);
  background-color: var(--bg-color);
  line-height: 1.6;
}

/* Header */
header {
  background-color: var(--white);
  box-shadow: 0 2px 5px rgba(0,0,0,0.1);
  padding: 1rem 0;
  position: sticky;
  top: 0;
  z-index: 100;
}

nav {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 1.8rem;
  font-weight: bold;
  color: var(--primary-color);
  text-decoration: none;
}

.nav-links {
  display: flex;
  gap: 2rem;
  list-style: none;
  align-items: center;
}

.nav-links a {
  color: var(--text-color);
  text-decoration: none;
  transition: color 0.3s;
}

.nav-links a:hover {
  color: var(--primary-color);
}

.btn {
  padding: 0.6rem 1.5rem;
  border: none;
  border-radius: 5px;
  cursor: pointer;
  font-size: 1rem;
  text-decoration: none;
  display: inline-block;
  transition: all 0.3s;
}

.btn-primary {
  background-color: var(--primary-color);
  color: var(--white);
}

.btn-primary:hover {
  background-color: #1e4263;
}

.btn-secondary {
  background-color: var(--secondary-color);
  color: var(--white);
}

.btn-secondary:hover {
  background-color: #3a7080;
}

.btn-success {
  background-color: var(--success-color);
  color: var(--white);
}

.btn-danger {
  background-color: var(--error-color);
  color: var(--white);
}

.btn-small {
  padding: 0.4rem 1rem;
  font-size: 0.9rem;
}

/* Container */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 2rem;
}

/* Hero Section */
.hero {
  background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
  color: var(--white);
  padding: 4rem 2rem;
  text-align: center;
}

.hero h1 {
  font-size: 3rem;
  margin-bottom: 1rem;
}

.hero p {
  font-size: 1.2rem;
  margin-bottom: 2rem;
}

/* Section */
.section {
  margin: 3rem 0;
}

.section-title {
  font-size: 2rem;
  margin-bottom: 2rem;
  color: var(--primary-color);
}

/* Book Grid */
.books-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  gap: 2rem;
  margin-top: 2rem;
}

.book-card {
  background: var(--white);
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
  transition: transform 0.3s, box-shadow 0.3s;
  cursor: pointer;
}

.book-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}

.book-card img {
  width: 100%;
  height: 300px;
  object-fit: cover;
  display: block;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  transform: translateZ(0);
  will-change: transform;
}

.book-card-content {
  padding: 1rem;
}

.book-card-title {
  font-size: 1.1rem;
  font-weight: bold;
  margin-bottom: 0.5rem;
  color: var(--text-color);
}

.book-card-author {
  color: #666;
  font-size: 0.9rem;
  margin-bottom: 0.5rem;
}

.book-card-price {
  font-size: 1.2rem;
  font-weight: bold;
  color: var(--primary-color);
  margin-bottom: 0.5rem;
}

.book-card-rating {
  color: var(--warning-color);
  margin-bottom: 0.5rem;
}

/* Book Details */
.book-details {
  display: grid;
  grid-template-columns: 300px 1fr;
  gap: 3rem;
  background: var(--white);
  padding: 2rem;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.book-cover-wrap {
  width: 300px;
  max-width: 100%;
  height: 400px;
  border-radius: 8px;
  overflow: hidden;
  flex-shrink: 0;
  /* Isolate repaints to prevent flicker */
  contain: layout paint;
}

.book-details img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  border-radius: 8px;
  /* Prevent flicker – GPU layer, no sub-pixel jitter */
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  transform: translate3d(0, 0, 0);
  will-change: transform;
}

.book-info h1 {
  font-size: 2rem;
  margin-bottom: 1rem;
  color: var(--primary-color);
}

.book-info .author {
  font-size: 1.2rem;
  color: #666;
  margin-bottom: 1rem;
}

.book-info .price {
  font-size: 1.8rem;
  font-weight: bold;
  color: var(--primary-color);
  margin: 1rem 0;
}

.book-info .rating {
  font-size: 1.2rem;
  color: var(--warning-color);
  margin-bottom: 1rem;
}

.book-info .description {
  margin: 2rem 0;
  line-height: 1.8;
}

/* Forms */
.form-container {
  max-width: 500px;
  margin: 2rem auto;
  background: var(--white);
  padding: 2rem;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.form-group {
  margin-bottom: 1.5rem;
}

.form-group label {
  display: block;
  margin-bottom: 0.5rem;
  font-weight: 500;
}

.form-group input,
.form-group select,
.form-group textarea {
  width: 100%;
  padding: 0.8rem;
  border: 1px solid var(--border-color);
  border-radius: 5px;
  font-size: 1rem;
}

.form-group textarea {
  resize: vertical;
  min-height: 120px;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--primary-color);
}

/* Filters */
.filters {
  background: var(--white);
  padding: 1.5rem;
  border-radius: 8px;
  margin-bottom: 2rem;
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  align-items: center;
}

.filters input,
.filters select {
  padding: 0.6rem;
  border: 1px solid var(--border-color);
  border-radius: 5px;
}

/* Cart */
.cart-item {
  background: var(--white);
  padding: 1.5rem;
  border-radius: 8px;
  margin-bottom: 1rem;
  display: flex;
  gap: 1.5rem;
  align-items: center;
}

.cart-item img {
  width: 100px;
  height: 120px;
  object-fit: cover;
  border-radius: 5px;
}

.cart-item-info {
  flex: 1;
}

.cart-item-price {
  font-size: 1.2rem;
  font-weight: bold;
  color: var(--primary-color);
}

.cart-summary {
  background: var(--white);
  padding: 2rem;
  border-radius: 8px;
  margin-top: 2rem;
}

.cart-summary h3 {
  margin-bottom: 1rem;
}

.cart-summary .total {
  font-size: 1.5rem;
  font-weight: bold;
  margin-top: 1rem;
  padding-top: 1rem;
  border-top: 2px solid var(--border-color);
}

/* Dashboard */
.dashboard {
  display: grid;
  grid-template-columns: 250px 1fr;
  gap: 2rem;
}

.dashboard-menu-btn {
  display: none;
  width: 100%;
  padding: 0.8rem 1rem;
  border-radius: 8px;
  border: 1px solid var(--border-color);
  background: var(--white);
  font-weight: 600;
}

.dashboard-sidebar {
  background: var(--white);
  padding: 1.5rem;
  border-radius: 8px;
  height: fit-content;
}

.dashboard-sidebar ul {
  list-style: none;
}

.dashboard-sidebar li {
  margin-bottom: 0.5rem;
}

.dashboard-sidebar a {
  color: var(--text-color);
  text-decoration: none;
  padding: 0.5rem;
  display: block;
  border-radius: 5px;
  transition: background-color 0.3s;
}

.dashboard-sidebar a:hover,
.dashboard-sidebar a.active {
  background-color: var(--bg-color);
  color: var(--primary-color);
}

.dashboard-content {
  background: var(--white);
  padding: 2rem;
  border-radius: 8px;
}

@media (max-width: 768px) {
  .dashboard {
    grid-template-columns: 1fr;
    gap: 1rem;
  }

  .dashboard-menu-btn {
    display: block;
  }

  .dashboard-sidebar {
    display: none;
  }

  .dashboard-sidebar.is-open {
    display: block;
  }

  .dashboard-content {
    padding: 1.25rem;
  }
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1.5rem;
  margin-bottom: 2rem;
}

.stat-card {
  background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
  color: var(--white);
  padding: 1.5rem;
  border-radius: 8px;
}

.stat-card h3 {
  font-size: 0.9rem;
  opacity: 0.9;
  margin-bottom: 0.5rem;
}

.stat-card .value {
  font-size: 2rem;
  font-weight: bold;
}

/* Table */
table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 1rem;
}

table th,
table td {
  padding: 1rem;
  text-align: left;
  border-bottom: 1px solid var(--border-color);
}

table th {
  background-color: var(--bg-color);
  font-weight: 600;
}

table tr:hover {
  background-color: var(--bg-color);
}

/* Alerts */
.alert {
  padding: 1rem;
  border-radius: 5px;
  margin-bottom: 1rem;
}

.alert-success {
  background-color: #d4edda;
  color: #155724;
  border: 1px solid #c3e6cb;
}

.alert-error {
  background-color: #f8d7da;
  color: #721c24;
  border: 1px solid #f5c6cb;
}

.alert-info {
  background-color: #d1ecf1;
  color: #0c5460;
  border: 1px solid #bee5eb;
}

/* Loading */
.loading {
  text-align: center;
  padding: 2rem;
  color: #666;
}

/* Desktop – normalno */
.nav-links {
  display: flex;
  gap: 1.5rem;
}

.menu-btn {
  display: none;
}


/* MOBILNI DROPDOWN */
@media (max-width: 768px) {

  header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 16px;
    position: relative; /* da dropdown može ispod biti */
  }

  /* dugme – prikazano i malo odmaknuto */
  .menu-btn {
    display: block;
    font-size: 28px;
    background: none;
    border: none;
    cursor: pointer;
    margin-left: 10px;
  }

  /* dropdown box (skriven) */
  .nav-links {
    display: none;
    flex-direction: column;
    gap: 8px;
    position: absolute;
    top: 100%;              /* odmah ispod headera */
    right: 16px;            /* malo odmaknuto od desne strane */
    background: white;
    padding: 10px 14px;
    border-radius: 6px;
    border: 1px solid #ddd;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
    width: max-content;     /* taman širine sadržaja */
    z-index: 10;
  }

  /* kada se otvori */
  .nav-links.open {
    display: flex;
  }

  /* izgled linkova */
  .nav-links a {
    padding: 4px 0;
    text-align: left;
    white-space: nowrap; /* da ne prelazi u drugi red */
  }
}
.book-purchase-box {
  margin-top: 20px;
  padding: 16px;
  border: 1px solid #e0e0e0;
  border-radius: 8px;
}

.coupon-row {
  margin: 10px 0;
  display: flex;
  gap: 8px;
}

.coupon-row input[type="text"] {
  flex: 1;
  padding: 8px 10px;
  border-radius: 6px;
  border: 1px solid #ccc;
}

.coupon-row button {
  padding: 8px 14px;
  border-radius: 6px;
  border: none;
  cursor: pointer;
  background-color: #f0f0f0;
  font-weight: 500;
}

.coupon-row button:hover {
  background-color: #e0e0e0;
}

#coupon-message {
  font-size: 14px;
  margin-top: 4px;
}


/* Badges */
.badge {
  display: inline-block;
  padding: 4px 10px;
  border-radius: 999px;
  font-size: 12px;
  font-weight: 600;
}
.badge-success { background: #e6f7ed; color: #1e7e34; }
.badge-danger { background: #fdecea; color: #b02a37; }
.badge-warning { background: #fff4e5; color: #8a5a00; }


/* =========================
   MOBILE RESPONSIVE FIXES
========================= */
@media (max-width: 768px) {
  body { padding: 0; margin: 0; }
  .container { padding: 1rem; }
  header nav { flex-direction: column; gap: 10px; text-align: center; }
  .nav-links { flex-direction: column; gap: 10px; }
  .books-grid { grid-template-columns: 1fr !important; gap: 15px; }
  .book-card { width: 100%; }
  .book-details { grid-template-columns: 1fr; gap: 15px; }
  .book-cover-wrap { width: 100%; max-width: 280px; height: auto; aspect-ratio: 3/4; margin: 0 auto; }
  .book-cover-wrap img { width: 100%; height: 100%; }
  .book-cover img { width: 100%; height: auto; }
  .form-container { width: 100%; padding: 20px; }
  button, .btn { width: 100%; font-size: 16px; }
  table { font-size: 14px; }
  td, th { padding: 8px; }
}

/* Legal pages card */
.page-card{
  max-width: 900px;
  margin: 2rem auto;
  background: var(--white);
  padding: 2rem;
  border-radius: 12px;
  box-shadow: 0 2px 10px rgba(0,0,0,0.08);
}
.muted{ color:#666; margin-bottom:1.25rem; }
.page-card h1{ margin-bottom: .5rem; }
.page-card h2{ margin-top: 1.5rem; }
.page-card ul{ padding-left: 1.2rem; }


/* Prevent occasional image flicker on hover transforms (GPU compositing) */
.book-card img {
  backface-visibility: hidden;
  transform: translateZ(0);
}


/* Prevent cover image flicker / repaint on some GPUs */
.book-card img,
.book-details img,
img.book-cover,
.cart-item img {
  display: block;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  transform: translateZ(0);
  -webkit-transform: translateZ(0);
}


/* ===== Dashboard (Pro UI) ===== */
.page-title{
  font-size: 1.6rem;
  margin-bottom: 0.25rem;
  letter-spacing: -0.02em;
}
.page-subtitle{
  color:#666;
  margin-bottom: 1.25rem;
}

.section-card{
  background: var(--white);
  border: 1px solid rgba(0,0,0,0.06);
  border-radius: 14px;
  padding: 1.25rem;
  box-shadow: 0 10px 30px rgba(0,0,0,0.06);
}

.section-card + .section-card{
  margin-top: 1.25rem;
}

.section-header{
  display:flex;
  align-items:flex-start;
  justify-content:space-between;
  gap:1rem;
  margin-bottom: 0.75rem;
}

.section-header h2{
  font-size: 1.15rem;
  margin: 0;
}

.muted{
  color:#666;
}

.kpi-grid{
  display:grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 1rem;
  margin-bottom: 1.25rem;
}

.kpi{
  border-radius: 14px;
  padding: 1rem;
  background: linear-gradient(135deg, rgba(44,95,141,0.98) 0%, rgba(74,144,164,0.98) 100%);
  color: var(--white);
  min-height: 92px;
}

.kpi .label{
  font-size: 0.85rem;
  opacity: 0.9;
  margin-bottom: 0.35rem;
}

.kpi .value{
  font-size: 1.8rem;
  font-weight: 800;
  line-height: 1.1;
}

.fee-grid{
  display:grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
  margin-top: 1rem;
}

.fee-box{
  border: 1px solid rgba(0,0,0,0.08);
  border-radius: 14px;
  padding: 1rem;
  background: rgba(245,245,245,0.6);
}

.fee-amount{
  font-size: 1.4rem;
  font-weight: 900;
  margin-top: 0.25rem;
}

.badge{
  display:inline-flex;
  align-items:center;
  gap:0.35rem;
  padding: 0.25rem 0.55rem;
  border-radius: 999px;
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0.02em;
  border: 1px solid rgba(0,0,0,0.08);
}

.badge-success{ background: rgba(40,167,69,0.12); color: #1e7e34; }
.badge-warning{ background: rgba(255,193,7,0.16); color: #856404; }
.badge-danger{ background: rgba(220,53,69,0.12); color: #b02a37; }
.badge-info{ background: rgba(23,162,184,0.12); color: #0c5460; }

.btn-row{
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.table-wrap{
  width: 100%;
  overflow-x: auto;
  border-radius: 14px;
  border: 1px solid rgba(0,0,0,0.06);
}

table{
  margin-top: 0;
  min-width: 820px;
  background: var(--white);
}

table thead th{
  background: rgba(245,245,245,0.8);
  font-weight: 800;
}

table td img{
  width: 52px;
  height: 66px;
  object-fit: cover;
  border-radius: 10px;
  display:block;
  backface-visibility: hidden;
  transform: translateZ(0);
}

@media (max-width: 1024px){
  .kpi-grid{ grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 768px) {
  .fee-grid{ grid-template-columns: 1fr; }
  .dashboard-menu-btn{
    position: sticky;
    top: 0.75rem;
    z-index: 5;
  }
  .dashboard-sidebar.is-open{
    margin-top: 0.5rem;
    border-radius: 14px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.08);
  }
}


.reports-row{display:flex;flex-wrap:wrap;gap:0.75rem;align-items:flex-end;margin-top:0.75rem;}



/* =========================
   MOBILE CARDS / ACCORDION
========================= */
.mobile-cards{
  display:flex;
  flex-direction:column;
  gap:12px;
}
.mobile-card{
  background: var(--white);
  border: 1px solid rgba(0,0,0,0.08);
  border-radius: 12px;
  padding: 12px;
  box-shadow: 0 2px 10px rgba(0,0,0,0.06);
}
.mobile-card-header{
  display:flex;
  align-items:flex-start;
  justify-content:space-between;
  gap:10px;
}
.mobile-card-title{
  font-weight:800;
  line-height:1.25;
}
.mobile-card-subtitle{
  color:#666;
  font-size:0.9rem;
  margin-top:4px;
}
.mobile-card-actions{
  display:flex;
  gap:8px;
  align-items:center;
  flex-wrap:wrap;
}
.mobile-toggle{
  background: rgba(245,245,245,0.9);
  border: 1px solid rgba(0,0,0,0.08);
  border-radius: 999px;
  padding: 6px 10px;
  cursor:pointer;
  font-weight:700;
  font-size:0.85rem;
}
.mobile-card-details{
  display:none;
  margin-top:10px;
  border-top: 1px solid rgba(0,0,0,0.06);
  padding-top:10px;
  color:#333;
  font-size:0.95rem;
}
.mobile-card.is-open .mobile-card-details{
  display:block;
}
.mobile-kv{
  display:flex;
  justify-content:space-between;
  gap:10px;
  padding:6px 0;
  border-bottom: 1px dashed rgba(0,0,0,0.06);
}
.mobile-kv:last-child{ border-bottom:none; }
.mobile-kv .k{ color:#666; }
.mobile-kv .v{ font-weight:700; }

/* Tighter UI on very small phones */
@media (max-width: 420px){
  .hero h1{ font-size: 2.1rem; }
  .btn{ padding: 0.55rem 1rem; font-size: 0.95rem; }
  .kpi .value{ font-size: 1.5rem; }
}


/* =========================
   MOBILE: TOUCH-FRIENDLY BUTTONS (min 44px)
   Apple HIG: tap targets ≥ 44×44pt
========================= */
@media (max-width: 768px) {
  .btn,
  button.btn,
  .btn-primary,
  .btn-secondary,
  .btn-success,
  .btn-danger,
  .btn-warning,
  .btn-small,
  .mobile-toggle {
    min-height: 44px;
    min-width: 44px;
    padding: 12px 18px;
    font-size: 16px; /* prevents zoom on iOS when focusing inputs */
    -webkit-tap-highlight-color: transparent;
  }
  .mobile-card-actions .btn,
  .mobile-card-actions .mobile-toggle {
    min-height: 44px;
    min-width: 44px;
    padding: 12px 16px;
  }
  /* Table action buttons - ensure tap-friendly */
  table .btn,
  .table-wrap .btn {
    min-height: 44px;
    min-width: 44px;
    padding: 12px 16px;
  }
}