:root {
  color-scheme: light;
  --color-canvas: oklch(98% 0.009 82);
  --color-surface: oklch(96% 0.014 82);
  --color-surface-raised: oklch(99% 0.006 82);
  --color-ink: oklch(23% 0.018 258);
  --color-ink-soft: oklch(43% 0.022 258);
  --color-ink-faint: oklch(55% 0.018 258);
  --color-border: oklch(84% 0.018 258);
  --color-border-strong: oklch(65% 0.028 258);
  --color-primary: oklch(46% 0.19 258);
  --color-primary-hover: oklch(40% 0.18 258);
  --color-primary-soft: oklch(95% 0.028 258);
  --color-primary-pressed: oklch(36% 0.16 258);
  --color-success: oklch(49% 0.13 155);
  --color-success-soft: oklch(95% 0.035 155);
  --color-attention: oklch(51% 0.105 78);
  --color-attention-soft: oklch(95% 0.038 78);
  --color-disabled: oklch(92% 0.01 258);
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.25rem;
  --text-xl: 1.5rem;
  --text-2xl: 2rem;
  --text-3xl: 2.75rem;
  --space-2xs: 0.25rem;
  --space-xs: 0.5rem;
  --space-sm: 0.75rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  --radius-sm: 0.375rem;
  --radius-md: 0.625rem;
  --radius-lg: 0.875rem;
  --shadow-selected: 0 0 0 0.25rem oklch(86% 0.055 258);
  --shadow-low: 0 0.5rem 1.75rem oklch(34% 0.02 258 / 0.08);
  --duration-instant: 120ms;
  --duration-state: 220ms;
  --ease-out-quart: cubic-bezier(0.25, 1, 0.5, 1);
  font-family: var(--font-sans);
  font-synthesis: none;
  font-kerning: normal;
  background: var(--color-canvas);
  color: var(--color-ink);
}

* {
  box-sizing: border-box;
}

html {
  min-width: 20rem;
  background: var(--color-canvas);
}

body {
  min-height: 100vh;
  margin: 0;
  background: var(--color-canvas);
  color: var(--color-ink);
  font-size: var(--text-base);
  line-height: 1.5;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

button,
input,
textarea {
  font: inherit;
}

button {
  touch-action: manipulation;
}

button:focus-visible,
input:focus-visible,
textarea:focus-visible,
a:focus-visible {
  outline: 0.1875rem solid var(--color-primary);
  outline-offset: 0.1875rem;
}

.skip-link {
  position: fixed;
  z-index: 20;
  top: var(--space-md);
  left: var(--space-md);
  transform: translateY(-200%);
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-sm);
  background: var(--color-ink);
  color: var(--color-canvas);
  font-weight: 700;
  transition: transform var(--duration-state) var(--ease-out-quart);
}

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

.app-shell {
  min-height: 100vh;
  padding: env(safe-area-inset-top) env(safe-area-inset-right) env(safe-area-inset-bottom) env(safe-area-inset-left);
}

.topbar {
  border-bottom: 0.0625rem solid var(--color-border);
  background: var(--color-surface-raised);
}

.topbar__inner {
  width: min(100%, 96rem);
  min-height: 4.75rem;
  margin: 0 auto;
  padding: var(--space-sm) var(--space-lg);
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-sm);
  align-items: center;
}

.brand-row,
.brand,
.topbar__tools,
.progress,
.actions,
.keyboard-note,
.stage-preview,
.source-fact,
.proof-line,
.upload-actions {
  display: flex;
  align-items: center;
}

.brand-row {
  justify-content: space-between;
  gap: var(--space-md);
}

.brand {
  gap: var(--space-sm);
  color: var(--color-ink);
  font-weight: 750;
  letter-spacing: -0.02em;
}

.brand__mark {
  display: grid;
  grid-template-columns: repeat(2, 0.3rem);
  gap: 0.2rem;
  height: 1.5rem;
  transform: skew(-22deg);
}

.brand__mark span {
  border-radius: 999px;
  background: var(--color-primary);
}

.brand__mark span:last-child {
  height: 70%;
  align-self: end;
  background: var(--color-success);
}

.mode-label {
  color: var(--color-ink-soft);
  font-size: var(--text-sm);
  white-space: nowrap;
}

.progress {
  justify-content: center;
  gap: var(--space-xs);
  list-style: none;
  margin: 0;
  padding: 0;
}

.progress__item {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  color: var(--color-ink-faint);
  font-size: var(--text-xs);
  font-weight: 750;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.progress__number {
  display: grid;
  width: 1.75rem;
  height: 1.75rem;
  place-items: center;
  border-radius: 50%;
  background: var(--color-disabled);
  color: var(--color-ink-soft);
  font-size: var(--text-sm);
  letter-spacing: normal;
}

.progress__item[aria-current="step"] {
  color: var(--color-primary);
}

.progress__item[aria-current="step"] .progress__number {
  background: var(--color-primary);
  color: var(--color-canvas);
}

.progress__item.is-complete {
  color: var(--color-success);
}

.progress__item.is-complete .progress__number {
  background: var(--color-success-soft);
  color: var(--color-success);
}

.progress__divider {
  color: var(--color-border-strong);
}

.topbar__tools {
  justify-content: flex-end;
  gap: var(--space-sm);
}

.text-button {
  min-height: 2.75rem;
  padding: var(--space-xs) var(--space-sm);
  border: 0;
  border-radius: var(--radius-sm);
  background: transparent;
  color: var(--color-primary);
  font-weight: 700;
  text-decoration: underline;
  text-decoration-color: var(--color-border-strong);
  text-underline-offset: 0.25em;
  cursor: pointer;
}

.text-button:hover {
  color: var(--color-primary-hover);
  text-decoration-color: currentColor;
}

.main {
  width: min(100%, 96rem);
  margin: 0 auto;
  padding: var(--space-2xl) var(--space-lg) var(--space-3xl);
}

.stage-heading {
  max-width: 64rem;
  margin-bottom: var(--space-2xl);
}

.stage-heading h1,
.completion h1,
.upload-view h1 {
  max-width: 24ch;
  margin: 0;
  font-size: var(--text-2xl);
  line-height: 1.12;
  letter-spacing: -0.035em;
  text-wrap: balance;
}

.stage-heading p,
.completion__lead,
.upload-view__lead {
  max-width: 68ch;
  margin: var(--space-md) 0 0;
  color: var(--color-ink-soft);
  font-size: var(--text-lg);
  line-height: 1.5;
  text-wrap: pretty;
}

.workspace {
  display: grid;
  gap: var(--space-xl);
}

.source-panel {
  align-self: start;
  padding: var(--space-xl);
  border-radius: var(--radius-lg);
  background: var(--color-surface);
}

.eyebrow {
  display: block;
  margin: 0 0 var(--space-lg);
  color: var(--color-ink-soft);
  font-size: var(--text-xs);
  font-weight: 800;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.source-amount {
  margin: 0 0 var(--space-xl);
  color: var(--color-ink);
  font-size: var(--text-3xl);
  font-variant-numeric: tabular-nums;
  font-weight: 720;
  line-height: 1;
  letter-spacing: -0.045em;
}

.source-facts {
  display: grid;
  gap: var(--space-md);
}

.source-fact {
  gap: var(--space-sm);
  margin: 0;
  color: var(--color-ink);
  line-height: 1.4;
}

.source-fact__icon {
  flex: 0 0 auto;
  display: grid;
  width: 2rem;
  height: 2rem;
  place-items: center;
  border-radius: 50%;
  background: var(--color-surface-raised);
  color: var(--color-primary);
  font-weight: 800;
}

.source-question {
  margin: var(--space-xl) 0 0;
  padding-top: var(--space-lg);
  border-top: 0.0625rem solid var(--color-border);
  color: var(--color-ink-soft);
}

.source-caption {
  margin: var(--space-xl) 0 0;
  padding-top: var(--space-md);
  border-top: 0.0625rem solid var(--color-border);
  color: var(--color-ink-faint);
  font-size: var(--text-sm);
}

.reasoning-panel {
  min-width: 0;
}

.step-group {
  border-top: 0.0625rem solid var(--color-border);
}

.reasoning-step {
  position: relative;
  width: 100%;
  min-height: 5.5rem;
  display: grid;
  grid-template-columns: 2.25rem 2.25rem 1fr;
  gap: var(--space-md);
  align-items: center;
  padding: var(--space-md) var(--space-lg);
  border: 0;
  border-bottom: 0.0625rem solid var(--color-border);
  background: transparent;
  color: var(--color-ink);
  text-align: left;
  cursor: pointer;
  transition: background var(--duration-state) var(--ease-out-quart), box-shadow var(--duration-instant) var(--ease-out-quart), transform var(--duration-instant) var(--ease-out-quart);
}

.reasoning-step:hover {
  background: var(--color-surface);
}

.reasoning-step:active {
  transform: translateY(0.0625rem);
}

.reasoning-step[aria-checked="true"] {
  z-index: 1;
  border-radius: var(--radius-sm);
  background: var(--color-primary-soft);
  box-shadow: inset 0 0 0 0.1875rem var(--color-primary), var(--shadow-selected);
}

.reasoning-step.is-reviewed {
  background: var(--color-success-soft);
  box-shadow: inset 0 0 0 0.125rem var(--color-success);
}

.step-marker {
  display: grid;
  width: 1.75rem;
  height: 1.75rem;
  place-items: center;
  border: 0.125rem solid var(--color-border-strong);
  border-radius: 50%;
  background: var(--color-surface-raised);
}

[aria-checked="true"] .step-marker {
  border: 0.5rem solid var(--color-primary);
}

.is-reviewed .step-marker {
  border-color: var(--color-success);
  background: var(--color-success);
  color: var(--color-canvas);
}

.step-number {
  color: var(--color-ink-soft);
  font-size: var(--text-xl);
  font-variant-numeric: tabular-nums;
}

.step-text {
  font-size: var(--text-lg);
  line-height: 1.45;
}

.actions {
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-top: var(--space-lg);
}

.button {
  min-height: 3.25rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-xs);
  padding: var(--space-sm) var(--space-xl);
  border: 0.0625rem solid transparent;
  border-radius: var(--radius-sm);
  font-weight: 760;
  cursor: pointer;
  transition: background var(--duration-state) var(--ease-out-quart), color var(--duration-state) var(--ease-out-quart), border-color var(--duration-state) var(--ease-out-quart), transform var(--duration-instant) var(--ease-out-quart);
}

.button:hover:not(:disabled) {
  transform: translateY(-0.0625rem);
}

.button:active:not(:disabled) {
  transform: translateY(0.0625rem);
}

.button:disabled {
  border-color: var(--color-border);
  background: var(--color-disabled);
  color: var(--color-ink-faint);
  cursor: not-allowed;
}

.button--primary {
  background: var(--color-primary);
  color: var(--color-canvas);
}

.button--primary:hover:not(:disabled) {
  background: var(--color-primary-hover);
}

.button--primary:active:not(:disabled) {
  background: var(--color-primary-pressed);
}

.button--secondary {
  border-color: var(--color-border-strong);
  background: var(--color-surface-raised);
  color: var(--color-ink);
}

.button--secondary:hover:not(:disabled) {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.feedback {
  margin-top: var(--space-lg);
  padding: var(--space-md);
  border: 0.0625rem solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-attention-soft);
  color: var(--color-ink);
}

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

.nudge {
  margin-top: var(--space-md);
  padding: var(--space-md);
  border: 0.0625rem solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-surface);
  color: var(--color-ink-soft);
}

.workflow-footer {
  display: grid;
  gap: var(--space-md);
  margin-top: var(--space-xl);
  padding-top: var(--space-lg);
  border-top: 0.0625rem solid var(--color-border);
}

.keyboard-note,
.stage-preview {
  gap: var(--space-xs);
  color: var(--color-ink-soft);
  font-size: var(--text-sm);
}

.keyboard-note kbd {
  min-width: 1.75rem;
  padding: 0.1rem 0.35rem;
  border: 0.0625rem solid var(--color-border-strong);
  border-radius: var(--radius-sm);
  background: var(--color-surface-raised);
  color: var(--color-ink);
  font-family: var(--font-sans);
  text-align: center;
  box-shadow: inset 0 -0.125rem 0 var(--color-border);
}

.stage-preview {
  justify-content: flex-start;
}

.stage-preview strong {
  color: var(--color-ink);
}

.explain-layout,
.prove-layout {
  display: grid;
  gap: var(--space-xl);
}

.answer-panel {
  min-width: 0;
}

.reviewed-step {
  margin-bottom: var(--space-xl);
  padding: var(--space-md) var(--space-lg);
  border: 0.0625rem solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-primary-soft);
}

.reviewed-step__label {
  display: block;
  margin-bottom: var(--space-xs);
  color: var(--color-primary);
  font-size: var(--text-xs);
  font-weight: 800;
  letter-spacing: 0.09em;
  text-transform: uppercase;
}

.field-label {
  display: block;
  margin-bottom: var(--space-xs);
  font-weight: 760;
}

.field-help,
.character-count {
  color: var(--color-ink-soft);
  font-size: var(--text-sm);
}

.field-help {
  margin: 0 0 var(--space-sm);
}

.textarea,
.number-input {
  width: 100%;
  border: 0.125rem solid var(--color-border-strong);
  border-radius: var(--radius-sm);
  background: var(--color-surface-raised);
  color: var(--color-ink);
}

.textarea {
  min-height: 9rem;
  resize: vertical;
  padding: var(--space-md);
  line-height: 1.5;
}

.number-field {
  position: relative;
  max-width: 22rem;
}

.number-input {
  min-height: 4rem;
  padding: var(--space-sm) 4.25rem var(--space-sm) var(--space-md);
  font-size: var(--text-xl);
  font-variant-numeric: tabular-nums;
}

.number-unit {
  position: absolute;
  top: 50%;
  right: var(--space-md);
  transform: translateY(-50%);
  color: var(--color-ink-soft);
  font-weight: 700;
}

.textarea:focus,
.number-input:focus {
  border-color: var(--color-primary);
}

.field-meta {
  display: flex;
  justify-content: flex-end;
  margin-top: var(--space-xs);
}

.completion {
  max-width: 58rem;
  margin: 0 auto;
}

.completion__signal {
  display: grid;
  width: 4.5rem;
  height: 4.5rem;
  margin-bottom: var(--space-xl);
  place-items: center;
  border-radius: 50%;
  background: var(--color-success-soft);
  color: var(--color-success);
  font-size: var(--text-2xl);
  font-weight: 850;
  box-shadow: inset 0 0 0 0.125rem var(--color-success);
}

.proof {
  margin: var(--space-2xl) 0;
  border-top: 0.0625rem solid var(--color-border);
}

.proof-line {
  align-items: flex-start;
  gap: var(--space-md);
  padding: var(--space-lg) 0;
  border-bottom: 0.0625rem solid var(--color-border);
}

.proof-line__number {
  display: grid;
  flex: 0 0 auto;
  width: 2rem;
  height: 2rem;
  place-items: center;
  border-radius: 50%;
  background: var(--color-success-soft);
  color: var(--color-success);
  font-weight: 800;
}

.proof-line p {
  margin: 0;
}

.proof-line strong {
  display: block;
  margin-bottom: var(--space-2xs);
}

.upload-view {
  max-width: 64rem;
  margin: 0 auto;
}

.upload-panel {
  margin-top: var(--space-2xl);
  padding: var(--space-xl);
  border: 0.0625rem solid var(--color-border);
  border-radius: var(--radius-lg);
  background: var(--color-surface);
}

.connection-status {
  display: flex;
  align-items: flex-start;
  gap: var(--space-md);
  margin-top: var(--space-xl);
  padding: var(--space-md);
  border: 0.0625rem solid var(--color-border-strong);
  border-radius: var(--radius-sm);
  background: var(--color-attention-soft);
  color: var(--color-ink);
}

.connection-status--live {
  background: var(--color-success-soft);
}

.connection-status__signal {
  flex: 0 0 auto;
  display: grid;
  width: 2rem;
  height: 2rem;
  place-items: center;
  border: 0.125rem solid var(--color-attention);
  border-radius: 50%;
  color: var(--color-attention);
  font-weight: 800;
}

.connection-status--live .connection-status__signal {
  border-color: var(--color-success);
  color: var(--color-success);
}

.connection-status strong {
  display: block;
  margin-bottom: var(--space-2xs);
}

.connection-status p {
  max-width: 68ch;
  margin: 0;
  color: var(--color-ink-soft);
}

.file-field {
  display: grid;
  gap: var(--space-sm);
}

.access-field {
  max-width: 28rem;
  margin-top: var(--space-lg);
}

.file-input {
  width: 100%;
  min-height: 3.25rem;
  padding: var(--space-sm);
  border: 0.125rem dashed var(--color-border-strong);
  border-radius: var(--radius-sm);
  background: var(--color-surface-raised);
  color: var(--color-ink);
}

.access-input {
  width: 100%;
  min-height: 3.25rem;
  padding: var(--space-sm) var(--space-md);
  border: 0.125rem solid var(--color-border-strong);
  border-radius: var(--radius-sm);
  background: var(--color-surface-raised);
  color: var(--color-ink);
}

.access-input:focus {
  border-color: var(--color-primary);
}

.upload-preview {
  width: min(100%, 32rem);
  max-height: 18rem;
  margin-top: var(--space-md);
  border-radius: var(--radius-sm);
  object-fit: contain;
  object-position: left center;
}

.privacy-note {
  margin: var(--space-md) 0 0;
  color: var(--color-ink-soft);
  font-size: var(--text-sm);
}

.selected-file {
  margin: var(--space-sm) 0 0;
  color: var(--color-ink);
  font-size: var(--text-sm);
  font-weight: 700;
  overflow-wrap: anywhere;
}

.upload-actions {
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-top: var(--space-lg);
}

.skeleton {
  position: relative;
  overflow: hidden;
  background: var(--color-disabled);
}

.skeleton::after {
  content: "";
  position: absolute;
  inset: 0;
  background: var(--color-surface-raised);
  opacity: 0;
  animation: skeleton-pulse 1.2s infinite var(--ease-out-quart);
}

.skeleton-line {
  height: 1rem;
  margin-bottom: var(--space-sm);
  border-radius: var(--radius-sm);
}

.skeleton-line:last-child {
  width: 65%;
}

.visually-hidden {
  position: absolute !important;
  width: 0.0625rem !important;
  height: 0.0625rem !important;
  padding: 0 !important;
  margin: -0.0625rem !important;
  overflow: hidden !important;
  clip: rect(0, 0, 0, 0) !important;
  white-space: nowrap !important;
  border: 0 !important;
}

@keyframes skeleton-pulse {
  50% { opacity: 0.72; }
}

@media (min-width: 48rem) {
  .topbar__inner {
    min-height: 5rem;
    grid-template-columns: minmax(15rem, 1fr) auto minmax(15rem, 1fr);
    gap: var(--space-lg);
  }

  .brand-row {
    display: contents;
  }

  .mode-label {
    display: none;
  }

  .main {
    padding-top: var(--space-3xl);
  }

  .stage-heading h1,
  .completion h1,
  .upload-view h1 {
    font-size: var(--text-3xl);
  }

  .workflow-footer {
    grid-template-columns: 1fr 1fr;
  }

  .stage-preview {
    justify-content: flex-end;
  }
}

@media (min-width: 60rem) {
  .workspace,
  .explain-layout,
  .prove-layout {
    grid-template-columns: minmax(18rem, 0.38fr) minmax(0, 0.62fr);
    gap: var(--space-2xl);
  }

  .source-panel {
    position: sticky;
    top: var(--space-lg);
  }
}

@media (pointer: coarse) {
  .button,
  .text-button,
  .reasoning-step {
    min-height: 3.5rem;
  }
}

@media (hover: none) {
  .button:hover:not(:disabled) {
    transform: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}