/* The Peptide Observer.
 *
 * A reading publication. The whole stylesheet is built around one decision: text is set at a
 * size and measure somebody can read for ten minutes, and everything else gets out of the way.
 *
 * There is no card, no pill, no gradient, no shadow and no icon in this file. Grouping is done
 * with space; separation is done with a single hairline; emphasis is done with one red. The
 * publication's visual identity is the type and the diagrams, not decoration.
 */

:root {
  --paper: #faf7f1;
  --paper-deep: #f1ebe0;
  --ink: #221d18;
  --ink-soft: #6c6158;
  --rule: #ded5c7;
  --accent: #a8261c;
  --accent-ink: #8c1f16;
  --bar: #7d7266;
  --bar-2: #a1988c;
  --bar-3: #c3bcb1;
  --bar-4: #ded5c7;

  --serif: "Iowan Old Style", "Palatino Linotype", Palatino, "Book Antiqua", Georgia, serif;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;

  --shell: 44rem;
  --measure: 34rem;
  --pad: 1.25rem;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--serif);
  font-size: 1.1875rem;
  line-height: 1.72;
  overflow-wrap: break-word;
}

body > * {
  max-width: var(--shell);
  margin-inline: auto;
  padding-inline: var(--pad);
}

a { color: var(--accent-ink); text-underline-offset: 0.14em; text-decoration-thickness: 1px; }
a:hover { color: var(--accent); }
a:focus-visible, .skip-link:focus { outline: 2px solid var(--accent); outline-offset: 3px; }

.skip-link {
  position: absolute;
  left: -9999px;
  font-family: var(--sans);
}
.skip-link:focus { position: static; display: inline-block; padding: 0.5rem 0; }

/* ---------------------------------------------------------------- masthead */

.masthead {
  padding-top: 1.75rem;
  padding-bottom: 1rem;
}

.wordmark {
  margin: 0;
  font-size: 1.4375rem;
  font-weight: 600;
  letter-spacing: -0.01em;
}
.wordmark a { color: var(--ink); text-decoration: none; }

.standfirst {
  margin: 0.2rem 0 1rem;
  font-family: var(--sans);
  font-size: 0.875rem;
  color: var(--ink-soft);
}

.masthead nav ul,
#site-disclaimer nav ul {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem 1.4rem;
  margin: 0;
  padding: 0;
  font-family: var(--sans);
  font-size: 0.9375rem;
}
.masthead nav a { color: var(--ink); text-decoration: none; border-bottom: 1px solid var(--rule); }
.masthead nav a:hover { color: var(--accent); border-bottom-color: var(--accent); }

/* ---------------------------------------------------------------- research-use notice */

#ruo-notice {
  border-top: 1px solid var(--rule);
  border-bottom: 1px solid var(--rule);
  padding-top: 0.9rem;
  padding-bottom: 0.9rem;
  font-family: var(--sans);
  font-size: 0.8125rem;
  line-height: 1.6;
  color: var(--ink-soft);
}
#ruo-notice p { margin: 0 0 0.4rem; }
#ruo-notice p:last-child { margin-bottom: 0; }
#ruo-notice .ruo-headline { color: var(--accent); }
#ruo-notice strong { font-weight: 600; }

/* ---------------------------------------------------------------- breadcrumb and stamp */

nav[aria-label="Breadcrumb"] ol {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin: 1.1rem 0 0;
  padding: 0;
  font-family: var(--sans);
  font-size: 0.8125rem;
  color: var(--ink-soft);
}
nav[aria-label="Breadcrumb"] li + li::before { content: "/ "; color: var(--rule); }
nav[aria-label="Breadcrumb"] a { color: var(--ink-soft); }

main { padding-top: 0.25rem; padding-bottom: 3rem; }

.kicker {
  margin: 1.6rem 0 0;
  font-family: var(--sans);
  font-size: 0.6875rem;
  font-weight: 600;
  letter-spacing: 0.11em;
  text-transform: uppercase;
  color: var(--accent);
}

.stamp {
  display: flex;
  flex-wrap: wrap;
  gap: 0.2rem 1.1rem;
  margin: 0 0 2.4rem;
  padding-bottom: 0.9rem;
  border-bottom: 1px solid var(--rule);
  font-family: var(--sans);
  font-size: 0.8125rem;
  color: var(--ink-soft);
}
.stamp a { color: var(--ink-soft); }

/* ---------------------------------------------------------------- type scale */

h1 {
  max-width: var(--measure);
  margin: 0.4rem 0 1rem;
  font-size: 2.125rem;
  font-weight: 600;
  line-height: 1.18;
  letter-spacing: -0.015em;
}

h2 {
  max-width: var(--measure);
  margin: 3rem 0 0.8rem;
  font-size: 1.375rem;
  font-weight: 600;
  line-height: 1.3;
}

h3 {
  max-width: var(--measure);
  margin: 2rem 0 0.5rem;
  font-size: 1.125rem;
  font-weight: 600;
}

main p,
main ul,
main ol,
main blockquote {
  max-width: var(--measure);
}

main p { margin: 0 0 1.15rem; }
main ul, main ol { margin: 0 0 1.3rem; padding-left: 1.2rem; }
main li { margin-bottom: 0.65rem; }

/* ---------------------------------------------------------------- the answer block */

.answer-block {
  max-width: var(--measure);
  margin: 0 0 2.6rem;
  padding-left: 1.25rem;
  border-left: 3px solid var(--accent);
}
.answer {
  margin: 0;
  font-size: 1.4375rem;
  line-height: 1.45;
  letter-spacing: -0.005em;
}
.answer-note {
  margin: 0.8rem 0 0;
  font-family: var(--sans);
  font-size: 0.9375rem;
  line-height: 1.6;
  color: var(--ink-soft);
}

/* ---------------------------------------------------------------- what is not known */

.not-known h2 { color: var(--accent); }
.not-known ul { list-style: none; padding-left: 0; }
.not-known li { position: relative; padding-left: 1.5rem; }
.not-known li::before {
  content: "\2014";
  position: absolute;
  left: 0;
  color: var(--accent);
}

.plain-list { list-style: none; padding-left: 0; }
.plain-list li { position: relative; padding-left: 1.5rem; }
.plain-list li::before {
  content: "\2014";
  position: absolute;
  left: 0;
  color: var(--rule);
}

/* ---------------------------------------------------------------- lists of questions */

.question-list { list-style: none; padding-left: 0; margin: 0; max-width: var(--measure); }
.question-list > li {
  margin: 0;
  padding: 1.15rem 0;
  border-bottom: 1px solid var(--rule);
}
.question-list > li:first-child { padding-top: 0.4rem; }
.question-list .q { margin: 0; font-size: 1.1875rem; line-height: 1.35; }
.question-list .q a { color: var(--ink); text-decoration-color: var(--rule); }
.question-list .q a:hover { color: var(--accent); text-decoration-color: var(--accent); }
.question-list .a {
  margin: 0.35rem 0 0;
  font-family: var(--sans);
  font-size: 0.9375rem;
  line-height: 1.55;
  color: var(--ink-soft);
}

.question-list .count {
  font-family: var(--sans);
  font-size: 0.8125rem;
  color: var(--ink-soft);
  white-space: nowrap;
}

.read-next { list-style: none; padding-left: 0; font-family: var(--sans); font-size: 0.9375rem; }
.read-next li { margin-bottom: 0.5rem; }

/* ---------------------------------------------------------------- diagrams */

.diagram {
  max-width: var(--shell);
  margin: 2rem 0 2.4rem;
  padding: 0;
}

.diagram-svg {
  display: block;
  width: 100%;
  height: auto;
  overflow: visible;
}

.diagram figcaption {
  max-width: var(--measure);
  margin-top: 1rem;
  font-family: var(--sans);
  font-size: 0.875rem;
  line-height: 1.6;
  color: var(--ink-soft);
}

/* The values behind a figure sit under its caption and need to read as a separate object,
 * which here is done with space and a rule rather than by boxing either of them. */
.diagram .scroll {
  margin-top: 1.6rem;
  padding-top: 1.2rem;
  border-top: 1px solid var(--rule);
}

.d-axis { stroke: var(--ink); stroke-width: 1; fill: none; }
.d-axis-end { stroke: var(--ink-soft); stroke-width: 1; fill: none; }
.d-tick { stroke: var(--accent); stroke-width: 1.5; opacity: 0.6; }
.d-track { fill: var(--paper-deep); }
.d-bar { fill: var(--bar); }
.d-bar-empty { fill: none; }
.d-seg-accent { fill: var(--accent); }
.d-seg-1 { fill: var(--bar); }
.d-seg-2 { fill: var(--bar-2); }
.d-seg-3 { fill: var(--bar-3); }
.d-seg-4 { fill: var(--bar-4); }
.d-leader { stroke: var(--accent); stroke-width: 1; fill: none; }
.d-leader-head { fill: var(--accent); }

.d-text { font-family: var(--sans); font-size: 14px; fill: var(--ink); }
.d-text-sm { font-family: var(--sans); font-size: 12px; fill: var(--ink-soft); }
.d-value { font-family: var(--sans); font-size: 14px; font-weight: 600; fill: var(--ink); }

/* ---------------------------------------------------------------- tables */

.scroll { overflow-x: auto; max-width: var(--shell); margin: 0 0 1.6rem; }
.scroll:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; }

table {
  border-collapse: collapse;
  width: 100%;
  font-family: var(--sans);
  font-size: 0.9375rem;
  line-height: 1.5;
}
caption {
  text-align: left;
  padding-bottom: 0.7rem;
  font-family: var(--sans);
  font-size: 0.8125rem;
  color: var(--ink-soft);
}
th, td {
  padding: 0.6rem 1rem 0.6rem 0;
  border-bottom: 1px solid var(--rule);
  vertical-align: top;
  text-align: left;
}
th[scope="col"] {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--ink-soft);
  border-bottom-color: var(--ink-soft);
}
th[scope="row"] { font-weight: 600; }

/* ---------------------------------------------------------------- small print inside prose */

.note { font-family: var(--sans); font-size: 0.875rem; line-height: 1.6; color: var(--ink-soft); }
.unknown { color: var(--ink-soft); font-variant: small-caps; letter-spacing: 0.03em; }
.derived { font-family: var(--sans); font-size: 0.8125rem; color: var(--ink-soft); }
.caution { border-left: 3px solid var(--rule); padding-left: 1.1rem; }

sup.ref { font-size: 0.6875rem; font-family: var(--sans); }
sup.ref a { text-decoration: none; }

blockquote.scope {
  margin: 1.6rem 0;
  padding-left: 1.25rem;
  border-left: 1px solid var(--rule);
  color: var(--ink-soft);
  font-size: 1.0625rem;
}
blockquote.scope .attribution { font-family: var(--sans); font-size: 0.8125rem; }

ol.sources {
  max-width: var(--measure);
  font-family: var(--sans);
  font-size: 0.875rem;
  line-height: 1.55;
  padding-left: 1.4rem;
}
ol.sources li { margin-bottom: 0.7rem; }
ol.sources cite { font-style: normal; }
.src-id { color: var(--ink-soft); font-size: 0.8125rem; }

/* ---------------------------------------------------------------- outbound block and footer */

.slot-block {
  max-width: var(--measure);
  margin-top: 3rem;
  padding-top: 1rem;
  border-top: 1px solid var(--rule);
  font-family: var(--sans);
  font-size: 0.9375rem;
}
.sponsored {
  font-size: 0.6875rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-soft);
}

#site-disclaimer {
  border-top: 1px solid var(--rule);
  padding-top: 1.6rem;
  padding-bottom: 3rem;
  font-family: var(--sans);
  font-size: 0.8125rem;
  line-height: 1.65;
  color: var(--ink-soft);
}
#site-disclaimer p { max-width: var(--measure); margin: 0 0 0.8rem; }
#site-disclaimer .footer-ruo strong { color: var(--accent); font-weight: 600; }
#site-disclaimer .tagline { margin-top: 1.4rem; color: var(--ink); }
#site-disclaimer nav ul { margin-top: 1.2rem; font-size: 0.8125rem; }
#site-disclaimer a { color: var(--ink-soft); }

/* ---------------------------------------------------------------- narrow screens */

@media (max-width: 34rem) {
  :root { --pad: 1rem; }
  body { font-size: 1.0625rem; line-height: 1.68; }
  h1 { font-size: 1.75rem; }
  h2 { font-size: 1.25rem; margin-top: 2.4rem; }
  .answer { font-size: 1.25rem; }
  .answer-block { padding-left: 1rem; }
  .wordmark { font-size: 1.25rem; }
  th, td { padding-right: 0.75rem; }
}

@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; }
}