:root {
  --bg: #f7f8f5;
  --surface: #ffffff;
  --surface-muted: #eef5f4;
  --text: #20242c;
  --muted: #68737d;
  --accent: #2f6f73;
  --accent-strong: #23565a;
  --accent-warm: #8a4b3f;
  --gold: #b4872f;
  --line: #d8ddd5;
  --line-strong: #bcc7c1;
  --topbar-bg: rgba(255, 255, 255, .94);
  --sidebar-bg: rgba(255, 255, 255, .72);
  --bg-gradient-start: rgba(238, 245, 244, .65);
  --bg-gradient-end: rgba(247, 248, 245, 0);
  --segmented-bg: #f0f3ef;
  --soft-bg: #fafbf8;
  --warm-bg: #f6efeb;
  --exercise-bg: #fffaf6;
  --field-bg: #fffdf9;
  --progress-track: #e5e9e2;
  --focus-ring: rgba(47, 111, 115, .16);
  --accent-border: rgba(47, 111, 115, .36);
  --accent-border-strong: rgba(47, 111, 115, .44);
  --exercise-border: rgba(138, 75, 63, .25);
  --mark-bg: rgba(180, 135, 47, .28);
  --mobile-overlay: rgba(32, 36, 44, .18);
  --shadow: 0 16px 36px rgba(32, 36, 44, .08);
  --small-shadow: 0 1px 3px rgba(32, 36, 44, .08);
  --max: 900px;
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --bg: #15191d;
  --surface: #20262b;
  --surface-muted: #263839;
  --text: #eef2ed;
  --muted: #a9b5b5;
  --accent: #76b7b5;
  --accent-strong: #a8d7d3;
  --accent-warm: #e0a58d;
  --gold: #d1aa57;
  --line: #354147;
  --line-strong: #53636a;
  --topbar-bg: rgba(28, 33, 38, .96);
  --sidebar-bg: rgba(28, 33, 38, .88);
  --bg-gradient-start: rgba(38, 56, 57, .72);
  --bg-gradient-end: rgba(21, 25, 29, 0);
  --segmented-bg: #171f23;
  --soft-bg: #1b2226;
  --warm-bg: #342720;
  --exercise-bg: #2a231f;
  --field-bg: #1c2227;
  --progress-track: #303b40;
  --focus-ring: rgba(118, 183, 181, .22);
  --accent-border: rgba(118, 183, 181, .36);
  --accent-border-strong: rgba(118, 183, 181, .46);
  --exercise-border: rgba(224, 165, 141, .3);
  --mark-bg: rgba(209, 170, 87, .32);
  --mobile-overlay: rgba(0, 0, 0, .36);
  --shadow: 0 16px 36px rgba(0, 0, 0, .28);
  --small-shadow: 0 1px 3px rgba(0, 0, 0, .24);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: var(--text);
  background:
    linear-gradient(180deg, var(--bg-gradient-start), var(--bg-gradient-end) 280px),
    var(--bg);
  line-height: 1.65;
}

button,
input,
textarea {
  font: inherit;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 30;
  min-height: 64px;
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  gap: 14px;
  align-items: center;
  padding: 10px clamp(14px, 3vw, 28px);
  border-bottom: 1px solid var(--line);
  background: var(--topbar-bg);
  backdrop-filter: blur(12px);
}

.icon-button {
  position: relative;
  width: 42px;
  height: 42px;
  display: inline-grid;
  place-items: center;
  border: 1px solid var(--line-strong);
  border-radius: 8px;
  color: var(--accent-strong);
  background: var(--surface);
  cursor: pointer;
}

.icon-button:hover {
  border-color: var(--accent);
}

.top-actions {
  display: flex;
  gap: 8px;
  align-items: center;
}

.theme-button::before {
  content: "";
  width: 18px;
  height: 18px;
  border: 2px solid currentColor;
  border-radius: 999px;
  box-shadow: inset -6px -4px 0 0 currentColor;
}

:root[data-theme="dark"] .theme-button::before {
  background: currentColor;
  box-shadow: 0 0 0 4px var(--accent-border);
}

.search-button::before,
.search-button::after {
  content: "";
  position: absolute;
  display: block;
}

.search-button::before {
  top: 50%;
  left: 50%;
  width: 14px;
  height: 14px;
  border: 2px solid currentColor;
  border-radius: 999px;
  transform: translate(-62%, -62%);
}

.search-button::after {
  top: 50%;
  left: 50%;
  width: 9px;
  height: 2px;
  border-radius: 999px;
  background: currentColor;
  transform: translate(2px, 3px) rotate(45deg);
}

body.search-open .search-button {
  border-color: var(--accent);
  background: var(--surface-muted);
}

.brand {
  min-width: 0;
  border: 0;
  padding: 0;
  color: inherit;
  background: transparent;
  text-align: left;
  cursor: pointer;
}

.brand strong,
.brand span {
  display: block;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.brand strong {
  font-size: 1.04rem;
  letter-spacing: .01em;
}

.brand span {
  color: var(--muted);
  font-size: .86rem;
}

.brand:focus-visible {
  outline: 3px solid var(--focus-ring);
  outline-offset: 4px;
  border-radius: 6px;
}

.search-wrap {
  display: none;
  grid-column: 1 / -1;
  justify-self: end;
  width: min(460px, 100%);
}

body.search-open .search-wrap {
  display: block;
}

.search-wrap input {
  width: 100%;
  min-height: 42px;
  border: 1px solid var(--line-strong);
  border-radius: 8px;
  padding: 9px 12px;
  color: var(--text);
  background: var(--surface);
}

.search-wrap input:focus {
  outline: 3px solid var(--focus-ring);
  border-color: var(--accent);
}

.shell {
  width: min(1240px, 100%);
  margin: 0 auto;
  display: grid;
  grid-template-columns: 310px minmax(0, 1fr);
}

body.nav-collapsed .shell {
  grid-template-columns: minmax(0, 1fr);
}

.sidebar {
  position: sticky;
  top: 64px;
  align-self: start;
  height: calc(100vh - 64px);
  padding: 22px 16px;
  overflow-y: auto;
  border-right: 1px solid var(--line);
  background: var(--sidebar-bg);
}

body.nav-collapsed .sidebar {
  display: none;
}

.segmented {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 3px;
  padding: 3px;
  margin-bottom: 22px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--segmented-bg);
}

.segmented button {
  min-width: 0;
  min-height: 34px;
  border: 0;
  border-radius: 6px;
  color: var(--muted);
  background: transparent;
  cursor: pointer;
  font-size: .84rem;
}

.segmented button.is-active {
  color: var(--accent-strong);
  background: var(--surface);
  box-shadow: var(--small-shadow);
}

.nav-panel {
  display: none;
}

.nav-panel.is-active {
  display: block;
}

.nav-panel h2 {
  margin: 0 0 10px;
  color: var(--muted);
  font-size: .76rem;
  font-weight: 700;
  letter-spacing: .09em;
  text-transform: uppercase;
}

.nav-panel nav {
  display: grid;
  gap: 4px;
}

.nav-link {
  display: grid;
  gap: 2px;
  padding: 9px 10px;
  border: 0;
  border-radius: 8px;
  color: var(--text);
  background: transparent;
  text-align: left;
  text-decoration: none;
  cursor: pointer;
}

.nav-link:hover,
.nav-link.is-active {
  color: var(--accent-strong);
  background: var(--surface-muted);
}

.nav-link span {
  color: var(--muted);
  font-size: .78rem;
}

#content {
  width: min(var(--max), 100%);
  margin: 0 auto;
  padding: 42px 28px 90px;
  outline: none;
}

.chapter-kicker {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
  margin-bottom: 14px;
}

.pill {
  display: inline-flex;
  align-items: center;
  min-height: 28px;
  padding: 4px 9px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--accent-strong);
  background: var(--surface-muted);
  font-size: .8rem;
  font-weight: 650;
}

.pill.is-warm {
  color: var(--accent-warm);
  background: var(--warm-bg);
}

.title-block {
  margin-bottom: 30px;
  padding-bottom: 26px;
  border-bottom: 1px solid var(--line);
}

.title-block h1 {
  max-width: 780px;
  margin: 0 0 12px;
  font-size: clamp(2rem, 4.8vw, 3.6rem);
  line-height: 1.04;
  letter-spacing: 0;
}

.title-block p {
  max-width: 720px;
  margin: 0;
  color: var(--muted);
  font-size: 1.05rem;
}

.meta-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
  gap: 10px;
  margin: 24px 0 10px;
}

.meta-item {
  min-height: 74px;
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
}

.meta-item span {
  display: block;
  color: var(--muted);
  font-size: .78rem;
}

.meta-item strong {
  display: block;
  margin-top: 2px;
  line-height: 1.35;
}

.schedule-panel,
.reader-progress,
.audio-player {
  display: grid;
  gap: 14px;
  margin-top: 14px;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
}

.schedule-panel {
  grid-template-columns: minmax(0, 1fr) minmax(260px, 360px);
  align-items: center;
}

.schedule-copy span,
.progress-copy span,
.audio-copy span {
  display: block;
  color: var(--muted);
  font-size: .78rem;
}

.schedule-copy strong,
.progress-copy strong,
.audio-copy strong {
  display: block;
  margin-top: 2px;
  line-height: 1.35;
}

.day-strip {
  display: grid;
  grid-template-columns: repeat(7, minmax(0, 1fr));
  gap: 5px;
  padding: 0;
  margin: 0;
  list-style: none;
}

.day-chip {
  min-height: 34px;
  display: grid;
  place-items: center;
  border: 1px solid var(--line);
  border-radius: 8px;
  color: var(--muted);
  background: var(--soft-bg);
  font-size: .76rem;
  font-weight: 700;
}

.day-chip.is-active {
  color: var(--accent-strong);
  border-color: var(--accent-border);
  background: var(--surface-muted);
}

.reader-progress {
  grid-template-columns: minmax(0, 1fr) minmax(260px, 380px);
  align-items: center;
}

.audio-player {
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: center;
  border-color: var(--exercise-border);
  background: var(--exercise-bg);
}

.audio-player.is-active {
  border-color: var(--accent-border-strong);
}

.audio-controls {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  justify-content: flex-end;
}

.audio-button {
  min-height: 38px;
  border: 1px solid var(--line-strong);
  border-radius: 8px;
  padding: 7px 10px;
  color: var(--accent-strong);
  background: var(--surface);
  cursor: pointer;
  font-weight: 700;
}

.audio-button.is-primary {
  color: var(--surface);
  background: var(--accent-strong);
  border-color: var(--accent-strong);
}

.audio-button:hover:not(:disabled) {
  border-color: var(--accent);
  box-shadow: var(--small-shadow);
}

.audio-button:disabled {
  opacity: .48;
  cursor: default;
}

.reader-progress.is-footer {
  margin-top: 28px;
}

.progress-controls {
  display: grid;
  grid-template-columns: minmax(120px, 1fr) auto;
  gap: 12px;
  align-items: center;
}

.progress-bar {
  height: 9px;
  overflow: hidden;
  border-radius: 999px;
  background: var(--progress-track);
}

.progress-bar span {
  display: block;
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--accent), var(--gold));
}

.progress-toggle {
  min-height: 38px;
  display: inline-flex;
  gap: 8px;
  align-items: center;
  padding: 7px 10px;
  border: 1px solid var(--line-strong);
  border-radius: 8px;
  color: var(--accent-strong);
  background: var(--surface);
  cursor: pointer;
  font-weight: 650;
  white-space: nowrap;
}

.progress-toggle input {
  width: 16px;
  height: 16px;
  accent-color: var(--accent);
}

.progress-toggle.is-done {
  border-color: var(--accent-border);
  background: var(--surface-muted);
}

.nav-link.is-complete {
  color: var(--accent-strong);
}

.content-section {
  scroll-margin-top: 86px;
  margin: 0 0 18px;
  padding: 22px 0;
  border-bottom: 1px solid var(--line);
}

.content-section h2 {
  margin: 0 0 10px;
  font-size: 1.35rem;
  line-height: 1.22;
}

.content-section h3 {
  margin: 20px 0 8px;
  font-size: 1.02rem;
  line-height: 1.3;
  color: var(--accent-strong);
}

.content-section p {
  margin: 0 0 12px;
}

.content-section p:last-child,
.content-section ul:last-child,
.content-section ol:last-child {
  margin-bottom: 0;
}

blockquote {
  margin: 18px 0;
  padding: 12px 16px;
  border-left: 4px solid var(--accent);
  border-radius: 0 8px 8px 0;
  color: var(--accent-strong);
  background: var(--surface-muted);
  font-weight: 650;
}

.note,
.exercise {
  margin: 16px 0;
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
}

.note strong,
.exercise strong {
  color: var(--accent-strong);
}

.exercise {
  border-color: var(--exercise-border);
  background: var(--exercise-bg);
}

.interactive-exercise {
  display: grid;
  gap: 16px;
}

.activity-block {
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
}

.activity-block h3 {
  margin-top: 0;
}

.rating-list {
  display: grid;
  gap: 10px;
}

.rating-row {
  display: grid;
  grid-template-columns: minmax(180px, 1fr) minmax(210px, 260px);
  gap: 12px;
  align-items: center;
  min-width: 0;
  padding: 10px;
  border: 1px solid var(--line);
  border-radius: 8px;
}

.rating-row legend {
  padding: 0;
  font-weight: 650;
}

.rating-options {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 5px;
}

.rating-options label {
  min-width: 0;
}

.rating-options input {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}

.rating-options span {
  min-height: 34px;
  display: grid;
  place-items: center;
  border: 1px solid var(--line);
  border-radius: 8px;
  color: var(--muted);
  background: var(--soft-bg);
  cursor: pointer;
  font-weight: 700;
}

.rating-options input:checked + span {
  color: var(--accent-strong);
  border-color: var(--accent-border-strong);
  background: var(--surface-muted);
}

.rating-options input:focus-visible + span {
  outline: 3px solid var(--focus-ring);
  outline-offset: 2px;
}

.study-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin-top: 12px;
}

.study-field {
  display: grid;
  gap: 6px;
  min-width: 0;
}

.study-field span {
  color: var(--accent-strong);
  font-size: .88rem;
  font-weight: 650;
  line-height: 1.35;
}

.study-field textarea {
  width: 100%;
  min-height: 80px;
  resize: vertical;
  border: 1px solid var(--line-strong);
  border-radius: 8px;
  padding: 10px 11px;
  color: var(--text);
  background: var(--field-bg);
  line-height: 1.45;
}

.study-field textarea:focus {
  outline: 3px solid var(--focus-ring);
  border-color: var(--accent);
}

.day-log {
  display: grid;
  gap: 8px;
}

.day-log details {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--soft-bg);
}

.day-log summary {
  min-height: 42px;
  padding: 9px 12px;
  color: var(--accent-strong);
  cursor: pointer;
  font-weight: 700;
}

.day-log details[open] {
  background: var(--surface);
}

.flashcard-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.flashcard {
  position: relative;
  display: grid;
  gap: 12px;
  min-height: 180px;
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: 8px;
  color: var(--text);
  background: var(--surface);
  text-align: left;
  cursor: pointer;
}

.flashcard:hover {
  border-color: var(--accent);
  box-shadow: var(--shadow);
}

.flashcard:focus-visible {
  outline: 3px solid var(--focus-ring);
  outline-offset: 2px;
}

.flashcard-number {
  width: 28px;
  height: 28px;
  display: grid;
  place-items: center;
  border-radius: 999px;
  color: var(--accent-strong);
  background: var(--surface-muted);
  font-size: .82rem;
  font-weight: 800;
}

.flashcard-face {
  min-height: 72px;
  align-content: center;
  font-size: 1rem;
  line-height: 1.45;
}

.flashcard-back {
  display: none;
  color: var(--accent-strong);
  font-weight: 650;
}

.flashcard.is-flipped {
  border-color: var(--accent-border-strong);
  background: var(--surface-muted);
}

.flashcard.is-flipped .flashcard-front {
  display: none;
}

.flashcard.is-flipped .flashcard-back {
  display: block;
}

.flashcard-hint {
  color: var(--muted);
  font-size: .82rem;
}

.term-cloud {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.term-chip {
  min-height: 34px;
  display: inline-flex;
  align-items: center;
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 6px 10px;
  color: var(--accent-strong);
  background: var(--surface-muted);
  text-decoration: none;
  cursor: pointer;
  font-size: .9rem;
  font-weight: 650;
}

.term-chip:hover {
  border-color: var(--accent);
}

.term-chip.is-pending {
  color: var(--muted);
  background: var(--soft-bg);
  cursor: default;
}

.glossary-entry h2 {
  color: var(--accent-strong);
}

.dashboard-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 20px;
}

.primary-action,
.secondary-action,
.card-action {
  min-height: 38px;
  border: 1px solid var(--line-strong);
  border-radius: 8px;
  padding: 8px 12px;
  cursor: pointer;
  font-weight: 700;
}

.primary-action,
.card-action {
  color: var(--surface);
  background: var(--accent-strong);
  border-color: var(--accent-strong);
}

.secondary-action {
  color: var(--accent-strong);
  background: var(--surface);
}

.primary-action:hover,
.secondary-action:hover,
.card-action:hover {
  border-color: var(--accent);
  box-shadow: var(--shadow);
}

.dashboard-stats {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
  margin: 14px 0;
}

.stat-card,
.program-card,
.chapter-card {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
}

.stat-card {
  display: grid;
  gap: 8px;
  min-height: 118px;
  padding: 14px;
}

.stat-card span,
.stat-card small,
.card-meta dt,
.mini-chapter-list {
  color: var(--muted);
  font-size: .82rem;
}

.stat-card strong {
  font-size: 1.8rem;
  line-height: 1;
}

.status-cloud {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 14px;
}

.status-chip,
.reader-state {
  min-height: 28px;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 4px 9px;
  color: var(--muted);
  background: var(--soft-bg);
  font-size: .8rem;
  font-weight: 700;
}

.reader-state.is-read {
  color: var(--accent-strong);
  border-color: var(--accent-border);
  background: var(--surface-muted);
}

.program-card-grid,
.chapter-card-grid {
  display: grid;
  gap: 12px;
}

.program-card-grid {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.chapter-card-grid {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.program-card,
.chapter-card {
  display: grid;
  gap: 12px;
  align-content: start;
  padding: 14px;
}

.chapter-card.is-read {
  border-color: var(--accent-border);
  background: var(--surface-muted);
}

.card-kicker {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 8px;
  align-items: center;
}

.program-card h3,
.chapter-card h3 {
  margin: 0;
  font-size: 1.05rem;
  line-height: 1.3;
}

.program-card p,
.chapter-card p {
  margin: 0;
  color: var(--muted);
  font-size: .92rem;
  line-height: 1.5;
}

.mini-chapter-list {
  display: grid;
  gap: 3px;
}

.card-meta {
  display: grid;
  gap: 8px;
  margin: 0;
}

.card-meta div {
  min-width: 0;
}

.card-meta dt,
.card-meta dd {
  margin: 0;
}

.card-meta dd {
  line-height: 1.35;
}

.card-controls {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: center;
  justify-content: space-between;
}

.compare {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin: 16px 0;
}

.compare > div {
  min-height: 86px;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
}

.table-wrap {
  overflow-x: auto;
}

table {
  width: 100%;
  min-width: 560px;
  border-collapse: collapse;
}

th,
td {
  padding: 10px;
  border-bottom: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}

th {
  color: var(--accent-strong);
  background: var(--surface-muted);
}

.checklist {
  list-style: none;
  padding: 0;
}

.checklist li {
  position: relative;
  padding-left: 24px;
}

.checklist li::before {
  content: "✓";
  position: absolute;
  left: 0;
  color: var(--accent);
  font-weight: 800;
}

.chapter-nav {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin-top: 32px;
}

.chapter-nav button {
  min-height: 70px;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 12px;
  color: var(--text);
  background: var(--surface);
  text-align: left;
  cursor: pointer;
}

.chapter-nav button:hover {
  border-color: var(--accent);
  box-shadow: var(--shadow);
}

.chapter-nav button:disabled {
  opacity: .48;
  cursor: default;
  box-shadow: none;
}

.chapter-nav span {
  display: block;
  color: var(--muted);
  font-size: .8rem;
}

.empty-search {
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  color: var(--muted);
  background: var(--surface);
}

.search-results {
  display: grid;
  gap: 10px;
}

.search-result {
  display: grid;
  gap: 5px;
  width: 100%;
  min-height: 94px;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 8px;
  color: var(--text);
  background: var(--surface);
  text-align: left;
  cursor: pointer;
}

.search-result:hover {
  border-color: var(--accent);
  box-shadow: var(--shadow);
}

.result-meta,
.result-snippet {
  color: var(--muted);
  font-size: .88rem;
  line-height: 1.45;
}

.result-meta {
  color: var(--accent-strong);
  font-weight: 650;
}

mark {
  border-radius: 4px;
  background: var(--mark-bg);
}

footer {
  padding: 24px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  text-align: center;
  font-size: .88rem;
}

@media (max-width: 880px) {
  .topbar {
    grid-template-columns: auto minmax(0, 1fr) auto;
  }

  body.menu-open::before {
    content: "";
    position: fixed;
    inset: 64px 0 0;
    z-index: 10;
    background: var(--mobile-overlay);
  }

  body.search-open.menu-open::before {
    inset: 118px 0 0;
  }

  .shell {
    display: block;
  }

  body.nav-collapsed .sidebar {
    display: block;
  }

  .sidebar {
    position: fixed;
    top: 64px;
    left: 0;
    z-index: 20;
    width: min(88vw, 360px);
    height: calc(100vh - 64px);
    transform: translateX(-105%);
    transition: transform .2s ease;
    border-right: 1px solid var(--line-strong);
    background: var(--surface);
    box-shadow: var(--shadow);
  }

  body.search-open .sidebar {
    top: 118px;
    height: calc(100vh - 118px);
  }

  body.menu-open .sidebar {
    transform: translateX(0);
  }

  #content {
    padding: 28px 16px 70px;
  }

  .schedule-panel,
  .reader-progress,
  .audio-player,
  .progress-controls,
  .rating-row,
  .study-grid,
  .flashcard-grid,
  .dashboard-stats,
  .program-card-grid,
  .chapter-card-grid,
  .compare,
  .chapter-nav {
    grid-template-columns: 1fr;
  }

  .audio-controls {
    justify-content: flex-start;
  }
}

@media (max-width: 520px) {
  .topbar {
    gap: 10px;
    padding: 9px 12px;
  }

  .brand strong {
    font-size: .98rem;
  }

  .title-block h1 {
    font-size: 2rem;
  }

  .segmented {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .rating-options {
    grid-template-columns: repeat(5, minmax(38px, 1fr));
  }
}