/* ==========================================================================
   RSJ Software -- rsjsoftware.com
   Plain CSS, no build step. Two colour schemes, chosen by the visitor's
   prefers-color-scheme. Every colour is a variable declared here and nowhere
   else. Fonts: IBM Plex Sans for text, IBM Plex Mono for small labels,
   self-hosted under /fonts/ as Latin-only WOFF2 subsets (tools/make_fonts.py)
   so the site makes no third-party requests. Licence: /fonts/LICENSE.txt (OFL).
   ========================================================================== */

@font-face { font-family: "IBM Plex Sans"; font-style: normal; font-weight: 400; font-display: swap; src: url("/fonts/ibm-plex-sans-400.woff2") format("woff2"); }
@font-face { font-family: "IBM Plex Sans"; font-style: normal; font-weight: 500; font-display: swap; src: url("/fonts/ibm-plex-sans-500.woff2") format("woff2"); }
@font-face { font-family: "IBM Plex Sans"; font-style: normal; font-weight: 600; font-display: swap; src: url("/fonts/ibm-plex-sans-600.woff2") format("woff2"); }
@font-face { font-family: "IBM Plex Sans"; font-style: normal; font-weight: 700; font-display: swap; src: url("/fonts/ibm-plex-sans-700.woff2") format("woff2"); }
@font-face { font-family: "IBM Plex Mono"; font-style: normal; font-weight: 400; font-display: swap; src: url("/fonts/ibm-plex-mono-400.woff2") format("woff2"); }
@font-face { font-family: "IBM Plex Mono"; font-style: normal; font-weight: 600; font-display: swap; src: url("/fonts/ibm-plex-mono-600.woff2") format("woff2"); }
@font-face { font-family: "IBM Plex Mono"; font-style: normal; font-weight: 700; font-display: swap; src: url("/fonts/ibm-plex-mono-700.woff2") format("woff2"); }

:root {
  color-scheme: light dark;

  /* Light: a drawing sheet */
  --bg: #eef1f5;
  --grid: #dde3ea;
  --paper: #ffffff;
  --ink: #17233b;
  --ink-soft: #4a5568;
  --line: #17233b;
  --line-soft: #c3cbd6;
  --accent: #9c4a0b;
  --accent-hover: #7a3a08;
  --btn-bg: #17233b;
  --btn-text: #eef1f5;
  --nav-bg: rgba(238, 241, 245, 0.9);
  --focus: #9c4a0b;

  --font-sans: "IBM Plex Sans", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, "Cascadia Mono", Consolas, monospace;
  --gutter: 16px;
  --max: 1120px;
}

@media (prefers-color-scheme: dark) {
  :root {
    /* Dark: the same sheet, after hours */
    --bg: #131b2b;
    --grid: #222d42;
    --paper: #182236;
    --ink: #e6ebf2;
    --ink-soft: #a7b1c2;
    --line: #e6ebf2;
    --line-soft: #3a4760;
    --accent: #e8a25c;
    --accent-hover: #f2bc85;
    --btn-bg: #e6ebf2;
    --btn-text: #131b2b;
    --nav-bg: rgba(19, 27, 43, 0.9);
    --focus: #e8a25c;
  }
}

@media (min-width: 720px) {
  :root { --gutter: 32px; }
}
@media (min-width: 1100px) {
  :root { --gutter: 40px; }
}

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

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

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

body {
  margin: 0;
  min-height: 100vh;
  background-color: var(--bg);
  background-image:
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px);
  background-size: 24px 24px;
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 17px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--accent);
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}
a:hover { color: var(--accent-hover); }

:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 3px;
}

h1, h2, h3 {
  font-weight: 700;
  color: var(--ink);
  margin: 0;
}

p { margin: 0; }

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

.skip {
  position: absolute;
  left: var(--gutter);
  top: -100px;
  padding: 10px 14px;
  background: var(--btn-bg);
  color: var(--btn-text);
  font-weight: 600;
  text-decoration: none;
  z-index: 20;
}
.skip:focus { top: 12px; }

.eyebrow {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
  margin: 0 0 16px;
}
@media (min-width: 720px) {
  .eyebrow { font-size: 13px; }
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: var(--nav-bg);
  -webkit-backdrop-filter: blur(6px);
  backdrop-filter: blur(6px);
  border-bottom: 1px solid var(--line);
}
.site-header .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  min-height: 60px;
}

.lockup {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  text-decoration: none;
  font-family: var(--font-mono);
  font-size: 16px;
  font-weight: 700;
  letter-spacing: 0.02em;
  white-space: nowrap;
}
.lockup:hover { color: var(--ink); }
.lockup .mark {
  width: 26px;
  height: 26px;
  flex: none;
  color: var(--ink);
}
.lockup .word { font-weight: 400; }
@media (max-width: 419px) {
  .lockup .word { display: none; }
}

.site-nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 18px;
}
.site-nav a {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  color: var(--ink);
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
}
.site-nav a:hover,
.site-nav a[aria-current="page"] {
  color: var(--ink);
  text-decoration: underline;
  text-underline-offset: 6px;
  text-decoration-thickness: 1.5px;
}
@media (min-width: 720px) {
  .site-nav ul { gap: 32px; }
  .site-nav a { font-size: 15px; }
}

/* ---- Hero ----------------------------------------------------------------- */

/* Words only (2026-09-22): the section drawing used to sit here, and a first-time
   visitor saw a steel beam before knowing it was a joke -- it read as a builder's
   site. It now sits beside "About the name", after the explanation. */
.hero {
  padding-block: clamp(40px, 7vw, 80px) clamp(36px, 5vw, 60px);
}

h1 {
  font-size: clamp(2.1rem, 1.2rem + 3.6vw, 3.5rem);
  line-height: 1.08;
  letter-spacing: -0.025em;
  max-width: 20ch;
  margin: 0 0 20px;
}

.lede {
  font-size: clamp(1.05rem, 1rem + 0.4vw, 1.2rem);
  line-height: 1.5;
  color: var(--ink-soft);
  max-width: 34em;
  margin: 0 0 28px;
}

.cta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 16px 28px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 0 22px;
  background: var(--btn-bg);
  color: var(--btn-text);
  border: 1px solid var(--btn-bg);
  border-radius: 2px;
  font-weight: 600;
  font-size: 15px;
  text-decoration: none;
}
.btn:hover {
  background: transparent;
  color: var(--ink);
}

.link-quiet {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  color: var(--ink);
  font-size: 15px;
  font-weight: 500;
  text-decoration: underline;
  text-underline-offset: 4px;
}
.link-quiet:hover { color: var(--accent-hover); }

/* ---- Figures: the drawings ------------------------------------------------ */

.fig {
  margin: 0;
  width: 100%;
}
.fig-name {
  max-width: 360px;
  margin: 8px 0 24px;
}
.fig svg {
  display: block;
  width: 100%;
  height: auto;
  color: var(--ink);
}
.fig figcaption {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--ink-soft);
  text-align: center;
}
.fig .steel {
  stroke: currentColor;
  stroke-width: 2.5;
}
.fig .dim {
  stroke: var(--accent);
  stroke-width: 1;
  fill: none;
}
.fig .lbl {
  fill: var(--accent);
  font-family: var(--font-mono);
  font-size: 12px;
}
.fig .box {
  fill: var(--paper);
  stroke: currentColor;
  stroke-width: 1.5;
}
.fig .box-lbl {
  fill: currentColor;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 600;
}

.fig-wide {
  max-width: 640px;
  margin: 40px auto 0;
}

@media (prefers-reduced-motion: no-preference) {
  html { scroll-behavior: smooth; }
  .fig .draw {
    stroke-dasharray: 1;
    stroke-dashoffset: 1;
    animation: draw 0.9s ease-out 0.3s forwards;
  }
  .fig .lbl {
    opacity: 0;
    animation: fade 0.5s ease-out 1s forwards;
  }
  @keyframes draw { to { stroke-dashoffset: 0; } }
  @keyframes fade { to { opacity: 1; } }
}

/* ---- Sections ------------------------------------------------------------- */

.section {
  border-top: 1px solid var(--line);
  padding-block: clamp(48px, 7vw, 88px);
}

.section-head {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  justify-content: space-between;
  gap: 16px 40px;
  margin-bottom: 28px;
}

h2 {
  font-size: clamp(1.7rem, 1.2rem + 2vw, 2.25rem);
  line-height: 1.12;
  letter-spacing: -0.02em;
}

.note {
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.55;
  color: var(--ink-soft);
  max-width: 46ch;
}

/* ---- Product sheets ------------------------------------------------------- */

.sheets {
  display: grid;
  gap: 24px;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 280px), 1fr));
}

.sheet {
  background: var(--paper);
  border: 1px solid var(--line);
  display: flex;
  flex-direction: column;
}
.sheet-body {
  flex: 1 1 auto;
  display: flex;
  flex-direction: column;
  gap: 12px;
  padding: 24px 24px 20px;
}
.sheet h3 {
  font-size: 1.4rem;
  letter-spacing: -0.01em;
}
.sheet .strap {
  font-size: 1.05rem;
  font-weight: 500;
  line-height: 1.35;
}
.sheet .body {
  flex: 1 1 auto;
  font-size: 15px;
  line-height: 1.55;
  color: var(--ink-soft);
}
.sheet .go {
  font-weight: 600;
  text-decoration: none;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
}
.sheet .go:hover { text-decoration: underline; }
.sheet .status-text {
  font-size: 15px;
  font-weight: 500;
  color: var(--ink-soft);
  min-height: 44px;
  display: inline-flex;
  align-items: center;
}

.title-block {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  border-top: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--ink-soft);
}
.title-block > div { padding: 8px 10px; }
.title-block > div + div { border-left: 1px solid var(--line); }
.title-block b {
  display: block;
  margin-top: 2px;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.02em;
  text-transform: none;
  color: var(--ink);
}

/* ---- About ---------------------------------------------------------------- */

.about .wrap {
  display: grid;
  gap: 36px;
}
@media (min-width: 880px) {
  .about .wrap {
    grid-template-columns: minmax(0, 5fr) minmax(0, 4fr);
    gap: 64px;
    align-items: start;
  }
}
.prose p {
  max-width: 60ch;
  margin-bottom: 1em;
}
.prose p:last-child { margin-bottom: 0; }
.prose h3 {
  font-size: 1.2rem;
  margin: 1.6em 0 0.5em;
}

.spec {
  margin: 0;
  background: var(--paper);
  border: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.5;
}
.spec > div {
  display: grid;
  grid-template-columns: minmax(0, 9em) minmax(0, 1fr);
}
.spec > div + div { border-top: 1px solid var(--line-soft); }
.spec dt {
  padding: 12px 14px;
  font-size: 11px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--ink-soft);
  border-right: 1px solid var(--line-soft);
}
.spec dd {
  margin: 0;
  padding: 12px 14px;
}

/* ---- Contact -------------------------------------------------------------- */

.contact .wrap {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 18px;
}
.contact .eyebrow { margin-bottom: 0; }
.contact p {
  max-width: 48ch;
  color: var(--ink-soft);
}
.btn-mail {
  font-family: var(--font-mono);
  font-size: clamp(1rem, 0.85rem + 0.8vw, 1.3rem);
  font-weight: 600;
  letter-spacing: 0.01em;
  padding: 0 20px;
  overflow-wrap: anywhere;
  text-align: center;
}

/* Contact page */
.contact-page main { padding-block: clamp(40px, 7vw, 80px); }
.contact-page .sheet { max-width: 640px; margin: 32px auto 0; }
.contact-page .sheet-body { align-items: flex-start; }
.contact-page .prose { margin: 40px auto 0; max-width: 640px; }
.contact-page .prose ul {
  margin: 0.5em 0 1em;
  padding-left: 1.2em;
}
.contact-page .prose li { margin-bottom: 0.3em; }

/* ---- Footer --------------------------------------------------------------- */

.site-footer {
  border-top: 1px solid var(--line);
  padding-block: 40px 48px;
  font-size: 14px;
  color: var(--ink-soft);
}
.site-footer .wrap {
  display: grid;
  gap: 24px;
}
@media (min-width: 720px) {
  .site-footer .wrap {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: start;
  }
}
.site-footer .lockup { font-size: 15px; }
.site-footer .strap { margin-top: 10px; }
.site-footer ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px 24px;
}
.site-footer ul a {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  color: var(--ink);
}
.site-footer .fine {
  font-family: var(--font-mono);
  font-size: 12px;
  margin-top: 16px;
}