:root {
  --study-bg: #090b0d;
  --study-surface: #0d1114;
  --study-surface-raised: #11171a;
  --study-ink: #e7ecee;
  --study-muted: #8c999f;
  --study-dim: #78868c;
  --study-rule: #273137;
  --study-rule-strong: #3a464c;
  --study-accent: #78d4c5;
  --study-contact: #d4aa70;
  --study-mono: "SF Mono", "IBM Plex Mono", Consolas, Menlo, monospace;
}

body.echo-page {
  background: var(--study-bg);
  color: var(--study-ink);
  min-height: 100vh;
  overflow-x: hidden;
}

.echo-page a { color: inherit; }

.echo-header {
  align-items: center;
  border-bottom: 1px solid var(--study-rule);
  display: flex;
  justify-content: space-between;
  min-height: 76px;
  padding: 14px clamp(22px, 4.2vw, 72px);
}

.echo-brand,
.echo-header-meta,
.echo-local {
  align-items: center;
  display: flex;
}

.echo-brand {
  gap: 20px;
  text-decoration: none;
}

.echo-brand img {
  filter: grayscale(1) brightness(0) invert(1);
  height: 25px;
  opacity: .86;
  width: auto;
}

.echo-brand span,
.echo-local,
.echo-exit {
  font-family: var(--study-mono);
  font-size: 10px;
  letter-spacing: .11em;
  text-transform: uppercase;
}

.echo-brand span {
  border-left: 1px solid var(--study-rule-strong);
  color: var(--study-muted);
  padding-left: 20px;
}

.echo-header-meta { gap: clamp(22px, 4vw, 52px); }

.echo-local {
  color: var(--study-muted);
  gap: 9px;
}

.echo-local i {
  background: var(--study-accent);
  border-radius: 50%;
  height: 6px;
  width: 6px;
}

.echo-exit {
  color: var(--study-ink) !important;
  text-decoration-color: var(--study-rule-strong);
}

.echo-page main {
  margin: 0 auto;
  max-width: 1520px;
  padding: 0 clamp(22px, 4.2vw, 72px) 96px;
}

.echo-intro {
  display: grid;
  gap: 0 clamp(40px, 7vw, 110px);
  grid-template-columns: minmax(0, 1.3fr) minmax(320px, .7fr);
  padding: clamp(64px, 9vw, 132px) 0 clamp(58px, 7vw, 100px);
}

.echo-kicker,
.echo-panel-head span,
.echo-figure-head span,
.echo-method-title > span {
  color: var(--study-accent);
  font-family: var(--study-mono);
  font-size: 10px;
  font-weight: 600;
  letter-spacing: .15em;
  text-transform: uppercase;
}

.echo-kicker {
  grid-column: 1 / -1;
  margin: 0 0 24px;
}

.echo-intro h1 {
  color: var(--study-ink);
  font-family: var(--sans);
  font-size: clamp(54px, 7.7vw, 112px);
  font-weight: 500;
  letter-spacing: -.055em;
  line-height: .88;
  margin: 0;
}

.echo-deck {
  align-self: end;
  border-left: 1px solid var(--study-rule-strong);
  color: #b7c0c4;
  font-size: clamp(17px, 1.5vw, 21px);
  line-height: 1.55;
  margin: 0 0 4px;
  max-width: 510px;
  padding: 3px 0 3px clamp(22px, 3vw, 42px);
}

.echo-frame {
  align-items: center;
  border-bottom: 1px solid var(--study-rule);
  border-top: 1px solid var(--study-rule);
  display: grid;
  gap: 18px clamp(20px, 3vw, 46px);
  grid-template-columns: minmax(210px, .7fr) auto minmax(260px, 1fr);
  margin-bottom: clamp(62px, 8vw, 118px);
  padding: clamp(24px, 3vw, 38px) 0;
}

.echo-frame span,
.echo-frame label {
  color: var(--study-muted);
  font: 500 9px/1.4 var(--study-mono);
  letter-spacing: .12em;
  text-transform: uppercase;
}

.echo-frame h2 {
  color: var(--study-ink);
  font-size: clamp(24px, 3vw, 42px);
  font-weight: 500;
  letter-spacing: -.035em;
  line-height: 1;
  margin: 9px 0 0;
}

.echo-frame label {
  position: absolute;
  transform: translateY(-10000px);
}

.echo-frame select {
  background: var(--study-surface);
  border: 1px solid var(--study-rule-strong);
  color: var(--study-ink);
  font: 500 10px/1 var(--study-mono);
  min-height: 48px;
  padding: 0 38px 0 16px;
  text-transform: uppercase;
}

.echo-frame select:focus {
  border-color: var(--study-accent);
  outline: 2px solid rgba(120, 212, 197, .22);
  outline-offset: 3px;
}

.echo-frame p {
  color: #b9c4c7;
  font-size: 15px;
  line-height: 1.6;
  margin: 0;
  max-width: 680px;
}

.echo-frame-answers {
  border-top: 1px solid var(--study-rule);
  display: grid;
  gap: 0;
  grid-column: 1 / -1;
  grid-template-columns: repeat(2, 1fr);
  margin-top: 8px;
  padding-top: 22px;
}

.echo-frame-answers > div {
  display: grid;
  gap: 10px;
  grid-template-columns: minmax(110px, .35fr) 1fr;
  padding-right: clamp(18px, 3vw, 44px);
}

.echo-frame-answers > div + div {
  border-left: 1px solid var(--study-rule);
  padding-left: clamp(18px, 3vw, 44px);
}

.echo-frame-answers p {
  color: #c6cfd2;
  font-size: 13px;
  line-height: 1.55;
}

.echo-path {
  border: 1px solid var(--study-rule);
  margin-bottom: clamp(62px, 8vw, 118px);
}

.echo-path-head {
  align-items: end;
  display: grid;
  gap: 18px clamp(28px, 4vw, 72px);
  grid-template-columns: minmax(300px, 1.15fr) minmax(280px, .85fr);
  padding: clamp(28px, 4vw, 54px);
}

.echo-path-head > span {
  color: var(--study-accent);
  font: 600 9px/1.4 var(--study-mono);
  grid-column: 1 / -1;
  letter-spacing: .14em;
  text-transform: uppercase;
}

.echo-path h2 {
  color: var(--study-ink);
  font-size: clamp(34px, 4.2vw, 64px);
  font-weight: 500;
  letter-spacing: -.045em;
  line-height: .98;
  margin: 0;
}

.echo-path-head p,
.echo-path li p,
.echo-path-summary {
  color: #aeb9bd;
  line-height: 1.6;
  margin: 0;
}

.echo-path-head p {
  font-size: 15px;
  max-width: 510px;
}

.echo-path ol {
  border-bottom: 1px solid var(--study-rule);
  border-top: 1px solid var(--study-rule);
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  list-style: none;
  margin: 0;
  padding: 0;
}

.echo-path li {
  min-height: 230px;
  padding: clamp(24px, 2.8vw, 40px);
}

.echo-path li + li { border-left: 1px solid var(--study-rule); }

.echo-path li span {
  color: var(--study-muted);
  display: block;
  font: 500 9px/1 var(--study-mono);
  letter-spacing: .12em;
  margin-bottom: 38px;
  text-transform: uppercase;
}

.echo-path li strong {
  color: #dce4e6;
  display: block;
  font-size: 20px;
  font-weight: 500;
  letter-spacing: -.02em;
  margin-bottom: 12px;
}

.echo-path li p { font-size: 12px; }

.echo-path-summary {
  color: #c6cfd2;
  font-size: 13px;
  padding: 22px clamp(28px, 4vw, 54px);
}

.echo-brief {
  border-bottom: 1px solid var(--study-rule);
  border-top: 1px solid var(--study-rule);
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  margin-bottom: clamp(62px, 8vw, 118px);
}

.echo-brief div {
  min-height: 142px;
  padding: 28px clamp(20px, 2.7vw, 42px);
}

.echo-brief div + div { border-left: 1px solid var(--study-rule); }

.echo-brief span,
.echo-readout span,
.echo-fingerprint-row span,
.echo-range-scale,
.echo-instruction span,
.echo-instruction small,
.echo-method dt {
  color: var(--study-muted);
  font-family: var(--study-mono);
  font-size: 9px;
  letter-spacing: .12em;
  text-transform: uppercase;
}

.echo-brief p {
  color: #c9d0d3;
  font-size: 14px;
  line-height: 1.55;
  margin: 15px 0 0;
  max-width: 310px;
}

.mirror-source {
  border: 1px solid var(--study-rule);
  margin-bottom: clamp(62px, 8vw, 118px);
}

.mirror-source-head {
  align-items: end;
  border-bottom: 1px solid var(--study-rule);
  display: grid;
  gap: 30px;
  grid-template-columns: 1fr minmax(280px, 540px);
  padding: clamp(24px, 3vw, 42px);
}

.mirror-source-head span,
.mirror-session-state span {
  color: var(--study-muted);
  font: 400 9px/1 var(--study-mono);
  letter-spacing: .12em;
  text-transform: uppercase;
}

.mirror-source-head h2 {
  color: #dce4e6;
  font-size: clamp(29px, 3.8vw, 56px);
  font-weight: 500;
  letter-spacing: -.04em;
  line-height: 1;
  margin: 10px 0 0;
}

.mirror-source-head p {
  color: #aeb9bd;
  font-size: 15px;
  line-height: 1.6;
  margin: 0;
}

.mirror-source-grid {
  display: grid;
  grid-template-columns: minmax(280px, .9fr) minmax(340px, 1.1fr);
}

.mirror-drop {
  align-content: center;
  background: linear-gradient(135deg, rgba(120, 212, 197, .04), transparent 68%), var(--study-surface);
  border-right: 1px solid var(--study-rule);
  display: grid;
  gap: 16px;
  min-height: 272px;
  padding: clamp(28px, 4vw, 54px);
  position: relative;
  transition: background 160ms ease, border-color 160ms ease;
}

.mirror-drop.is-over {
  background: rgba(120, 212, 197, .09);
  box-shadow: inset 0 0 0 1px var(--study-accent);
}

.mirror-drop input {
  height: 1px;
  opacity: 0;
  overflow: hidden;
  position: absolute;
  width: 1px;
}

.mirror-drop label {
  cursor: pointer;
  display: grid;
  gap: 9px;
}

.mirror-drop label strong {
  color: #dbe3e5;
  font-size: clamp(22px, 2.4vw, 34px);
  font-weight: 500;
  letter-spacing: -.025em;
}

.mirror-drop label span,
.mirror-signature-note,
.mirror-status {
  color: var(--study-muted);
  font-size: 11px;
  line-height: 1.55;
}

.mirror-drop button,
.mirror-actions button {
  background: transparent;
  border: 1px solid var(--study-rule-strong);
  color: #cbd2d5;
  cursor: pointer;
  font: 600 10px/1 var(--study-mono);
  letter-spacing: .09em;
  min-height: 44px;
  padding: 0 16px;
  text-transform: uppercase;
}

.mirror-drop button {
  justify-self: start;
  min-width: 180px;
}

.mirror-drop button:hover,
.mirror-actions button:hover:not(:disabled) {
  background: var(--study-surface-raised);
  border-color: var(--study-accent);
}

.mirror-session {
  display: grid;
  gap: 18px;
  padding: clamp(28px, 4vw, 54px);
}

.mirror-session-state {
  border-bottom: 1px solid var(--study-rule);
  border-top: 1px solid var(--study-rule);
  display: grid;
  grid-template-columns: repeat(4, 1fr);
}

.mirror-session-state div {
  display: grid;
  gap: 12px;
  min-height: 82px;
  padding: 17px 14px;
}

.mirror-session-state div + div { border-left: 1px solid var(--study-rule); }

.mirror-session-state output {
  align-self: end;
  color: var(--study-accent);
  font: 500 13px/1.2 var(--study-mono);
  overflow-wrap: anywhere;
  text-transform: uppercase;
}

.mirror-status { margin: 0; min-height: 34px; }

.mirror-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 9px;
}

.mirror-actions button:last-child {
  border-color: var(--study-accent);
  color: var(--study-accent);
  margin-left: auto;
}

.mirror-actions button:disabled {
  cursor: not-allowed;
  opacity: .38;
}

.mirror-signature-note {
  border-left: 1px solid var(--study-rule-strong);
  margin: 0;
  padding-left: 13px;
}

.mirror-continuity {
  border-top: 1px solid var(--study-rule);
  display: grid;
  gap: 15px;
  margin-top: 4px;
  padding-top: 20px;
}

.mirror-continuity-head {
  align-items: center;
  display: flex;
  justify-content: space-between;
}

.mirror-continuity-head span,
.mirror-continuity-head strong {
  font: 500 9px/1 var(--study-mono);
  letter-spacing: .11em;
  text-transform: uppercase;
}

.mirror-continuity-head span { color: var(--study-muted); }
.mirror-continuity-head strong { color: var(--study-accent); }

.mirror-continuity-choice {
  align-items: start;
  cursor: pointer;
  display: grid;
  gap: 12px;
  grid-template-columns: 18px 1fr;
}

.mirror-continuity-choice input {
  accent-color: var(--study-accent);
  height: 16px;
  margin: 2px 0 0;
  width: 16px;
}

.mirror-continuity-choice span { display: grid; gap: 5px; }

.mirror-continuity-choice strong {
  color: #d4dcde;
  font-size: 12px;
  font-weight: 500;
}

.mirror-continuity-choice small,
.mirror-local-status {
  color: var(--study-muted);
  font-size: 10px;
  line-height: 1.55;
}

.mirror-local-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.mirror-local-actions input {
  height: 1px;
  opacity: 0;
  overflow: hidden;
  position: absolute;
  width: 1px;
}

.mirror-local-actions label,
.mirror-local-actions button {
  align-items: center;
  background: transparent;
  border: 1px solid var(--study-rule-strong);
  color: #cbd2d5;
  cursor: pointer;
  display: inline-flex;
  font: 600 9px/1 var(--study-mono);
  justify-content: center;
  letter-spacing: .08em;
  min-height: 38px;
  padding: 0 13px;
  text-transform: uppercase;
}

.mirror-local-actions label:hover,
.mirror-local-actions button:hover { border-color: var(--study-accent); }

.mirror-local-status {
  margin: 0;
  min-height: 16px;
}

.echo-workbench {
  align-items: start;
  display: grid;
  gap: clamp(28px, 4vw, 64px);
  grid-template-columns: minmax(285px, 342px) minmax(0, 1fr);
}

.echo-controls {
  background: var(--study-surface);
  border: 1px solid var(--study-rule);
  display: grid;
  position: sticky;
  top: 24px;
}

.echo-panel-head {
  align-items: center;
  border-bottom: 1px solid var(--study-rule);
  display: flex;
  justify-content: space-between;
  min-height: 58px;
  padding: 0 22px;
}

.echo-panel-head strong {
  color: var(--study-dim);
  font: 400 12px/1 var(--study-mono);
}

.echo-control-block {
  border-bottom: 1px solid var(--study-rule);
  margin: 0;
  padding: 22px;
}

.echo-control-label {
  color: #c5cdd0;
  display: block;
  font: 500 11px/1.3 var(--study-mono);
  letter-spacing: .08em;
  margin: 0 0 14px;
  padding: 0;
  text-transform: uppercase;
}

.echo-controls fieldset { border-left: 0; border-right: 0; border-top: 0; }

.echo-controls input[type="text"] {
  background: #090d0f;
  border: 1px solid var(--study-rule-strong);
  border-radius: 1px;
  color: var(--study-ink);
  font: 500 13px/1.4 var(--study-mono);
  letter-spacing: .07em;
  min-height: 46px;
  padding: 11px 13px;
  width: 100%;
}

.echo-controls input[type="text"]:focus { border-color: var(--study-accent); }

.echo-choice {
  align-items: center;
  border-top: 1px solid var(--study-rule);
  cursor: pointer;
  display: grid;
  gap: 12px;
  grid-template-columns: 15px 1fr;
  padding: 13px 0;
}

.echo-choice:last-child { padding-bottom: 0; }

.echo-choice input {
  accent-color: var(--study-accent);
  height: 13px;
  margin: 0;
  width: 13px;
}

.echo-choice span {
  align-items: baseline;
  display: flex;
  justify-content: space-between;
}

.echo-choice strong {
  color: #d1d8da;
  font-size: 13px;
  font-weight: 500;
}

.echo-choice small {
  color: var(--study-dim);
  font: 400 9px/1 var(--study-mono);
  letter-spacing: .06em;
  text-transform: uppercase;
}

.echo-label-row {
  align-items: baseline;
  display: flex;
  justify-content: space-between;
}

.echo-label-row output {
  color: var(--study-accent);
  font: 500 12px/1 var(--study-mono);
}

.echo-controls input[type="range"] {
  accent-color: var(--study-accent);
  cursor: ew-resize;
  margin: 7px 0 8px;
  width: 100%;
}

.echo-range-scale {
  display: flex;
  justify-content: space-between;
}

.echo-generate,
.echo-actions button {
  border-radius: 1px;
  cursor: pointer;
  font-family: var(--study-mono);
  font-size: 10px;
  font-weight: 600;
  letter-spacing: .09em;
  min-height: 46px;
  text-transform: uppercase;
}

.echo-generate {
  background: var(--study-accent);
  border: 1px solid var(--study-accent);
  color: #07100f;
  margin: 22px 22px 0;
}

.echo-generate:hover { background: #92e3d6; }

.echo-privacy {
  color: var(--study-muted);
  font-size: 11px;
  line-height: 1.55;
  margin: 15px 22px 20px;
}

.echo-fingerprint-row {
  align-items: center;
  border-top: 1px solid var(--study-rule);
  display: flex;
  justify-content: space-between;
  min-height: 52px;
  padding: 0 22px;
}

.echo-fingerprint-row code {
  color: #bdc7ca;
  font-size: 10px;
  letter-spacing: .07em;
}

.echo-stage { min-width: 0; }

.echo-figure-head {
  align-items: end;
  border-bottom: 1px solid var(--study-rule);
  display: flex;
  justify-content: space-between;
  min-height: 58px;
  padding: 0 0 15px;
}

.echo-figure-head > div:first-child {
  display: grid;
  gap: 5px;
}

.echo-figure-head strong {
  color: #cbd3d6;
  font-size: 13px;
  font-weight: 500;
  letter-spacing: .05em;
  text-transform: uppercase;
}

.echo-figure-tools {
  align-items: flex-end;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.echo-observer-state {
  align-items: center;
  color: var(--study-muted);
  display: flex;
  font: 500 9px/1 var(--study-mono);
  gap: 8px;
  letter-spacing: .1em;
  text-transform: uppercase;
}

.echo-observer-state i {
  background: var(--study-accent);
  border-radius: 50%;
  box-shadow: 0 0 0 3px rgba(120, 212, 197, .08), 0 0 12px rgba(120, 212, 197, .35);
  height: 5px;
  width: 5px;
}

.echo-legend {
  display: flex;
  gap: 20px;
}

.echo-legend span {
  align-items: center;
  color: var(--study-muted);
  display: flex;
  font: 400 9px/1 var(--study-mono);
  gap: 7px;
  letter-spacing: .08em;
  text-transform: uppercase;
}

.echo-legend i {
  border: 1px solid var(--study-muted);
  border-radius: 50%;
  display: inline-block;
  height: 7px;
  width: 7px;
}

.echo-legend i.contact { border-color: var(--study-contact); }
.echo-legend i.trace { border-color: transparent; border-radius: 0; border-top-color: var(--study-contact); width: 13px; }

.echo-canvas {
  aspect-ratio: 1 / 1;
  background-color: var(--study-surface);
  background-image:
    linear-gradient(rgba(120, 212, 197, .035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(120, 212, 197, .035) 1px, transparent 1px);
  background-size: 40px 40px;
  border: 1px solid var(--study-rule);
  border-top: 0;
  max-height: 860px;
  overflow: hidden;
  position: relative;
  transition: border-color 240ms ease, box-shadow 240ms ease;
}

.echo-canvas::before {
  background:
    radial-gradient(circle at center, rgba(120, 212, 197, .065), transparent 44%),
    conic-gradient(from 0deg at 50% 50%, transparent 0 76%, rgba(120, 212, 197, .075) 88%, transparent 100%);
  content: "";
  inset: 0;
  opacity: 0;
  pointer-events: none;
  position: absolute;
  transform: scale(.92);
  transition: opacity 320ms ease, transform 700ms cubic-bezier(.2, .8, .2, 1);
  z-index: 0;
}

.echo-canvas.is-observing {
  border-color: rgba(120, 212, 197, .48);
  box-shadow: 0 22px 80px rgba(0, 0, 0, .25), inset 0 0 54px rgba(120, 212, 197, .025);
}

.echo-canvas.is-observing::before {
  opacity: 1;
  transform: scale(1);
}

.echo-canvas::after {
  border: 1px solid rgba(120, 212, 197, .08);
  content: "";
  inset: 18px;
  pointer-events: none;
  position: absolute;
  z-index: 2;
}

.echo-field {
  cursor: crosshair;
  display: block;
  height: 100%;
  position: relative;
  touch-action: none;
  width: 100%;
  z-index: 1;
}

.echo-field:focus-visible {
  outline: 1px solid var(--study-accent);
  outline-offset: -4px;
}

.field-axis,
.field-calibration-ring,
.field-tick,
.field-spoke,
.field-loop,
.field-scan-ray,
.field-scan-ring,
.field-boundary,
.field-trail,
.field-probe-ring,
.field-probe-cross {
  vector-effect: non-scaling-stroke;
}

.field-scan {
  opacity: 0;
  pointer-events: none;
  transform-box: view-box;
  transform-origin: 400px 400px;
  transition: opacity 260ms ease;
}

.field-scan-ray {
  stroke: rgba(120, 212, 197, .58);
  stroke-dasharray: 1 6;
  stroke-width: 1;
}

.field-scan-ring {
  fill: none;
  stroke: rgba(120, 212, 197, .18);
  stroke-dasharray: 2 12;
  stroke-width: 1;
}

.echo-field.is-observing .field-scan {
  animation: scan-rotate 5.6s linear infinite;
  opacity: 1;
}

.field-axis {
  stroke: rgba(120, 212, 197, .12);
  stroke-width: 1;
}

.field-calibration-ring {
  fill: none;
  stroke: rgba(165, 183, 188, .12);
  stroke-dasharray: 2 7;
  stroke-width: 1;
}

.field-tick {
  stroke: rgba(165, 183, 188, .28);
  stroke-width: 1;
}

.field-tick-major { stroke: rgba(120, 212, 197, .6); }

.field-point { fill: #a9b5b9; }

.field-spoke {
  stroke: rgba(120, 212, 197, .16);
  stroke-dasharray: 2 8;
  stroke-width: 1;
}

.field-loop {
  fill: rgba(120, 212, 197, .018);
  stroke: rgba(166, 181, 186, .48);
  stroke-dasharray: 7 9;
  stroke-width: 1.25;
  animation: field-flow 24s linear infinite;
}

.field-boundary {
  fill: none;
  stroke: var(--study-accent);
  stroke-width: 1.5;
}

.echo-field[data-frame="trust"] .field-boundary { stroke-width: 3; }
.echo-field[data-frame="mission"] .field-loop { stroke-dasharray: 7 9; }
.echo-field[data-frame="ai"] .field-spoke { opacity: .78; }
.echo-field[data-frame="enterprise"] .field-calibration-ring { stroke-dasharray: 2 8; }
.echo-field[data-frame="research"] .field-point { opacity: .88; }

.field-anchor-outer {
  fill: var(--study-surface);
  stroke: rgba(120, 212, 197, .7);
  stroke-width: 1.2;
  transition: fill 150ms ease, stroke 150ms ease;
}

.field-anchor-core {
  fill: var(--study-accent);
  transition: fill 150ms ease;
}

.field-anchor.is-active .field-anchor-outer {
  animation: contact-pulse 720ms cubic-bezier(.2, .8, .2, 1);
  fill: rgba(212, 170, 112, .08);
  stroke: var(--study-contact);
  stroke-width: 2.5;
}

.field-anchor.is-active .field-anchor-core { fill: var(--study-contact); }

.field-trail {
  fill: none;
  filter: drop-shadow(0 0 4px rgba(212, 170, 112, .24));
  opacity: .78;
  stroke: var(--study-contact);
  stroke-linecap: round;
  stroke-width: 1.5;
}

.field-probe { cursor: grab; }
.field-probe:active { cursor: grabbing; }

.field-probe-halo {
  fill: var(--study-accent);
  opacity: .08;
}

.field-probe-ring {
  fill: var(--study-surface);
  stroke: var(--study-ink);
  stroke-width: 1.2;
}

.field-probe-core { fill: var(--study-accent); }

.field-probe-cross {
  stroke: rgba(231, 236, 238, .5);
  stroke-width: 1;
}

.field-probe.is-held .field-probe-halo { fill: var(--study-contact); opacity: .18; }
.field-probe.is-held .field-probe-core { fill: var(--study-contact); }
.echo-field.is-observing .field-probe-halo { animation: observer-pulse 1.8s ease-in-out infinite; }

.echo-instruction {
  background: rgba(9, 11, 13, .9);
  border-left: 1px solid var(--study-rule-strong);
  border-top: 1px solid var(--study-rule-strong);
  bottom: 0;
  display: grid;
  min-width: 230px;
  padding: 13px 17px 14px;
  position: absolute;
  right: 0;
  z-index: 2;
}

.echo-instruction strong {
  color: #d4dbdd;
  font-size: 12px;
  font-weight: 500;
  margin: 3px 0;
}

.echo-scan-label {
  backdrop-filter: blur(10px);
  background: rgba(9, 11, 13, .74);
  border-bottom: 1px solid var(--study-rule-strong);
  border-right: 1px solid var(--study-rule-strong);
  display: grid;
  gap: 6px;
  left: 0;
  min-width: 164px;
  padding: 13px 16px 14px;
  position: absolute;
  top: 0;
  z-index: 3;
}

.echo-scan-label span {
  color: var(--study-muted);
  font: 400 8px/1 var(--study-mono);
  letter-spacing: .12em;
  text-transform: uppercase;
}

.echo-scan-label output {
  color: var(--study-accent);
  font: 500 11px/1 var(--study-mono);
  letter-spacing: .08em;
  text-transform: uppercase;
}

.echo-readout {
  border: 1px solid var(--study-rule);
  border-top: 0;
  display: grid;
  grid-template-columns: 1.3fr .55fr .65fr .8fr .8fr;
}

.echo-readout > div {
  display: grid;
  min-height: 82px;
  padding: 17px 20px;
}

.echo-readout > div + div { border-left: 1px solid var(--study-rule); }

.echo-readout strong,
.echo-readout output {
  align-self: end;
  color: var(--study-ink);
  font: 500 12px/1.2 var(--study-mono);
  letter-spacing: .05em;
  text-transform: uppercase;
}

#echo-observer-readout { font-size: 12px; }

.echo-readout output {
  color: var(--study-accent);
  font-size: 18px;
}

.echo-status {
  color: var(--study-muted);
  font: 400 11px/1.5 var(--study-mono);
  margin: 14px 0;
  min-height: 18px;
}

.echo-actions {
  display: flex;
  gap: 10px;
  justify-content: flex-end;
}

.echo-actions button {
  background: transparent;
  border: 1px solid var(--study-rule-strong);
  color: #cbd2d5;
  min-width: 142px;
  padding: 0 17px;
}

.echo-actions button:first-child {
  border-color: var(--study-accent);
  color: var(--study-accent);
}

.echo-actions button[aria-pressed="true"] {
  background: rgba(120, 212, 197, .09);
  box-shadow: inset 0 0 0 1px rgba(120, 212, 197, .15), 0 0 26px rgba(120, 212, 197, .08);
}

.echo-actions button:hover:not(:disabled) { background: var(--study-surface-raised); }
.echo-actions button:disabled { cursor: wait; opacity: .42; }

.echo-method {
  border-top: 1px solid var(--study-rule);
  display: grid;
  gap: clamp(42px, 7vw, 110px);
  grid-template-columns: .85fr 1.15fr;
  margin-top: clamp(88px, 12vw, 174px);
  padding-top: clamp(40px, 5vw, 70px);
}

.echo-method-title h2 {
  color: #d6dcde;
  font-size: clamp(27px, 3.1vw, 46px);
  font-weight: 400;
  letter-spacing: -.03em;
  line-height: 1.08;
  margin: 18px 0 0;
}

.echo-method dl { margin: 0; }

.echo-method dl > div {
  border-top: 1px solid var(--study-rule);
  display: grid;
  gap: 24px;
  grid-template-columns: 120px 1fr;
  padding: 22px 0;
}

.echo-method dl > div:first-child { border-top: 0; padding-top: 0; }

.echo-method dd {
  color: #aab4b8;
  font-size: 14px;
  line-height: 1.65;
  margin: 0;
  max-width: 560px;
}

.echo-noscript {
  border: 1px solid var(--study-contact);
  color: var(--study-contact);
  margin: 48px 0 0;
  padding: 16px;
}

.echo-artifact {
  border-bottom: 1px solid var(--study-rule);
  border-top: 1px solid var(--study-rule);
  display: grid;
  grid-template-columns: minmax(280px, .7fr) minmax(0, 1.3fr);
  margin: 0 clamp(22px, 4.2vw, 72px) 96px;
}

.echo-artifact-copy { padding: clamp(28px, 5vw, 64px); }
.echo-artifact-copy > span { color: var(--study-accent); font: 500 9px/1.4 var(--study-mono); letter-spacing: .13em; text-transform: uppercase; }
.echo-artifact-copy h2 { font-size: clamp(34px, 4vw, 58px); font-weight: 400; letter-spacing: -.04em; line-height: 1.02; margin: 18px 0 28px; }
.echo-artifact-copy > p { color: #aab4b8; font-size: 14px; line-height: 1.65; }
.echo-artifact-copy input { height: 1px; opacity: 0; overflow: hidden; position: absolute; width: 1px; }
.echo-artifact-copy label { border: 1px solid var(--study-rule-strong); cursor: pointer; display: inline-block; margin-top: 18px; padding: 13px 18px; }
.echo-artifact-copy input:focus-visible + label { outline: 2px solid var(--study-accent); outline-offset: 3px; }
.echo-artifact-status { border-left: 2px solid var(--study-accent); font-size: 12px !important; margin-top: 22px; padding-left: 14px; }
.echo-artifact-view { background: #0d1215; border-left: 1px solid var(--study-rule); min-height: 520px; position: relative; }
.echo-artifact-view iframe { border: 0; height: 100%; inset: 0; position: absolute; width: 100%; z-index: 2; }
.echo-artifact-view iframe:not([hidden]) + .echo-artifact-empty { display: none; }
.echo-artifact-empty { align-items: center; display: flex; flex-direction: column; inset: 0; justify-content: center; position: absolute; text-align: center; }
.echo-artifact-empty span { color: var(--study-accent); font: 400 clamp(54px, 8vw, 110px)/1 var(--study-mono); opacity: .72; }
.echo-artifact-empty strong { font-size: 18px; margin-top: 18px; }
.echo-artifact-empty small { color: var(--study-muted); margin-top: 9px; }

.echo-footer {
  align-items: center;
  border-top: 1px solid var(--study-rule);
  color: var(--study-muted);
  display: flex;
  font: 400 9px/1.4 var(--study-mono);
  justify-content: space-between;
  letter-spacing: .1em;
  min-height: 82px;
  padding: 14px clamp(22px, 4.2vw, 72px);
  text-transform: uppercase;
}

.echo-footer div { display: flex; gap: 28px; }
.echo-footer a { text-decoration-color: var(--study-rule-strong); }

@keyframes field-flow { to { stroke-dashoffset: -160; } }

@keyframes scan-rotate { to { transform: rotate(360deg); } }

@keyframes observer-pulse {
  0%, 100% { opacity: .07; transform: scale(.82); }
  50% { opacity: .2; transform: scale(1.12); }
}

@keyframes contact-pulse {
  0% { opacity: 1; stroke-width: 5; }
  100% { opacity: 1; stroke-width: 2.5; }
}

@media (max-width: 1000px) {
  .echo-intro { grid-template-columns: 1fr; }
  .echo-deck { margin-top: 42px; max-width: 620px; }
  .echo-frame { grid-template-columns: minmax(210px, .7fr) minmax(260px, 1.3fr); }
  .echo-frame select { grid-column: 1; }
  .echo-frame p { grid-column: 2; grid-row: 1 / span 2; }
  .echo-frame-answers { grid-column: 1 / -1; grid-row: auto; }
  .echo-frame-answers p { grid-column: auto; grid-row: auto; }
  .echo-path ol { grid-template-columns: repeat(2, 1fr); }
  .echo-path li:nth-child(3) { border-left: 0; border-top: 1px solid var(--study-rule); }
  .echo-path li:nth-child(4) { border-top: 1px solid var(--study-rule); }
  .mirror-source-head { grid-template-columns: 1fr; }
  .mirror-source-grid { grid-template-columns: 1fr; }
  .echo-artifact { grid-template-columns: 1fr; }
  .echo-artifact-view { border-left: 0; border-top: 1px solid var(--study-rule); }
  .mirror-drop { border-bottom: 1px solid var(--study-rule); border-right: 0; }
  .echo-workbench { grid-template-columns: 1fr; }
  .echo-controls { grid-template-columns: repeat(2, 1fr); position: static; }
  .echo-panel-head,
  .echo-generate,
  .echo-privacy,
  .echo-fingerprint-row { grid-column: 1 / -1; }
  .echo-control-block { border-right: 1px solid var(--study-rule); }
  .echo-control-block:nth-of-type(3) { border-right: 0; }
  .echo-generate { margin-top: 22px; }
}

@media (max-width: 720px) {
  .echo-header { align-items: flex-start; gap: 18px; min-height: 92px; }
  .echo-brand { align-items: flex-start; flex-direction: column; gap: 8px; }
  .echo-brand span { border-left: 0; padding-left: 0; }
  .echo-header-meta { align-items: flex-end; flex-direction: column; gap: 8px; }
  .echo-local { display: none; }
  .echo-intro { padding-top: 72px; }
  .echo-intro h1 { font-size: clamp(52px, 16vw, 78px); }
  .echo-deck { border-left: 0; border-top: 1px solid var(--study-rule); padding: 24px 0 0; }
  .echo-frame { grid-template-columns: 1fr; }
  .echo-frame p { grid-column: 1; grid-row: auto; }
  .echo-frame-answers { grid-template-columns: 1fr; }
  .echo-frame-answers > div { grid-template-columns: 1fr; padding-right: 0; }
  .echo-frame-answers > div + div { border-left: 0; border-top: 1px solid var(--study-rule); margin-top: 20px; padding: 20px 0 0; }
  .echo-path-head { grid-template-columns: 1fr; }
  .echo-path ol { grid-template-columns: 1fr; }
  .echo-path li { min-height: 0; }
  .echo-path li + li,
  .echo-path li:nth-child(4) { border-left: 0; border-top: 1px solid var(--study-rule); }
  .echo-path li span { margin-bottom: 22px; }
  .echo-brief { grid-template-columns: 1fr; }
  .echo-brief div { min-height: auto; padding: 24px 0; }
  .echo-brief div + div { border-left: 0; border-top: 1px solid var(--study-rule); }
  .mirror-session-state { grid-template-columns: repeat(2, 1fr); }
  .mirror-session-state div:nth-child(3) { border-left: 0; border-top: 1px solid var(--study-rule); }
  .mirror-session-state div:nth-child(4) { border-top: 1px solid var(--study-rule); }
  .mirror-actions { display: grid; }
  .mirror-actions button:last-child { margin-left: 0; }
  .echo-controls { grid-template-columns: 1fr; }
  .echo-control-block { border-right: 0; }
  .echo-figure-head { align-items: flex-start; flex-direction: column; gap: 16px; }
  .echo-figure-tools { align-items: flex-start; }
  .echo-legend { gap: 14px; }
  .echo-canvas::after { inset: 9px; }
  .echo-instruction { display: none; }
  .echo-readout { grid-template-columns: 1fr 1fr; }
  .echo-state-cell { grid-column: 1 / -1; }
  .echo-readout > div + div { border-left: 0; border-top: 1px solid var(--study-rule); }
  .echo-readout > div:nth-child(3),
  .echo-readout > div:nth-child(5) { border-left: 1px solid var(--study-rule); }
  .echo-actions { display: grid; grid-template-columns: 1fr 1fr; }
  .echo-actions button { min-width: 0; }
  #echo-observer-toggle { grid-column: 1 / -1; }
  .echo-method { grid-template-columns: 1fr; }
  .echo-method dl > div { gap: 14px; grid-template-columns: 1fr; }
  .echo-footer { align-items: flex-start; flex-direction: column; gap: 15px; padding-bottom: 25px; padding-top: 25px; }
}

@media (prefers-reduced-motion: reduce) {
  .field-loop,
  .echo-field.is-observing .field-scan,
  .echo-field.is-observing .field-probe-halo,
  .field-anchor.is-active .field-anchor-outer { animation: none; }
  .echo-canvas,
  .echo-canvas::before,
  .field-scan,
  .field-anchor-outer,
  .field-anchor-core { transition: none; }
}