:root {
  color-scheme: light;
  --navy-950: #102a33;
  --navy-800: #173f4a;
  --teal-700: #126b68;
  --teal-600: #17817c;
  --teal-100: #d9f0ed;
  --sand-100: #f5f1e8;
  --sand-50: #fbfaf6;
  --white: #ffffff;
  --ink: #17262b;
  --muted: #52666d;
  --line: #c9d4d5;
  --success: #176b45;
  --success-bg: #e6f5ec;
  --warning: #7a4d05;
  --warning-bg: #fff4d6;
  --danger: #a23232;
  --danger-bg: #fdeaea;
  --focus: #ef8f00;
  --shadow: 0 18px 45px rgba(16, 42, 51, 0.12);
  --radius-lg: 1.25rem;
  --radius-md: 0.75rem;
  --font-scale: 1;
  font-family: Inter, Aptos, "Segoe UI", Arial, sans-serif;
  font-size: calc(100% * var(--font-scale));
}

* {
  box-sizing: border-box;
}

html {
  min-width: 320px;
  background: var(--sand-50);
}

body {
  min-height: 100vh;
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at 8% 4%, rgba(23, 129, 124, 0.12), transparent 27rem),
    linear-gradient(180deg, var(--sand-50), #f5f8f6 70%);
  line-height: 1.55;
}

button,
input,
select {
  font: inherit;
}

button,
select,
input[type="file"],
input[type="checkbox"],
input[type="radio"] {
  cursor: pointer;
}

button:focus-visible,
input:focus-visible,
select:focus-visible,
[tabindex]:focus-visible {
  outline: 0.2rem solid var(--focus);
  outline-offset: 0.18rem;
}

[hidden] {
  display: none !important;
}

.skip-link {
  position: fixed;
  z-index: 100;
  top: 0.5rem;
  left: 0.5rem;
  padding: 0.75rem 1rem;
  color: var(--white);
  background: var(--navy-950);
  border-radius: 0.5rem;
  transform: translateY(-160%);
}

.skip-link:focus {
  transform: translateY(0);
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  max-width: 92rem;
  margin: 0 auto;
  padding: 1.25rem clamp(1rem, 4vw, 4rem);
  border-bottom: 1px solid rgba(23, 63, 74, 0.14);
}

.brand-block p,
.site-footer p {
  margin: 0;
}

.eyebrow,
.step-marker,
.meta-label {
  margin: 0 0 0.25rem;
  color: var(--teal-700);
  font-size: 0.75rem;
  font-weight: 800;
  letter-spacing: 0.09em;
  text-transform: uppercase;
}

.brand-name {
  color: var(--navy-950);
  font-size: clamp(1.1rem, 2vw, 1.45rem);
  font-weight: 850;
  line-height: 1.1;
}

.brand-subtitle {
  color: var(--muted);
  font-size: 0.88rem;
}

.header-actions,
.activity-actions,
.summary-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.button,
.icon-button {
  min-height: 2.75rem;
  padding: 0.65rem 1rem;
  border: 2px solid transparent;
  border-radius: 0.65rem;
  font-weight: 750;
  transition: background-color 160ms ease, border-color 160ms ease, transform 160ms ease;
}

.button:hover:not(:disabled),
.icon-button:hover:not(:disabled) {
  transform: translateY(-1px);
}

.button:disabled {
  cursor: not-allowed;
  opacity: 0.55;
}

.button-primary {
  color: var(--white);
  background: var(--teal-700);
}

.button-primary:hover:not(:disabled) {
  background: #0d5a58;
}

.button-secondary {
  color: var(--navy-950);
  background: var(--white);
  border-color: var(--navy-800);
}

.button-quiet {
  color: var(--navy-800);
  background: transparent;
  border-color: var(--line);
}

.button-small {
  min-height: 2.75rem;
  padding: 0.45rem 0.7rem;
  font-size: 0.9rem;
}

.button-wide {
  width: 100%;
}

.icon-button {
  min-width: 2.75rem;
  padding: 0.35rem;
  color: var(--navy-950);
  background: var(--white);
  border-color: var(--line);
  font-size: 1.5rem;
}

main {
  min-height: calc(100vh - 13rem);
}

.view {
  width: min(92rem, 100%);
  margin: 0 auto;
  padding: clamp(2rem, 6vw, 5rem) clamp(1rem, 4vw, 4rem);
}

.intro-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(20rem, 0.85fr);
  align-items: center;
  gap: clamp(2rem, 7vw, 7rem);
}

.intro-copy h1,
.activity-heading h1,
.summary-card h1,
.teacher-heading h1 {
  max-width: 16ch;
  margin: 0.65rem 0 1rem;
  color: var(--navy-950);
  font-size: clamp(2rem, 5vw, 4.6rem);
  line-height: 1.02;
  letter-spacing: -0.035em;
}

.activity-heading h1,
.summary-card h1,
.teacher-heading h1 {
  max-width: none;
  font-size: clamp(1.8rem, 3.2vw, 3rem);
}

.lead,
.lead-small {
  max-width: 62ch;
  margin: 0;
  color: var(--muted);
  font-size: clamp(1.05rem, 1.8vw, 1.3rem);
}

.lead-small {
  font-size: 1.05rem;
}

.status-pill {
  display: inline-block;
  margin: 0;
  padding: 0.45rem 0.7rem;
  color: var(--navy-950);
  background: var(--teal-100);
  border-radius: 99rem;
  font-size: 0.83rem;
  font-weight: 800;
}

.trust-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.7rem 1.4rem;
  margin: 2rem 0 0;
  padding: 0;
  list-style: none;
  color: var(--navy-800);
  font-weight: 700;
}

.trust-list li::before {
  content: "✓";
  margin-right: 0.45rem;
  color: var(--teal-700);
}

.entry-card,
.activity-card,
.summary-card,
.import-card,
.progress-card {
  background: rgba(255, 255, 255, 0.94);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
}

.entry-card {
  display: grid;
  gap: 0.85rem;
  padding: clamp(1.25rem, 3vw, 2.2rem);
}

.form-heading h2,
.panel-heading h2,
.progress-card h2 {
  margin: 0 0 0.5rem;
  color: var(--navy-950);
}

label,
legend {
  color: var(--navy-950);
  font-weight: 750;
}

input[type="text"],
select,
input[type="file"] {
  width: 100%;
  min-height: 3rem;
  padding: 0.65rem 0.75rem;
  color: var(--ink);
  background: var(--white);
  border: 2px solid var(--line);
  border-radius: 0.55rem;
}

.helper-text {
  margin: -0.35rem 0 0.4rem;
  color: var(--muted);
  font-size: 0.88rem;
}

.mode-fieldset {
  display: grid;
  gap: 0.65rem;
  margin: 0.3rem 0;
  padding: 0;
  border: 0;
}

.mode-fieldset legend {
  margin-bottom: 0.5rem;
}

.mode-option,
.switch-row {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  min-height: 3.5rem;
  padding: 0.75rem;
  background: var(--sand-50);
  border: 2px solid var(--line);
  border-radius: 0.65rem;
}

.mode-option:has(input:checked),
.switch-row:has(input:checked) {
  background: var(--teal-100);
  border-color: var(--teal-700);
}

.mode-option input,
.switch-row input {
  width: 1.35rem;
  height: 1.35rem;
  flex: 0 0 auto;
}

.mode-option span {
  display: grid;
}

.mode-option small {
  color: var(--muted);
  font-weight: 500;
}

.accessibility-panel {
  position: fixed;
  z-index: 50;
  top: 1rem;
  right: 1rem;
  width: min(38rem, calc(100% - 2rem));
  max-height: calc(100vh - 2rem);
  overflow: auto;
  padding: 1.25rem;
  background: var(--white);
  border: 2px solid var(--navy-800);
  border-radius: var(--radius-lg);
  box-shadow: 0 30px 80px rgba(16, 42, 51, 0.3);
}

.confirm-dialog {
  width: min(34rem, calc(100% - 2rem));
  padding: 1.5rem;
  color: var(--ink);
  background: var(--white);
  border: 3px solid var(--navy-800);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
}

.confirm-dialog::backdrop {
  background: rgba(16, 42, 51, 0.7);
}

.panel-heading,
.teacher-heading {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 1rem;
}

.settings-grid {
  display: grid;
  gap: 0.75rem;
  margin: 1rem 0;
}

.font-controls {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.65rem;
  padding: 0.75rem;
  border: 2px solid var(--line);
  border-radius: 0.65rem;
  font-weight: 750;
}

.font-controls span {
  margin-right: auto;
}

.session-bar {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem 2rem;
  margin-bottom: 1.25rem;
  padding: 1rem 1.25rem;
  background: var(--navy-950);
  color: var(--white);
  border-radius: var(--radius-md);
}

.session-bar > div {
  display: grid;
}

.session-bar .meta-label {
  color: #9fe1da;
}

.timer-box {
  display: flex !important;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-left: auto;
}

.activity-layout {
  display: grid;
  grid-template-columns: minmax(13rem, 18rem) minmax(0, 1fr);
  align-items: start;
  gap: 1.25rem;
}

.progress-card {
  position: sticky;
  top: 1rem;
  padding: 1.25rem;
  box-shadow: none;
}

.progress-track {
  height: 0.65rem;
  overflow: hidden;
  margin: 0.75rem 0 1rem;
  background: #e1e8e7;
  border-radius: 99rem;
}

.progress-track span {
  display: block;
  width: 0;
  height: 100%;
  background: var(--teal-600);
  transition: width 200ms ease;
}

.progress-list {
  display: grid;
  gap: 0.45rem;
  margin: 0;
  padding-left: 1.4rem;
  color: var(--muted);
  font-size: 0.9rem;
}

.progress-list .current {
  color: var(--navy-950);
  font-weight: 800;
}

.progress-list .complete {
  color: var(--success);
}

.activity-card,
.summary-card {
  min-height: 31rem;
  padding: clamp(1.25rem, 4vw, 3rem);
}

.activity-region {
  margin: 2rem 0 1rem;
}

.canonical-visual {
  margin: 1.25rem 0;
  padding: 0.75rem;
  background: var(--white);
  border: 2px solid var(--line);
  border-radius: var(--radius-md);
}

.canonical-visual img {
  display: block;
  width: 100%;
  height: auto;
  max-height: 34rem;
  object-fit: contain;
}

.canonical-visual figcaption {
  margin-top: 0.65rem;
  color: var(--muted);
  font-size: 0.9rem;
}

.concept-bridge,
.support-text {
  padding: 0.9rem 1rem;
  background: var(--teal-100);
  border-left: 0.35rem solid var(--teal-700);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
}

.tutorial-status-grid,
.state-comparison,
.diagnosis-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
  margin: 1rem 0;
}

.tutorial-status-grid p,
.state-comparison p {
  margin: 0;
  padding: 1rem;
  background: var(--sand-50);
  border: 2px solid var(--line);
  border-radius: var(--radius-md);
}

.mode-disabled {
  opacity: 0.72;
}

.challenge-card {
  margin-top: 1rem;
  padding: 1rem;
  background: var(--sand-50);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
}

.challenge-card summary {
  cursor: pointer;
  color: var(--navy-950);
  font-weight: 800;
}

.challenge-criterion {
  padding: 0.75rem;
  background: var(--teal-100);
  border-left: 0.3rem solid var(--teal-700);
}

.feedback-region {
  min-height: 1rem;
  margin: 1rem 0;
}

.choice-list {
  display: grid;
  gap: 0.75rem;
  margin: 0;
  padding: 0;
  border: 0;
}

.choice-list legend {
  margin-bottom: 0.75rem;
  font-size: 1.05rem;
}

.choice-option {
  display: flex;
  align-items: flex-start;
  gap: 0.8rem;
  min-height: 3.25rem;
  padding: 0.85rem 1rem;
  background: var(--sand-50);
  border: 2px solid var(--line);
  border-radius: var(--radius-md);
}

.choice-option:has(input:checked) {
  background: var(--teal-100);
  border-color: var(--teal-700);
}

.choice-option input {
  width: 1.35rem;
  height: 1.35rem;
  flex: 0 0 auto;
}

.classification-list,
.ordering-list,
.action-channel-grid {
  display: grid;
  gap: 0.8rem;
}

.classification-row,
.ordering-item {
  display: grid;
  grid-template-columns: minmax(10rem, 1fr) minmax(12rem, 0.7fr);
  align-items: center;
  gap: 1rem;
  min-height: 4rem;
  padding: 0.8rem 1rem;
  background: var(--sand-50);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
}

.ordering-list {
  margin: 0;
  padding: 0;
  list-style: none;
  counter-reset: order;
}

.ordering-item {
  grid-template-columns: minmax(10rem, 1fr) auto;
  counter-increment: order;
}

.ordering-item > span:first-child::before {
  content: counter(order) ". ";
  color: var(--teal-700);
  font-weight: 850;
}

.ordering-controls {
  display: flex;
  gap: 0.4rem;
}

.action-channel-grid {
  grid-template-columns: 1fr 1fr;
}

.action-channel-grid label {
  align-self: end;
}

.message-sample {
  margin: 0 0 1.5rem;
  padding: 1rem 1.25rem;
  color: var(--navy-950);
  background: var(--warning-bg);
  border-left: 0.35rem solid var(--warning);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
}

.message-sample p {
  margin: 0.25rem 0;
}

.message-sample p:first-child {
  font-weight: 800;
}

.simulation-panel,
.route-panel,
.log-panel,
.browser-simulation,
.review-detail,
.review-practice,
.mission-intro,
.time-contract {
  margin: 0 0 1.25rem;
  padding: 1rem 1.15rem;
  background: var(--sand-50);
  border: 2px solid var(--line);
  border-radius: var(--radius-md);
}

.simulation-tag {
  margin: 0 0 0.65rem;
  color: var(--teal-700);
  font-size: 0.78rem;
  font-weight: 850;
  letter-spacing: 0.08em;
}

.status-line,
.log-panel p,
.route-panel p,
.review-detail p {
  margin: 0.4rem 0;
}

.browser-simulation {
  display: grid;
  gap: 0.7rem;
  background: #f1f5f5;
  border-color: var(--navy-800);
}

.browser-simulation input {
  width: 100%;
  min-width: 0;
  min-height: 3rem;
  padding: 0.65rem 0.75rem;
  color: var(--ink);
  background: var(--white);
  border: 2px solid var(--line);
  border-radius: 0.55rem;
}

.address-segments {
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem;
}

.segment-button {
  min-height: 3rem;
  max-width: 100%;
  overflow-wrap: anywhere;
  padding: 0.65rem 0.85rem;
  color: var(--navy-950);
  background: var(--white);
  border: 2px solid var(--line);
  border-radius: 0.55rem;
  font-weight: 750;
}

.segment-button.selected,
.segment-button[aria-pressed="true"] {
  background: var(--teal-100);
  border-color: var(--teal-700);
}

.internal-result {
  margin: 0;
  padding: 0.7rem;
  background: var(--white);
  border-left: 0.3rem solid var(--teal-700);
}

.direction-diagram {
  display: grid;
  grid-template-columns: minmax(10rem, 1fr) minmax(15rem, 1.4fr) minmax(8rem, 1fr);
  align-items: center;
  gap: 1rem;
  margin-bottom: 1rem;
}

.participant-card,
.direction-control {
  padding: 1rem;
  background: var(--sand-50);
  border: 2px solid var(--line);
  border-radius: var(--radius-md);
}

.participant-card {
  color: var(--navy-950);
  font-weight: 850;
  text-align: center;
}

.direction-lines {
  display: grid;
  gap: 0.75rem;
}

.direction-control {
  display: grid;
  gap: 0.45rem;
}

.direction-control select {
  width: 100%;
  min-width: 0;
  min-height: 3rem;
}

.comparison-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
  margin-bottom: 1rem;
}

.report-card {
  padding: 1rem;
  background: var(--sand-50);
  border: 2px solid var(--line);
  border-radius: var(--radius-md);
}

.report-card h3,
.report-card p,
.mission-intro h2 {
  margin-top: 0;
}

.compact-choices {
  margin-top: 1rem;
}

.delivery-list {
  display: grid;
  gap: 0.7rem;
  padding-left: 1.5rem;
}

.delivery-list li {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.75rem;
  background: var(--sand-50);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
}

.time-contract {
  color: var(--navy-950);
  background: var(--teal-100);
  font-weight: 750;
}

.pair-counter {
  color: var(--navy-950);
  font-weight: 850;
}

.pair-board {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: clamp(1rem, 4vw, 3rem);
}

.pair-column {
  display: grid;
  align-content: start;
  gap: 0.7rem;
}

.pair-column h3 {
  margin: 0 0 0.2rem;
  color: var(--muted);
  font-size: 0.85rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.pair-item {
  width: 100%;
  min-height: 4rem;
  padding: 0.85rem;
  color: var(--navy-950);
  background: var(--white);
  border: 2px solid var(--line);
  border-radius: var(--radius-md);
  font-weight: 750;
  text-align: left;
}

.pair-item:hover,
.pair-item.selected {
  background: var(--teal-100);
  border-color: var(--teal-700);
}

.message,
.feedback-box {
  padding: 0.9rem 1rem;
  border: 2px solid currentColor;
  border-radius: var(--radius-md);
}

.message-error,
.feedback-error {
  color: var(--danger);
  background: var(--danger-bg);
}

.feedback-success {
  color: var(--success);
  background: var(--success-bg);
}

.feedback-neutral {
  color: var(--navy-800);
  background: #edf4f5;
}

.feedback-warning {
  color: var(--warning);
  background: var(--warning-bg);
}

.metric-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(8rem, 1fr));
  gap: 1rem;
  margin: 2rem 0;
}

.metric-card {
  padding: 1rem;
  background: var(--sand-50);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
}

.metric-card span,
.metric-card strong {
  display: block;
}

.metric-card span {
  color: var(--muted);
  font-size: 0.86rem;
}

.metric-card strong {
  color: var(--navy-950);
  font-size: 1.7rem;
}

.review-region {
  margin-top: 2rem;
}

.section-heading h2,
.dashboard-section h2 {
  margin-bottom: 0.35rem;
  color: var(--navy-950);
}

.section-heading p {
  margin-top: 0;
  color: var(--muted);
}

.review-card,
.dashboard-section,
.empty-state {
  margin-top: 1rem;
  padding: 1.15rem;
  background: var(--sand-50);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
}

.review-card h3,
.review-card p {
  margin-top: 0;
}

.table-scroll {
  max-width: 100%;
  overflow-x: auto;
}

table {
  width: 100%;
  border-collapse: collapse;
  background: var(--white);
}

th,
td {
  padding: 0.75rem;
  border: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}

th {
  color: var(--white);
  background: var(--navy-800);
}

tbody tr:nth-child(even) {
  background: var(--sand-50);
}

.teacher-view {
  display: grid;
  gap: 1.5rem;
}

.import-card {
  padding: 1.25rem;
  box-shadow: none;
}

.teacher-dashboard {
  display: grid;
  gap: 1rem;
}

.site-footer {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  padding: 1.25rem clamp(1rem, 4vw, 4rem);
  color: #d9ecea;
  background: var(--navy-950);
  font-size: 0.85rem;
}

body[data-contrast="high"] {
  --sand-50: #ffffff;
  --sand-100: #ffffff;
  --ink: #000000;
  --muted: #202020;
  --navy-950: #000000;
  --navy-800: #000000;
  --teal-700: #005a55;
  --line: #000000;
  --focus: #ff7a00;
  background: #ffffff;
}

body[data-contrast="high"] .canonical-visual,
body[data-contrast="high"] .choice-option,
body[data-contrast="high"] .ordering-item,
body[data-contrast="high"] .classification-row {
  border-width: 3px;
}

body[data-reduce-motion="true"] *,
body[data-reduce-motion="true"] *::before,
body[data-reduce-motion="true"] *::after {
  scroll-behavior: auto !important;
  animation-duration: 0.001ms !important;
  animation-iteration-count: 1 !important;
  transition-duration: 0.001ms !important;
}

@media (max-width: 62rem) {
  .intro-grid,
  .activity-layout {
    grid-template-columns: 1fr;
  }

  .progress-card {
    position: static;
  }

  .progress-list {
    grid-template-columns: repeat(auto-fit, minmax(9rem, 1fr));
  }
}

@media (max-width: 44rem) {
  .site-header,
  .site-footer,
  .teacher-heading {
    align-items: stretch;
    flex-direction: column;
  }

  .header-actions .button {
    flex: 1;
  }

  .view {
    padding-top: 2rem;
  }

  .intro-copy h1 {
    font-size: clamp(2rem, 11vw, 3.2rem);
  }

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

  .timer-box {
    width: 100%;
    margin-left: 0;
  }

  .classification-row,
  .ordering-item,
  .action-channel-grid,
  .direction-diagram,
  .comparison-grid,
  .tutorial-status-grid,
  .state-comparison,
  .diagnosis-grid {
    grid-template-columns: 1fr;
  }

  .delivery-list li {
    align-items: stretch;
    flex-direction: column;
  }

  .ordering-controls .button {
    flex: 1;
  }

  .pair-board {
    gap: 0.65rem;
  }

  .pair-item {
    min-height: 4.5rem;
    padding: 0.65rem;
    font-size: 0.92rem;
  }
}

@media print {
  .site-header,
  .site-footer,
  .accessibility-panel,
  .summary-actions,
  .button {
    display: none !important;
  }

  body {
    background: #ffffff;
  }

  .view,
  .summary-card {
    width: 100%;
    margin: 0;
    padding: 0;
    border: 0;
    box-shadow: none;
  }
}