:root {
  font-family: "Atkinson Hyperlegible", "Source Sans 3", "Nunito Sans", "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  font-size: 16px;
  line-height: 1.5;
  --bg-page: linear-gradient(160deg, #eef3fb 0%, #edf4fb 50%, #f8fbff 100%);
  --bg-panel: #ffffff;
  --bg-subtle: #f8fbff;
  --bg-subtle-2: #f1f6ff;
  --text-main: #182233;
  --text-muted: #4e5f7c;
  --text-status: #0f4f8f;
  --border-main: #d1ddf0;
  --border-soft: #dbe4f3;
  --shadow-main: 0 10px 20px rgba(16, 34, 66, 0.08);
  --btn-primary: #1f5fb8;
  --btn-primary-text: #ffffff;
  --btn-secondary-bg: #edf2fb;
  --btn-secondary-text: #17385f;
  --btn-secondary-border: #c3d0e7;
  --dropzone-border: #9fb6db;
  --dropzone-text: #35517e;
  --dropzone-hover: #eff5ff;
  --ok-bg: #eefaf3;
  --ok-border: #37a86a;
  --bad-bg: #fff2f2;
  --bad-border: #d94a4a;
  --focus-ring: #87b3ef;
}

html[data-theme="dark"] {
  --bg-page: linear-gradient(180deg, #121922 0%, #0f151d 100%);
  --bg-panel: #18212d;
  --bg-subtle: #1c2633;
  --bg-subtle-2: #202c3b;
  --text-main: #e5ebf5;
  --text-muted: #aab6c8;
  --text-status: #9fc2f3;
  --border-main: #2d3a4d;
  --border-soft: #324156;
  --shadow-main: 0 6px 16px rgba(0, 0, 0, 0.28);
  --btn-primary: #5d87c8;
  --btn-primary-text: #f5f8ff;
  --btn-secondary-bg: #223042;
  --btn-secondary-text: #dce8fb;
  --btn-secondary-border: #344861;
  --dropzone-border: #4e6f99;
  --dropzone-text: #c6d7f1;
  --dropzone-hover: #253852;
  --ok-bg: #1e3f30;
  --ok-border: #58b883;
  --bad-bg: #44272d;
  --bad-border: #d36f7f;
  --focus-ring: #7baef7;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  color: var(--text-main);
  background: var(--bg-page);
  text-rendering: optimizeLegibility;
}

h1,
h2,
h3,
h4,
h5 {
  line-height: 1.3;
}

button:focus-visible,
input:focus-visible,
textarea:focus-visible,
select:focus-visible {
  outline: 3px solid var(--focus-ring);
  outline-offset: 1px;
}

.hidden {
  display: none !important;
}

.app-shell {
  min-height: 100vh;
  padding: 1rem;
}

.panel {
  background: var(--bg-panel);
  border: 1px solid var(--border-main);
  border-radius: 12px;
  box-shadow: var(--shadow-main);
}

.login-panel {
  width: min(520px, 100%);
  margin: 5vh auto 0;
  padding: 1rem;
}

.topbar {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto auto;
  align-items: center;
  gap: 0.9rem;
  padding: 0.95rem 1.1rem;
  margin-bottom: 1rem;
}

.topbar-brand {
  min-width: 0;
  display: grid;
  gap: 0.2rem;
}

.topbar-brand h2 {
  margin: 0;
}

.topbar-brand #session-line {
  margin: 0;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.topbar-main-actions,
.topbar-actions {
  display: flex;
  gap: 0.4rem;
  flex-wrap: wrap;
  align-items: center;
}

.topbar-main-actions {
  justify-content: flex-end;
}

.mobile-menu-toggle {
  display: none;
}

.mobile-menu {
  position: absolute;
  top: calc(100% + 0.55rem);
  right: 1.1rem;
  width: min(280px, calc(100vw - 2rem));
  padding: 0.75rem;
  border: 1px solid var(--border-main);
  border-radius: 14px;
  background: var(--bg-panel);
  box-shadow: var(--shadow-main);
  display: grid;
  gap: 0.6rem;
  z-index: 40;
}

.mobile-menu-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  width: 100%;
}

.theme-switch {
  --toggle-size: 18px;
  --container-width: 5.625em;
  --container-height: 2.5em;
  --container-radius: 6.25em;
  --container-light-bg: #3d7eae;
  --container-night-bg: #1d1f2c;
  --circle-container-diameter: 3.375em;
  --sun-moon-diameter: 2.125em;
  --sun-bg: #ecca2f;
  --moon-bg: #c4c9d1;
  --spot-color: #959db1;
  --circle-container-offset: calc((var(--circle-container-diameter) - var(--container-height)) / 2 * -1);
  --stars-color: #fff;
  --clouds-color: #f3fdff;
  --back-clouds-color: #aacadf;
  --transition: .5s cubic-bezier(0, -0.02, 0.4, 1.25);
  --circle-transition: .3s cubic-bezier(0, -0.02, 0.35, 1.17);
}

.theme-switch,
.theme-switch *,
.theme-switch *::before,
.theme-switch *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-size: var(--toggle-size);
}

.theme-switch__checkbox {
  display: none;
}

.theme-switch__container {
  width: var(--container-width);
  height: var(--container-height);
  background-color: var(--container-light-bg);
  border-radius: var(--container-radius);
  overflow: hidden;
  cursor: pointer;
  box-shadow: 0 0.08em 0.2em rgba(0, 0, 0, 0.28);
  transition: var(--transition);
  position: relative;
}

.theme-switch__clouds {
  width: 1.25em;
  height: 1.25em;
  background-color: var(--clouds-color);
  border-radius: var(--container-radius);
  position: absolute;
  bottom: -0.625em;
  left: 0.312em;
  box-shadow:
    0.937em 0.312em var(--clouds-color),
    -0.312em -0.312em var(--back-clouds-color),
    1.437em 0.375em var(--clouds-color),
    2.187em 0 var(--clouds-color),
    2.937em 0.312em var(--clouds-color);
  transition: var(--transition);
}

.theme-switch__stars-container {
  position: absolute;
  color: var(--stars-color);
  letter-spacing: 0.18em;
  top: -100%;
  left: 0.45em;
  transition: var(--transition);
}

.theme-switch__circle-container {
  width: var(--circle-container-diameter);
  height: var(--circle-container-diameter);
  background-color: rgba(255, 255, 255, 0.14);
  position: absolute;
  left: var(--circle-container-offset);
  top: var(--circle-container-offset);
  border-radius: var(--container-radius);
  display: flex;
  transition: var(--circle-transition);
}

.theme-switch__sun-moon-container {
  margin: auto;
  width: var(--sun-moon-diameter);
  height: var(--sun-moon-diameter);
  border-radius: var(--container-radius);
  background-color: var(--sun-bg);
  overflow: hidden;
  transition: var(--transition);
}

.theme-switch__moon {
  transform: translateX(100%);
  width: 100%;
  height: 100%;
  background-color: var(--moon-bg);
  border-radius: inherit;
  transition: var(--transition);
  position: relative;
}

.theme-switch__spot {
  position: absolute;
  top: 0.75em;
  left: 0.312em;
  width: 0.75em;
  height: 0.75em;
  border-radius: var(--container-radius);
  background-color: var(--spot-color);
}

.theme-switch__spot:nth-of-type(2) {
  width: 0.375em;
  height: 0.375em;
  top: 0.937em;
  left: 1.375em;
}

.theme-switch__spot:nth-last-of-type(3) {
  width: 0.25em;
  height: 0.25em;
  top: 0.312em;
  left: 0.812em;
}

.theme-switch__checkbox:checked + .theme-switch__container {
  background-color: var(--container-night-bg);
}

.theme-switch__checkbox:checked + .theme-switch__container .theme-switch__circle-container {
  left: calc(100% - var(--circle-container-offset) - var(--circle-container-diameter));
}

.theme-switch__checkbox:checked + .theme-switch__container .theme-switch__moon {
  transform: translateX(0);
}

.theme-switch__checkbox:checked + .theme-switch__container .theme-switch__clouds {
  bottom: -4.062em;
}

.theme-switch__checkbox:checked + .theme-switch__container .theme-switch__stars-container {
  top: 50%;
  transform: translateY(-50%);
}

.layout {
  display: grid;
  grid-template-columns: minmax(260px, 340px) 1fr;
  gap: 1rem;
}

.layout.study-layout {
  grid-template-columns: 1fr;
}

.sidebar,
.workspace,
.subpanel {
  padding: 0.9rem;
}

.sidebar-tabs {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.4rem;
  margin-bottom: 0.6rem;
}

.workspace-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
}

.workspace-grid.study-focused {
  grid-template-columns: 1fr;
}

.workspace-grid.study-focused .subpanel:not(#pdf-panel) {
  order: 1;
}

.workspace-grid.study-focused #pdf-panel {
  order: 2;
}

.workspace-head {
  margin-bottom: 0.75rem;
}

.stack {
  display: grid;
  gap: 0.65rem;
}

label {
  display: grid;
  gap: 0.25rem;
  font-size: 0.98rem;
}

input,
textarea,
select,
button {
  font: inherit;
}

input,
textarea,
select {
  color: var(--text-main);
  background: var(--bg-subtle);
  border: 1px solid var(--border-main);
  border-radius: 8px;
  padding: 0.55rem 0.65rem;
}

textarea {
  min-height: 70px;
  resize: vertical;
}

button {
  border: 1px solid transparent;
  border-radius: 8px;
  padding: 0.45rem 0.65rem;
  background: var(--btn-primary);
  color: var(--btn-primary-text);
  cursor: pointer;
}

button.secondary {
  background: var(--btn-secondary-bg);
  color: var(--btn-secondary-text);
  border-color: var(--btn-secondary-border);
}

.dropzone {
  border: 2px dashed var(--dropzone-border);
  border-radius: 10px;
  padding: 0.9rem;
  text-align: center;
  color: var(--dropzone-text);
}

.dropzone.dragover {
  background: var(--dropzone-hover);
  border-color: var(--btn-primary);
}

.muted {
  color: var(--text-muted);
  margin: 0;
}

.small {
  font-size: 0.85rem;
}

.status {
  color: var(--text-status);
  margin: 0.2rem 0;
  min-height: 1.2em;
}

.tree {
  margin-top: 0.6rem;
  display: grid;
  gap: 0.45rem;
  max-height: 44vh;
  overflow: auto;
}

.tree-block {
  border: 1px solid var(--border-soft);
  border-radius: 8px;
  padding: 0.45rem;
  display: grid;
  gap: 0.35rem;
}

.tree-sub {
  padding-left: 0.55rem;
  display: grid;
  gap: 0.25rem;
}

.tree-item {
  text-align: left;
  background: var(--bg-subtle);
  color: var(--btn-secondary-text);
  border: 1px solid var(--border-soft);
}


.pdf-toolbar {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.45rem;
  margin-bottom: 0.55rem;
}

.pdf-canvas-wrap {
  width: 100%;
  height: clamp(520px, 72vh, 960px);
  border: 1px solid var(--border-main);
  border-radius: 8px;
  background: transparent;
  overflow: auto;
}

.pdf-stage {
  position: relative;
  margin: 0 auto;
}

.pdf-canvas {
  display: block;
  background: transparent;
}

.pdf-highlight-layer {
  position: absolute;
  inset: 0;
  pointer-events: none;
}

.pdf-highlight-box {
  position: absolute;
  background: rgba(255, 214, 10, 0.26);
  border: 1px solid rgba(214, 146, 0, 0.62);
  border-radius: 4px;
  box-shadow: 0 0 0 1px rgba(255, 247, 204, 0.22);
}

.cards-head,
.filters {
  display: flex;
  gap: 0.6rem;
  align-items: center;
  flex-wrap: wrap;
}

.mode-switch {
  display: flex;
  gap: 0.5rem;
  margin: 0.5rem 0;
}

button.active-mode {
  background: var(--btn-primary);
  color: var(--btn-primary-text);
  border-color: var(--btn-primary);
}

.cards-list {
  margin-top: 0.65rem;
  display: grid;
  gap: 0.55rem;
  max-height: 60vh;
  overflow: auto;
}

.flags-panel {
  margin-top: 0.6rem;
  border: 1px solid var(--border-soft);
  border-radius: 10px;
  padding: 0.55rem;
  background: var(--bg-subtle);
}

.flags-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
}

.flags-head h5 {
  margin: 0;
}

.flags-list {
  margin-top: 0.45rem;
  max-height: 24vh;
  overflow: auto;
  display: grid;
  gap: 0.45rem;
}

.flag-item {
  border: 1px solid var(--border-soft);
  border-radius: 8px;
  background: var(--bg-panel);
  padding: 0.45rem;
}

.card-editor {
  border: 1px solid var(--border-soft);
  border-radius: 10px;
  padding: 0.55rem;
  display: grid;
  gap: 0.45rem;
  background: var(--bg-subtle);
}

.card-editor-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.row-actions {
  display: flex;
  gap: 0.4rem;
}

.study-controls {
  display: flex;
  gap: 0.65rem;
  flex-wrap: wrap;
  justify-content: flex-end;
  align-items: end;
}

.study-inline-control {
  display: grid;
  gap: 0.3rem;
  min-width: 150px;
}

.study-inline-control input,
.study-inline-control select {
  min-width: 120px;
  height: 2.2rem;
}

.study-inline-check {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.32rem 0.5rem;
  border: 1px solid var(--border-soft);
  border-radius: 999px;
  background: var(--bg-subtle);
  height: 2.2rem;
}

.study-inline-check input {
  margin: 0;
}

#study-view {
  display: grid;
  gap: 0.9rem;
}

.study-utility-row {
  display: flex;
  justify-content: flex-end;
  min-height: 0;
}

.study-setup {
  border: 1px solid var(--border-soft);
  border-radius: 16px;
  background: var(--bg-subtle);
  padding: 1.05rem 1.1rem;
}

.study-setup-head {
  display: grid;
  gap: 0.32rem;
}

.study-setup h5 {
  margin: 0;
  font-size: 1.05rem;
}

.study-setup-head p {
  margin: 0;
  max-width: 64ch;
}

.study-setup-body {
  margin-top: 0.95rem;
}

.study-setup-footer {
  margin-top: 1rem;
  padding-top: 0.9rem;
  border-top: 1px solid var(--border-soft);
}

.deck-catalog {
  display: grid;
  gap: 0.9rem;
  max-height: 42vh;
  overflow: auto;
  padding-right: 0.15rem;
}

.deck-group {
  padding-top: 0.05rem;
}

.deck-group + .deck-group {
  padding-top: 1rem;
  border-top: 1px solid var(--border-soft);
}

.deck-group-title {
  margin: 0;
  font-size: 0.98rem;
  color: var(--text-main);
}

.study-step-caption {
  margin: 0.25rem 0 0;
}

.subject-row-list {
  display: grid;
  gap: 0.55rem;
}

.subject-row {
  border: 1px solid var(--border-soft);
  border-radius: 14px;
  padding: 0.8rem 0.9rem;
  background: var(--bg-subtle);
  transition: border-color 120ms ease, background-color 120ms ease, transform 120ms ease;
}

.subject-row.selected {
  border-color: var(--btn-primary);
  background: var(--bg-subtle-2);
}

.subject-row-top {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 0.8rem;
  align-items: start;
}

.subject-row-copy {
  min-width: 0;
  display: grid;
  gap: 0.18rem;
}

.subject-row-metrics {
  display: grid;
  gap: 0.18rem;
  justify-items: end;
}

.subject-chip {
  text-align: left;
  border: 0;
  background: transparent;
  color: var(--text-main);
  font-weight: 700;
  padding: 0;
  border-radius: 0;
}

.session-chip.selected {
  background: var(--btn-primary);
  border-color: var(--btn-primary);
  color: var(--btn-primary-text);
}

.subject-chip.selected {
  color: var(--btn-primary);
}

.session-chip {
  border: 1px solid var(--btn-secondary-border);
  background: var(--btn-secondary-bg);
  color: var(--btn-secondary-text);
  border-radius: 999px;
  padding: 0.38rem 0.78rem;
  font-size: 0.85rem;
}

.subject-count {
  font-size: 0.82rem;
  color: var(--text-muted);
  white-space: nowrap;
}

.chapter-pickers {
  margin-top: 0.3rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
}

.chapter-material-block {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  align-items: center;
  width: 100%;
}

.tree-material-group {
  margin-top: 0.2rem;
}

.chapter-chip {
  border: 1px solid var(--btn-secondary-border);
  background: var(--btn-secondary-bg);
  color: var(--btn-secondary-text);
  border-radius: 999px;
  padding: 0.3rem 0.68rem;
  font-size: 0.82rem;
}

.chapter-chip.selected {
  border-color: var(--btn-primary);
  color: var(--btn-primary-text);
  background: var(--btn-primary);
}

.selected-decks {
  display: grid;
  gap: 0.65rem;
}

.selected-decks__summary {
  margin: 0;
}

.loaded-deck-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem;
}

.selected-deck-list {
  display: grid;
  gap: 0.75rem;
}

.selected-deck-card {
  border: 1px solid var(--border-soft);
  border-radius: 16px;
  padding: 0.85rem 0.95rem;
  background: var(--bg-subtle);
  display: grid;
  gap: 0.7rem;
}

.selected-deck-card.focused {
  border-color: var(--btn-primary);
  box-shadow: 0 0 0 2px rgba(31, 95, 184, 0.16);
  background: var(--bg-subtle-2);
}

.selected-deck-card.collapsed .selected-deck-body {
  display: none;
}

.selected-deck-toggle {
  width: 100%;
  border: 0;
  border-radius: 0;
  background: transparent;
  color: inherit;
  padding: 0;
  text-align: left;
}

.selected-deck-head {
  display: flex;
  justify-content: space-between;
  align-items: start;
  gap: 0.6rem;
}

.selected-deck-copy {
  min-width: 0;
  display: grid;
  gap: 0.12rem;
}

.selected-deck-body {
  display: grid;
  gap: 0.7rem;
}

.selected-deck-meta {
  margin: 0;
}

.loaded-deck-entry {
  display: inline-flex;
  gap: 0.35rem;
  align-items: center;
  flex-wrap: nowrap;
  padding: 0.2rem 0.22rem 0.2rem 0.24rem;
  border-radius: 999px;
  border: 1px solid var(--border-soft);
  background: var(--bg-subtle-2);
}

.loaded-deck-entry .session-chip.focused {
  box-shadow: 0 0 0 2px rgba(31, 95, 184, 0.2);
}

.loaded-deck-chip {
  max-width: 100%;
}

.loaded-deck-remove {
  padding: 0.32rem 0.58rem;
  border-radius: 999px;
}

.deck-limit-wrap {
  display: grid;
  gap: 0.3rem;
  margin-top: 0.35rem;
}

.deck-limit-input {
  text-align: left;
  padding: 0.55rem 0.7rem;
}

.study-session-bar {
  display: flex;
  justify-content: space-between;
  align-items: end;
  gap: 0.9rem;
  padding: 0.95rem 1.05rem;
  border-radius: 16px;
}

.study-session-bar__summary {
  min-width: 0;
  display: grid;
  gap: 0.28rem;
}

.study-session-bar__summary p,
#study-context,
#study-meta {
  margin: 0;
}

.study-session-bar__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.85rem;
}

.study-stage {
  display: grid;
  gap: 0.85rem;
  padding: 1.05rem 1.1rem 1.15rem;
  border-radius: 18px;
}

#study-view.training-active .study-stage {
  box-shadow: 0 16px 30px rgba(3, 7, 15, 0.22);
}

#study-view.training-active .study-session-bar {
  border-color: var(--btn-primary);
}

.teacher-tracker {
  --tracker-columns: minmax(260px, 1.8fr) 56px 88px 56px 88px minmax(220px, 1.2fr) 72px;
  grid-column: 1 / -1;
  margin-top: 0;
  padding: 0.9rem;
  border: 1px solid var(--border-soft);
  border-radius: 10px;
  background: var(--bg-subtle-2);
}

.tracker-head {
  display: grid;
  gap: 0.25rem;
}

.tracker-head strong,
.tracker-head p {
  margin: 0;
}

.tracker-section-label {
  font-size: 0.74rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-muted);
}

.tracker-filters,
.tracker-add-row {
  display: grid;
  gap: 0.55rem;
  align-items: end;
}

.tracker-filters {
  grid-template-columns: minmax(180px, 220px) minmax(180px, 220px) auto;
}

.tracker-add-row {
  grid-template-columns: minmax(0, 1fr) auto;
}

.tracker-field {
  min-width: 0;
}

.tracker-inline-toggle {
  display: flex;
  align-items: center;
  gap: 0.45rem;
  align-self: end;
  min-height: 42px;
}

.tracker-list {
  display: grid;
  gap: 0.35rem;
}

.tracker-summary {
  display: grid;
  gap: 0.45rem;
  margin-bottom: 0.2rem;
}

.tracker-summary-card {
  border: 1px solid var(--border-soft);
  border-radius: 10px;
  padding: 0.65rem 0.75rem;
  background: var(--bg-panel);
}

.tracker-summary-card strong,
.tracker-summary-card p {
  margin: 0;
}

.tracker-summary-list {
  display: grid;
  gap: 0.3rem;
}

.tracker-summary-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.6rem;
  flex-wrap: wrap;
}

.tracker-summary-item strong {
  font-size: 0.95rem;
}

.tracker-status-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  border-radius: 999px;
  padding: 0.15rem 0.55rem;
  border: 1px solid var(--border-soft);
  background: var(--bg-subtle);
  color: var(--text-muted);
  font-size: 0.82rem;
}

.tracker-status-chip.missing {
  border-color: var(--bad-border);
  background: var(--bad-bg);
  color: var(--text-main);
}

.tracker-status-chip.done {
  border-color: var(--ok-border);
  background: var(--ok-bg);
  color: var(--text-main);
}

.tracker-row {
  display: grid;
  grid-template-columns: var(--tracker-columns);
  gap: 0.4rem;
  align-items: center;
  border: 1px solid var(--border-soft);
  border-radius: 8px;
  padding: 0.4rem;
  background: var(--bg-panel);
}

.tracker-row-header {
  background: transparent;
  border-style: dashed;
  font-size: 0.84rem;
  color: var(--text-muted);
}

.tracker-row-header strong:not(:first-child):not(:nth-child(6)) {
  text-align: center;
}

.tracker-row-header strong:nth-child(6) {
  padding-left: 0.2rem;
}

.tracker-row.is-hidden {
  opacity: 0.72;
}

.tracker-row.is-note-row {
  border-style: dashed;
}

.tracker-name-cell {
  display: grid;
  gap: 0.15rem;
}

.tracker-check-cell {
  display: flex;
  align-items: center;
  justify-content: center;
}

.tracker-audit-btn,
.tracker-done-btn {
  width: 100%;
  white-space: nowrap;
}

.tracker-row input[type='text'] {
  min-width: 0;
  width: 100%;
}

.delete-guard {
  margin-top: 0.5rem;
  padding: 0.55rem;
  border: 1px solid var(--border-soft);
  border-radius: 10px;
  background: var(--bg-subtle-2);
}

.pdf-panel-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.55rem;
  gap: 0.6rem;
}

.study-card {
  border: 1px solid var(--border-soft);
  border-radius: 16px;
  padding: 1.05rem 1.1rem;
  background: var(--bg-subtle);
  min-height: 220px;
}

.study-question {
  font-size: 1.08rem;
  margin-bottom: 0.8rem;
}

.study-options {
  display: grid;
  gap: 0.55rem;
}

.study-option {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  border: 1px solid var(--border-soft);
  border-radius: 12px;
  padding: 0.7rem 0.75rem;
  background: var(--bg-panel);
}

.study-option.correct {
  border-color: var(--ok-border);
  background: var(--ok-bg);
}

.study-option.incorrect {
  border-color: var(--bad-border);
  background: var(--bad-bg);
}

.study-actions {
  display: flex;
  gap: 0.6rem;
  flex-wrap: wrap;
}

.study-answer {
  margin-top: 0.85rem;
  padding: 0.7rem 0.8rem;
  border-radius: 12px;
  border: 1px solid var(--border-soft);
  background: var(--bg-subtle-2);
}

.audit-picker-controls {
  display: grid;
  gap: 0.65rem;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
}

#audit-chapter-select {
  min-height: 2.4rem;
}

.audit-selection-summary {
  margin: -0.2rem 0 0;
}

.audit-review {
  border: 1px solid var(--border-soft);
  border-radius: 14px;
  padding: 0.85rem;
  background: var(--bg-subtle-2);
}

.study-stage.audit-active .audit-review {
  border-color: var(--btn-primary);
}

.audit-review-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.6rem;
  margin-bottom: 0.45rem;
}

.audit-review-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  margin-bottom: 0.5rem;
}

.audit-review textarea {
  min-height: 74px;
}

hr {
  border: none;
  border-top: 1px solid var(--border-soft);
  margin: 0.75rem 0;
}

@media (max-width: 1100px) {
  .layout {
    grid-template-columns: 1fr;
  }

  .workspace-grid {
    grid-template-columns: 1fr;
  }

  .pdf-canvas-wrap {
    height: clamp(360px, 66vh, 780px);
  }

  .study-session-bar {
    align-items: start;
    flex-direction: column;
  }

  .study-controls {
    width: 100%;
    justify-content: flex-start;
  }
}

@media (max-width: 760px) {
  .app-shell {
    padding: 0.7rem;
  }

  .topbar {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: start;
    gap: 0.7rem;
    padding: 0.8rem 0.85rem;
  }

  .topbar-brand h2 {
    font-size: 1.08rem;
  }

  .topbar-brand #session-line {
    font-size: 0.82rem;
  }

  .desktop-actions {
    display: none;
  }

  .mobile-menu-toggle {
    display: inline-flex;
  }

  .topbar-main-actions {
    justify-content: flex-end;
    gap: 0.35rem;
  }

  .topbar-main-actions button.secondary {
    padding: 0.42rem 0.58rem;
  }

  .mobile-menu {
    right: 0.85rem;
  }

  .mobile-menu .theme-switch {
    --toggle-size: 15px;
  }

  #study-view {
    gap: 0.75rem;
  }

  .study-setup,
  .study-session-bar,
  .study-stage {
    border-radius: 14px;
  }

  .study-setup {
    padding: 0.9rem;
  }

  .deck-catalog {
    max-height: none;
    overflow: visible;
    padding-bottom: 5.25rem;
  }

  .subject-row-top {
    grid-template-columns: 1fr;
    gap: 0.45rem;
  }

  .tracker-row {
    grid-template-columns: 1fr;
  }

  .tracker-row-header {
    display: none;
  }

  .tracker-filters,
  .tracker-add-row {
    grid-template-columns: 1fr;
  }

  .tracker-inline-toggle {
    min-height: 0;
  }

  .subject-row,
  .selected-deck-card {
    padding: 0.75rem 0.8rem;
  }

  .subject-row-metrics {
    justify-items: start;
    grid-auto-flow: column;
    justify-content: start;
    column-gap: 0.7rem;
    row-gap: 0.2rem;
  }

  .selected-deck-toggle {
    padding-right: 0.1rem;
  }

  .loaded-deck-list {
    display: grid;
    gap: 0.45rem;
  }

  .loaded-deck-entry {
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: center;
    border-radius: 14px;
    padding: 0.35rem;
  }

  .loaded-deck-chip {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
  }

  .study-session-bar {
    padding: 0.85rem 0.9rem;
  }

  .study-session-bar__meta {
    gap: 0.45rem;
    flex-direction: column;
  }

  .study-controls {
    align-items: stretch;
  }

  .study-inline-control,
  .study-inline-check {
    width: 100%;
  }

  .study-inline-check {
    justify-content: center;
  }

  .study-controls button {
    width: 100%;
  }

  #study-view:not(.training-active) .study-controls {
    position: sticky;
    bottom: 0;
    z-index: 8;
    background: var(--bg-panel);
    padding: 0.7rem 0 calc(0.7rem + env(safe-area-inset-bottom, 0px));
    border-top: 1px solid var(--border-main);
  }

  .study-stage {
    padding: 0.9rem;
  }

  .study-card {
    min-height: 240px;
    padding: 0.95rem;
  }

  .study-actions {
    position: sticky;
    bottom: 0;
    z-index: 7;
    background: var(--bg-panel);
    padding: 0.65rem 0 calc(0.65rem + env(safe-area-inset-bottom, 0px));
    border-top: 1px solid var(--border-main);
  }

  #study-view.training-active .study-stage {
    order: 2;
  }

  #study-view.training-active .study-session-bar {
    order: 1;
  }

  #study-view.training-active .study-utility-row {
    order: 3;
  }

  #study-view.training-active #study-setup {
    order: 4;
  }
}

@media (prefers-reduced-motion: reduce) {
  * {
    animation: none !important;
    transition: none !important;
    scroll-behavior: auto !important;
  }
}