/* Hyperbaric Buyer's Guide — warm editorial handbook
   Display: Zodiak (Fontshare) · Body: Source Serif 4 (Google) · UI: Switzer (Fontshare) */

:root {
  --paper:      #F6F1E6;
  --paper-warm: #EFE7D7;
  --paper-deep: #E6DCC7;
  --card:       #FDFBF6;
  --ink:        #1D1A14;
  --ink-soft:   #4E463A;
  --ink-faint:  #665B4A;
  --rule:       #D5C9B1;
  --rule-soft:  #E4DAC5;
  --accent:     #8A3618;
  --accent-dk:  #6A2810;
  --accent-wash:#F3E4D9;
  --flag:       #6E6029;

  --font-display: 'Zodiak', 'Source Serif 4', Georgia, serif;
  --font-body: 'Source Serif 4', Georgia, 'Times New Roman', serif;
  --font-ui: 'Switzer', 'Helvetica Neue', Arial, sans-serif;

  --measure: 40rem;
  --wide: 64rem;

  /* --step--1 is the smallest size used for continuous reading: never below 16px. */
  --step--1: clamp(1rem, 0.96rem + 0.2vw, 1.09rem);
  --step-0:  clamp(1.15rem, 1.08rem + 0.34vw, 1.27rem);
  --step-1:  clamp(1.34rem, 1.24rem + 0.42vw, 1.56rem);
  --step-2:  clamp(1.62rem, 1.42rem + 0.8vw, 2.05rem);
  --step-3:  clamp(2.02rem, 1.68rem + 1.4vw, 2.8rem);
  --step-4:  clamp(2.4rem, 1.75rem + 2.8vw, 4.1rem);
  /* tracked uppercase micro-labels — not continuous reading */
  --label:   0.82rem;
  --label-s: 0.8rem;
}

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

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

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: var(--step-0);
  line-height: 1.72;
  font-weight: 400;
  font-feature-settings: "onum" 1;
  text-rendering: optimizeLegibility;
}

/* subtle paper tooth */
body::before {
  content: "";
  position: fixed; inset: 0; pointer-events: none; z-index: 0;
  opacity: .5;
  background-image: radial-gradient(rgba(120,100,70,.10) .6px, transparent .7px);
  background-size: 4px 4px;
}
body > * { position: relative; z-index: 1; }

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

a { color: var(--accent-dk); text-decoration-thickness: 1.5px; text-underline-offset: .18em; }
a:hover { color: var(--accent); }
a:focus-visible, button:focus-visible, summary:focus-visible {
  outline: 2px solid var(--accent); outline-offset: 3px; border-radius: 2px;
}

.skip {
  position: absolute; left: -9999px; top: 0;
  background: var(--ink); color: var(--paper); padding: .8rem 1.1rem;
  font-family: var(--font-ui); font-size: 1rem; font-weight: 600; z-index: 50;
}
.skip:focus { left: .75rem; top: .75rem; }

/* ---------- layout ---------- */
.shell { width: min(100% - 2.5rem, var(--wide)); margin-inline: auto; }
@media (max-width: 640px) { .shell { width: min(100% - 1.75rem, var(--wide)); } }

.prose { width: min(100%, var(--measure)); }
.prose p, .prose li { text-wrap: pretty; }
.shell.solo { width: min(100% - 2.5rem, 52rem); }
@media (max-width: 640px) { .shell.solo { width: min(100% - 1.75rem, 52rem); } }
.solo .prose { width: min(100%, var(--measure)); }
.solo.hero h1 { max-width: 22ch; }
.solo .standfirst { max-width: 54ch; }
.page { display: grid; grid-template-columns: minmax(0,1fr); gap: 3rem; }
@media (min-width: 62rem) {
  .page { grid-template-columns: minmax(0, 1fr) 15rem; gap: 3.5rem; align-items: start; }
}

/* ---------- masthead ---------- */
.masthead {
  border-bottom: 1px solid var(--rule);
  background: linear-gradient(180deg, var(--paper-warm), var(--paper));
}
.masthead-in {
  display: flex; align-items: center; justify-content: space-between;
  gap: 1.5rem; padding: 1.1rem 0;
}
.brand { display: flex; align-items: center; gap: .7rem; text-decoration: none; color: var(--ink); }
.brand:hover { color: var(--ink); }
.brand svg { display: block; color: var(--accent); flex: none; }
.brand-words { font-family: var(--font-display); line-height: 1.06; }
.brand-words b { display: block; font-size: 1.28rem; font-weight: 700; letter-spacing: -.012em; }
.brand-words span {
  display: block; font-family: var(--font-ui); font-size: .72rem; font-weight: 600;
  letter-spacing: .16em; text-transform: uppercase; color: var(--ink-faint); margin-top: .2rem;
}

.nav { font-family: var(--font-ui); }
.nav ul { display: flex; flex-wrap: wrap; gap: 1.35rem; list-style: none; margin: 0; padding: 0; }
.nav a {
  font-size: var(--label); font-weight: 600; letter-spacing: .08em; text-transform: uppercase;
  text-decoration: none; color: var(--ink-soft); padding-bottom: .2rem;
  border-bottom: 2px solid transparent;
}
.nav a:hover { color: var(--accent); border-bottom-color: var(--accent); }
.nav a[aria-current="true"] { color: var(--ink); border-bottom-color: var(--accent); }

.navtoggle {
  display: none; font-family: var(--font-ui); font-size: var(--label); font-weight: 600;
  letter-spacing: .08em;
  text-transform: uppercase; background: none; border: 1px solid var(--rule);
  color: var(--ink-soft); min-height: 44px; padding: .5rem .9rem; border-radius: 2px; cursor: pointer;
}
@media (max-width: 61.99rem) {
  .navtoggle { display: block; }
  .nav { display: none; width: 100%; padding: .25rem 0 1rem; }
  .nav.open { display: block; }
  .nav ul { flex-direction: column; gap: .1rem; }
  .nav a { display: block; padding: .85rem 0; min-height: 44px; border-bottom: 1px solid var(--rule-soft); }
  .masthead-in { flex-wrap: wrap; }
}

/* ---------- article head ---------- */
.kicker {
  font-family: var(--font-ui); font-size: var(--label-s); font-weight: 700; letter-spacing: .17em;
  text-transform: uppercase; color: var(--accent); margin: 0 0 1rem;
}
h1 {
  font-family: var(--font-display); font-weight: 700; font-size: var(--step-3);
  line-height: 1.06; letter-spacing: -.02em; margin: 0 0 1rem; max-width: 30ch;
}
.hero h1 { font-size: var(--step-4); max-width: 24ch; }
.standfirst {
  font-size: var(--step-1); line-height: 1.5; color: var(--ink-soft); font-weight: 400;
  margin: 0 0 1.6rem; max-width: 46ch;
}
.dateline {
  font-family: var(--font-ui); font-size: var(--label-s); font-weight: 600; letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--ink-faint); padding-top: 1rem; border-top: 1px solid var(--rule);
}
.articlehead { padding: 3.4rem 0 2.4rem; }
.hero.articlehead { padding: 4.5rem 0 3rem; }

h2 {
  font-family: var(--font-display); font-weight: 700; font-size: var(--step-2);
  line-height: 1.14; letter-spacing: -.015em; margin: 3.2rem 0 .9rem; max-width: 32ch;
}
h3 {
  font-family: var(--font-ui); font-weight: 700; font-size: 1.08rem; letter-spacing: .005em;
  margin: 2.3rem 0 .6rem; color: var(--ink);
}
p { margin: 0 0 1.25rem; }
strong, b { font-weight: 600; }
.prose > p:first-of-type { margin-top: 0; }

.lede::first-letter {
  float: left; font-family: var(--font-display); font-size: 3.5em; line-height: .82;
  padding: .06em .09em 0 0; color: var(--accent);
}

ul, ol { margin: 0 0 1.3rem; padding-left: 1.35rem; }
li { margin-bottom: .5rem; }
li::marker { color: var(--accent); }

blockquote {
  margin: 1.8rem 0; padding: 0 0 0 1.3rem; border-left: 2px solid var(--accent);
  font-style: italic; color: var(--ink-soft);
}
blockquote p:last-child { margin-bottom: 0; }
blockquote cite {
  display: block; font-family: var(--font-ui); font-style: normal; font-size: .78rem;
  letter-spacing: .04em; color: var(--ink-faint); margin-top: .6rem;
}

hr { border: 0; border-top: 1px solid var(--rule); margin: 3rem 0; }

/* ---------- components ---------- */
.note {
  background: var(--card); border: 1px solid var(--rule-soft);
  border-left: 3px solid var(--flag); padding: 1.2rem 1.3rem; margin: 2rem 0;
  font-size: var(--step--1); line-height: 1.65;
}
.note p:last-child { margin-bottom: 0; }
.note .note-t {
  font-family: var(--font-ui); font-size: var(--label-s); font-weight: 700; letter-spacing: .15em;
  text-transform: uppercase; color: var(--flag); display: block; margin-bottom: .5rem;
}

.note--interest { border-left-color: var(--accent); }
.note--interest .note-t { color: var(--accent); }

.notpublished {
  font-family: var(--font-ui); font-size: var(--label-s); font-weight: 600; letter-spacing: .06em;
  text-transform: uppercase; color: var(--ink-faint);
}

.datatable { margin: 2rem 0; overflow-x: auto; border: 1px solid var(--rule); background: var(--card); }
table { border-collapse: collapse; width: 100%; font-family: var(--font-ui); font-size: 1rem; }
caption {
  caption-side: top; text-align: left; font-family: var(--font-ui); font-size: var(--label-s);
  font-weight: 700; letter-spacing: .14em; text-transform: uppercase; color: var(--ink-faint);
  padding: .9rem 1rem .2rem;
}
th, td { text-align: left; padding: .72rem .9rem; border-bottom: 1px solid var(--rule-soft); vertical-align: top; }
thead th {
  font-size: var(--label-s); letter-spacing: .09em; text-transform: uppercase; color: var(--ink-faint);
  border-bottom: 2px solid var(--rule); font-weight: 700;
}
tbody tr:last-child td { border-bottom: 0; }
td.num { font-variant-numeric: tabular-nums; }

.checklist { list-style: none; padding: 0; margin: 1.6rem 0; }
.checklist li {
  position: relative; padding-left: 2.1rem; margin-bottom: 1rem;
  font-size: var(--step--1); line-height: 1.65;
}
.checklist li::before {
  content: ""; position: absolute; left: 0; top: .2em;
  width: 1.05rem; height: 1.05rem; border: 1.5px solid var(--accent); border-radius: 2px;
}

.sourcebox {
  margin: 2.4rem 0; padding: 1.3rem 1.4rem; background: var(--paper-warm);
  border: 1px solid var(--rule); font-size: var(--step--1);
}
.sourcebox h3 {
  margin: 0 0 .7rem; font-size: var(--label-s); font-weight: 700; letter-spacing: .15em;
  text-transform: uppercase; color: var(--ink-faint);
}
.sourcebox ol { margin: 0; padding-left: 1.25rem; }
.sourcebox li { margin-bottom: .6rem; line-height: 1.55; }
.sourcebox a { overflow-wrap: anywhere; }

/* rail */
.rail { font-family: var(--font-ui); font-size: .97rem; }
.rail-block { border-top: 3px solid var(--ink); padding-top: .9rem; margin-bottom: 2.4rem; }
.rail-block h2 {
  font-family: var(--font-ui); font-size: var(--label-s); font-weight: 700; letter-spacing: .15em;
  text-transform: uppercase; color: var(--ink-faint); margin: 0 0 .8rem;
}
.rail ul { list-style: none; margin: 0; padding: 0; }
.rail li { margin-bottom: .7rem; line-height: 1.45; }
.rail a { text-decoration: none; border-bottom: 1px solid var(--rule); color: var(--ink); display: inline-block; }
.rail a:hover { color: var(--accent); border-bottom-color: var(--accent); }
.rail strong { font-weight: 700; }
.rail p { font-size: .95rem; line-height: 1.55; color: var(--ink-soft); }
@media (min-width: 62rem) { .rail { position: sticky; top: 2rem; } }

/* index */
.chapters { display: grid; gap: 1.75rem; margin: 0; padding: 0; list-style: none; }
@media (min-width: 46rem) { .chapters { grid-template-columns: 1fr 1fr; } }
.chapter {
  background: var(--card); border: 1px solid var(--rule); padding: 1.6rem 1.7rem;
}
.chapter .num {
  font-family: var(--font-ui); font-size: var(--label-s); font-weight: 700; letter-spacing: .15em;
  text-transform: uppercase; color: var(--accent); display: block; margin-bottom: .6rem;
}
.chapter h2 { font-size: var(--step-1); margin: 0 0 .6rem; }
.chapter p { font-size: var(--step--1); color: var(--ink-soft); margin-bottom: 1rem; }
.chapter ul { list-style: none; padding: 0; margin: 0; font-family: var(--font-ui); font-size: 1rem; }
.chapter li { margin-bottom: .5rem; padding-left: 1rem; position: relative; }
.chapter li::before {
  content: ""; position: absolute; left: 0; top: .62em; width: .38rem; height: 1px; background: var(--accent);
}
.chapter a { text-decoration: none; border-bottom: 1px solid var(--rule-soft); color: var(--ink); }
.chapter a:hover { color: var(--accent); border-bottom-color: var(--accent); }

.next {
  display: block; margin: 3.5rem 0 0; padding: 1.4rem 1.5rem; background: var(--accent-wash);
  border: 1px solid var(--rule); text-decoration: none; color: var(--ink);
}
.next span {
  font-family: var(--font-ui); font-size: var(--label-s); font-weight: 700; letter-spacing: .15em;
  text-transform: uppercase; color: var(--accent); display: block; margin-bottom: .4rem;
}
.next strong { font-family: var(--font-display); font-weight: 700; font-size: var(--step-1); }
.next:hover { background: #EEDDD0; }

/* ---------- footer ---------- */
.foot { margin-top: 5rem; border-top: 1px solid var(--rule); background: var(--paper-warm); }
.foot-in { padding: 3rem 0 3.5rem; display: grid; gap: 2.5rem; }
@media (min-width: 52rem) { .foot-in { grid-template-columns: 1.15fr 1fr; gap: 4rem; } }
.foot h2 {
  font-family: var(--font-ui); font-size: var(--label-s); font-weight: 700; letter-spacing: .15em;
  text-transform: uppercase; color: var(--ink-faint); margin: 0 0 .9rem;
}
.disclosure { font-size: var(--step--1); line-height: 1.65; max-width: 56ch; }
.disclosure p { margin-bottom: .9rem; }
.disclosure p:last-child { margin-bottom: 0; }
.disclosure strong { font-weight: 700; }
.footnav { font-family: var(--font-ui); font-size: .97rem; }
.footnav ul { list-style: none; padding: 0; margin: 0 0 1.5rem; columns: 2; column-gap: 2rem; }
.footnav li { margin-bottom: .65rem; break-inside: avoid; }
.footnav a { color: var(--ink); text-decoration: none; border-bottom: 1px solid var(--rule); }
.footnav a:hover { color: var(--accent); border-bottom-color: var(--accent); }
.footmeta {
  border-top: 1px solid var(--rule); padding: 1.2rem 0 2.5rem;
  font-family: var(--font-ui); font-size: .9rem; color: var(--ink-faint);
  display: flex; flex-wrap: wrap; gap: .4rem 1.4rem;
}
.footmeta a { color: var(--ink-faint); }

/* ---------- Field Notes ---------- */
.byline {
  font-family: var(--font-ui); font-size: .95rem; font-weight: 500; color: var(--ink-soft);
  margin: 0 0 .3rem;
}
.byline strong { font-weight: 700; color: var(--ink); }

.fn-list { list-style: none; margin: 0; padding: 0; }
.fn-item { border-top: 3px solid var(--ink); padding: 1.3rem 0 2.4rem; }
.fn-item + .fn-item { border-top-width: 1px; border-top-color: var(--rule); }
.fn-when {
  font-family: var(--font-ui); font-size: var(--label-s); font-weight: 700; letter-spacing: .13em;
  text-transform: uppercase; color: var(--ink-faint); display: block; margin-bottom: .7rem;
}
.fn-item h2 {
  font-size: var(--step-2); margin: 0 0 .7rem; max-width: 34ch; line-height: 1.12;
}
.fn-item h2 a { color: var(--ink); text-decoration: none; border-bottom: 2px solid var(--rule); }
.fn-item h2 a:hover { color: var(--accent-dk); border-bottom-color: var(--accent); }
.fn-item p { margin: 0 0 .9rem; color: var(--ink-soft); max-width: 62ch; }
.fn-read {
  font-family: var(--font-ui); font-size: 1rem; font-weight: 700; letter-spacing: .02em;
  text-decoration: none; color: var(--accent-dk); border-bottom: 2px solid var(--accent-wash);
  display: inline-block; min-height: 1.5rem;
}
.fn-read:hover { border-bottom-color: var(--accent); }

.fn-back {
  display: inline-block; margin: 3rem 0 0; font-family: var(--font-ui); font-weight: 700;
  font-size: 1rem; color: var(--accent-dk); text-decoration: none;
  border-bottom: 2px solid var(--accent-wash);
}
.fn-back:hover { border-bottom-color: var(--accent); }

.fn-also { margin: 3.2rem 0 0; padding-top: 1.4rem; border-top: 3px solid var(--ink); }
.fn-also h2 {
  font-family: var(--font-ui); font-size: var(--label-s); font-weight: 700; letter-spacing: .15em;
  text-transform: uppercase; color: var(--ink-faint); margin: 0 0 .9rem;
}
.fn-also ul { list-style: none; margin: 0; padding: 0; font-family: var(--font-ui); font-size: 1rem; }
.fn-also li { margin-bottom: .7rem; line-height: 1.45; }
.fn-also a { color: var(--ink); text-decoration: none; border-bottom: 1px solid var(--rule); }
.fn-also a:hover { color: var(--accent); border-bottom-color: var(--accent); }

.feedline {
  font-family: var(--font-ui); font-size: 1rem; color: var(--ink-soft);
  margin: 2.4rem 0 0; padding-top: 1.1rem; border-top: 1px solid var(--rule);
}

/* Touch targets: link lists get a 44px minimum hit area on small screens. */
@media (max-width: 61.99rem) {
  .footnav li { margin-bottom: 0; }
  .footnav a,
  .rail a,
  .fn-also a { padding: .8rem 0; min-height: 44px; display: inline-block; line-height: 1.45; }
  .fn-also li { margin-bottom: 0; }
}

@media print {
  body::before { display: none; }
  .masthead, .rail, .navtoggle, .next { display: none; }
}