:root {
  color-scheme: dark;
  --ground: #131a10;
  --ground-2: #1a2315;
  --ground-3: #24301d;
  --ground-deep: #0d1209;
  --rule: #46563a;
  --head: #f0f3e6;
  --text: #dee3d2;
  --dim: #aebb9c;
  --moss: #9cbe75;
  --moss-mid: #5f7a42;
  --moss-deep: #2a3720;
  --cyan: #63d2df;
  --cyan-b: #8ee6f0;
  --chip: #cfe0bc;
  --chip-ink: #14190f;
  --track: #6a7360;
  --font-text: "Iowan Old Style", "Palatino Linotype", Palatino, "Book Antiqua", Georgia, serif;
  --font-ui: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
  --gut: clamp(20px, 5vw, 48px);
  --rhythm: clamp(64px, 9vw, 128px);
}

*, *::before, *::after { box-sizing: border-box; }
[hidden] { display: none !important; }

html { scroll-behavior: smooth; scroll-padding-top: 5.5rem; -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--ground);
  color: var(--text);
  font-family: var(--font-text);
  font-size: 1.0625rem;
  line-height: 1.65;
  text-rendering: optimizeLegibility;
}

h1, h2, h3 { color: var(--head); font-weight: 600; letter-spacing: -0.012em; margin: 0; text-wrap: balance; }
p { margin: 0 0 1.1em; max-width: 68ch; }
b { color: var(--moss); font-family: var(--font-ui); font-size: .78em; font-weight: 600; }
b { letter-spacing: .06em; text-transform: uppercase; margin-right: .5em; }

a { color: var(--cyan); text-underline-offset: .18em; text-decoration-thickness: 1px; }
a:hover { color: var(--head); }

:focus-visible { outline: 2px solid var(--cyan-b); outline-offset: 3px; border-radius: 1px; }

.vh {
  position: absolute; width: 1px; height: 1px; overflow: hidden;
  clip-path: inset(50%); white-space: nowrap;
}

.skip {
  position: absolute; left: 12px; top: -4rem; z-index: 20; padding: .7rem 1rem;
  background: var(--chip); color: var(--chip-ink); font-family: var(--font-ui); font-size: .8rem;
  text-decoration: none; transition: top .15s ease;
}
.skip:focus { top: 12px; color: var(--chip-ink); }

.wrap { width: 100%; max-width: 72rem; margin-inline: auto; padding-inline: var(--gut); }

.strip {
  height: 14px;
  background-image:
    repeating-linear-gradient(90deg, var(--strip-bg, var(--ground)) 0 4px, transparent 4px 6px),
    linear-gradient(90deg, var(--moss-mid) 0%, var(--moss) 26%, var(--cyan) 70%, var(--cyan-b) 100%);
}

.masthead { position: sticky; top: 0; z-index: 10; background: var(--ground); }
.masthead-in { display: flex; align-items: center; gap: 1.5rem; min-height: 4.25rem; }
.brand { display: inline-flex; align-items: center; gap: .6rem; color: var(--head); text-decoration: none; }
.brand-mark { width: 44px; height: 24px; color: var(--cyan); flex: none; }
.brand-name {
  font-family: var(--font-ui); font-size: .82rem; font-weight: 600;
  letter-spacing: .18em; text-transform: uppercase;
}
.nav { margin-left: auto; }
.nav ul { display: flex; gap: 1.4rem; list-style: none; margin: 0; padding: 0; }
.nav a {
  font-family: var(--font-ui); font-size: .76rem; letter-spacing: .1em; text-transform: uppercase;
  color: var(--dim); text-decoration: none; padding-block: .3rem; border-bottom: 2px solid transparent;
}
.nav a:hover { color: var(--head); border-bottom-color: var(--cyan-b); }

.nav-toggle {
  display: none; margin-left: auto; align-items: center; gap: .6rem; padding: .55rem .8rem;
  background: none; border: 1px solid var(--rule); color: var(--text); cursor: pointer;
  font-family: var(--font-ui); font-size: .76rem; letter-spacing: .1em; text-transform: uppercase;
}
.nav-toggle-mark { width: 14px; height: 10px; background:
  repeating-linear-gradient(180deg, currentColor 0 2px, transparent 2px 4px); }
.nav-toggle[aria-expanded="true"] .nav-toggle-mark { background:
  repeating-linear-gradient(90deg, currentColor 0 2px, transparent 2px 4px); }

.hero-in { padding-block: clamp(2.5rem, 6vw, 5rem) clamp(1.75rem, 3vw, 2.75rem); }
.eyebrow {
  font-family: var(--font-ui); font-size: .74rem; letter-spacing: .18em; text-transform: uppercase;
  color: var(--cyan); margin-bottom: 1.4rem;
}
.hero h1 { font-size: clamp(2.05rem, 7vw, 4.15rem); line-height: 1.04; max-width: 20ch; }
.standfirst {
  margin-top: 1.5rem; font-size: clamp(1.05rem, 1.6vw, 1.3rem); line-height: 1.55; max-width: 54ch;
  color: var(--dim);
}
.hero-meta {
  display: flex; flex-wrap: wrap; gap: .5rem 1.6rem; list-style: none; margin: 2rem 0 0; padding: 0;
  font-family: var(--font-ui); font-size: .74rem; letter-spacing: .1em; text-transform: uppercase;
  color: var(--dim);
}
.hero-meta li::before {
  content: ""; display: inline-block; width: 15px; height: 8px; margin-right: .7em;
  background: repeating-linear-gradient(90deg, var(--cyan-b) 0 2px, transparent 2px 5px);
}

.wave { margin: 0; padding-inline: 0; }
.wave svg { display: block; width: 100%; height: clamp(104px, 15vw, 190px); }
.wave-axis { stroke: var(--rule); stroke-width: 1; }
.wave-body { fill: var(--moss-mid); }
.wave-mark { stroke: var(--cyan-b); stroke-width: 2; stroke-dasharray: 6 5; }
.wave figcaption {
  max-width: 72rem; margin-inline: auto; padding: .7rem var(--gut) 0;
  font-family: var(--font-ui); font-size: .72rem; line-height: 1.5; color: var(--dim);
}

.section-h { font-size: clamp(1.4rem, 3vw, 2rem); line-height: 1.15; }
.section-h .num { color: var(--cyan); }
.num {
  font-family: var(--font-ui); font-size: .72em; font-weight: 500; letter-spacing: .06em;
  color: var(--dim); margin-right: .7em;
}
.section-lede { margin-top: .9rem; max-width: 56ch; color: var(--dim); }

.contents { padding-block: var(--rhythm) 0; }
.toc { list-style: none; margin: 1.75rem 0 0; padding: 0; border-top: 1px solid var(--rule); }
.toc li {
  display: grid; grid-template-columns: 3rem minmax(0, 1fr) auto; align-items: baseline;
  gap: 0 1rem; padding: .85rem 0; border-bottom: 1px solid var(--rule);
}
.toc a {
  font-size: clamp(1.05rem, 2vw, 1.35rem); color: var(--head); text-decoration: none;
  border-bottom: 1px solid transparent;
}
.toc a:hover { color: var(--cyan); border-bottom-color: var(--cyan); }
.toc-note {
  font-family: var(--font-ui); font-size: .72rem; letter-spacing: .05em; color: var(--dim);
  text-align: right;
}

.guides { padding-block: var(--rhythm); }
.tablist { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 2px; margin-top: 2.25rem; }
.tablist [role="tab"] {
  padding: .7rem .6rem; background: var(--ground-3); border: 0; border-bottom: 3px solid var(--rule);
  color: var(--dim); cursor: pointer; font-family: var(--font-ui); font-size: .76rem;
  letter-spacing: .08em; text-transform: uppercase; white-space: nowrap; overflow: hidden;
}
.tablist [role="tab"]:hover { color: var(--head); }
.tablist [aria-selected="true"] {
  background: var(--chip); color: var(--chip-ink); border-bottom-color: var(--cyan-b);
}
.t-num { margin-right: .5em; }
.t-mini { display: none; }
.panels { margin-top: 2rem; }
.guide { padding-top: 1.75rem; border-top: 1px solid var(--rule); }
.guide + .guide { margin-top: 3.25rem; }
.guide[role="tabpanel"] { border-top: 0; padding-top: 0; }
.guide[role="tabpanel"] + .guide { margin-top: 0; }
.guide h3 { font-size: clamp(1.25rem, 2.6vw, 1.75rem); line-height: 1.18; margin-bottom: 1.1rem; }
.guide p { font-size: 1.075rem; }
.guide-body > :last-child { margin-bottom: 0; }

.polars { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 1rem 1.25rem;
  margin: 1.9rem 0 1.8rem; max-width: 36rem; }
.polar svg { display: block; width: 100%; height: auto; }
.polar p {
  margin: .5rem 0 0; font-family: var(--font-ui); font-size: .68rem; letter-spacing: .04em;
  color: var(--dim);
}
.polar-grid { fill: none; stroke: var(--rule); stroke-width: 1; }
.polar-shape { fill: rgba(156, 190, 117, .18); stroke: var(--moss); stroke-width: 2; }
.polar-axis { stroke: var(--cyan-b); stroke-width: 2; }
.polars figcaption {
  grid-column: 1 / -1; font-family: var(--font-ui); font-size: .7rem; line-height: 1.5;
  color: var(--dim); border-top: 1px solid var(--rule); padding-top: .6rem;
}

.explorer {
  background: var(--ground-2); border-block: 1px solid var(--rule); padding-block: var(--rhythm);
}
.explorer .section-h .num, .explorer .num { color: var(--cyan-b); }

.exp-ui { margin-top: 2.5rem; }
.exp-readout { display: flex; align-items: baseline; gap: 1.1rem; flex-wrap: wrap; }
.exp-hz {
  margin: 0; font-family: var(--font-ui); font-size: clamp(1.9rem, 5vw, 3rem); font-weight: 600;
  color: var(--cyan-b); letter-spacing: -.02em; font-variant-numeric: tabular-nums;
}
.exp-band {
  margin: 0; font-family: var(--font-ui); font-size: .82rem; letter-spacing: .16em;
  text-transform: uppercase; color: var(--head);
}

.exp-strip { position: relative; margin-top: 1.1rem; }
.seg-row { display: flex; gap: 2px; }
.seg {
  flex: var(--seg) 1 0%; height: clamp(58px, 8vw, 84px); border: 0; padding: 0; cursor: pointer;
  background-color: var(--moss-deep); background-image:
    repeating-linear-gradient(90deg, var(--moss) 0 2px, transparent 2px 6px);
  background-position: bottom; transition: background-color .18s ease;
}
.seg:hover { background-color: #38492a; }
.seg[aria-pressed="true"] {
  background-color: #17535e; box-shadow: inset 0 3px 0 var(--cyan-b);
  background-image: repeating-linear-gradient(90deg, var(--cyan-b) 0 2px, transparent 2px 6px);
}
.playhead {
  position: absolute; inset-block: -6px; left: var(--pos, 50%); width: 2px; margin-left: -1px;
  background: var(--head); pointer-events: none;
}
.playhead::after {
  content: ""; position: absolute; top: -5px; left: -4px; width: 10px; height: 10px;
  background: var(--head); transform: rotate(45deg);
}

.exp-scale {
  position: relative; height: 1.5rem; margin: .5rem 0 0; max-width: none;
  font-family: var(--font-ui); font-size: .7rem; color: var(--dim);
}
.exp-scale span { position: absolute; left: var(--x); transform: translateX(-50%); white-space: nowrap; }
.exp-scale span:first-child { transform: none; }
.exp-scale span:last-child { transform: translateX(-100%); }

.exp-label {
  display: block; margin-top: .9rem; font-family: var(--font-ui); font-size: .72rem;
  letter-spacing: .1em; text-transform: uppercase; color: var(--dim);
}
.exp-range {
  -webkit-appearance: none; appearance: none; width: 100%; margin: .6rem 0 0;
  background: transparent; cursor: ew-resize;
}
.exp-range::-webkit-slider-runnable-track { height: 4px; background: var(--track); }
.exp-range::-moz-range-track { height: 4px; background: var(--track); }
.exp-range::-webkit-slider-thumb {
  -webkit-appearance: none; appearance: none; width: 14px; height: 26px; margin-top: -11px;
  background: var(--cyan-b); border: 0;
}
.exp-range::-moz-range-thumb { width: 14px; height: 26px; background: var(--cyan-b); border: 0; border-radius: 0; }

.bands { list-style: none; margin: 2.25rem 0 0; padding: 0; }
.band { padding-top: 1.4rem; border-top: 1px solid var(--rule); }
.band + .band { margin-top: 1.9rem; }
.band h3 { font-size: clamp(1.15rem, 2.4vw, 1.5rem); margin-bottom: .8rem; }
.band-range {
  font-family: var(--font-ui); font-size: .72em; font-weight: 500; color: var(--cyan-b);
  letter-spacing: .04em; margin-left: .6em;
}
.band p { color: var(--text); max-width: 62ch; }
.band b { color: var(--cyan-b); }
.explorer .bands.is-single .band { border-top: 0; padding-top: 0; margin-top: 0; }

.specs { padding-block: var(--rhythm); }
.gloss { margin: 2rem 0 0; display: grid; gap: 0; border-top: 1px solid var(--rule); }
.gloss > div {
  display: grid; grid-template-columns: minmax(11rem, 17rem) minmax(0, 1fr); gap: .3rem 2rem;
  padding: 1.05rem 0; border-bottom: 1px solid var(--rule);
}
.gloss dt {
  font-family: var(--font-ui); font-size: .78rem; letter-spacing: .06em; text-transform: uppercase;
  color: var(--head); padding-top: .2rem;
}
.gloss dt .unit { text-transform: none; }
.gloss dd { margin: 0; max-width: 60ch; }

.foot { background: var(--ground-deep); color: var(--text); --strip-bg: var(--ground-deep); }
.foot-in { padding-block: clamp(2.5rem, 5vw, 4rem); }
.foot-brand {
  font-family: var(--font-ui); font-size: .82rem; font-weight: 600; letter-spacing: .18em;
  text-transform: uppercase; color: var(--head); margin-bottom: 1.3rem;
}
.foot-nav ul {
  display: flex; flex-wrap: wrap; gap: .5rem 1.5rem; list-style: none; margin: 0 0 1.6rem; padding: 0;
}
.foot-nav a {
  font-family: var(--font-ui); font-size: .74rem; letter-spacing: .08em; text-transform: uppercase;
  color: var(--cyan); text-decoration: none; border-bottom: 1px solid transparent;
}
.foot-nav a:hover { color: var(--head); border-bottom-color: var(--cyan-b); }
.foot-note { font-size: .92rem; line-height: 1.6; max-width: 56ch; margin: 0; color: var(--dim); }

@media (max-width: 860px) {
  .masthead-in { flex-wrap: wrap; }
  .nav { width: 100%; margin: 0 0 .9rem; }
  .nav ul { flex-direction: column; gap: 0; }
  .nav a { display: block; padding: .8rem 0; border-bottom: 1px solid var(--rule); }
  .masthead.nav-js .nav { display: none; border-top: 1px solid var(--rule); }
  .masthead.nav-js .nav.is-open { display: block; }
  .masthead.nav-js .nav-toggle { display: inline-flex; }
}

@media (min-width: 861px) {
  .guide { display: grid; grid-template-columns: minmax(0, 16rem) minmax(0, 1fr); gap: 0 3rem; }
  .guide h3 { grid-column: 1; margin-bottom: 0; align-self: start; position: sticky; top: 6rem; }
  .guide-body { grid-column: 2; }
}

@media (max-width: 760px) {
  .tablist [role="tab"] {
    padding: .7rem .45rem; font-size: clamp(.66rem, 2.2vw, .76rem); letter-spacing: .05em;
  }
  .t-full { display: none; }
  .t-mini { display: inline; }
}

@media (max-width: 430px) {
  .tablist [role="tab"] {
    padding: .7rem .3rem; font-size: clamp(.62rem, 3.2vw, .76rem); letter-spacing: .03em;
  }
  .t-num { display: none; }
}

@media (max-width: 640px) {
  .hero h1 br { display: none; }
  .toc li { grid-template-columns: 2.4rem minmax(0, 1fr); }
  .toc-note { grid-column: 2; text-align: left; margin-top: .2rem; }
  .gloss > div { grid-template-columns: minmax(0, 1fr); gap: .35rem; }
  .polars { grid-template-columns: repeat(3, minmax(0, 1fr)); gap: .6rem; }
  .polar p { font-size: .66rem; letter-spacing: .02em; }
  .exp-readout { gap: .2rem 1rem; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition-duration: .001ms !important; animation-duration: .001ms !important; }
}

@media (prefers-contrast: more) {
  :root { --dim: #d6ddca; --rule: #6d7c5b; --cyan: #92e5f2; --text: #f2f5ea; }
}