@font-face {
  font-family: "Archivo Narrow";
  src: url("./fonts/ArchivoNarrow.woff2") format("woff2");
  font-style: normal;
  font-weight: 400 900;
  font-display: swap;
}

@font-face {
  font-family: "Atkinson Hyperlegible Next";
  src: url("./fonts/AtkinsonHyperlegibleNext.woff2") format("woff2");
  font-style: normal;
  font-weight: 300 800;
  font-display: swap;
}

@font-face {
  font-family: "IBM Plex Mono";
  src: url("./fonts/IBMPlexMono-Regular.woff2") format("woff2");
  font-style: normal;
  font-weight: 400;
  font-display: swap;
}

:root {
  --table: #edf7f8;
  --ice: #d6f4f6;
  --ice-bright: #f8ffff;
  --fracture: #72aeb8;
  --ink: #16343b;
  --ink-soft: #3f5d63;
  --cobalt: #0b6388;
  --signal: #e34b2f;
  --line: #b8d0d4;
  --white: #ffffff;
  --display: "Archivo Narrow", "Arial Narrow", sans-serif;
  --body: "Atkinson Hyperlegible Next", Arial, sans-serif;
  --mono: "IBM Plex Mono", ui-monospace, monospace;
  color-scheme: light;
}

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

html {
  background: var(--table);
  color: var(--ink);
  scroll-behavior: smooth;
  text-rendering: optimizeLegibility;
}

body {
  margin: 0;
  min-width: 320px;
  overflow-x: clip;
  background: var(--table);
  font-family: var(--body);
  font-size: 1.125rem;
  line-height: 1.55;
}

a {
  color: inherit;
  text-decoration-thickness: 0.08em;
  text-underline-offset: 0.18em;
}

a:hover {
  text-decoration-color: var(--signal);
}

button,
input {
  font: inherit;
}

button,
a,
input {
  -webkit-tap-highlight-color: transparent;
}

:focus-visible {
  outline: 3px solid var(--signal);
  outline-offset: 4px;
}

::selection {
  background: var(--signal);
  color: var(--white);
}

.page-grid {
  width: min(100% - 48px, 1320px);
  margin-inline: auto;
}

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

.skip-link {
  position: fixed;
  z-index: 100;
  top: 12px;
  left: 12px;
  padding: 10px 14px;
  transform: translateY(-160%);
  background: var(--ink);
  color: var(--white);
}

.skip-link:focus {
  transform: none;
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 72px;
  border-bottom: 1px solid var(--line);
  font-family: var(--display);
  font-size: 0.96rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
}

.brand-glyph {
  display: grid;
  width: 34px;
  height: 28px;
  place-items: center;
  border: 1px solid var(--ink);
  background: var(--ice-bright);
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0;
}

.header-nav {
  display: flex;
  align-items: center;
  gap: clamp(18px, 3vw, 42px);
}

.header-nav a {
  text-decoration: none;
}

.language-link {
  display: grid;
  width: 42px;
  height: 42px;
  place-items: center;
  border: 1px solid var(--ink);
  background: transparent;
  transition: background-color 160ms ease, color 160ms ease;
}

.language-link:hover {
  background: var(--ink);
  color: var(--white);
}

.hero {
  min-height: calc(100svh - 72px);
  padding: clamp(66px, 9vw, 132px) 0 clamp(70px, 9vw, 126px);
  background:
    linear-gradient(90deg, transparent calc(50% - 1px), rgba(114, 174, 184, 0.2) 50%, transparent calc(50% + 1px)),
    var(--table);
}

.eyebrow,
.section-kicker {
  margin: 0 0 22px;
  color: var(--cobalt);
  font-family: var(--mono);
  font-size: 0.74rem;
  letter-spacing: 0.08em;
  line-height: 1.4;
  text-transform: uppercase;
}

.hero h1,
h2,
.not-found h1 {
  margin: 0;
  font-family: var(--display);
  font-weight: 800;
  letter-spacing: -0.045em;
}

.hero h1 {
  max-width: 10.6ch;
  font-size: clamp(4.6rem, 11.2vw, 10.4rem);
  line-height: 0.82;
}

.hero-deck {
  max-width: 720px;
  margin: clamp(34px, 5vw, 66px) 0 0;
  color: var(--ink-soft);
  font-size: clamp(1.25rem, 2vw, 1.65rem);
  line-height: 1.42;
}

.co2-scale {
  margin: clamp(64px, 9vw, 126px) 0 0;
}

.scale-axis {
  position: relative;
  height: 31px;
  border-bottom: 1px solid var(--ink);
  font-family: var(--mono);
  font-size: 0.66rem;
}

.scale-axis span {
  position: absolute;
  bottom: 7px;
  left: var(--tick);
  transform: translateX(-50%);
  white-space: nowrap;
}

.scale-axis span:first-child {
  transform: none;
}

.scale-axis span:last-child {
  transform: translateX(-100%);
}

.scale-axis span:last-child::after {
  content: " ppm";
}

.scale-field {
  position: relative;
  height: 196px;
  overflow: visible;
  border-bottom: 1px solid var(--line);
  background: repeating-linear-gradient(90deg, transparent 0, transparent calc(5% - 1px), rgba(114, 174, 184, 0.25) 5%);
}

.ancient-band {
  position: absolute;
  top: 62px;
  left: var(--ancient-start);
  width: calc(var(--ancient-end) - var(--ancient-start));
  height: 36px;
  border: 1px solid var(--cobalt);
  background: var(--ice);
}

.ancient-band::before {
  content: "";
  position: absolute;
  inset: 7px 0;
  background: repeating-linear-gradient(90deg, transparent 0 11px, rgba(11, 99, 136, 0.16) 11px 12px);
}

.minimum-pin,
.maximum-pin,
.current-pin {
  position: absolute;
  z-index: 2;
  display: flex;
  flex-direction: column;
  gap: 2px;
  font-style: normal;
  line-height: 1.15;
  white-space: nowrap;
}

.minimum-pin b,
.maximum-pin b,
.current-pin b {
  font-family: var(--mono);
  font-size: clamp(0.84rem, 1.4vw, 1rem);
  font-weight: 400;
}

.minimum-pin i,
.maximum-pin i,
.current-pin i {
  color: var(--ink-soft);
  font-family: var(--display);
  font-size: 0.68rem;
  font-style: normal;
  font-weight: 700;
  letter-spacing: 0.07em;
  text-transform: uppercase;
}

.minimum-pin {
  top: 18px;
  left: var(--ancient-start);
  transform: translateX(-3px);
}

.maximum-pin {
  top: 107px;
  left: var(--ancient-end);
  transform: translateX(-100%);
  text-align: right;
}

.current-pin {
  top: 18px;
  left: var(--current);
  transform: translateX(-100%);
  color: var(--signal);
  text-align: right;
}

.current-pin i {
  color: var(--signal);
}

.minimum-pin::after,
.maximum-pin::before,
.current-pin::after {
  content: "";
  position: absolute;
  width: 1px;
  background: currentColor;
}

.minimum-pin::after {
  top: 37px;
  left: 2px;
  height: 44px;
}

.maximum-pin::before {
  right: 2px;
  bottom: 36px;
  height: 45px;
}

.current-pin::after {
  top: 38px;
  right: 2px;
  height: 109px;
  width: 3px;
  background: var(--signal);
}

.range-bracket {
  position: absolute;
  top: 151px;
  height: 14px;
  border: solid currentColor;
  border-width: 0 1px 1px;
}

.ancient-bracket {
  left: var(--ancient-start);
  width: calc(var(--ancient-end) - var(--ancient-start));
  color: var(--cobalt);
}

.current-bracket {
  left: var(--ancient-end);
  width: calc(var(--current) - var(--ancient-end));
  color: var(--signal);
}

.co2-scale figcaption {
  display: flex;
  gap: 24px;
  justify-content: space-between;
  margin-top: 16px;
  color: var(--ink-soft);
  font-size: 0.88rem;
}

.co2-scale figcaption span {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.legend-swatch {
  width: 22px;
  height: 8px;
}

.legend-swatch.ancient {
  border: 1px solid var(--cobalt);
  background: var(--ice);
}

.legend-swatch.current {
  width: 3px;
  height: 18px;
  background: var(--signal);
}

.scale-intervals {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: clamp(20px, 4vw, 64px);
  margin-top: 40px;
}

.scale-intervals span {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 8px 16px;
  border-top: 2px solid currentColor;
  padding-top: 12px;
  color: var(--cobalt);
  font-family: var(--display);
  font-size: 0.92rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.scale-intervals .current-interval {
  color: var(--signal);
}

.scale-intervals b {
  font-family: var(--mono);
  font-size: clamp(1.45rem, 3vw, 2.4rem);
  font-weight: 400;
  letter-spacing: -0.05em;
}

.instrument-section {
  padding: clamp(88px, 11vw, 160px) 0;
  border-top: 1px solid var(--line);
  background: var(--white);
}

.instrument-heading {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: 0 24px;
}

.instrument-heading .section-kicker {
  grid-column: 1 / -1;
}

.instrument-heading h2 {
  grid-column: 1 / span 8;
  font-size: clamp(3.4rem, 7vw, 7.2rem);
  line-height: 0.88;
}

.instrument-heading .section-intro {
  grid-column: 9 / -1;
  align-self: end;
  margin: 0;
  color: var(--ink-soft);
  font-size: 1.16rem;
}

.lab-bench {
  position: relative;
  width: min(100% - 48px, 1420px);
  margin: clamp(58px, 8vw, 108px) auto 0;
  padding: clamp(26px, 4vw, 56px);
  border: 1px solid #9bbbc0;
  background:
    linear-gradient(135deg, rgba(255, 255, 255, 0.86), rgba(237, 247, 248, 0.38)),
    repeating-linear-gradient(90deg, transparent 0 39px, rgba(114, 174, 184, 0.08) 39px 40px),
    var(--ice-bright);
  box-shadow: 0 28px 72px rgba(22, 52, 59, 0.12), inset 0 0 0 8px rgba(255, 255, 255, 0.5);
}

.bench-stamp {
  position: absolute;
  top: 14px;
  right: 18px;
  color: #66858b;
  font-family: var(--mono);
  font-size: 0.58rem;
  letter-spacing: 0.08em;
}

.core-caption {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 14px;
  margin: 18px 0 14px;
  color: var(--ink-soft);
  font-family: var(--display);
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.07em;
  text-transform: uppercase;
}

.core-caption b {
  color: var(--ink);
  font-family: var(--mono);
  font-size: 0.64rem;
  font-weight: 400;
}

.core-caption span:last-child {
  text-align: right;
}

.core-machine {
  position: relative;
  height: clamp(128px, 14vw, 190px);
  border-block: 1px solid #8eb0b5;
  background: linear-gradient(180deg, #d8e7e9, #f8ffff 24%, #edf7f8 78%, #c9dade);
  box-shadow: inset 0 12px 24px rgba(22, 52, 59, 0.09), inset 0 -12px 24px rgba(22, 52, 59, 0.08);
}

.core-machine::before,
.core-machine::after {
  content: "";
  position: absolute;
  z-index: 4;
  top: 0;
  bottom: 0;
  width: 34px;
  pointer-events: none;
}

.core-machine::before {
  left: 0;
  background: linear-gradient(90deg, rgba(22, 52, 59, 0.22), transparent);
}

.core-machine::after {
  right: 0;
  background: linear-gradient(270deg, rgba(22, 52, 59, 0.22), transparent);
}

.core-tube {
  position: absolute;
  top: 50%;
  right: 2.5%;
  left: 2.5%;
  height: 62%;
  overflow: hidden;
  transform: translateY(-50%);
  border: 2px solid #6f979e;
  border-radius: 999px;
  background: #bde5e9;
  box-shadow: inset 0 14px 17px rgba(255, 255, 255, 0.88), inset 0 -17px 24px rgba(11, 99, 136, 0.21), 0 8px 16px rgba(22, 52, 59, 0.12);
}

.core-moving {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 9% 58%, rgba(255, 255, 255, 0.95) 0 3px, rgba(11, 99, 136, 0.25) 4px 5px, transparent 6px),
    radial-gradient(circle at 31% 30%, rgba(255, 255, 255, 0.95) 0 2px, rgba(11, 99, 136, 0.2) 3px 4px, transparent 5px),
    radial-gradient(circle at 54% 66%, rgba(255, 255, 255, 0.96) 0 5px, rgba(11, 99, 136, 0.2) 6px 7px, transparent 8px),
    radial-gradient(circle at 77% 39%, rgba(255, 255, 255, 0.94) 0 3px, rgba(11, 99, 136, 0.22) 4px 5px, transparent 6px),
    repeating-linear-gradient(94deg, transparent 0 47px, rgba(11, 99, 136, 0.11) 48px, transparent 50px 93px),
    linear-gradient(180deg, rgba(255, 255, 255, 0.42), rgba(114, 174, 184, 0.12));
  background-position: var(--core-shift) center;
  transition: background-position 360ms cubic-bezier(0.2, 0.7, 0.2, 1);
}

.core-moving .fracture {
  position: absolute;
  width: 120px;
  height: 1px;
  background: rgba(11, 99, 136, 0.28);
  transform-origin: left;
}

.core-moving .fracture.one {
  top: 22%;
  left: 30%;
  transform: rotate(14deg);
}

.core-moving .fracture.two {
  right: 18%;
  bottom: 28%;
  transform: rotate(-17deg);
}

.core-moving .bubble {
  position: absolute;
  width: 8px;
  height: 8px;
  border: 1px solid rgba(11, 99, 136, 0.38);
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.7);
}

.core-moving .bubble.one { top: 28%; left: 38%; }
.core-moving .bubble.two { right: 35%; bottom: 21%; width: 13px; height: 13px; }
.core-moving .bubble.three { top: 19%; right: 18%; width: 5px; height: 5px; }

.extraction-gate {
  position: absolute;
  z-index: 5;
  top: -14px;
  bottom: -14px;
  left: 50%;
  width: clamp(72px, 8vw, 116px);
  transform: translateX(-50%);
  border: solid var(--ink);
  border-width: 0 7px;
  background: linear-gradient(90deg, rgba(255, 255, 255, 0.03), rgba(255, 255, 255, 0.5), rgba(255, 255, 255, 0.03));
  box-shadow: -10px 0 16px rgba(22, 52, 59, 0.08), 10px 0 16px rgba(22, 52, 59, 0.08);
}

.extraction-gate::before,
.extraction-gate::after {
  content: "";
  position: absolute;
  right: -12px;
  left: -12px;
  height: 15px;
  border: 2px solid var(--ink);
  background: linear-gradient(#f8ffff, #a9c0c4);
}

.extraction-gate::before { top: 0; }
.extraction-gate::after { bottom: 0; }

.extraction-gate span {
  position: absolute;
  top: -28px;
  left: 50%;
  width: max-content;
  transform: translateX(-50%);
  padding: 2px 7px;
  background: var(--ink);
  color: var(--white);
  font-family: var(--mono);
  font-size: 0.56rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.extraction-gate i {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 22px;
  height: 22px;
  transform: translate(-50%, -50%);
  border: 3px solid var(--signal);
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.78);
  box-shadow: 0 0 0 8px rgba(227, 75, 47, 0.09);
}

.sample-trace {
  display: block;
  width: 100%;
  height: clamp(86px, 10vw, 132px);
  margin-top: 18px;
  overflow: visible;
}

.trace-base {
  stroke: var(--line);
  stroke-width: 1;
}

.trace-line {
  fill: none;
  stroke: var(--cobalt);
  stroke-width: 2;
  vector-effect: non-scaling-stroke;
}

.trace-point {
  fill: var(--signal);
  stroke: var(--white);
  stroke-width: 4;
  vector-effect: non-scaling-stroke;
  transition: cx 240ms ease, cy 240ms ease;
}

.readout-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  margin: 16px 0 0;
  border-block: 1px solid var(--ink);
}

.readout-grid > div {
  min-width: 0;
  padding: clamp(18px, 3vw, 32px) clamp(10px, 2vw, 24px);
  border-left: 1px solid var(--line);
}

.readout-grid > div:first-child {
  border-left: 0;
}

.readout-grid dt {
  margin-bottom: 16px;
  color: var(--ink-soft);
  font-family: var(--display);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.readout-grid dd {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 4px 9px;
  margin: 0;
  font-family: var(--mono);
}

.readout-grid output {
  min-width: 0;
  overflow-wrap: anywhere;
  color: var(--ink);
  font-size: clamp(1.4rem, 3.5vw, 3rem);
  letter-spacing: -0.07em;
  line-height: 1;
}

.readout-grid > div:last-child output {
  color: var(--cobalt);
}

.readout-grid dd > span {
  color: var(--ink-soft);
  font-size: 0.76rem;
}

.readout-grid small {
  flex-basis: 100%;
  margin-top: 7px;
  color: var(--ink-soft);
  font-size: 0.62rem;
}

.sample-context {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  margin-top: 28px;
}

.sample-context p {
  margin: 0;
  padding-left: 15px;
  border-left: 3px solid var(--fracture);
  color: var(--ink-soft);
  font-size: 0.98rem;
}

.sample-context p:last-child {
  border-color: var(--cobalt);
}

.sample-context strong {
  color: var(--ink);
  font-family: var(--mono);
  font-weight: 400;
}

.instrument-controls {
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: clamp(12px, 2vw, 26px);
  align-items: end;
  margin-top: 44px;
}

.step-button,
.preset-row button {
  min-height: 48px;
  border: 1px solid var(--ink);
  border-radius: 0;
  background: transparent;
  color: var(--ink);
  cursor: pointer;
  font-family: var(--display);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  transition: background-color 150ms ease, color 150ms ease;
}

.step-button {
  padding: 10px 17px;
}

.step-button:hover:not(:disabled),
.preset-row button:hover {
  background: var(--ink);
  color: var(--white);
}

.step-button:disabled {
  opacity: 0.34;
  cursor: not-allowed;
}

.range-shell label {
  display: block;
  margin-bottom: 11px;
  color: var(--ink-soft);
  font-size: 0.79rem;
}

input[type="range"] {
  width: 100%;
  height: 30px;
  margin: 0;
  appearance: none;
  background: transparent;
  cursor: ew-resize;
}

input[type="range"]::-webkit-slider-runnable-track {
  height: 3px;
  border: 0;
  background: linear-gradient(90deg, var(--cobalt), var(--fracture));
}

input[type="range"]::-webkit-slider-thumb {
  width: 24px;
  height: 24px;
  margin-top: -10px;
  appearance: none;
  border: 5px solid var(--white);
  border-radius: 0;
  background: var(--signal);
  box-shadow: 0 0 0 1px var(--ink);
}

input[type="range"]::-moz-range-track {
  height: 3px;
  border: 0;
  background: linear-gradient(90deg, var(--cobalt), var(--fracture));
}

input[type="range"]::-moz-range-thumb {
  width: 16px;
  height: 16px;
  border: 5px solid var(--white);
  border-radius: 0;
  background: var(--signal);
  box-shadow: 0 0 0 1px var(--ink);
}

.range-ends {
  display: flex;
  justify-content: space-between;
  color: var(--ink-soft);
  font-family: var(--mono);
  font-size: 0.62rem;
}

.range-ends span::after {
  content: " m";
}

.preset-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-top: 24px;
}

.preset-row > span {
  margin-right: 6px;
  color: var(--ink-soft);
  font-family: var(--mono);
  font-size: 0.62rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.preset-row button {
  min-height: 38px;
  padding: 7px 12px;
  border-color: var(--line);
  font-size: 0.69rem;
}

.nojs-samples {
  margin-top: 52px;
  border-top: 1px solid var(--ink);
  padding-top: 30px;
}

.js .nojs-samples {
  display: none;
}

.no-js .js-controls {
  display: none;
}

.nojs-samples h3 {
  margin: 0;
  font-family: var(--display);
  font-size: 2rem;
}

.nojs-samples > p {
  max-width: 62ch;
  color: var(--ink-soft);
}

.table-scroll {
  overflow-x: auto;
}

table {
  width: 100%;
  border-collapse: collapse;
  font-family: var(--mono);
  font-size: 0.78rem;
}

th,
td {
  padding: 12px 10px;
  border-bottom: 1px solid var(--line);
  text-align: left;
  white-space: nowrap;
}

th {
  color: var(--ink-soft);
  font-family: var(--display);
  font-size: 0.68rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.comparison-section {
  padding: clamp(92px, 12vw, 170px) 0;
  border-top: 1px solid var(--line);
  background: var(--table);
}

.comparison-grid {
  display: grid;
  grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
  gap: clamp(52px, 9vw, 130px);
  align-items: end;
}

.comparison-copy h2,
.mechanism-section h2,
.method-copy h2 {
  font-size: clamp(3.3rem, 6.7vw, 7rem);
  line-height: 0.9;
}

.comparison-copy > p:not(.section-kicker),
.method-copy > p:not(.section-kicker) {
  margin: 30px 0 0;
  color: var(--ink-soft);
}

.interval-figure {
  margin: 0;
  border-block: 1px solid var(--ink);
  padding: clamp(26px, 4vw, 52px) 0;
}

.interval-row + .interval-row {
  margin-top: 48px;
}

.interval-label {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 20px;
  margin-bottom: 12px;
}

.interval-label span {
  font-family: var(--display);
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.interval-label b {
  font-family: var(--mono);
  font-size: clamp(1.05rem, 2vw, 1.4rem);
  font-weight: 400;
}

.interval-track {
  height: 42px;
  border: 1px solid var(--line);
  background: var(--white);
}

.interval-track span {
  display: block;
  width: 100%;
  height: 100%;
  background: var(--cobalt);
}

.interval-row.current .interval-track span {
  background: var(--signal);
}

.interval-ends {
  display: flex;
  justify-content: space-between;
  margin-top: 7px;
  color: var(--ink-soft);
  font-family: var(--mono);
  font-size: 0.68rem;
}

.interval-figure figcaption {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 20px;
  align-items: start;
  margin-top: 54px;
  border-top: 1px solid var(--line);
  padding-top: 22px;
  color: var(--ink-soft);
  font-size: 0.9rem;
}

.interval-figure figcaption strong {
  color: var(--signal);
  font-family: var(--mono);
  font-size: 1.05rem;
  font-weight: 400;
  white-space: nowrap;
}

.mechanism-section {
  padding: clamp(92px, 12vw, 170px) 0;
  border-top: 1px solid var(--line);
  background: var(--ice);
}

.mechanism-section h2 {
  max-width: 9ch;
}

.mechanism-section .section-intro {
  max-width: 700px;
  margin: 34px 0 0;
  color: var(--ink-soft);
  font-size: 1.2rem;
}

.firn-stages {
  position: relative;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0;
  margin: clamp(62px, 9vw, 112px) 0 0;
  padding: 0;
  list-style: none;
  border-block: 1px solid var(--ink);
}

.firn-stages li {
  position: relative;
  padding: 30px clamp(20px, 3vw, 42px) 40px;
  border-left: 1px solid rgba(22, 52, 59, 0.35);
}

.firn-stages li:first-child {
  border-left: 0;
}

.firn-stages svg {
  display: block;
  width: 100%;
  height: 120px;
  margin-bottom: 24px;
  color: var(--cobalt);
  fill: none;
  stroke: currentColor;
  stroke-width: 2;
}

.firn-stages .snow-dots {
  fill: rgba(255, 255, 255, 0.86);
  stroke: var(--cobalt);
}

.firn-stages li:nth-child(3) svg path {
  fill: rgba(255, 255, 255, 0.52);
}

.firn-stages li:nth-child(3) svg circle {
  fill: var(--ice-bright);
}

.firn-stages li > span {
  font-family: var(--mono);
  font-size: 0.66rem;
}

.firn-stages h3 {
  margin: 10px 0 0;
  font-family: var(--display);
  font-size: 2rem;
  line-height: 1;
}

.firn-stages p {
  margin: 18px 0 0;
  color: var(--ink-soft);
  font-size: 0.96rem;
}

.selected-gap {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 24px;
  margin-top: 40px;
  border-bottom: 1px solid var(--ink);
  padding-bottom: 16px;
  font-family: var(--display);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.selected-gap p {
  margin: 0;
  color: var(--cobalt);
  font-family: var(--mono);
  font-size: clamp(1.5rem, 4vw, 3.2rem);
  font-weight: 400;
  letter-spacing: -0.06em;
  text-transform: none;
}

.method-section {
  padding: clamp(92px, 12vw, 170px) 0;
  background: var(--white);
}

.method-grid {
  display: grid;
  grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
  gap: clamp(52px, 9vw, 130px);
}

.sources-block {
  align-self: start;
  border-top: 1px solid var(--ink);
  padding-top: 22px;
}

.sources-block h3 {
  margin: 0;
  font-family: var(--display);
  font-size: 2.2rem;
  line-height: 1;
}

.sources-block > p {
  color: var(--ink-soft);
  font-size: 0.94rem;
}

.sources-block ol {
  margin: 30px 0 0;
  padding: 0;
  list-style: none;
  counter-reset: sources;
}

.sources-block li {
  display: grid;
  grid-template-columns: 90px 1fr;
  gap: 14px;
  padding: 17px 0;
  border-top: 1px solid var(--line);
  counter-increment: sources;
}

.sources-block li > span {
  color: var(--ink-soft);
  font-family: var(--mono);
  font-size: 0.58rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.sources-block li a {
  font-size: 0.88rem;
  line-height: 1.35;
}

.sources-block .accessed {
  margin-top: 28px;
  color: var(--cobalt);
  font-family: var(--mono);
  font-size: 0.66rem;
  text-transform: uppercase;
}

.closing {
  padding: clamp(80px, 12vw, 170px) 0;
  border-block: 1px solid var(--ink);
  background: var(--ink);
  color: var(--ice-bright);
}

.closing p {
  max-width: 16ch;
  margin: 0;
  font-family: var(--display);
  font-size: clamp(3.5rem, 8vw, 8rem);
  font-weight: 800;
  letter-spacing: -0.045em;
  line-height: 0.88;
}

.site-footer {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 12px 32px;
  align-items: center;
  padding-block: 38px 48px;
  font-family: var(--mono);
  font-size: 0.67rem;
}

.site-footer p {
  margin: 0;
}

.site-footer p:last-child {
  grid-column: 2;
}

.back-to-top {
  grid-row: 1 / span 2;
  justify-self: start;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  min-height: 44px;
  font-family: var(--display);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-decoration: none;
  text-transform: uppercase;
}

.back-to-top span {
  color: var(--signal);
  font-family: var(--mono);
  font-size: 1rem;
}

.not-found {
  display: grid;
  min-height: 100svh;
  place-items: center;
  padding: 24px;
}

.not-found main {
  width: min(100%, 760px);
}

.not-found h1 {
  font-size: clamp(4rem, 12vw, 9rem);
  line-height: 0.86;
}

.not-found main > p:not(.eyebrow) {
  max-width: 48ch;
  color: var(--ink-soft);
}

@media (max-width: 900px) {
  .instrument-heading h2,
  .instrument-heading .section-intro {
    grid-column: 1 / -1;
  }

  .instrument-heading .section-intro {
    max-width: 680px;
    margin-top: 28px;
  }

  .comparison-grid,
  .method-grid {
    grid-template-columns: 1fr;
  }

  .comparison-copy h2,
  .method-copy h2 {
    max-width: 10ch;
  }

  .interval-figure {
    max-width: 760px;
  }
}

@media (max-width: 680px) {
  body {
    font-size: 1.03rem;
  }

  .page-grid,
  .lab-bench {
    width: min(100% - 28px, 1320px);
  }

  .site-header {
    min-height: 62px;
    font-size: 0.78rem;
  }

  .brand {
    gap: 7px;
  }

  .brand-glyph {
    width: 30px;
    height: 26px;
    font-size: 0.6rem;
  }

  .header-nav {
    gap: 14px;
  }

  .language-link {
    width: 38px;
    height: 38px;
  }

  .hero {
    min-height: 0;
    padding-top: 70px;
    background: var(--table);
  }

  .hero h1 {
    max-width: 9.4ch;
    font-size: clamp(4.15rem, 20vw, 6.3rem);
  }

  .hero-deck {
    font-size: 1.18rem;
  }

  .co2-scale {
    margin-top: 70px;
  }

  .scale-field {
    height: 224px;
  }

  .ancient-band {
    top: 72px;
  }

  .minimum-pin {
    top: 26px;
  }

  .minimum-pin::after {
    height: 46px;
  }

  .maximum-pin {
    top: 117px;
  }

  .current-pin {
    top: 14px;
    transform: translateX(-100%);
  }

  .current-pin i {
    width: 110px;
    white-space: normal;
  }

  .current-pin::after {
    height: 153px;
  }

  .range-bracket {
    top: 181px;
  }

  .co2-scale figcaption {
    flex-direction: column;
    gap: 8px;
  }

  .scale-intervals {
    grid-template-columns: 1fr;
  }

  .instrument-heading h2,
  .comparison-copy h2,
  .mechanism-section h2,
  .method-copy h2 {
    font-size: clamp(3.4rem, 16vw, 5.2rem);
  }

  .lab-bench {
    padding: 24px 14px 30px;
    box-shadow: 0 18px 42px rgba(22, 52, 59, 0.12);
  }

  .bench-stamp {
    display: none;
  }

  .core-caption {
    grid-template-columns: 1fr 1fr;
  }

  .core-caption b {
    display: none;
  }

  .core-machine {
    height: 126px;
  }

  .core-tube {
    right: -28px;
    left: -28px;
  }

  .extraction-gate {
    width: 76px;
  }

  .readout-grid {
    grid-template-columns: 1fr 1fr;
  }

  .readout-grid > div:nth-child(3) {
    border-left: 0;
    border-top: 1px solid var(--line);
  }

  .readout-grid > div:nth-child(4) {
    border-top: 1px solid var(--line);
  }

  .readout-grid output {
    font-size: clamp(1.3rem, 8vw, 2.2rem);
  }

  .sample-context {
    grid-template-columns: 1fr;
  }

  .instrument-controls {
    grid-template-columns: 1fr 1fr;
    align-items: stretch;
  }

  .range-shell {
    grid-row: 1;
    grid-column: 1 / -1;
  }

  .step-button {
    grid-row: 2;
    padding: 9px 8px;
    font-size: 0.68rem;
  }

  .preset-row > span {
    flex-basis: 100%;
  }

  .comparison-grid {
    gap: 62px;
  }

  .interval-label {
    align-items: flex-start;
  }

  .interval-label span {
    max-width: 21ch;
  }

  .interval-track {
    height: 34px;
  }

  .interval-figure figcaption {
    grid-template-columns: 1fr;
  }

  .firn-stages {
    grid-template-columns: 1fr;
  }

  .firn-stages li {
    display: grid;
    grid-template-columns: 130px 1fr;
    gap: 0 22px;
    border-top: 1px solid rgba(22, 52, 59, 0.35);
    border-left: 0;
  }

  .firn-stages li:first-child {
    border-top: 0;
  }

  .firn-stages svg {
    grid-row: 1 / span 3;
    height: 100px;
    margin: 0;
  }

  .firn-stages h3 {
    font-size: 1.8rem;
  }

  .firn-stages p {
    margin-top: 12px;
  }

  .selected-gap {
    display: block;
  }

  .selected-gap p {
    margin-top: 8px;
  }

  .sources-block li {
    grid-template-columns: 1fr;
    gap: 5px;
  }

  .closing p {
    font-size: clamp(3.5rem, 15.5vw, 5.7rem);
  }

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

  .site-footer p:last-child {
    grid-column: 1;
  }

  .back-to-top {
    grid-row: auto;
    margin-bottom: 16px;
  }
}

@media (max-width: 430px) {
  .page-grid,
  .lab-bench {
    width: min(100% - 24px, 1320px);
  }

  .hero h1 {
    font-size: clamp(4rem, 19.5vw, 5.25rem);
  }

  .scale-axis span:nth-child(2),
  .scale-axis span:nth-child(4) {
    display: none;
  }

  .minimum-pin i,
  .maximum-pin i {
    max-width: 86px;
    white-space: normal;
  }

  .readout-grid > div {
    padding-inline: 8px;
  }

  .firn-stages li {
    grid-template-columns: 96px 1fr;
    gap: 0 15px;
    padding-inline: 8px;
  }
}

.js .back-to-top {
  position: fixed;
  z-index: 20;
  right: clamp(12px, 2.5vw, 32px);
  bottom: var(--back-top-bottom, 20px);
  width: 52px;
  height: 52px;
  min-height: 52px;
  justify-content: center;
  margin: 0;
  border: 1px solid var(--ink);
  background: rgba(237, 247, 248, 0.96);
  box-shadow: 5px 5px 0 rgba(22, 52, 59, 0.14);
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transform: translateY(10px);
  transition: opacity 160ms ease, transform 160ms ease, visibility 160ms ease, bottom 120ms linear;
}

.js .back-to-top.is-visible {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
  transform: translateY(0);
}

.js .back-to-top:hover {
  background: var(--ice);
}

.js .back-to-top .back-label {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
}

.js .back-to-top .back-arrow {
  color: var(--signal);
  font-size: 1.35rem;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition-duration: 0.001ms !important;
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
  }
}

@media print {
  .site-header,
  .site-footer,
  .js-controls,
  .skip-link {
    display: none !important;
  }

  body,
  .hero,
  .instrument-section,
  .comparison-section,
  .mechanism-section,
  .method-section,
  .closing {
    background: white !important;
    color: black !important;
  }

  .closing p {
    color: black;
  }

  a {
    text-decoration: none;
  }
}

.co2-scale {
  --ancient-start: 4.896%;
  --ancient-end: 49.500%;
  --current: 94.864%;
}
.scale-axis span:nth-child(1) { --tick: 0%; }
.scale-axis span:nth-child(2) { --tick: 14.286%; }
.scale-axis span:nth-child(3) { --tick: 50%; }
.scale-axis span:nth-child(4) { --tick: 85.714%; }
.scale-axis span:nth-child(5) { --tick: 100%; }
.instrument-section { --core-shift: 100%; }
.interval-row.old .interval-track span { width: 98.323%; }