.powers-page {
  color-scheme: light;
  --powers-canvas: #f4f6f8;
  --powers-surface: #fff;
  --powers-soft: #eef3f1;
  --powers-ink: #17201d;
  --powers-muted: #52635c;
  --powers-border: #cbd7d2;
  --powers-control-border: #73847c;
  --powers-primary: #176b5f;
  --powers-primary-hover: #0f4d44;
  --powers-primary-active: #0b3b34;
  --powers-selected: #dcebe8;
  --powers-success: #2d6f48;
  --powers-warning: #805413;
  --powers-danger: #a33a3a;
  --powers-focus: #176b5f;
  --powers-radius: 8px;
  --powers-shadow: 0 6px 20px rgb(23 32 29 / 5%);
  --powers-gap: 1rem;
  margin: 0;
  background: var(--powers-canvas);
  color: var(--powers-ink);
  font: 400 1rem/1.55 "Segoe UI", system-ui, sans-serif;
}

.powers-page *,
.powers-page *::before,
.powers-page *::after {
  box-sizing: border-box;
}

.powers-page [hidden] {
  display: none !important;
}

.powers-shell {
  max-width: 58rem;
  margin: 0 auto;
  padding: clamp(1rem, 4vw, 2.5rem);
}

.powers-header {
  margin-bottom: 1.5rem;
}

.powers-brand {
  display: flex;
  align-items: center;
  gap: 0.65rem;
}

.powers-brand > svg {
  width: 2rem;
  height: 2rem;
  flex-shrink: 0;
  color: var(--powers-primary);
}

.powers-header h1 {
  font-size: clamp(1.8rem, 5vw, 2.4rem);
  margin: .5rem 0 0;
  letter-spacing: -.025em;
}

.powers-header p {
  margin: .25rem 0 0;
  color: var(--powers-muted);
}

.powers-page a {
  color: var(--powers-primary);
  text-underline-offset: .2em;
  display: inline-flex;
  align-items: center;
  min-height: 44px;
}

.powers-page h2 {
  font-size: 1.25rem;
  line-height: 1.5;
  margin: .5rem 0 1rem;
  overflow-wrap: anywhere;
}

.powers-page h3 {
  font-size: 1rem;
  margin: .75rem 0 .25rem;
}

.powers-panel {
  padding: clamp(1rem, 3vw, 1.75rem);
  background: var(--powers-surface);
  border: 1px solid var(--powers-border);
  border-radius: var(--powers-radius);
  box-shadow: var(--powers-shadow);
}

.powers-settings {
  display: flex;
  flex-wrap: wrap;
  gap: .75rem var(--powers-gap);
  align-items: end;
  margin-bottom: 1rem;
  position: relative;
  z-index: 1;
}

.powers-settings > .powers-field {
  min-width: 10rem;
}

.powers-settings-note {
  width: 100%;
  margin: 0;
}

.powers-settings-note:not([hidden]) {
  color: var(--powers-warning);
}

#powers-topic-summary {
  width: 100%;
  margin: 0;
}

.powers-muted {
  color: var(--powers-muted);
}

.powers-field {
  display: flex;
  flex-direction: column;
  gap: .3rem;
  font-weight: 600;
  min-width: 0;
}

.powers-page button,
.powers-page input,
.powers-page select {
  min-height: 44px;
  border: 1px solid var(--powers-control-border);
  border-radius: 6px;
  font: inherit;
  color: inherit;
  background: var(--powers-surface);
  max-width: 100%;
}

.powers-page button {
  cursor: pointer;
  padding: .55rem 1rem;
  font-weight: 600;
}

.powers-page input,
.powers-page select {
  padding: .5rem .65rem;
}

.powers-page select {
  width: 100%;
}

.powers-page input[type="text"] {
  width: 9rem;
}

.powers-page input[type="radio"],
.powers-page input[type="checkbox"] {
  width: 1.2rem;
  height: 1.2rem;
  min-height: 0;
  margin: 0;
  flex: 0 0 auto;
  accent-color: var(--powers-primary);
}

.powers-page button:hover:not(:disabled) {
  background: var(--powers-soft);
}

.powers-page button:active:not(:disabled) {
  background: var(--powers-selected);
}

.powers-page .powers-primary {
  background: var(--powers-primary);
  color: #fff;
  border-color: var(--powers-primary);
}

.powers-page .powers-primary:hover:not(:disabled) {
  background: var(--powers-primary-hover);
}

.powers-page .powers-primary:active:not(:disabled) {
  background: var(--powers-primary-active);
}

.powers-page button:disabled {
  opacity: .6;
  cursor: default;
}

.powers-page :focus-visible {
  outline: 3px solid var(--powers-focus);
  outline-offset: 3px;
}

.powers-page fieldset {
  border: 0;
  margin: 0;
  padding: 0;
  min-width: 0;
}

.powers-page legend {
  font-weight: 600;
  margin-bottom: .6rem;
  padding: 0;
}

.powers-topics {
  position: static;
}

.powers-topic-panel {
  position: absolute;
  top: calc(100% - .5rem);
  left: 1rem;
  right: 1rem;
  max-width: 26rem;
  max-height: min(70vh, 36rem);
  overflow-y: auto;
  padding: 1rem;
  background: var(--powers-surface);
  border: 1px solid var(--powers-control-border);
  border-radius: var(--powers-radius);
  box-shadow: 0 8px 24px rgb(23 32 29 / 12%);
}

.powers-topic-option {
  display: flex;
  align-items: center;
  gap: .75rem;
  min-height: 44px;
  cursor: pointer;
}

.powers-task > .powers-muted:first-child {
  margin: 0;
}

.powers-prompt {
  font-size: 1.65rem;
  padding: .5rem 0 1.25rem;
  overflow-wrap: anywhere;
}

.powers-math {
  display: inline-block;
  font-family: "Cambria Math", Cambria, serif;
  max-width: 100%;
  white-space: normal;
  vertical-align: middle;
  line-height: 1.6;
}

.powers-expression sup {
  font-size: .7em;
  line-height: 0;
  vertical-align: super;
}

.powers-fraction {
  display: inline-flex;
  max-width: 100%;
  flex-direction: column;
  align-items: stretch;
  vertical-align: middle;
  text-align: center;
  line-height: 1.4;
  gap: .15em;
}

.powers-fraction > :first-child {
  border-bottom: 1px solid currentColor;
  padding: 0 .2em .15em;
}

.powers-fraction > :last-child {
  padding: 0 .2em;
}

#powers-form {
  margin-top: 1rem;
}

#powers-controls > .powers-field input {
  width: min(100%, 24rem);
}

.powers-power-input {
  display: inline-grid;
  grid-template-columns: minmax(0, 8rem) minmax(0, 6rem);
  align-items: start;
  gap: .35rem;
  max-width: 100%;
}

.powers-base-input {
  padding-top: 2.25rem;
}

.powers-power-input input {
  width: 100%;
}

.powers-exponent-input .powers-field {
  font-size: .875rem;
}

.powers-fraction-input {
  gap: .4rem;
  max-width: 100%;
}

.powers-fraction-input > :first-child {
  padding-bottom: .6rem;
}

.powers-fraction-input > :last-child {
  padding-top: .2rem;
}

.powers-fraction-input .powers-field {
  text-align: left;
}

.powers-compound-input {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: .75rem;
}

.powers-operator {
  font-size: 1.5rem;
}

.powers-monomial-input {
  display: flex;
  align-items: end;
  flex-wrap: wrap;
  gap: 1rem;
}

.powers-variable-input {
  display: flex;
  align-items: end;
  gap: .4rem;
}

.powers-variable {
  font: italic 2rem Cambria, serif;
}

.powers-variable-input .powers-field {
  padding-bottom: 1.5rem;
}

.powers-variable-input input {
  width: 5rem;
}

.powers-choices {
  display: flex;
  flex-wrap: wrap;
  gap: .5rem;
}

.powers-choice {
  display: flex;
  align-items: center;
  gap: .75rem;
  min-height: 48px;
  padding: .55rem 1rem;
  border: 1px solid var(--powers-control-border);
  border-radius: 6px;
  cursor: pointer;
}

.powers-choice:has(input:checked) {
  background: var(--powers-selected);
  border-color: var(--powers-primary);
}

.powers-matching {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 17rem), 1fr));
  gap: 1rem;
}

.powers-matching select {
  text-overflow: ellipsis;
}

.powers-insert {
  margin-top: .5rem;
}

.powers-actions {
  display: flex;
  flex-wrap: wrap;
  gap: .75rem;
  margin-top: 1.25rem;
}

.powers-feedback {
  border-left: 3px solid var(--powers-warning);
  background: var(--powers-soft);
  border-radius: 0 6px 6px 0;
  padding: 1rem;
  margin-top: 1.25rem;
  overflow-wrap: anywhere;
}

.powers-feedback p {
  margin: 0;
}

.powers-feedback[data-status="correct"] {
  border-color: var(--powers-success);
}

.powers-feedback[data-status="incorrect"] {
  border-color: var(--powers-danger);
}

.powers-feedback ol {
  padding-left: 1.5rem;
  margin-bottom: 0;
}

.powers-feedback li + li {
  margin-top: .6rem;
}

#powers-next {
  margin-top: 1.25rem;
}

.powers-sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

@media (prefers-reduced-motion: reduce) {
  .powers-page *,
  .powers-page *::before,
  .powers-page *::after {
    animation: none !important;
    transition: none !important;
    scroll-behavior: auto !important;
  }
}

.powers-expression-root {
  display: inline-flex;
  align-items: flex-start;
  max-width: 100%;
  vertical-align: middle;
}

.powers-root-index {
  margin-right: -.18em;
  align-self: flex-start;
  font-size: .55em;
  line-height: 1;
}

.powers-root-sign {
  font-size: 1.3em;
  line-height: 1.25;
}

.powers-root-radicand {
  display: inline-block;
  max-width: 100%;
  border-top: .075em solid currentColor;
  padding: 0 .18em;
}

.powers-answer-root {
  align-self: end;
  padding-bottom: .45rem;
  font: 1.5rem "Cambria Math", Cambria, serif;
}

.powers-topic-panel fieldset + fieldset {
  margin-top: 1rem;
  padding-top: 1rem;
  border-top: 1px solid var(--powers-control-border);
}