:root {
  color-scheme: light;
  --ink: #16211f;
  --muted: #5b6967;
  --line: #dce5e2;
  --surface: #ffffff;
  --panel: #f6f8f7;
  --accent: #0f766e;
  --accent-2: #9a3412;
  --gold: #b7791f;
  --shadow: 0 18px 45px rgba(15, 36, 32, 0.12);
  --reader-font-size: 16px;
  --reader-line-height: 1.62;
}

[data-theme="warm"] {
  --ink: #2d1b09;
  --muted: #73563a;
  --line: #ecd7bc;
  --surface: #fffaf5;
  --panel: #fff2df;
  --accent: #9a3412;
  --accent-2: #0f766e;
  --gold: #a16207;
  --shadow: 0 18px 45px rgba(97, 51, 18, 0.12);
}

[data-theme="mint"] {
  --ink: #14352d;
  --muted: #4c6f62;
  --line: #c7e7d6;
  --surface: #ffffff;
  --panel: #ebfbf3;
  --accent: #15803d;
  --accent-2: #0f766e;
  --gold: #a16207;
  --shadow: 0 18px 45px rgba(17, 94, 54, 0.12);
}

[data-theme="dark"] {
  color-scheme: dark;
  --ink: #eef7f4;
  --muted: #a8bbb6;
  --line: #38514b;
  --surface: #152522;
  --panel: #1d332f;
  --accent: #5eead4;
  --accent-2: #fdba74;
  --gold: #fbbf24;
  --shadow: 0 18px 45px rgba(0, 0, 0, 0.32);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  color: var(--ink);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: #edf3f1;
}

[data-theme="warm"] body {
  background: #f8efe5;
}

[data-theme="mint"] body {
  background: #eaf7ef;
}

[data-theme="dark"] body {
  background: #0c1715;
}

button,
input,
select {
  font: inherit;
}

button {
  border: 1px solid var(--line);
  background: var(--surface);
  color: var(--ink);
  border-radius: 6px;
  min-height: 38px;
  cursor: pointer;
}

button:hover {
  border-color: #98b8b2;
}

a {
  color: inherit;
}

.link-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 38px;
  border-radius: 6px;
  padding: 8px 14px;
  text-decoration: none;
}

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

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding: 18px 24px;
  background: #12312d;
  color: #f8fbfa;
}

.eyebrow,
.source-label {
  margin: 0 0 4px;
  color: #bfd3cf;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0;
  text-transform: uppercase;
}

.eyebrow.dark {
  color: var(--accent);
}

h1,
h2,
h3 {
  margin: 0;
  letter-spacing: 0;
}

h1 {
  font-size: 24px;
}

.stats {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  justify-content: flex-end;
}

.topbar-actions {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
  justify-content: flex-end;
}

.theme-control {
  display: flex;
  align-items: center;
  gap: 8px;
  color: #edf8f5;
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
}

.theme-control select {
  width: auto;
  min-height: 34px;
  border-color: rgba(255, 255, 255, 0.25);
  background: rgba(255, 255, 255, 0.08);
  color: #f8fbfa;
}

.theme-control option {
  color: #16211f;
}

.stats span {
  border: 1px solid rgba(255, 255, 255, 0.22);
  border-radius: 999px;
  padding: 7px 10px;
  color: #edf8f5;
  white-space: nowrap;
}

.start-view {
  display: grid;
  min-height: calc(100vh - 78px);
  place-items: center;
  padding: 28px;
}

.launch-hero {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 260px;
  gap: 18px;
  width: min(1120px, 100%);
  margin-bottom: 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 26px;
  background: var(--surface);
  box-shadow: var(--shadow);
}

.launch-hero h2 {
  max-width: 780px;
  font-size: 34px;
}

.hero-copy {
  max-width: 760px;
  margin: 12px 0 0;
  color: var(--muted);
  font-size: 16px;
  line-height: 1.55;
}

.hero-actions {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  margin-top: 18px;
}

.launch-card {
  display: grid;
  align-content: center;
  gap: 6px;
  border: 1px solid color-mix(in srgb, var(--gold) 45%, var(--line));
  border-radius: 8px;
  padding: 18px;
  background: color-mix(in srgb, var(--gold) 9%, var(--surface));
}

.launch-card strong {
  color: var(--accent-2);
  font-size: 34px;
}

.launch-card span,
.launch-card small {
  color: var(--muted);
}

.offer-strip {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
  width: min(1120px, 100%);
  margin-bottom: 18px;
}

.offer-strip span {
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 12px 14px;
  background: var(--surface);
  color: var(--muted);
  box-shadow: var(--shadow);
}

.offer-strip strong {
  display: block;
  color: var(--ink);
}

.price-label {
  color: var(--accent) !important;
  font-size: 12px;
  font-weight: 800;
  text-transform: uppercase;
}

.home-grid {
  display: grid;
  grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.1fr);
  gap: 18px;
  width: min(1120px, 100%);
}

.secondary-grid {
  margin-top: 18px;
}

.start-panel,
.setup-panel,
.smart-panel,
.progress-panel,
.subject-panel,
.interactive-panel,
.pricing-panel {
  min-height: 100%;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 24px;
  background: var(--surface);
  box-shadow: var(--shadow);
}

.start-panel h2,
.setup-panel h2,
.smart-panel h2,
.progress-panel h2,
.subject-panel h2,
.interactive-panel h2,
.pricing-panel h2 {
  margin-bottom: 18px;
  font-size: 28px;
}

.subject-panel,
.interactive-panel,
.pricing-panel {
  width: min(1120px, 100%);
  margin-top: 18px;
}

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

.workflow-grid article {
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 16px;
  background: var(--panel);
}

.workflow-grid span {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 34px;
  height: 34px;
  margin-bottom: 12px;
  border-radius: 50%;
  background: var(--accent);
  color: var(--surface);
  font-size: 13px;
  font-weight: 800;
}

.workflow-grid h3 {
  margin-bottom: 8px;
  font-size: 18px;
}

.workflow-grid p,
.unlock-grid p,
.comparison-panel p {
  margin: 0;
  color: var(--muted);
  line-height: 1.5;
}

.unlock-grid {
  display: grid;
  gap: 10px;
  margin-top: 14px;
}

.unlock-grid details {
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 14px 16px;
  background: var(--surface);
}

.unlock-grid summary {
  cursor: pointer;
  font-weight: 800;
}

.unlock-grid details p {
  margin-top: 10px;
}

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

.pricing-grid article {
  display: grid;
  align-content: start;
  gap: 10px;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 16px;
  background: var(--panel);
}

.pricing-grid h3 {
  font-size: 18px;
}

.pricing-grid strong {
  color: var(--accent);
  font-size: 30px;
}

.pricing-grid p {
  margin: 0;
  color: var(--muted);
  line-height: 1.5;
}

.plan-badge {
  justify-self: start;
  border: 1px solid color-mix(in srgb, var(--accent) 35%, var(--line));
  border-radius: 999px;
  padding: 4px 8px;
  background: color-mix(in srgb, var(--accent) 8%, var(--surface));
  color: var(--accent);
  font-size: 12px;
  font-weight: 800;
  text-transform: uppercase;
}

.plan-badge.value {
  border-color: color-mix(in srgb, var(--gold) 45%, var(--line));
  background: color-mix(in srgb, var(--gold) 10%, var(--surface));
  color: var(--accent-2);
}

.featured-plan {
  border-color: color-mix(in srgb, var(--accent) 45%, var(--line)) !important;
  background: color-mix(in srgb, var(--accent) 7%, var(--surface)) !important;
}

.secondary-link-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 38px;
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 8px 14px;
  background: var(--surface);
  text-decoration: none;
}

.comparison-panel {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin-top: 14px;
}

.comparison-panel div {
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 14px 16px;
  background: var(--surface);
}

.comparison-panel strong {
  display: block;
  margin-bottom: 6px;
}

.disclaimer {
  margin: 14px 0 0;
  color: var(--muted);
  font-size: 12px;
  line-height: 1.5;
}

.section-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.subject-tiles {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(170px, 1fr));
  gap: 10px;
}

.subject-tile {
  display: grid;
  grid-template-columns: 12px minmax(0, 1fr) auto;
  align-items: center;
  gap: 9px;
  min-height: 54px;
  padding: 10px 12px;
  text-align: left;
  border-top: 3px solid var(--tile-color);
}

.subject-tile:hover {
  border-color: var(--tile-color);
  transform: translateY(-1px);
}

.subject-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--tile-color);
}

.subject-name {
  overflow: hidden;
  font-weight: 800;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.subject-count {
  color: var(--muted);
  font-size: 12px;
  font-weight: 700;
  white-space: nowrap;
}

.collection-grid,
.progress-metrics,
.paper-progress {
  display: grid;
  gap: 10px;
}

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

.progress-metrics {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.progress-metrics span,
.paper-progress span {
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 10px;
  background: var(--panel);
  color: var(--muted);
}

.progress-metrics strong {
  display: block;
  color: var(--ink);
  font-size: 22px;
}

.progress-bar {
  height: 10px;
  overflow: hidden;
  margin: 14px 0;
  border-radius: 999px;
  background: #dbe7e4;
}

.progress-bar span {
  display: block;
  width: 0;
  height: 100%;
  border-radius: inherit;
  background: var(--accent);
}

.paper-progress {
  grid-template-columns: repeat(2, minmax(0, 1fr));
  font-size: 13px;
}

.start-actions,
.setup-actions,
.toolbar-actions {
  display: flex;
  align-items: center;
  gap: 10px;
}

.start-actions,
.setup-actions {
  justify-content: flex-end;
  margin-top: 14px;
}

.primary-button {
  border-color: var(--accent);
  background: var(--accent);
  color: #fff;
  font-weight: 750;
}

.primary-button:hover {
  border-color: #0b5751;
  background: #0b5751;
}

.results-view {
  min-height: calc(100vh - 78px);
  padding: 24px;
}

.results-shell {
  display: flex;
  min-height: calc(100vh - 126px);
  flex-direction: column;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #f9fbfa;
}

[data-theme="dark"] .results-shell {
  background: #101d1a;
}

.study-toolbar {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 12px;
  padding: 14px 16px;
  border-bottom: 1px solid var(--line);
}

.filter-chips {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
  min-height: 44px;
  padding: 10px 16px;
  border-bottom: 1px solid var(--line);
  background: var(--panel);
}

.filter-chips button {
  min-height: 30px;
  padding: 4px 10px;
  border-color: color-mix(in srgb, var(--accent) 45%, var(--line));
  border-radius: 999px;
  background: var(--surface);
  color: var(--accent);
  font-size: 12px;
  font-weight: 750;
}

.filter-chips button span {
  margin-left: 4px;
  color: var(--muted);
}

.empty-chips {
  color: var(--muted);
  font-size: 12px;
}

.study-toolbar span,
#filter-preview-count,
#search-preview-count {
  display: block;
  color: var(--muted);
  font-size: 12px;
}

.study-toolbar strong {
  display: block;
  margin-top: 4px;
  font-size: 16px;
}

.results-shell > .mode-row {
  margin: 0;
  padding: 12px 16px;
  border-bottom: 1px solid var(--line);
}

.search-panel {
  padding: 16px;
  border-bottom: 1px solid var(--line);
}

.field-label {
  display: block;
  margin-bottom: 6px;
  color: var(--muted);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0;
}

input,
select {
  width: 100%;
  min-height: 42px;
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 9px 11px;
  background: var(--surface);
  color: var(--ink);
}

.filter-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
  margin-top: 12px;
}

.filter-summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  margin-top: 12px;
  color: var(--muted);
  font-size: 12px;
}

#active-filters {
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

#clear-filters,
#clear-progress {
  min-height: 30px;
  padding: 4px 8px;
  font-size: 13px;
  white-space: nowrap;
}

.mode-row {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px;
  margin-top: 14px;
}

.mode-button.active {
  border-color: var(--accent);
  background: #e4f3ef;
  color: #0b5751;
  font-weight: 700;
}

.list-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 16px;
  color: var(--muted);
  font-size: 13px;
}

.question-list {
  margin: 0;
  padding: 0;
  list-style: none;
  overflow: auto;
  flex: 1;
}

.question-card {
  display: grid;
  grid-template-columns: 42px minmax(0, 1fr);
  gap: 10px;
  width: 100%;
  padding: 14px 18px;
  border: 0;
  border-top: 1px solid var(--line);
  border-radius: 0;
  text-align: left;
  background: transparent;
}

.question-card.active {
  background: #e8f5f2;
}

.q-num {
  display: inline-grid;
  place-items: center;
  width: 34px;
  height: 34px;
  border-radius: 50%;
  background: #dfe9e6;
  color: #29443f;
  font-size: 12px;
  font-weight: 800;
}

.q-title {
  display: block;
  color: var(--ink);
  font-weight: 750;
  line-height: 1.32;
}

.q-meta {
  display: block;
  margin-top: 4px;
  color: var(--muted);
  font-size: 12px;
  line-height: 1.35;
}

.pagination {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  flex-wrap: wrap;
  padding: 12px 16px;
  border-top: 1px solid var(--line);
  background: var(--surface);
}

.pagination button {
  min-width: 38px;
  min-height: 34px;
  padding: 4px 10px;
  font-size: 13px;
}

.pagination button.active {
  border-color: var(--accent);
  background: var(--accent);
  color: #fff;
  font-weight: 800;
}

.pagination button:disabled {
  cursor: not-allowed;
  opacity: 0.45;
}

.page-gap {
  color: var(--muted);
  padding: 0 2px;
}

#bookmark-button {
  width: 42px;
  font-size: 22px;
  line-height: 1;
}

#bookmark-button.active {
  color: var(--gold);
  border-color: #d9a441;
  background: #fff7df;
}

#studied-button.active {
  border-color: var(--accent);
  background: #e4f3ef;
  color: #0b5751;
  font-weight: 750;
}

.hidden {
  display: none !important;
}

.answer-view {
  min-height: calc(100vh - 78px);
  background: var(--surface);
}

.answer-page {
  max-width: 920px;
  margin: 0 auto;
  padding: 36px 28px 28px;
}

.answer-page .source-label {
  color: var(--accent);
}

.answer-page h2 {
  max-width: 900px;
  font-size: 30px;
  line-height: 1.2;
}

.reader-controls {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-top: 16px;
}

.reader-hint {
  margin: 8px 0 0;
  color: var(--muted);
  font-size: 12px;
}

.answer-content {
  padding-top: 10px;
}

.answer-bottom-nav {
  display: flex;
  justify-content: center;
  gap: 10px;
  max-width: 920px;
  margin: 0 auto;
  padding: 16px 28px 28px;
  border-top: 1px solid var(--line);
  background: var(--surface);
}

[data-theme="dark"] .answer-bottom-nav {
  background: var(--surface);
}

.answer-bottom-nav button:disabled {
  cursor: not-allowed;
  opacity: 0.45;
}

.section {
  margin-top: 24px;
}

.section h3 {
  margin-bottom: 10px;
  color: #0f3f39;
  font-size: 18px;
}

.answer-content p,
.answer-content li,
.answer-content td,
.answer-content th {
  font-size: var(--reader-font-size);
  line-height: var(--reader-line-height);
}

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

.answer-content ul {
  margin: 0;
  padding-left: 22px;
}

.answer-content li {
  margin-bottom: 8px;
}

.callout {
  padding: 14px 16px;
  border-left: 4px solid var(--accent);
  border-radius: 0 8px 8px 0;
  background: var(--panel);
}

.mindmap {
  border-left-color: var(--accent-2);
  background: #fff7ed;
}

table {
  width: 100%;
  border-collapse: collapse;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 8px;
}

th,
td {
  border-bottom: 1px solid var(--line);
  padding: 10px 12px;
  text-align: left;
  vertical-align: top;
}

th {
  background: #e9f1ef;
  color: #173c37;
}

tr:last-child td {
  border-bottom: 0;
}

.diagram {
  max-width: 720px;
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  box-shadow: var(--shadow);
}

.empty-state {
  padding: 20px;
  color: var(--muted);
}

mark {
  background: #fde68a;
  color: inherit;
  padding: 0 2px;
}

@media (max-width: 900px) {
  .topbar {
    align-items: flex-start;
    flex-direction: column;
  }

  .topbar-actions,
  .stats {
    justify-content: flex-start;
  }

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

  .launch-hero,
  .offer-strip,
  .workflow-grid,
  .comparison-panel,
  .pricing-grid {
    grid-template-columns: 1fr;
  }

  .results-shell {
    min-height: auto;
  }

  #studied-button {
    flex: 1;
  }
}

@media (max-width: 560px) {
  body {
    overflow-x: hidden;
  }

  .topbar,
  .answer-page {
    padding-left: 16px;
    padding-right: 16px;
  }

  .start-view {
    align-items: start;
    padding: 16px;
  }

  .start-panel,
  .setup-panel,
  .smart-panel,
  .progress-panel,
  .subject-panel,
  .interactive-panel,
  .pricing-panel,
  .launch-hero {
    padding: 18px;
  }

  .start-panel h2,
  .setup-panel h2,
  .smart-panel h2,
  .progress-panel h2,
  .subject-panel h2,
  .interactive-panel h2,
  .pricing-panel h2,
  .launch-hero h2 {
    font-size: 22px;
  }

  .start-actions,
  .setup-actions,
  .study-toolbar {
    align-items: stretch;
    flex-direction: column;
  }

  .topbar-actions,
  .theme-control,
  .theme-control select {
    width: 100%;
  }

  .theme-control {
    align-items: stretch;
    flex-direction: column;
  }

  .start-actions button,
  .setup-actions button,
  .toolbar-actions,
  .toolbar-actions button {
    width: 100%;
  }

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

  .filter-summary {
    align-items: stretch;
    flex-direction: column;
  }

  .collection-grid,
  .progress-metrics,
  .paper-progress {
    grid-template-columns: 1fr;
  }

  .subject-tiles {
    grid-template-columns: 1fr;
  }

  .results-view {
    min-height: calc(100vh - 168px);
    padding: 10px;
  }

  .results-shell {
    min-height: calc(100vh - 188px);
    border-radius: 6px;
  }

  .filter-chips,
  .results-shell > .mode-row,
  .list-meta,
  .study-toolbar {
    padding-left: 12px;
    padding-right: 12px;
  }

  .question-card {
    grid-template-columns: 34px minmax(0, 1fr);
    gap: 8px;
    min-height: auto;
    padding: 13px 12px;
  }

  .q-num {
    width: 30px;
    height: 30px;
    font-size: 11px;
  }

  .q-title {
    font-size: 14px;
    overflow-wrap: anywhere;
  }

  .q-meta {
    overflow-wrap: anywhere;
  }

  .pagination {
    justify-content: flex-start;
    overflow-x: auto;
    flex-wrap: nowrap;
    padding: 10px 12px;
  }

  .pagination button {
    flex: 0 0 auto;
  }

  .reader-controls button {
    flex: 1 1 calc(50% - 8px);
  }

  .answer-page h2 {
    font-size: 20px;
  }

  .answer-bottom-nav {
    display: grid;
    grid-template-columns: 1fr 1fr;
    padding: 14px 16px 22px;
  }
}

@media print {
  .topbar,
  .reader-controls,
  .answer-bottom-nav {
    display: none !important;
  }

  body {
    background: #fff;
  }

  .answer-view,
  .answer-page {
    min-height: auto;
    padding: 0;
  }

  .answer-page {
    max-width: none;
    margin: 0;
  }

  .diagram {
    max-width: 100%;
    box-shadow: none;
  }
}