:root {
  /* Wong / Okabe-Ito palette — organisations */
  --color-anthropic: #56b4e9;
  --color-deepseek: #cc79a7;
  --color-meta: #0072b2;
  --color-mistral: #d55e00;
  --color-openai: #e69f00;

  /* Semantic — visualisation metrics */
  --color-energy: #0072b2;
  --color-water: #56b4e9;
  --color-carbon: #d55e00;

  /* Surfaces and text */
  --color-bg: #fafafa;
  --color-surface: #ffffff;
  --color-border: #e0e0e0;
  --color-text: #1a1a1a;
  --color-text-muted: #666666;

  --font-family:
    -apple-system, "Inter", "Segoe UI", Roboto, Helvetica, Arial, sans-serif;

  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-pill: 999px;

  --gap-xs: 6px;
  --gap-sm: 10px;
  --gap-md: 16px;
  --gap-lg: 24px;
  --gap-xl: 32px;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--font-family);
  color: var(--color-text);
  font-size: 16px;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  /* Soft-blue page base. White panels lift off the page tonally so the
     three-layer hierarchy (page → panel → elevated card) reads at all
     viewing distances. */
  background-color: #dfe8f4;
}

/* ---------- layout ---------- */

.pipeline {
  max-width: 1280px;
  margin: 0 auto;
  padding: var(--gap-xl) var(--gap-lg);
  display: grid;
  grid-template-rows: auto auto 1fr auto;
  gap: var(--gap-lg);
  min-height: 100vh;
}

/* Three layered surfaces: soft-blue page → white panels → elevated
   cards. White panels lift cleanly above the #dfe8f4 page; the 9%
   border defines panel edges crisply, and the 8%/6% shadow stack lifts
   the panel above the page. margin-bottom is intentionally omitted
   because .pipeline is a CSS Grid with gap. */
.panel {
  background: #ffffff;
  border: 1px solid rgba(0, 0, 0, 0.09);
  border-radius: 16px;
  padding: 28px 32px;
  box-shadow:
    0 4px 16px rgba(0, 0, 0, 0.08),
    0 1px 3px rgba(0, 0, 0, 0.06);
}

/* ---------- header ---------- */

.pipeline__header {
  text-align: left;
}

.header-eyebrow {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: #6b7280;
  margin: 0 0 8px;
}

.pipeline__title {
  font-size: 30px;
  font-weight: 600;
  letter-spacing: -0.01em;
  margin: 0 0 6px;
  color: var(--color-text);
}

.pipeline__subtitle {
  font-size: 16px;
  color: var(--color-text-muted);
  margin: 0;
}

/* Energy-blue anchor tying the header visually to the energy counter.
   Sized at 8×96 — masthead scale that lands as a deliberate publication
   element rather than a hairline. */
.header-accent {
  width: 96px;
  height: 8px;
  background: var(--color-energy);
  border-radius: 4px;
  margin-top: 14px;
  margin-bottom: 28px;
}

/* ---------- controls ---------- */

.controls {
  display: flex;
  flex-direction: column;
  gap: var(--gap-md);
}

.controls__group {
  border: none;
  margin: 0;
  padding: 0;
  display: flex;
  align-items: center;
  gap: var(--gap-md);
  flex-wrap: wrap;
}

.controls__legend {
  font-size: 13px;
  font-weight: 600;
  color: var(--color-text-muted);
  letter-spacing: 0.02em;
  padding: 0;
  margin-right: 4px;
  min-width: 56px;
}

.controls__row {
  display: flex;
  flex-wrap: wrap;
  gap: var(--gap-sm);
}

.controls__bottom-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--gap-md);
  flex-wrap: wrap;
}

/* ---------- buttons ---------- */

.btn {
  font-family: inherit;
  font-size: 14px;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  border: 1px solid var(--color-border);
  background: var(--color-surface);
  color: var(--color-text);
  padding: 8px 16px;
  transition:
    background-color 120ms ease,
    color 120ms ease,
    border-color 120ms ease;
}

.btn--pill {
  border-radius: var(--radius-pill);
}

.btn:hover {
  background: #f0f0f0;
}

.btn.is-selected {
  background: var(--color-text);
  color: var(--color-surface);
  border-color: var(--color-text);
}

.btn:focus-visible {
  outline: 2px solid var(--color-energy);
  outline-offset: 2px;
}

.btn__swatch {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  flex: 0 0 auto;
  background: var(--color-border);
}

.btn--model[data-org="meta"] .btn__swatch {
  background: var(--color-meta);
}
.btn--model[data-org="openai"] .btn__swatch {
  background: var(--color-openai);
}
.btn--model[data-org="anthropic"] .btn__swatch {
  background: var(--color-anthropic);
}
.btn--model[data-org="deepseek"] .btn__swatch {
  background: var(--color-deepseek);
}
.btn--model[data-org="mistral"] .btn__swatch {
  background: var(--color-mistral);
}

.btn--send {
  background: var(--color-energy);
  color: var(--color-surface);
  border-color: var(--color-energy);
  font-weight: 600;
  padding: 10px 20px;
  border-radius: var(--radius-pill);
}

.btn--send:hover {
  background: #005a8e;
  border-color: #005a8e;
}

.btn--send:focus-visible {
  outline-color: var(--color-text);
}

.btn__icon {
  font-size: 12px;
  line-height: 1;
}

/* ---------- visualization row ---------- */

.visualization {
  display: grid;
  grid-template-columns: minmax(220px, 260px) 1fr minmax(240px, 300px);
  gap: var(--gap-lg);
  align-items: start;
}

.viz-column {
  display: flex;
  flex-direction: column;
  gap: var(--gap-sm);
}

.viz-column--phone {
  align-items: center;
}

.viz-column__caption {
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-text-muted);
  margin: 4px 0 0;
}

/* ---------- phone ---------- */

.phone {
  width: 220px;
  height: 360px;
  background: var(--color-text);
  border-radius: 28px;
  padding: 14px;
  /* Same elevation tier as the counter cards — both are layer-3 cards
     sitting on the visualisation panel, calibrated above panel shadow. */
  box-shadow:
    0 8px 20px rgba(0, 0, 0, 0.1),
    0 2px 6px rgba(0, 0, 0, 0.06);
  display: flex;
  align-items: stretch;
  justify-content: stretch;
  position: relative;
}

.phone__status {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 24px;
  padding: 0 4px;
  margin: -2px 0 8px;
  font-size: 12.5px;
  font-weight: 500;
  font-variant-numeric: tabular-nums;
  color: #374151;
  border-bottom: 1px solid #e5e7eb;
}

.phone__status-time {
  letter-spacing: 0.01em;
}

.phone__status-icons {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.phone__icon {
  display: block;
}

.phone::before {
  /* speaker / notch */
  content: "";
  position: absolute;
  top: 6px;
  left: 50%;
  transform: translateX(-50%);
  width: 56px;
  height: 4px;
  background: #2b2b2b;
  border-radius: 2px;
}

.phone__screen {
  flex: 1;
  background: #f5f5f5;
  border-radius: 18px;
  padding: 16px 14px;
  display: flex;
  flex-direction: column;
  position: relative;
  overflow: hidden;
}

.phone__input {
  /* Sized to its rows attribute (six lines) but capped at 45% of the
     screen so the response area below has guaranteed space. */
  flex: 0 0 auto;
  max-height: 45%;
  width: 100%;
  border: none;
  outline: none;
  background: transparent;
  resize: none;
  font-family: inherit;
  font-size: 14px;
  line-height: 1.4;
  color: var(--color-text);
  cursor: default;
}

.phone__input:focus {
  outline: none;
}

.phone__input::placeholder {
  color: var(--color-text-muted);
}

/* Streaming model response. Monospace deliberately reads as "AI output"
   register — and the long-tier response IS code, which mono renders
   correctly. pre-wrap preserves newlines from the JSON string. */
.phone__response {
  flex: 1 1 auto;
  margin-top: 10px;
  padding-top: 10px;
  border-top: 1px solid rgba(0, 0, 0, 0.06);
  font-size: 12px;
  line-height: 1.55;
  color: var(--color-text);
  font-family: ui-monospace, "SF Mono", Menlo, monospace;
  overflow-y: auto;
  overflow-x: hidden;
  word-wrap: break-word;
  white-space: pre-wrap;
}

.phone__response[hidden] {
  display: none;
}

.phone__response-cursor {
  display: inline-block;
  width: 2px;
  height: 1em;
  background: var(--color-text);
  margin-left: 2px;
  vertical-align: text-bottom;
  animation: phone-response-blink 0.6s steps(2, start) infinite;
}

.phone__response-cursor[hidden] {
  display: none;
}

@keyframes phone-response-blink {
  to {
    visibility: hidden;
  }
}

.phone__caret {
  position: absolute;
  bottom: 14px;
  right: 14px;
  width: 2px;
  height: 16px;
  background: var(--color-energy);
  animation: phoneBlink 1100ms steps(2, jump-none) infinite;
}

@keyframes phoneBlink {
  to {
    opacity: 0;
  }
}

/* ---------- pipeline svg ---------- */

.viz-column--pipeline {
  align-self: stretch;
  justify-content: center;
}

.pipeline-svg {
  width: 100%;
  height: 100%;
  min-height: 220px;
  display: block;
}

.pipeline-track {
  fill: none;
  stroke: #d1d5db;
  stroke-width: 2.5;
  stroke-dasharray: 4 4;
  /* Slow drift makes the system feel alive when idle; -16 is exactly
     two dash-units (4 dash + 4 gap) so the loop is seamless. */
  animation: pipeline-track-shimmer 6s linear infinite;
}

@keyframes pipeline-track-shimmer {
  0% {
    stroke-dashoffset: 0;
  }
  100% {
    stroke-dashoffset: -16;
  }
}

.pipeline-stage {
  fill: #f9fafb;
  stroke: #9ca3af;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.pipeline-stage text {
  fill: #6b7280;
  stroke: none;
  font-size: 11px;
  font-weight: 500;
  font-family: inherit;
  text-anchor: middle;
}

.pipeline-stage__led {
  fill: var(--color-carbon);
  stroke: none;
}

/* White circular backdrops give each stage substance and visually break
   the dashed track into discrete waypoints. The data centre's backdrop
   is slightly larger and casts a soft drop shadow to mark it as the
   focal point of the pipeline. */
.pipeline-stage__backdrop {
  fill: #ffffff;
  stroke: rgba(0, 0, 0, 0.06);
  stroke-width: 1;
}

.pipeline-stage--datacentre .pipeline-stage__backdrop {
  filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.06));
}

/* Geographic callout above the data centre during the work phase. Two
   lines: region name (slightly bolder), then grid carbon + water stress
   (muted). opacity is set on the SVG group via setAttribute from JS so
   it interpolates through the CSS transition rather than snapping. */
.region-callout {
  transition: opacity 400ms ease;
}

.region-callout__line1 {
  fill: var(--color-text);
  font-size: 11px;
  font-weight: 600;
  font-family: inherit;
  letter-spacing: 0.02em;
}

.region-callout__line2 {
  fill: var(--color-text-muted);
  font-size: 10px;
  font-weight: 400;
  font-family: inherit;
}

/* ---------- counter cards ---------- */

.viz-column--counters {
  gap: var(--gap-md);
}

.counter {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 16px 18px;
  /* Card elevation calibrated above the panel's 8% shadow so the
     three-layer hierarchy reads cleanly: soft-blue page → white panel
     → elevated card. Cards now sit ~50% higher than panels. */
  box-shadow:
    0 8px 20px rgba(0, 0, 0, 0.1),
    0 2px 6px rgba(0, 0, 0, 0.06);
}

.counter__icon {
  font-size: 24px;
  line-height: 1;
  flex: 0 0 auto;
  margin-top: 2px;
}

.counter__body {
  display: flex;
  flex-direction: column;
  gap: 4px;
  min-width: 0;
}

.counter__label {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  margin: 0;
}

.counter__value {
  display: flex;
  align-items: baseline;
  gap: 6px;
  margin: 0;
  line-height: 1;
}

.counter__number {
  font-size: 44px;
  font-weight: 700;
  letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
  color: var(--color-text);
}

.counter__unit {
  font-size: 14px;
  color: var(--color-text-muted);
  font-weight: 500;
}

.counter__equiv {
  font-size: 12.5px;
  color: var(--color-text-muted);
  margin: 2px 0 0;
}

.counter[data-metric="energy"] .counter__icon {
  color: var(--color-energy);
}
.counter[data-metric="water"] .counter__icon {
  color: var(--color-water);
}
.counter[data-metric="carbon"] .counter__icon {
  color: var(--color-carbon);
}

/* ---------- insight ---------- */

.insight {
  font-size: 15px;
  font-style: italic;
  color: var(--color-text-muted);
  margin: 0;
  text-align: left;
  max-width: 75ch;
  /* Pretty is broadly supported; balance is the better choice for short
     paragraphs but not yet universal. Fall back gracefully. */
  text-wrap: pretty;
  text-wrap: balance;
}

.insight::before {
  content: "→ ";
  font-style: normal;
  color: var(--color-text-muted);
}

/* ---------- accessibility ---------- */

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* ---------- responsive ---------- */

@media (max-width: 900px) {
  .visualization {
    grid-template-columns: 1fr;
  }

  .viz-column--phone,
  .viz-column--pipeline,
  .viz-column--counters {
    align-self: stretch;
  }

  .viz-column--counters {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--gap-md);
  }

  .pipeline-svg {
    min-height: 200px;
  }
}

@media (max-width: 600px) {
  .pipeline {
    padding: var(--gap-lg) var(--gap-md);
    gap: var(--gap-md);
  }

  .panel {
    padding: 20px 18px;
    border-radius: 12px;
  }

  .pipeline__title {
    font-size: 24px;
  }

  .controls__bottom-row {
    flex-direction: column;
    align-items: stretch;
  }

  .btn--send {
    align-self: stretch;
    justify-content: center;
  }

  .counter__number {
    font-size: 36px;
  }

  .phone {
    width: 200px;
    height: 320px;
  }
}

/* ---------- reduced motion ---------- */

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

  .phone__caret {
    animation: none;
    opacity: 1;
  }

  .pipeline-track {
    animation: none;
  }

  .phone__response-cursor {
    animation: none;
  }

  .region-callout {
    transition: none;
  }
}

/* ---------- step 4: animation ---------- */

/* Stage stroke transitions when .is-active is toggled. The data centre's
   LED is excluded so its orange fill stays the only colour spot, and the
   stage backdrop is excluded so the white waypoint stays white. */
.pipeline-stage path,
.pipeline-stage line,
.pipeline-stage rect,
.pipeline-stage
  > circle:not(.pipeline-stage__led):not(.pipeline-stage__backdrop) {
  transition: stroke 200ms ease;
}

.pipeline-stage.is-active path,
.pipeline-stage.is-active line,
.pipeline-stage.is-active rect,
.pipeline-stage.is-active
  > circle:not(.pipeline-stage__led):not(.pipeline-stage__backdrop) {
  stroke: var(--color-text);
}

/* Travelling particle: subtle stroke for visual depth on light backgrounds. */
.particle {
  stroke: rgba(0, 0, 0, 0.12);
  stroke-width: 1;
}

/* Phone receive flash. Inset box-shadow keeps the screen layout pinned
   (a real border would shift the textarea by 2px on each toggle). */
.phone__screen {
  box-shadow: inset 0 0 0 0 transparent;
  transition: box-shadow 250ms ease;
}

.phone__screen.is-receiving {
  box-shadow: inset 0 0 0 2px var(--color-energy);
}

/* Disabled state during animation: visual cue beyond the browser default. */
.btn:disabled,
.btn[aria-disabled="true"] {
  opacity: 0.55;
  cursor: not-allowed;
}

/* ---------- comparison memory ---------- */

/* Header above the counter column when a previous run exists. Quiet
   muted register so it reads as context, not as primary content. */
.comparison-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  font-size: 12px;
  color: var(--color-text-muted);
}

.comparison-header__model {
  color: var(--color-text);
  font-weight: 500;
}

.comparison-header__clear {
  background: transparent;
  border: 0;
  font-size: 11px;
  color: var(--color-text-muted);
  cursor: pointer;
  padding: 4px 6px;
  font-family: inherit;
  border-radius: 4px;
}

.comparison-header__clear:hover {
  color: var(--color-text);
  background: rgba(0, 0, 0, 0.04);
}

.comparison-header__clear:focus-visible {
  outline: 2px solid var(--color-energy);
  outline-offset: 2px;
}

/* Per-card previous value. Italic differentiates from the equivalence
   line above it without changing the muted register. */
.counter__previous {
  font-size: 12.5px;
  color: var(--color-text-muted);
  font-style: italic;
  margin: 2px 0 0;
}

/* When the counter column reflows to a grid at narrow widths, the
   comparison header should span every column rather than collapse into
   the first cell. */
@media (max-width: 900px) {
  .comparison-header {
    grid-column: 1 / -1;
  }
}