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

:root {
  --color-bg: #0f1117;
  --color-surface: #1a1d27;
  --color-surface-hover: #222632;
  --color-border: #2a2e3b;
  --color-text: #e4e6eb;
  --color-text-muted: #8b8fa3;
  --color-primary: #4f8cff;
  --color-primary-hover: #3a7bf0;
  --color-success: #34d399;
  --color-warning: #fbbf24;
  --color-danger: #f87171;
  --color-info: #60a5fa;
  --radius: 8px;
  --radius-lg: 12px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

a {
  color: var(--color-primary);
  text-decoration: none;
}
a:hover {
  text-decoration: underline;
}

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

/* Header / Nav */
.site-header {
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  padding: 0 1.5rem;
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}

.logo {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text);
  letter-spacing: -0.02em;
}
.logo:hover { text-decoration: none; }

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.25rem;
}
.nav-links a {
  color: var(--color-text-muted);
  font-size: 0.88rem;
  transition: color 0.15s;
}
.nav-links a:hover {
  color: var(--color-text);
  text-decoration: none;
}
.nav-user {
  color: var(--color-primary);
  font-size: 0.88rem;
  font-weight: 500;
}

/* Language Toggle */
.lang-toggle {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  margin-left: 0.5rem;
  padding-left: 0.75rem;
  border-left: 1px solid var(--color-border);
}
.lang-btn {
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--color-text-muted);
  padding: 0.15rem 0.35rem;
  border-radius: 3px;
  transition: color 0.15s;
}
.lang-btn:hover {
  color: var(--color-text);
  text-decoration: none;
}
.lang-active {
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--color-primary);
  padding: 0.15rem 0.35rem;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.6rem 1.2rem;
  border-radius: var(--radius);
  font-size: 0.9rem;
  font-weight: 500;
  border: 1px solid transparent;
  cursor: pointer;
  transition: background 0.15s, color 0.15s, border-color 0.15s;
  text-decoration: none;
}
.btn:hover { text-decoration: none; }

.btn-primary { background: var(--color-primary); color: #fff; }
.btn-primary:hover { background: var(--color-primary-hover); }

.btn-outline { background: transparent; border-color: var(--color-border); color: var(--color-text-muted); }
.btn-outline:hover { border-color: var(--color-text-muted); color: var(--color-text); }

.btn-success { background: var(--color-success); color: #000; }
.btn-warning { background: var(--color-warning); color: #000; }
.btn-danger { background: var(--color-danger); color: #000; }

.btn-sm { padding: 0.3rem 0.7rem; font-size: 0.8rem; }
.btn-block { width: 100%; }

.btn-row {
  display: flex;
  gap: 0.5rem;
}

.btn-copy {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  color: var(--color-text);
  padding: 0.3rem 0.8rem;
  border-radius: var(--radius);
  cursor: pointer;
  font-size: 0.8rem;
  margin-left: 0.5rem;
}
.btn-copy:hover { background: var(--color-surface-hover); }

/* Main content */
main {
  flex: 1;
  max-width: 1200px;
  margin: 0 auto;
  padding: 2rem 1.5rem;
  width: 100%;
}

/* Hero */
.hero {
  text-align: center;
  padding: 6rem 1rem;
}
.hero h1 {
  font-size: 2.5rem;
  font-weight: 800;
  margin-bottom: 1rem;
  letter-spacing: -0.03em;
}
.hero p {
  color: var(--color-text-muted);
  font-size: 1.1rem;
  max-width: 600px;
  margin: 0 auto 0.5rem;
}
.hero-actions {
  margin-top: 2rem;
  display: flex;
  gap: 0.75rem;
  justify-content: center;
}

/* Auth */
.auth-container {
  max-width: 420px;
  margin: 4rem auto;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 2rem;
}
.auth-container h1 { font-size: 1.5rem; margin-bottom: 1.5rem; text-align: center; }

.auth-form .form-group { margin-bottom: 1rem; }

.form-group label {
  display: block;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--color-text-muted);
  margin-bottom: 0.3rem;
}

.form-group input,
.form-group select,
.form-group textarea {
  width: 100%;
  padding: 0.6rem 0.8rem;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  color: var(--color-text);
  font-size: 0.9rem;
  outline: none;
  transition: border-color 0.15s;
  font-family: inherit;
}
.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
  border-color: var(--color-primary);
}

.info-text { text-align: center; color: var(--color-text-muted); margin-bottom: 1.5rem; font-size: 0.9rem; }

.success-message { text-align: center; padding: 2rem 0; }
.success-message h1 { color: var(--color-success); margin-bottom: 1rem; }

/* Alerts */
.alert {
  padding: 0.75rem 1rem;
  border-radius: var(--radius);
  margin-bottom: 1rem;
  font-size: 0.9rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.5rem;
}
.alert-error { background: rgba(248, 113, 113, 0.1); border: 1px solid rgba(248, 113, 113, 0.3); color: var(--color-danger); }
.alert-success { background: rgba(52, 211, 153, 0.1); border: 1px solid rgba(52, 211, 153, 0.3); color: var(--color-success); }
.alert-warning { background: rgba(251, 191, 36, 0.1); border: 1px solid rgba(251, 191, 36, 0.3); color: var(--color-warning); }

/* Page Header */
.page-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  margin-bottom: 1.5rem;
  gap: 1rem;
  flex-wrap: wrap;
}
.page-header h1 { margin-bottom: 0.25rem; }
.page-actions { display: flex; gap: 0.5rem; flex-shrink: 0; }

/* Dashboard */
.dashboard-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
  margin-bottom: 1.5rem;
}

.dashboard-container {
  max-width: 800px;
  margin: 2rem auto;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 2rem;
}
.dashboard-container h1 { margin-bottom: 1rem; }
.dashboard-container .btn { margin-top: 1rem; }

/* Quick Links */
.quick-links {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}
.quick-link {
  display: block;
  padding: 0.6rem 0.8rem;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  color: var(--color-text);
  font-size: 0.9rem;
  transition: border-color 0.15s;
}
.quick-link:hover {
  border-color: var(--color-primary);
  text-decoration: none;
}

/* Role badges */
.role-badge {
  display: inline-block;
  padding: 0.15rem 0.5rem;
  border-radius: 4px;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}
.role-admin { background: rgba(248, 113, 113, 0.15); color: var(--color-danger); }
.role-manager { background: rgba(251, 191, 36, 0.15); color: var(--color-warning); }
.role-user { background: rgba(79, 140, 255, 0.15); color: var(--color-primary); }

/* Panels */
.panel-container { margin: 0 auto; }
.panel-container h1 { margin-bottom: 1.5rem; }

.panel-section {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  margin-bottom: 1.5rem;
}
.panel-section h2 {
  font-size: 1.1rem;
  margin-bottom: 1rem;
  color: var(--color-text-muted);
}

.panel-form .form-row {
  display: flex;
  gap: 1rem;
  align-items: flex-end;
  flex-wrap: wrap;
}
.panel-form .form-row .form-group {
  flex: 1;
  min-width: 150px;
  margin-bottom: 0;
}

/* Form Grid */
.form-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin-bottom: 1.5rem;
}
.form-grid .full-width {
  grid-column: 1 / -1;
}

/* Checkbox */
.checkbox-label {
  display: flex !important;
  align-items: center;
  gap: 0.5rem;
  cursor: pointer;
  font-size: 0.9rem !important;
  color: var(--color-text) !important;
}
.checkbox-label input[type="checkbox"] {
  width: auto !important;
}

/* Table */
.data-table {
  width: 100%;
  border-collapse: collapse;
}
.data-table th,
.data-table td {
  padding: 0.6rem 0.8rem;
  text-align: left;
  border-bottom: 1px solid var(--color-border);
  font-size: 0.9rem;
}
.data-table th {
  color: var(--color-text-muted);
  font-weight: 500;
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}
.data-table tr:last-child td { border-bottom: none; }
.data-table .actions { display: flex; gap: 0.4rem; }

/* Cards */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1rem;
}

.card-link { text-decoration: none; }
.card-link:hover { text-decoration: none; }

.card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 1.25rem;
  transition: border-color 0.15s;
  height: 100%;
}
.card-link:hover .card { border-color: var(--color-primary); }

.card-header { margin-bottom: 0.75rem; }
.card-header h3 { font-size: 1.05rem; }

.card-desc { color: var(--color-text-muted); font-size: 0.88rem; margin-bottom: 0.75rem; }

.card-meta {
  display: flex;
  gap: 1rem;
  font-size: 0.8rem;
  color: var(--color-text-muted);
}

.empty-state {
  color: var(--color-text-muted);
  text-align: center;
  padding: 1rem;
}

/* Book Grid */
.book-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 1rem;
}

.book-card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: border-color 0.15s;
}
.book-card:hover { border-color: var(--color-primary); }

.book-cover {
  position: relative;
  height: 200px;
  background: var(--color-surface);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}
.book-cover img {
  height: 100%;
  width: 100%;
  object-fit: cover;
}

.book-cover-placeholder {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  height: 100%;
  background: linear-gradient(135deg, var(--color-surface) 0%, var(--color-border) 100%);
}
.book-cover-placeholder span {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--color-text-muted);
  opacity: 0.4;
}

.lent-badge {
  position: absolute;
  top: 0.5rem;
  right: 0.5rem;
  background: var(--color-warning);
  color: #000;
  padding: 0.15rem 0.5rem;
  border-radius: 4px;
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.book-info {
  padding: 1rem;
}

.book-title {
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 0.25rem;
  line-height: 1.3;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.book-author {
  color: var(--color-text-muted);
  font-size: 0.85rem;
  margin-bottom: 0.5rem;
}

.book-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-bottom: 0.5rem;
}

.genre-tag, .year-tag, .isbn-tag {
  display: inline-block;
  padding: 0.1rem 0.4rem;
  border-radius: 3px;
  font-size: 0.7rem;
  font-weight: 500;
  background: rgba(79, 140, 255, 0.1);
  color: var(--color-primary);
}
.year-tag { background: rgba(52, 211, 153, 0.1); color: var(--color-success); }
.isbn-tag { background: rgba(139, 143, 163, 0.1); color: var(--color-text-muted); }

.book-owner {
  font-size: 0.8rem;
  color: var(--color-text-muted);
  margin-bottom: 0.5rem;
}

/* Filter Form */
.filter-form {
  margin-bottom: 0;
}

.filter-row {
  display: flex;
  gap: 0.75rem;
  align-items: flex-end;
  flex-wrap: wrap;
}
.filter-row .form-group {
  flex: 1;
  min-width: 130px;
  margin-bottom: 0;
}
.filter-btn {
  flex-shrink: 0;
}

/* Search Results */
.search-results {
  margin-top: 1rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  overflow: hidden;
}

.search-result-item {
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--color-border);
  cursor: pointer;
  transition: background 0.1s;
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
}
.search-result-item:last-child { border-bottom: none; }
.search-result-item:hover { background: var(--color-surface-hover); }

.search-result-cover {
  flex-shrink: 0;
  width: 48px;
  height: 64px;
  border-radius: 4px;
  overflow: hidden;
  background: var(--color-surface);
  display: flex;
  align-items: center;
  justify-content: center;
}
.search-result-cover img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.search-result-cover-placeholder {
  width: 100%;
  height: 100%;
  background: linear-gradient(135deg, var(--color-surface) 0%, var(--color-border) 100%);
}

.search-result-info {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
  min-width: 0;
}
.search-result-info strong {
  font-size: 0.9rem;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.search-result-info .text-muted { font-size: 0.8rem; }

/* Cover Preview */
.cover-preview {
  margin: 1rem 0;
  text-align: center;
}
.cover-preview img {
  max-height: 240px;
  border-radius: var(--radius);
  border: 1px solid var(--color-border);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}

/* Scanner */
.scanner-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.85);
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
}

.scanner-container {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  max-width: 500px;
  width: 90%;
}

.scanner-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1rem;
}

#scanner-video {
  width: 100%;
  border-radius: var(--radius);
  background: #000;
}

.scanner-hint {
  text-align: center;
  color: var(--color-text-muted);
  font-size: 0.85rem;
  margin-top: 0.75rem;
}

.scanner-result {
  text-align: center;
  margin-top: 0.75rem;
  font-weight: 500;
  color: var(--color-success);
}

/* ISBN Lookup */
.isbn-lookup {
  margin-bottom: 0;
}

/* Status badges */
.status-badge {
  display: inline-block;
  padding: 0.15rem 0.5rem;
  border-radius: 4px;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.03em;
}
.status-available { background: rgba(139, 143, 163, 0.15); color: var(--color-text-muted); }
.status-requested { background: rgba(251, 191, 36, 0.15); color: var(--color-warning); }
.status-borrowed { background: rgba(52, 211, 153, 0.15); color: var(--color-success); }
.status-returning { background: rgba(96, 165, 250, 0.15); color: var(--color-info); }
.status-returned { background: rgba(139, 143, 163, 0.15); color: var(--color-text-muted); }

/* Tabs */
.tab-bar {
  display: flex;
  gap: 0;
  border-bottom: 1px solid var(--color-border);
  margin-bottom: 1.5rem;
  overflow-x: auto;
}

.group-tab-bar {
  display: flex;
  gap: 0;
  border-bottom: 1px solid var(--color-border);
  margin-bottom: 1.5rem;
  overflow-x: auto;
}

.tab {
  padding: 0.6rem 1.2rem;
  color: var(--color-text-muted);
  font-size: 0.88rem;
  font-weight: 500;
  border-bottom: 2px solid transparent;
  transition: color 0.15s, border-color 0.15s;
  white-space: nowrap;
}
.tab:hover {
  color: var(--color-text);
  text-decoration: none;
}
.tab-active {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
}

.book-lent-to {
  font-size: 0.8rem;
  color: var(--color-warning);
  margin-bottom: 0.5rem;
}

/* Rankings */
.stat-lent { color: var(--color-success); font-weight: 600; }
.stat-borrowed { color: var(--color-info); font-weight: 600; }

/* Footer */
.site-footer {
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding: 1.5rem;
  text-align: center;
  color: var(--color-text-muted);
  font-size: 0.85rem;
  margin-top: auto;
}

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

@media (max-width: 600px) {
  .hero h1 { font-size: 1.8rem; }
  .hero-actions { flex-direction: column; align-items: center; }
  .panel-form .form-row { flex-direction: column; }
  .page-header { flex-direction: column; }
  .data-table { font-size: 0.8rem; }
  .book-grid { grid-template-columns: repeat(auto-fill, minmax(160px, 1fr)); }
  .book-cover { height: 140px; }
  .card-grid { grid-template-columns: 1fr; }
  .nav-links { gap: 0.8rem; flex-wrap: wrap; }
  .filter-row { flex-direction: column; }
}