/* ---------------------------------------------------------------
   Tokens
   --------------------------------------------------------------- */

:root {
  --bg: #fbfbfa;
  --surface: #ffffff;
  --text: #16161a;
  --muted: #6b6b76;
  --line: #e6e6e1;
  --line-strong: #d5d5cf;

  --band-cooling: #2563eb;
  --band-easing: #0e8a94;
  --band-neutral: #64748b;
  --band-elevated: #c2710c;
  --band-high: #d0342c;

  --accent: var(--band-neutral);

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

  --shell: 1080px;
  --shell-narrow: 680px;
  --gutter: 1.5rem;

  --radius: 10px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0d0d0f;
    --surface: #141417;
    --text: #ededef;
    --muted: #8e8e99;
    --line: #26262b;
    --line-strong: #35353c;

    --band-cooling: #6ea8fe;
    --band-easing: #3ec6d0;
    --band-neutral: #9aa6b6;
    --band-elevated: #f0a53c;
    --band-high: #ff6b60;
  }
}

[data-band="cooling"] { --accent: var(--band-cooling); }
[data-band="easing"] { --accent: var(--band-easing); }
[data-band="neutral"] { --accent: var(--band-neutral); }
[data-band="elevated"] { --accent: var(--band-elevated); }
[data-band="high"] { --accent: var(--band-high); }

/* ---------------------------------------------------------------
   Base
   --------------------------------------------------------------- */

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

html {
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 1rem;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

main {
  flex: 1 0 auto;
}

a {
  color: inherit;
  text-decoration-color: var(--line-strong);
  text-underline-offset: 0.2em;
  transition: text-decoration-color 0.15s ease, color 0.15s ease;
}

a:hover {
  text-decoration-color: currentColor;
}

h1,
h2,
h3 {
  line-height: 1.2;
  letter-spacing: -0.02em;
  font-weight: 600;
}

img,
svg {
  max-width: 100%;
}

::selection {
  background: var(--accent);
  color: var(--bg);
}

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

.shell {
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.shell--narrow {
  max-width: var(--shell-narrow);
}

.muted {
  color: var(--muted);
}

.eyebrow {
  margin: 0 0 0.75rem;
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.13em;
  text-transform: uppercase;
  color: var(--muted);
}

.lede {
  font-size: 1.15rem;
  color: var(--muted);
  max-width: 34em;
}

.dot {
  display: inline-block;
  width: 3px;
  height: 3px;
  border-radius: 50%;
  background: var(--line-strong);
  vertical-align: middle;
  margin-inline: 0.15rem;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  padding: 0.6rem 1rem;
  background: var(--text);
  color: var(--bg);
  z-index: 10;
}

.skip-link:focus {
  left: 0.5rem;
  top: 0.5rem;
}

/* ---------------------------------------------------------------
   Header / footer
   --------------------------------------------------------------- */

.site-header {
  padding-block: 1.6rem;
}

.site-header .shell {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
}

.wordmark {
  font-weight: 600;
  letter-spacing: -0.015em;
  text-decoration: none;
}

.site-nav {
  display: flex;
  gap: 1.75rem;
  font-size: 0.925rem;
}

.site-nav a {
  text-decoration: none;
  color: var(--muted);
}

.site-nav a:hover {
  color: var(--text);
}

.site-nav a[aria-current="page"] {
  color: var(--text);
}

.site-footer {
  margin-top: 6rem;
  padding-block: 2rem 3rem;
  border-top: 1px solid var(--line);
  font-size: 0.85rem;
}

.site-footer p {
  margin: 0;
}

.site-footer .muted {
  margin-top: 0.25rem;
  max-width: 40em;
}

/* ---------------------------------------------------------------
   Indicator (home page)
   --------------------------------------------------------------- */

.page-home .site-footer {
  margin-top: 3rem;
}

.indicator {
  padding-block: clamp(2rem, 7vw, 5rem);
  text-align: center;
}

.indicator__mascot {
  display: block;
  margin: 0 auto 1.25rem;
}

.reading {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
}

.reading__value {
  margin: 0;
  font-size: clamp(5rem, 21vw, 10.5rem);
  font-weight: 600;
  line-height: 0.95;
  letter-spacing: -0.045em;
  font-variant-numeric: tabular-nums;
  color: var(--accent);
}

.reading__band {
  margin: 0;
  display: inline-flex;
  align-items: center;
  padding: 0.3rem 0.85rem;
  border: 1px solid color-mix(in srgb, var(--accent) 35%, transparent);
  border-radius: 999px;
  background: color-mix(in srgb, var(--accent) 9%, transparent);
  color: var(--accent);
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 0.09em;
  text-transform: uppercase;
}

.reading__meta {
  margin: 1.5rem 0 0;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  font-size: 0.925rem;
}

.delta {
  font-variant-numeric: tabular-nums;
  font-weight: 500;
}

.delta--up { color: var(--band-high); }
.delta--down { color: var(--band-cooling); }
.delta--flat { color: var(--muted); }

/* Scale track */

.track {
  margin: 3.25rem auto 0;
  max-width: 34rem;
}

.track__rail {
  position: relative;
  height: 6px;
  border-radius: 999px;
  background: linear-gradient(
    to right,
    color-mix(in srgb, var(--band-cooling) 30%, transparent),
    color-mix(in srgb, var(--band-neutral) 22%, transparent) 50%,
    color-mix(in srgb, var(--band-high) 34%, transparent)
  );
}

.track__neutral {
  position: absolute;
  top: -4px;
  width: 1px;
  height: 14px;
  background: var(--line-strong);
  transform: translateX(-50%);
}

.track__marker {
  position: absolute;
  top: 50%;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--accent);
  border: 3px solid var(--bg);
  transform: translate(-50%, -50%);
  box-shadow: 0 0 0 1px color-mix(in srgb, var(--accent) 45%, transparent);
}

.track__labels {
  display: flex;
  justify-content: space-between;
  margin-top: 0.9rem;
  font-size: 0.75rem;
  color: var(--muted);
  font-variant-numeric: tabular-nums;
}

/* History chart */

.chart {
  margin: 3.5rem 0 0;
}

.chart svg {
  display: block;
  width: 100%;
  height: auto;
  overflow: visible;
  /* The area gradient picks this up via currentColor. */
  color: var(--accent);
}

.chart__area {
  fill: url(#chart-fade);
  stroke: none;
}

.chart__line {
  fill: none;
  stroke: var(--accent);
  stroke-width: 2.5;
  stroke-linecap: round;
  stroke-linejoin: round;
  vector-effect: non-scaling-stroke;
}

.chart__dot {
  fill: var(--accent);
  stroke: var(--bg);
  stroke-width: 3;
}

.chart__caption {
  display: flex;
  justify-content: space-between;
  margin-top: 0.75rem;
  font-size: 0.75rem;
  color: var(--muted);
}

.indicator__note {
  margin: 2.5rem auto 0;
  max-width: 30em;
  color: var(--muted);
}

/* ---------------------------------------------------------------
   Prose (About + blog posts)
   --------------------------------------------------------------- */

.section-head {
  padding-block: 2rem 3rem;
}

.section-head h1 {
  margin: 0 0 0.75rem;
  font-size: clamp(2rem, 5vw, 2.75rem);
}

.prose {
  padding-block: 2rem 1rem;
}

.prose h1 {
  margin: 0 0 1.25rem;
  font-size: clamp(2rem, 5vw, 2.75rem);
}

.prose h2 {
  margin: 2.75rem 0 0.75rem;
  font-size: 1.25rem;
}

.prose h3 {
  margin: 2rem 0 0.5rem;
  font-size: 1.05rem;
}

.prose p,
.prose li {
  max-width: 36em;
}

.prose ul,
.prose ol {
  padding-left: 1.15rem;
}

.prose li {
  margin-block: 0.35rem;
}

.prose blockquote {
  margin: 1.75rem 0;
  padding-left: 1.15rem;
  border-left: 2px solid var(--accent);
  color: var(--muted);
}

.prose code {
  font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, monospace;
  font-size: 0.875em;
  background: color-mix(in srgb, var(--text) 7%, transparent);
  padding: 0.15em 0.4em;
  border-radius: 4px;
}

.prose pre {
  overflow-x: auto;
  padding: 1rem 1.1rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
}

.prose pre code {
  background: none;
  padding: 0;
}

.prose hr {
  margin: 2.5rem 0;
  border: 0;
  border-top: 1px solid var(--line);
}

.prose table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.925rem;
}

.prose th,
.prose td {
  text-align: left;
  padding: 0.6rem 0.75rem;
  border-bottom: 1px solid var(--line);
}

.post-meta {
  margin: 0 0 2.5rem;
  font-size: 0.9rem;
  color: var(--muted);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.back-link {
  margin-top: 3.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--line);
  font-size: 0.925rem;
}

/* Band legend on the About page */

.bands {
  margin: 1.5rem 0 0;
  border-top: 1px solid var(--line);
}

.bands__row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.7rem 0;
  border-bottom: 1px solid var(--line);
}

.bands__row dt {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-weight: 500;
}

.bands__row dd {
  margin: 0;
  color: var(--muted);
  font-size: 0.9rem;
  font-variant-numeric: tabular-nums;
}

.bands__swatch {
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--accent);
}

/* ---------------------------------------------------------------
   Blog index
   --------------------------------------------------------------- */

.post-list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.post-list__item {
  border-bottom: 1px solid var(--line);
}

.post-list__link {
  display: block;
  padding: 1.9rem 0;
  text-decoration: none;
}

.post-list__date {
  display: block;
  font-size: 0.8rem;
  color: var(--muted);
  letter-spacing: 0.02em;
}

.post-list__title {
  margin: 0.4rem 0 0.5rem;
  font-size: 1.3rem;
}

.post-list__summary {
  margin: 0;
  max-width: 40em;
  color: var(--muted);
}

.post-list__more {
  display: inline-block;
  margin-top: 0.85rem;
  font-size: 0.875rem;
  color: var(--accent);
}

.post-list__link:hover .post-list__title {
  text-decoration: underline;
  text-underline-offset: 0.2em;
}

@media (prefers-reduced-motion: reduce) {
  * {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
  }
}