/* ===== CHAPTRACK - Complete Stylesheet ===== */
/* Design inspired by U.S. government digital services */

:root {
  --navy: #1a2744;
  --navy-dark: #0f1a2e;
  --navy-light: #243656;
  --blue: #005ea2;
  --blue-dark: #004a82;
  --blue-light: #0076d6;
  --white: #ffffff;
  --gray-100: #f5f6f8;
  --gray-200: #e8eaee;
  --gray-300: #c6cace;
  --gray-400: #a9aeb1;
  --gray-500: #71767a;
  --gray-600: #565c65;
  --gray-700: #3d4551;
  --gray-800: #2d3748;
  --gray-900: #1b1b1b;
  --red: #d83933;
  --red-dark: #b51d1d;
  --green: #2e8540;
  --green-dark: #216e30;
  --yellow: #f5a623;
  --orange: #e66f00;
  --max-width: 1200px;
  --header-height: 64px;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  --font-serif: 'Source Serif Pro', 'Merriweather', 'Georgia', serif;
  --radius: 4px;
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.15);
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  color: var(--gray-900);
  background: var(--gray-100);
  line-height: 1.6;
  min-height: 100vh;
}

/* ===== HEADER ===== */
.usa-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.5);
  z-index: 998;
  display: none;
}

.usa-overlay.active {
  display: block;
}

.usa-header {
  background: var(--navy);
  position: sticky;
  top: 0;
  z-index: 1000;
  box-shadow: var(--shadow-md);
}

.usa-navbar {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 16px;
  height: var(--header-height);
}

.usa-logo {
  display: flex;
  align-items: center;
  text-decoration: none;
}

.usa-logo svg {
  width: 40px;
  height: 40px;
  margin-right: 10px;
}

.usa-logo__text {
  font-family: var(--font-serif);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--white);
  letter-spacing: -0.3px;
}

.usa-logo__text a {
  text-decoration: none;
  color: inherit;
  display: flex;
  align-items: center;
}

.header-right {
  display: flex;
  align-items: center;
  gap: 16px;
}

/* Navigation */
.usa-nav {
  display: flex;
  align-items: center;
}

.usa-nav__primary {
  list-style: none;
  display: flex;
  gap: 4px;
  margin: 0;
  padding: 0;
}

.usa-nav__link {
  color: var(--white);
  text-decoration: none;
  padding: 8px 16px;
  border-radius: var(--radius);
  font-size: 0.9rem;
  font-weight: 500;
  transition: background 0.15s;
  display: flex;
  align-items: center;
  gap: 6px;
  white-space: nowrap;
}

.usa-nav__link:hover,
.usa-nav__link.active {
  background: rgba(255, 255, 255, 0.12);
}

.usa-nav__link svg {
  width: 18px;
  height: 18px;
  flex-shrink: 0;
}

/* Notification Bell */
.notification-bell {
  position: relative;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
  border-radius: var(--radius);
  transition: background 0.15s;
}

.notification-bell:hover {
  background: rgba(255, 255, 255, 0.12);
}

.notification-bell svg {
  width: 22px;
  height: 22px;
}

.notification-badge {
  position: absolute;
  top: 2px;
  right: 2px;
  background: var(--red);
  color: var(--white);
  font-size: 0.65rem;
  font-weight: 700;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 2px solid var(--navy);
}

/* Mobile hamburger */
.mobile-btn {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
  border-radius: var(--radius);
}

.mobile-btn:hover {
  background: rgba(255, 255, 255, 0.12);
}

.mobile-btn svg {
  width: 24px;
  height: 24px;
}

/* Mobile Menu */
.mobile-menu {
  display: none;
  position: fixed;
  top: var(--header-height);
  left: 0;
  width: 100%;
  background: var(--navy);
  z-index: 999;
  padding: 8px 16px;
  box-shadow: var(--shadow-lg);
  max-height: calc(100vh - var(--header-height));
  overflow-y: auto;
}

.mobile-menu.active {
  display: block;
}

.mobile-menu a {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--white);
  text-decoration: none;
  padding: 12px 16px;
  border-radius: var(--radius);
  font-size: 0.95rem;
  font-weight: 500;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.mobile-menu a:hover,
.mobile-menu a.active {
  background: rgba(255, 255, 255, 0.12);
}

.mobile-menu a svg {
  width: 20px;
  height: 20px;
  flex-shrink: 0;
}

/* Notification dropdown */
.notification-dropdown {
  display: none;
  position: absolute;
  top: calc(var(--header-height) - 4px);
  right: 16px;
  width: 380px;
  max-width: 95vw;
  background: var(--white);
  border-radius: 8px;
  box-shadow: var(--shadow-lg);
  z-index: 1001;
  overflow: hidden;
}

.notification-dropdown.active {
  display: block;
}

.notification-dropdown__header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 14px 16px;
  border-bottom: 1px solid var(--gray-200);
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--gray-800);
}

.notification-dropdown__list {
  max-height: 350px;
  overflow-y: auto;
}

.notification-item {
  padding: 12px 16px;
  border-bottom: 1px solid var(--gray-100);
  cursor: pointer;
  transition: background 0.1s;
}

.notification-item:hover {
  background: var(--gray-100);
}

.notification-item.unread {
  border-left: 3px solid var(--blue);
  background: #f0f7fc;
}

.notification-item.pinned {
  border-left: 3px solid var(--yellow);
}

.notification-item__title {
  font-weight: 600;
  font-size: 0.88rem;
  color: var(--gray-900);
  margin-bottom: 2px;
}

.notification-item__message {
  font-size: 0.8rem;
  color: var(--gray-500);
}

.notification-item__time {
  font-size: 0.72rem;
  color: var(--gray-400);
  margin-top: 4px;
}

/* ===== MAIN CONTENT ===== */
.main-content {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 24px 16px;
  min-height: calc(100vh - var(--header-height) - 300px);
}

/* ===== FOOTER ===== */
.usa-footer {
  background: var(--navy-dark);
  color: var(--white);
  margin-top: 48px;
}

.usa-footer__primary-section {
  padding: 40px 16px 32px;
}

.usa-footer__inner {
  max-width: var(--max-width);
  margin: 0 auto;
}

.footer-logo {
  text-align: center;
  margin-bottom: 32px;
}

.footer-logo svg {
  width: 60px;
  height: 60px;
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 32px;
}

.footer-column h3 {
  font-family: var(--font-serif);
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 12px;
  color: var(--white);
}

.footer-column ul {
  list-style: none;
  padding: 0;
}

.footer-column ul li {
  margin-bottom: 6px;
}

.footer-column ul li a {
  color: rgba(255, 255, 255, 0.75);
  text-decoration: none;
  font-size: 0.88rem;
  transition: color 0.15s;
}

.footer-column ul li a:hover {
  color: var(--white);
  text-decoration: underline;
}

.usa-footer__secondary-section {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding: 16px;
  text-align: center;
}

.usa-footer__secondary-section p {
  color: rgba(255, 255, 255, 0.5);
  font-size: 0.8rem;
}

.return-to-top {
  text-align: center;
  padding: 16px;
}

.return-to-top a {
  color: rgba(255, 255, 255, 0.6);
  text-decoration: none;
  font-size: 0.82rem;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: color 0.15s;
}

.return-to-top a:hover {
  color: var(--white);
}

.return-to-top svg {
  width: 16px;
  height: 16px;
}

/* ===== CARDS & COMPONENTS ===== */
.card {
  background: var(--white);
  border-radius: 8px;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--gray-200);
  overflow: hidden;
}

.card-header {
  padding: 16px 20px;
  border-bottom: 1px solid var(--gray-200);
  font-weight: 600;
  font-size: 1rem;
  color: var(--gray-800);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.card-header svg {
  width: 20px;
  height: 20px;
  color: var(--navy);
}

.card-body {
  padding: 20px;
}

.card-footer {
  padding: 12px 20px;
  border-top: 1px solid var(--gray-200);
  background: var(--gray-100);
}

/* Stat Cards */
.stat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 16px;
  margin-bottom: 24px;
}

.stat-card {
  background: var(--white);
  border-radius: 8px;
  padding: 20px;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--gray-200);
  border-top: 3px solid var(--navy);
}

.stat-card.blue { border-top-color: var(--blue); }
.stat-card.green { border-top-color: var(--green); }
.stat-card.red { border-top-color: var(--red); }
.stat-card.yellow { border-top-color: var(--yellow); }
.stat-card.orange { border-top-color: var(--orange); }

.stat-card__value {
  font-family: var(--font-serif);
  font-size: 2rem;
  font-weight: 700;
  color: var(--gray-900);
  line-height: 1;
  margin-bottom: 4px;
}

.stat-card__label {
  font-size: 0.82rem;
  color: var(--gray-500);
  font-weight: 500;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 10px 20px;
  border-radius: var(--radius);
  font-size: 0.9rem;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  border: none;
  transition: all 0.15s;
  font-family: var(--font-sans);
}

.btn svg {
  width: 18px;
  height: 18px;
}

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

.btn-primary:hover {
  background: var(--blue-dark);
}

.btn-secondary {
  background: var(--white);
  color: var(--gray-700);
  border: 1px solid var(--gray-300);
}

.btn-secondary:hover {
  background: var(--gray-100);
  border-color: var(--gray-400);
}

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

.btn-danger:hover {
  background: var(--red-dark);
}

.btn-sm {
  padding: 6px 12px;
  font-size: 0.8rem;
}

.btn-xs {
  padding: 3px 8px;
  font-size: 0.72rem;
  border-radius: 3px;
}

.btn-group {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

/* Forms */
.form-group {
  margin-bottom: 16px;
}

.form-label {
  display: block;
  font-weight: 600;
  font-size: 0.88rem;
  color: var(--gray-700);
  margin-bottom: 4px;
}

.form-input,
.form-select,
.form-textarea {
  width: 100%;
  padding: 10px 12px;
  border: 1px solid var(--gray-300);
  border-radius: var(--radius);
  font-size: 0.9rem;
  font-family: var(--font-sans);
  transition: border-color 0.15s;
  background: var(--white);
}

.form-input:focus,
.form-select:focus,
.form-textarea:focus {
  outline: none;
  border-color: var(--blue);
  box-shadow: 0 0 0 3px rgba(0, 94, 162, 0.1);
}

.form-textarea {
  resize: vertical;
  min-height: 80px;
}

/* Tables */
.table-wrapper {
  overflow-x: auto;
}

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.88rem;
}

thead th {
  background: var(--gray-100);
  padding: 12px 16px;
  text-align: left;
  font-weight: 600;
  color: var(--gray-700);
  border-bottom: 2px solid var(--gray-300);
  white-space: nowrap;
}

tbody td {
  padding: 10px 16px;
  border-bottom: 1px solid var(--gray-200);
}

tbody tr:hover {
  background: var(--gray-100);
}

/* Progress Bar */
.progress-bar {
  width: 100%;
  height: 8px;
  background: var(--gray-200);
  border-radius: 4px;
  overflow: hidden;
}

.progress-bar__fill {
  height: 100%;
  border-radius: 4px;
  transition: width 0.3s;
}

.progress-bar__fill.blue { background: var(--blue); }
.progress-bar__fill.green { background: var(--green); }
.progress-bar__fill.red { background: var(--red); }
.progress-bar__fill.yellow { background: var(--yellow); }

/* Badges */
.badge {
  display: inline-flex;
  align-items: center;
  padding: 3px 10px;
  border-radius: 12px;
  font-size: 0.72rem;
  font-weight: 600;
  white-space: nowrap;
}

.badge-blue { background: #e1f0fa; color: #005ea2; }
.badge-green { background: #e6f4ea; color: #2e8540; }
.badge-red { background: #fde7e7; color: #d83933; }
.badge-yellow { background: #fef3e0; color: #e66f00; }
.badge-gray { background: #f0f0f0; color: #565c65; }

/* Tags */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 4px 10px;
  border-radius: 4px;
  font-size: 0.78rem;
  font-weight: 500;
  background: var(--gray-100);
  color: var(--gray-600);
  border: 1px solid var(--gray-300);
}

.tag svg {
  width: 14px;
  height: 14px;
}

/* Grid Layouts */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}

.grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
}

/* Chapter List */
.chapter-list {
  list-style: none;
  padding: 0;
}

.chapter-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 16px;
  border-bottom: 1px solid var(--gray-200);
  transition: background 0.1s;
  gap: 12px;
}

.chapter-item:hover {
  background: var(--gray-100);
}

.chapter-item__info {
  flex: 1;
  min-width: 0;
}

.chapter-item__name {
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--gray-800);
  margin-bottom: 2px;
}

.chapter-item__meta {
  font-size: 0.76rem;
  color: var(--gray-500);
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.chapter-item__actions {
  display: flex;
  gap: 4px;
  flex-shrink: 0;
}

/* Accordion */
.accordion {
  border: 1px solid var(--gray-200);
  border-radius: 8px;
  overflow: hidden;
  margin-bottom: 8px;
}

.accordion__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  padding: 14px 20px;
  background: var(--white);
  border: none;
  cursor: pointer;
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--gray-800);
  text-align: left;
  transition: background 0.15s;
}

.accordion__header:hover {
  background: var(--gray-100);
}

.accordion__header svg {
  width: 20px;
  height: 20px;
  transition: transform 0.2s;
  flex-shrink: 0;
  color: var(--gray-500);
}

.accordion__header.open svg {
  transform: rotate(180deg);
}

.accordion__body {
  display: none;
  padding: 0 20px 16px;
  background: var(--white);
}

.accordion__body.open {
  display: block;
}

/* Section Headers */
.section-title {
  font-family: var(--font-serif);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--gray-900);
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.section-title svg {
  width: 28px;
  height: 28px;
  color: var(--navy);
}

.section-subtitle {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--gray-700);
  margin-bottom: 12px;
}

/* Empty State */
.empty-state {
  text-align: center;
  padding: 48px 20px;
  color: var(--gray-500);
}

.empty-state svg {
  width: 64px;
  height: 64px;
  margin-bottom: 16px;
  opacity: 0.4;
}

.empty-state h3 {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--gray-600);
  margin-bottom: 8px;
}

.empty-state p {
  font-size: 0.9rem;
  margin-bottom: 16px;
}

/* Modal */
.modal-overlay {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.5);
  z-index: 2000;
  align-items: center;
  justify-content: center;
}

.modal-overlay.active {
  display: flex;
}

.modal {
  background: var(--white);
  border-radius: 8px;
  box-shadow: var(--shadow-lg);
  width: 90%;
  max-width: 560px;
  max-height: 85vh;
  overflow-y: auto;
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 20px;
  border-bottom: 1px solid var(--gray-200);
  font-weight: 600;
  font-size: 1rem;
}

.modal-body {
  padding: 20px;
}

.modal-footer {
  display: flex;
  gap: 8px;
  justify-content: flex-end;
  padding: 16px 20px;
  border-top: 1px solid var(--gray-200);
  background: var(--gray-100);
}

.modal-close {
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
  border-radius: var(--radius);
  color: var(--gray-500);
}

.modal-close:hover {
  background: var(--gray-100);
  color: var(--gray-800);
}

.modal-close svg {
  width: 22px;
  height: 22px;
}

/* Toast */
.toast-container {
  position: fixed;
  bottom: 20px;
  right: 20px;
  z-index: 3000;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.toast {
  background: var(--gray-900);
  color: var(--white);
  padding: 12px 20px;
  border-radius: 8px;
  font-size: 0.88rem;
  box-shadow: var(--shadow-lg);
  animation: slideIn 0.3s ease;
  max-width: 400px;
}

.toast.success { background: var(--green); }
.toast.error { background: var(--red); }

@keyframes slideIn {
  from { transform: translateX(100%); opacity: 0; }
  to { transform: translateX(0); opacity: 1; }
}

/* Search */
.search-box {
  position: relative;
}

.search-box input {
  padding-left: 40px;
}

.search-box svg {
  position: absolute;
  left: 12px;
  top: 50%;
  transform: translateY(-50%);
  width: 18px;
  height: 18px;
  color: var(--gray-400);
  pointer-events: none;
}

/* Tabs */
.tabs {
  display: flex;
  border-bottom: 2px solid var(--gray-200);
  margin-bottom: 16px;
  gap: 0;
}

.tab {
  padding: 10px 20px;
  cursor: pointer;
  font-weight: 600;
  font-size: 0.88rem;
  color: var(--gray-500);
  border-bottom: 2px solid transparent;
  margin-bottom: -2px;
  transition: all 0.15s;
  background: none;
  border-top: none;
  border-left: none;
  border-right: none;
  font-family: var(--font-sans);
}

.tab:hover {
  color: var(--gray-700);
}

.tab.active {
  color: var(--blue);
  border-bottom-color: var(--blue);
}

/* Insights List */
.insight-list {
  list-style: none;
  padding: 0;
}

.insight-list li {
  padding: 10px 12px;
  border-bottom: 1px solid var(--gray-100);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
}

.insight-list li:last-child {
  border-bottom: none;
}

.insight-list__name {
  font-size: 0.88rem;
  font-weight: 500;
  color: var(--gray-800);
  flex: 1;
}

.insight-list__value {
  font-weight: 600;
  font-size: 0.85rem;
  color: var(--gray-600);
  flex-shrink: 0;
}

/* Time input group */
.time-input-group {
  display: flex;
  gap: 8px;
  align-items: center;
}

.time-input-group input {
  width: 80px;
  text-align: center;
}

.time-input-group span {
  color: var(--gray-500);
  font-size: 0.88rem;
}

/* Chapter Detail */
.chapter-detail-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 12px;
}

.chapter-detail-item {
  text-align: center;
  padding: 14px 12px;
  background: var(--gray-100);
  border-radius: 8px;
}

.chapter-detail-item__value {
  font-family: var(--font-serif);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--navy);
}

.chapter-detail-item__label {
  font-size: 0.72rem;
  color: var(--gray-500);
  font-weight: 500;
  margin-top: 2px;
}

/* Checkbox toggle */
.toggle-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 0;
}

.toggle-row label {
  font-size: 0.9rem;
  color: var(--gray-700);
  cursor: pointer;
}

.toggle-switch {
  position: relative;
  width: 44px;
  height: 24px;
  flex-shrink: 0;
}

.toggle-switch input {
  opacity: 0;
  width: 0;
  height: 0;
}

.toggle-slider {
  position: absolute;
  cursor: pointer;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: var(--gray-300);
  border-radius: 12px;
  transition: 0.2s;
}

.toggle-slider:before {
  content: '';
  position: absolute;
  height: 18px;
  width: 18px;
  left: 3px;
  bottom: 3px;
  background: var(--white);
  border-radius: 50%;
  transition: 0.2s;
}

.toggle-switch input:checked + .toggle-slider {
  background: var(--blue);
}

.toggle-switch input:checked + .toggle-slider:before {
  transform: translateX(20px);
}

/* ===== RESPONSIVE ===== */
@media (max-width: 1024px) {
  .footer-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .grid-3 {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .usa-nav__primary {
    display: none;
  }
  
  .mobile-btn {
    display: block;
  }
  
  .header-right {
    gap: 4px;
  }
  
  .usa-nav__link {
    font-size: 0.8rem;
    padding: 6px 10px;
  }
  
  .stat-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .grid-2 {
    grid-template-columns: 1fr;
  }
  
  .grid-3 {
    grid-template-columns: 1fr 1fr;
  }
  
  .grid-4 {
    grid-template-columns: 1fr 1fr;
  }
  
  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 20px;
  }
  
  .section-title {
    font-size: 1.25rem;
  }
  
  .chapter-detail-grid {
    grid-template-columns: repeat(3, 1fr);
  }
  
  .notification-dropdown {
    right: 0;
    width: 100vw;
    max-width: 100vw;
    border-radius: 0;
  }
  
  .modal {
    width: 95%;
    max-height: 90vh;
  }
}

@media (max-width: 480px) {
  .stat-grid {
    grid-template-columns: 1fr;
  }
  
  .grid-3 {
    grid-template-columns: 1fr;
  }
  
  .grid-4 {
    grid-template-columns: 1fr;
  }
  
  .footer-grid {
    grid-template-columns: 1fr;
  }
  
  .chapter-detail-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .btn-group {
    flex-direction: column;
  }
  
  .tabs {
    flex-wrap: wrap;
  }
  
  .chapter-item {
    flex-direction: column;
    align-items: flex-start;
  }
  
  .chapter-item__actions {
    align-self: flex-end;
  }
}