:root {
  color-scheme: light;
  --bg: #f4f6f2;
  --surface: #ffffff;
  --surface-soft: #eef2ed;
  --ink: #17201b;
  --muted: #62706a;
  --line: #d8dfd9;
  --primary: #2f6f5e;
  --primary-strong: #214f43;
  --blue: #315f88;
  --blue-soft: #edf4fa;
  --amber: #9a661b;
  --danger: #a33a30;
  --shadow: 0 14px 36px rgba(33, 47, 40, .10);
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
html { min-height: 100%; }
body {
  margin: 0;
  min-height: 100%;
  background: var(--bg);
  color: var(--ink);
  font-family: ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  letter-spacing: 0;
}

button, input, textarea { font: inherit; }
button, input, textarea {
  border-radius: 8px;
  border: 1px solid var(--line);
}
button {
  min-height: 44px;
  padding: 0 14px;
  background: var(--surface);
  color: var(--ink);
  cursor: pointer;
}
button:hover { border-color: var(--primary); }
button:disabled { cursor: wait; opacity: .72; }
button:focus-visible,
input:focus-visible,
textarea:focus-visible {
  outline: 3px solid rgba(47, 111, 94, .28);
  outline-offset: 2px;
}
button.primary {
  background: var(--primary);
  border-color: var(--primary);
  color: #fff;
  font-weight: 750;
}
button.primary:hover { background: var(--primary-strong); }
input, textarea {
  width: 100%;
  min-height: 44px;
  background: #fff;
  padding: 10px 12px;
  color: var(--ink);
}
textarea { resize: vertical; line-height: 1.55; }
label {
  font-size: 14px;
  font-weight: 750;
  color: #405047;
}
img { max-width: 100%; display: block; }

.shell {
  min-height: 100vh;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
}
.main {
  min-width: 0;
  padding: 20px 20px 34px;
}
.main:focus { outline: none; }
.topbar {
  max-width: 960px;
  margin: 0 auto 12px;
  display: flex;
  justify-content: space-between;
  gap: 16px;
  align-items: center;
}
.eyebrow {
  margin: 0;
  color: var(--primary-strong);
  font-size: 12px;
  font-weight: 850;
  text-transform: uppercase;
}
.topbar h1 {
  margin: 2px 0 0;
  font-size: 28px;
  line-height: 1.15;
}
.connection-state {
  min-height: 32px;
  display: inline-flex;
  align-items: center;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--surface);
  color: var(--muted);
  padding: 0 12px;
  font-size: 13px;
  font-weight: 750;
  white-space: nowrap;
}

.view { display: none; }
.view.active { display: block; }
.panel {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 8px;
  box-shadow: var(--shadow);
  padding: 18px;
}
.child-panel {
  max-width: 960px;
  margin: 0 auto;
  padding: 22px;
  box-shadow: 0 8px 24px rgba(31, 44, 39, .08);
}
.panel-head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 16px;
}
.child-panel h2 {
  margin: 2px 0 0;
  font-size: 26px;
  line-height: 1.2;
}
.pill {
  display: inline-flex;
  align-items: center;
  min-height: 32px;
  padding: 0 12px;
  border-radius: 999px;
  background: var(--blue-soft);
  color: var(--blue);
  font-weight: 750;
  font-size: 13px;
  white-space: nowrap;
}

.child-progress {
  display: grid;
  gap: 8px;
  margin: -4px 0 14px;
}
.child-progress > div:first-child {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  color: var(--muted);
  font-size: 13px;
  font-weight: 750;
}
.progress-track {
  height: 8px;
  border-radius: 999px;
  background: var(--surface-soft);
  overflow: hidden;
}
.progress-track span {
  display: block;
  height: 100%;
  width: 0;
  border-radius: inherit;
  background: var(--primary);
  transition: width .18s ease;
}
.error-panel {
  border: 1px solid rgba(154, 102, 27, .38);
  border-left: 4px solid var(--amber);
  border-radius: 8px;
  padding: 12px;
  margin: 0 0 14px;
  background: #fffaf0;
  display: grid;
  gap: 8px;
}
.error-panel:focus {
  outline: 3px solid rgba(154, 102, 27, .22);
  outline-offset: 2px;
}
.error-panel strong {
  font-size: 17px;
  line-height: 1.35;
}
.error-panel p {
  margin: 0;
  color: #4d4639;
  line-height: 1.55;
}
.error-action {
  justify-self: start;
  min-width: 136px;
  font-weight: 800;
  background: #fff;
}
.handoff-state {
  border: 1px solid var(--primary);
  border-radius: 8px;
  padding: 12px;
  margin-bottom: 14px;
  background: #eef7f2;
  display: grid;
  gap: 8px;
}
.handoff-state strong { font-size: 18px; }
.handoff-state span {
  color: var(--muted);
  line-height: 1.5;
}
.coach-points {
  display: grid;
  gap: 8px;
}
.review-points {
  display: grid;
  gap: 8px;
}
.review-points-title {
  font-size: 13px;
  font-weight: 850;
  color: var(--primary-strong);
}
.review-point {
  border: 1px solid rgba(49, 95, 136, .22);
  border-radius: 8px;
  background: #fbfdff;
  padding: 10px 12px;
}
.review-point strong {
  display: block;
  font-size: 14px;
  margin-bottom: 4px;
}
.review-point p {
  margin: 0;
  color: #34433b;
  line-height: 1.55;
}
.coach-point {
  border: 1px solid rgba(47, 111, 94, .18);
  border-radius: 8px;
  background: #fff;
  padding: 10px 12px;
}
.coach-point strong {
  display: block;
  font-size: 14px;
  margin-bottom: 4px;
}
.coach-point p {
  margin: 0;
  color: #34433b;
  line-height: 1.55;
}
.start-next {
  justify-self: start;
  margin-top: 2px;
}

.task-content {
  border: 1px solid var(--line);
  background: #fbfcf9;
  border-radius: 8px;
  padding: 16px;
  line-height: 1.65;
  margin-bottom: 16px;
  font-size: 16px;
}
.task-content p { margin: 8px 0; }
.child-support { display: grid; gap: 12px; }
.support-tabs {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 8px;
}
.support-tab {
  min-height: 44px;
  padding: 0 10px;
  font-weight: 800;
  background: #fff;
}
.support-tab.active {
  border-color: var(--primary);
  background: #eef7f2;
  color: var(--primary-strong);
}
.support-card { display: grid; gap: 8px; }
.support-card p { margin: 0; }
.support-title {
  margin: 0;
  font-weight: 900;
  font-size: 19px;
}
.thinking-line { color: #26332d; }
.question-block {
  border-left: 4px solid var(--blue);
  padding: 8px 0 8px 12px;
  background: linear-gradient(90deg, rgba(49, 95, 136, .08), rgba(49, 95, 136, 0));
}
.question-block-label {
  display: block;
  color: var(--blue);
  font-size: 13px;
  font-weight: 850;
  margin-bottom: 4px;
}
.question-block p { line-height: 1.65; }
.v5-teaching-sections {
  display: grid;
  gap: 10px;
  margin-top: 4px;
}
.v5-teaching-section {
  border-top: 1px solid var(--line);
  padding-top: 10px;
  display: grid;
  gap: 6px;
}
.v5-teaching-section h3 {
  margin: 0;
  font-size: 16px;
  line-height: 1.35;
  color: var(--primary-strong);
}
.v5-teaching-section p {
  margin: 0;
  line-height: 1.65;
}
.teaching-problem {
  color: #26332d;
  font-weight: 650;
}
.teaching-steps,
.teaching-points {
  margin: 0;
  padding-left: 22px;
  line-height: 1.65;
}
.teaching-steps li + li,
.teaching-points li + li {
  margin-top: 3px;
}
.teaching-check {
  border-left: 4px solid var(--primary);
  padding: 7px 0 7px 10px;
  background: linear-gradient(90deg, rgba(47, 111, 94, .08), rgba(47, 111, 94, 0));
}
.knowledge-card-runtime {
  display: grid;
  gap: 10px;
  margin-top: 4px;
}
.knowledge-card-component {
  display: grid;
  gap: 7px;
  padding-top: 10px;
  border-top: 1px solid var(--line);
}
.knowledge-card-component h3 {
  margin: 0;
  color: var(--primary-strong);
  font-size: 16px;
  line-height: 1.35;
}
.knowledge-card-component p {
  margin: 0;
  line-height: 1.65;
}
.knowledge-card-component.is-warning {
  border-left: 4px solid #a16a16;
  padding: 9px 0 9px 12px;
  border-top: 0;
  background: linear-gradient(90deg, rgba(161, 106, 22, .1), rgba(161, 106, 22, 0));
}
.knowledge-card-number-line {
  display: grid;
  gap: 12px;
  padding: 14px 10px 10px;
  border-top: 1px solid var(--line);
}
.knowledge-card-number-line p {
  margin: 0;
  color: var(--muted);
  line-height: 1.55;
}
.number-line-track {
  position: relative;
  height: 76px;
  margin: 4px 4px 0;
}
.number-line-track::before {
  content: "";
  position: absolute;
  right: 0;
  left: 0;
  top: 34px;
  border-top: 3px solid #315f88;
}
.number-line-track::after {
  content: "";
  position: absolute;
  top: 28px;
  right: -1px;
  width: 12px;
  height: 12px;
  border-top: 3px solid #315f88;
  border-right: 3px solid #315f88;
  transform: rotate(45deg);
}
.number-line-tick,
.number-line-point {
  position: absolute;
  top: 0;
  transform: translateX(-50%);
}
.number-line-tick i {
  display: block;
  width: 2px;
  height: 18px;
  margin: 26px auto 2px;
  background: #315f88;
}
.number-line-tick b,
.number-line-point b {
  display: block;
  color: var(--muted);
  font-size: 12px;
  font-weight: 850;
  text-align: center;
}
.number-line-point {
  top: 11px;
  z-index: 2;
}
.number-line-point i {
  display: block;
  width: 16px;
  height: 16px;
  margin: 16px auto 4px;
  border: 3px solid var(--primary);
  border-radius: 50%;
  background: #fff;
  box-shadow: 0 0 0 4px rgba(47, 111, 94, .14);
}
.number-line-point b {
  color: var(--primary-strong);
}
.row-title {
  font-weight: 850;
  display: block;
  margin-bottom: 4px;
}
.row-meta {
  color: var(--muted);
  font-size: 13px;
  line-height: 1.45;
}
.support-steps {
  margin: 0;
  padding-left: 22px;
  line-height: 1.65;
}
.support-steps li + li { margin-top: 4px; }
.interaction-answer-panel {
  display: grid;
  gap: 10px;
}
.interaction-answer-panel[hidden] { display: none; }
.child-prompt {
  white-space: pre-line;
  overflow-wrap: anywhere;
  word-break: break-word;
  max-width: 100%;
}
.math-power {
  display: inline;
  white-space: nowrap;
}
.math-power-caret {
  display: inline-block;
  width: 0;
  overflow: hidden;
  font-size: 0;
  line-height: 0;
}
.math-power sup {
  font-size: 0.72em;
  line-height: 1;
  vertical-align: super;
}
.attempt-error {
  margin: 0;
  color: #8b1e1e;
  font-weight: 750;
}
.interaction-card {
  border: 1px solid var(--line);
  background: #fbfcf9;
  border-radius: 8px;
  padding: 12px;
  display: grid;
  gap: 10px;
}
.interaction-title {
  margin: 0;
  font-weight: 850;
  color: var(--primary-strong);
}
.interaction-fields,
.interaction-choices {
  display: grid;
  gap: 10px;
}
.interaction-field {
  display: grid;
  gap: 6px;
  font-weight: 800;
}
.interaction-input-row {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  gap: 8px;
  align-items: center;
  font-weight: 650;
  color: var(--muted);
}
.interaction-field input[type="text"] {
  width: 100%;
  min-width: 0;
}
.interaction-choice {
  min-height: 44px;
  border: 1px solid var(--line);
  background: #fff;
  border-radius: 8px;
  padding: 10px 12px;
  display: grid;
  grid-template-columns: 22px minmax(0, 1fr);
  gap: 8px;
  align-items: center;
  font-weight: 750;
}
.interaction-choice input {
  width: 18px;
  height: 18px;
}
.stuck-actions {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 8px;
}
.stuck-actions button {
  height: auto;
  min-height: 44px;
  padding: 8px 10px;
  text-align: center;
  font-weight: 750;
}
.stuck-actions button.selected,
.stuck-actions button[aria-pressed="true"] {
  border-color: var(--primary);
  background: #eef7f2;
  color: var(--primary-strong);
}
.stuck-choice-panel {
  display: grid;
  gap: 8px;
  border: 1px solid rgba(154, 102, 27, .28);
  border-radius: 8px;
  background: #fffdf7;
  padding: 10px;
}
.stuck-choice-title {
  margin: 0;
  color: #5c4a24;
  font-size: 13px;
  font-weight: 850;
}
.stuck-cancel {
  justify-self: start;
  min-height: 44px;
  color: var(--primary-strong);
  font-weight: 800;
}

.answer-input-mode {
  display: grid;
  gap: 8px;
}
.answer-input-mode-label {
  color: #405047;
  font-size: 14px;
  font-weight: 800;
}
.segmented-control {
  display: grid;
  grid-auto-flow: column;
  grid-auto-columns: minmax(0, 1fr);
  gap: 6px;
  width: min(360px, 100%);
  padding: 4px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface-soft);
}
.segmented-control button {
  min-width: 0;
  border-color: transparent;
  background: transparent;
  font-weight: 800;
}
.segmented-control button.active,
.segmented-control button[aria-pressed="true"] {
  border-color: #bdcbc3;
  background: #fff;
  color: var(--primary-strong);
  box-shadow: 0 1px 3px rgba(33, 47, 40, .12);
}
.recognition-panel {
  display: grid;
  gap: 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #f8faf7;
  padding: 12px;
}
#handwritingCanvas {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 5 / 2;
  border: 1px solid #aebbb3;
  border-radius: 8px;
  background: #fff;
  box-shadow: inset 0 0 0 1px rgba(49, 95, 136, .05);
  cursor: crosshair;
  touch-action: none;
}
#handwritingCanvas[aria-busy="true"] {
  pointer-events: none;
  cursor: wait;
  opacity: .72;
}
.recognition-actions {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 8px;
}
.recognition-status {
  min-height: 22px;
  margin: 0;
  color: var(--muted);
  line-height: 1.5;
}
.voice-record {
  min-height: 56px;
  justify-self: start;
  min-width: min(260px, 100%);
  border-color: var(--blue);
  color: var(--blue);
  font-weight: 850;
}
.voice-record[aria-pressed="true"] {
  border-color: var(--danger);
  background: #fff3f1;
  color: var(--danger);
}
.recognition-confirm {
  display: grid;
  gap: 10px;
  border: 1px solid #b9c9d7;
  border-left: 4px solid var(--blue);
  border-radius: 8px;
  background: #f5f9fc;
  padding: 12px;
}
.recognition-confirm textarea {
  min-height: 112px;
}
.recognition-uncertainty {
  border: 1px solid rgba(154, 102, 27, .34);
  border-radius: 8px;
  background: #fffaf0;
  color: #5c4a24;
  padding: 10px;
  line-height: 1.5;
}
.recognition-check {
  display: grid;
  grid-template-columns: 22px minmax(0, 1fr);
  gap: 8px;
  align-items: start;
  min-height: 44px;
  padding: 10px;
  border: 1px solid #c7d3dc;
  border-radius: 8px;
  background: #fff;
  cursor: pointer;
}
.recognition-check input {
  width: 20px;
  height: 20px;
  min-height: 20px;
  margin: 1px 0 0;
  padding: 0;
}
.recognition-cancel {
  justify-self: start;
  min-height: 44px;
  color: var(--muted);
}

.attempt-form { display: grid; gap: 12px; }
.photo-field { display: grid; gap: 10px; }
.photo-input-row {
  display: flex;
  gap: 10px;
  align-items: center;
  flex-wrap: wrap;
}
.visually-hidden-file {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}
.photo-picker {
  min-height: 48px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  color: var(--ink);
  padding: 0 16px;
  cursor: pointer;
}
.photo-picker:hover { border-color: var(--primary); }
.visually-hidden-file:focus-visible + .photo-picker {
  outline: 3px solid rgba(47, 111, 94, .28);
  outline-offset: 2px;
}
.photo-hint {
  color: var(--muted);
  font-size: 13px;
}
.photo-preview {
  display: grid;
  grid-template-columns: 132px minmax(0, 1fr);
  gap: 12px;
  align-items: start;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fbfcf9;
  padding: 12px;
}
.photo-preview img {
  width: 132px;
  aspect-ratio: 4 / 3;
  object-fit: cover;
  border-radius: 8px;
  border: 1px solid var(--line);
  background: var(--surface-soft);
}
.photo-preview button { margin-top: 10px; }
.form-actions {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 12px;
  flex-wrap: wrap;
}

.assessment-feedback {
  display: grid;
  gap: 14px;
  margin-top: 16px;
  padding: 16px;
  border: 1px solid #cfd8d2;
  border-left: 4px solid #2f6f5e;
  border-radius: 8px;
  background: #fff;
}
.assessment-score-row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  color: var(--muted);
}
.assessment-score-row strong {
  color: #173f34;
  font-size: 24px;
}
.assessment-feedback-list {
  display: grid;
  gap: 12px;
  margin: 0;
}
.assessment-feedback-list > div {
  display: grid;
  grid-template-columns: minmax(96px, 132px) minmax(0, 1fr);
  gap: 12px;
  padding-top: 12px;
  border-top: 1px solid #e4e8e5;
}
.assessment-feedback-list dt {
  color: #31423c;
  font-weight: 800;
}
.assessment-feedback-list dd { margin: 0; }
.assessment-feedback-list ul {
  margin: 0;
  padding-left: 20px;
}
.assessment-group-items {
  display: grid;
  gap: 4px;
}
.assessment-group-item {
  padding-top: 16px;
  border-top: 2px solid #e0e7e2;
}
.assessment-group-item-title {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 4px;
}
.assessment-group-item-title strong { color: #173f34; }
.assessment-group-item-title span {
  color: #2f6f5e;
  font-weight: 800;
}

.toast {
  position: fixed;
  left: 50%;
  bottom: 22px;
  transform: translateX(-50%);
  background: #17201b;
  color: #fff;
  border-radius: 8px;
  padding: 11px 14px;
  opacity: 0;
  pointer-events: none;
  transition: opacity .18s ease;
  z-index: 20;
}
.toast.show { opacity: 1; }

@media (max-width: 620px) {
  .main { padding: 12px; }
  .topbar {
    display: grid;
    margin-bottom: 10px;
  }
  .topbar h1 { font-size: 24px; }
  .child-panel { padding: 14px; }
  .child-panel h2 { font-size: 22px; }
  .child-panel .panel-head { align-items: center; }
  .error-action { width: 100%; }
  .stuck-actions { grid-template-columns: 1fr; }
  .segmented-control { width: 100%; }
  #handwritingCanvas {
    height: 220px;
    aspect-ratio: auto;
  }
  .recognition-actions {
    grid-template-columns: 1fr 1fr;
  }
  .recognition-actions .primary {
    grid-column: 1 / -1;
  }
  .voice-record { width: 100%; }
  .support-tab {
    min-height: 48px;
    padding: 0 8px;
  }
  #childAttemptForm .form-actions,
  #childAttemptForm .form-actions button {
    width: 100%;
  }
  .photo-preview { grid-template-columns: 1fr; }
  .photo-preview img {
    width: 100%;
    max-height: 260px;
  }
  .assessment-feedback-list > div {
    grid-template-columns: 1fr;
    gap: 4px;
  }
}

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