/* fieldnotes.ai — design system
   Source of truth: "AI Blog Explorations" Claude Design export (2026-07-03),
   options 1c (home: bold minimal, oversized type, amber accent blocks,
   magazine rhythm) and 2a (article: bold minimal, mono schematic diagrams). */

@font-face { font-family: "Archivo"; font-weight: 800; src: url("fonts/Archivo_800.woff2") format("woff2"); font-display: swap; }
@font-face { font-family: "Archivo"; font-weight: 900; src: url("fonts/Archivo_900.woff2") format("woff2"); font-display: swap; }
@font-face { font-family: "Instrument Sans"; font-weight: 400; src: url("fonts/InstrumentSans_400.woff2") format("woff2"); font-display: swap; }
@font-face { font-family: "Instrument Sans"; font-weight: 500; src: url("fonts/InstrumentSans_500.woff2") format("woff2"); font-display: swap; }
@font-face { font-family: "Instrument Sans"; font-weight: 600; src: url("fonts/InstrumentSans_600.woff2") format("woff2"); font-display: swap; }
@font-face { font-family: "Instrument Sans"; font-weight: 700; src: url("fonts/InstrumentSans_700.woff2") format("woff2"); font-display: swap; }
@font-face { font-family: "IBM Plex Mono"; font-weight: 400; src: url("fonts/PlexMono_400.woff2") format("woff2"); font-display: swap; }
@font-face { font-family: "IBM Plex Mono"; font-weight: 500; src: url("fonts/PlexMono_500.woff2") format("woff2"); font-display: swap; }

:root {
  --paper: #ffffff;
  --ink: #151618;
  --ink-soft: #5d6064;
  --ink-faint: #8b8e93;
  --amber: #e8a33b;        /* fills, rules, markers */
  --amber-text: #c9821a;   /* small text on paper (legibility) */
  --panel: #f3f3f1;        /* diagram panels */
  --callout: #faf3e2;      /* key-idea cream */
  --black: #101012;        /* featured card, code blocks */
  --hairline: #e6e6e3;
  --sans: "Instrument Sans", system-ui, sans-serif;
  --display: "Archivo", var(--sans);
  --mono: "IBM Plex Mono", ui-monospace, monospace;
  --measure: 640px;
  --wide: 760px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.65;
  color: var(--ink);
  background: var(--paper);
  border-top: 4px solid var(--amber);
  -webkit-font-smoothing: antialiased;
}

/* ---------- masthead ---------- */
.masthead {
  display: flex; align-items: center; justify-content: space-between;
  max-width: 1080px; margin: 0 auto; padding: 28px 32px;
}
.wordmark {
  font-family: var(--display); font-weight: 900; font-size: 19px;
  letter-spacing: -0.02em; color: var(--ink); text-decoration: none;
}
.wordmark b { color: var(--amber); }
.masthead nav { display: flex; align-items: center; gap: 28px; }
.masthead nav a {
  font-size: 14.5px; font-weight: 500; color: var(--ink); text-decoration: none;
}
.masthead nav a:hover { color: var(--amber-text); }
.btn-pill {
  background: var(--black); color: #fff !important; font-weight: 600;
  padding: 9px 18px; border-radius: 999px; font-size: 14px;
}
.btn-pill:hover { background: #2a2a2e; }

/* ---------- home: hero ---------- */
.hero { max-width: 1080px; margin: 40px auto 8px; padding: 0 32px; }
.hero h1 {
  font-family: var(--display); font-weight: 900;
  font-size: clamp(46px, 7.2vw, 88px);
  line-height: 0.98; letter-spacing: -0.035em;
  max-width: 14ch;
  animation: rise 0.6s cubic-bezier(0.2, 0.7, 0.2, 1) both;
}
.hero h1 .dot { color: var(--amber); }

/* topic chips */
.chips { display: flex; flex-wrap: wrap; gap: 10px; max-width: 1080px; margin: 34px auto 0; padding: 0 32px; }
.chip {
  font-size: 13.5px; font-weight: 600; text-decoration: none; color: var(--ink);
  border: 1px solid var(--hairline); border-radius: 999px; padding: 7px 16px;
  transition: border-color 0.15s ease, background 0.15s ease;
}
.chip:hover { border-color: var(--amber); }
.chip.active { background: var(--amber); border-color: var(--amber); color: var(--ink); }

/* featured card */
.featured {
  display: grid; grid-template-columns: 1.15fr 1fr; gap: 32px; align-items: center;
  background: var(--black); color: #fff; border-radius: 14px;
  max-width: 1016px; margin: 36px auto 0; padding: 44px 48px;
  animation: rise 0.7s 0.08s cubic-bezier(0.2, 0.7, 0.2, 1) both;
}
.featured .kicker { color: var(--amber); }
.featured h2 {
  font-family: var(--display); font-weight: 800; font-size: clamp(26px, 3vw, 36px);
  letter-spacing: -0.02em; line-height: 1.08; margin: 14px 0 12px;
}
.featured p { color: #b9bbbf; font-size: 15.5px; max-width: 44ch; }
.featured .read-link {
  display: inline-block; margin-top: 18px; color: var(--amber);
  font-weight: 600; font-size: 15px; text-decoration: none;
}
.featured .read-link:hover { text-decoration: underline; }
.featured .fig { background: transparent; }
.featured .fig svg { width: 100%; height: auto; display: block; }

/* article index rows */
.index { max-width: 1016px; margin: 22px auto 90px; padding: 0 0 20px;
  display: grid; grid-template-columns: 1fr 1fr; gap: 0 56px; }
.row { border-top: 1px solid var(--hairline); padding: 22px 0 26px; }
.row .kicker { margin-bottom: 8px; }
.row h3 { font-family: var(--display); font-weight: 800; font-size: 22px; letter-spacing: -0.015em; line-height: 1.15; }
.row h3 a { color: var(--ink); text-decoration: none; }
.row h3 a:hover { color: var(--amber-text); }
.row p { color: var(--ink-soft); font-size: 15px; margin-top: 7px; max-width: 46ch; }

/* ---------- shared: mono kicker ---------- */
.kicker {
  font-family: var(--mono); font-weight: 500; font-size: 11.5px;
  letter-spacing: 0.14em; text-transform: uppercase; color: var(--amber-text);
}
.kicker .sep { color: var(--ink-faint); margin: 0 6px; }

/* ---------- article page ---------- */
.article-head { max-width: 720px; margin: 56px auto 0; padding: 0 32px; text-align: center; }
.article-head .kicker { display: block; }
.article-title {
  font-family: var(--display); font-weight: 900;
  font-size: clamp(38px, 5.6vw, 62px); line-height: 1.0; letter-spacing: -0.03em;
  margin: 18px auto 0; max-width: 16ch;
}
.article-title .dot { color: var(--amber); }
.deck { color: var(--ink-soft); font-size: 17.5px; max-width: 52ch; margin: 22px auto 0; line-height: 1.55; }

.article-body { max-width: var(--measure); margin: 48px auto 80px; padding: 0 24px; }
.article-body > p, .article-body > ul, .article-body > ol { margin-bottom: 22px; }
.article-body a { color: var(--ink); text-decoration: underline; text-decoration-color: var(--amber); text-underline-offset: 3px; }
.article-body a:hover { color: var(--amber-text); }

/* drop cap on the opening paragraph */
p.dropcap::first-letter {
  font-family: var(--display); font-weight: 900; color: var(--amber);
  float: left; font-size: 64px; line-height: 0.82; padding: 6px 10px 0 0;
}

.article-body h2 {
  font-family: var(--display); font-weight: 800;
  font-size: clamp(24px, 3vw, 30px); letter-spacing: -0.02em; line-height: 1.12;
  margin: 46px 0 16px;
}
.article-body h3 { font-family: var(--display); font-weight: 800; font-size: 20px; margin: 34px 0 12px; }
.article-body strong { font-weight: 700; }

/* numbered list — amber mono indices */
.article-body ol { list-style: none; counter-reset: item; }
.article-body ol li { counter-increment: item; padding-left: 44px; position: relative; margin-bottom: 10px; }
.article-body ol li::before {
  content: counter(item, decimal-leading-zero);
  position: absolute; left: 0; top: 3px;
  font-family: var(--mono); font-size: 12px; font-weight: 500; color: var(--amber-text);
}

/* bulleted list — amber dots */
.article-body ul { list-style: none; }
.article-body ul li { padding-left: 26px; position: relative; margin-bottom: 10px; }
.article-body ul li::before {
  content: ""; position: absolute; left: 4px; top: 0.62em;
  width: 7px; height: 7px; border-radius: 50%; background: var(--amber);
}

/* arrow list (next steps) */
.article-body ul.arrows li::before {
  content: "\2192"; background: none; width: auto; height: auto;
  top: 0; left: 0; color: var(--amber-text);
  font-family: var(--mono); font-size: 14px;
}

/* ---------- diagram panels ---------- */
figure.diagram {
  background: var(--panel); border-radius: 12px;
  margin: 34px 0; padding: 36px 32px;
  margin-left: calc((var(--wide) - var(--measure)) / -2);
  margin-right: calc((var(--wide) - var(--measure)) / -2);
}
figure.diagram svg { width: 100%; height: auto; display: block; }
figure.diagram .pending {
  font-family: var(--mono); font-size: 13px; line-height: 1.7; color: var(--ink-soft);
  border: 1px dashed #c9c9c4; border-radius: 8px; padding: 22px 24px;
}
figure.diagram .pending::before { content: "diagram \2192  "; color: var(--amber-text); }
figure.diagram figcaption {
  font-family: var(--sans); font-size: 13px; color: var(--ink-faint);
  text-align: center; margin-top: 16px;
}
/* mono voice inside svg diagrams */
figure.diagram text { font-family: var(--mono); }

/* ---------- callouts ---------- */
.callout {
  background: var(--callout); border-radius: 10px; padding: 20px 24px; margin: 30px 0;
}
.callout .label {
  font-family: var(--mono); font-weight: 500; font-size: 11px;
  letter-spacing: 0.16em; text-transform: uppercase; color: var(--amber-text);
  display: block; margin-bottom: 8px;
}
.callout p { font-size: 15.5px; margin: 0; }
.callout p + p { margin-top: 10px; }

/* ---------- code ---------- */
.article-body pre {
  background: var(--black); color: #e8e8e6; border-radius: 12px;
  padding: 26px 28px; margin: 30px 0; overflow-x: auto;
  font-family: var(--mono); font-size: 13px; line-height: 1.75;
  margin-left: calc((var(--wide) - var(--measure)) / -2);
  margin-right: calc((var(--wide) - var(--measure)) / -2);
}
.article-body code { font-family: var(--mono); font-size: 0.88em; background: var(--panel); padding: 2px 6px; border-radius: 5px; }
.article-body pre code { background: none; padding: 0; font-size: inherit; }

/* ---------- sources block ---------- */
.sources { border-top: 1px solid var(--ink); margin-top: 56px; padding-top: 18px; }
.sources .label {
  font-family: var(--mono); font-weight: 500; font-size: 11px;
  letter-spacing: 0.16em; text-transform: uppercase; color: var(--ink-faint);
  display: block; margin-bottom: 10px;
}
.sources p { font-size: 13.5px; color: var(--ink-soft); line-height: 1.7; margin: 0; }
.sources a { color: var(--ink-soft); }

/* series footer nav */
.series-nav { max-width: var(--measure); margin: 0 auto 90px; padding: 0 24px; display: flex; justify-content: space-between; gap: 20px; }
.series-nav a { font-size: 14px; font-weight: 600; color: var(--ink); text-decoration: none; }
.series-nav a span { display: block; font-family: var(--mono); font-size: 11px; letter-spacing: 0.12em; color: var(--amber-text); text-transform: uppercase; margin-bottom: 4px; }
.series-nav a:hover { color: var(--amber-text); }
.series-nav .next { text-align: right; }

/* footer */
.footer { border-top: 1px solid var(--hairline); }
.footer-inner { max-width: 1080px; margin: 0 auto; padding: 26px 32px; display: flex; justify-content: space-between; align-items: center; }
.footer-inner .fine { font-size: 13px; color: var(--ink-faint); }

@keyframes rise { from { opacity: 0; transform: translateY(14px); } to { opacity: 1; transform: none; } }

@media (max-width: 900px) {
  .featured { grid-template-columns: 1fr; padding: 34px 30px; }
  .index { grid-template-columns: 1fr; }
}
@media (max-width: 700px) {
  .masthead nav a:not(.btn-pill) { display: none; }
  figure.diagram, .article-body pre { margin-left: 0; margin-right: 0; }
}