/* Arx Borealis - cold, nordic, swiss-minimal holding page.
   System grotesk only. No external requests. */

/* ---------- Reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
* { margin: 0; }
html { -webkit-text-size-adjust: 100%; text-size-adjust: 100%; }
body { min-height: 100vh; line-height: 1.5; -webkit-font-smoothing: antialiased; text-rendering: optimizeLegibility; }
img, svg, video { display: block; max-width: 100%; }
input, button, textarea, select { font: inherit; color: inherit; }
button { background: none; border: none; cursor: pointer; }
a { color: inherit; text-decoration: none; }
ul, ol { list-style: none; padding: 0; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; border-radius: 1px; }

/* ---------- Tokens ---------- */
:root {
  --bg: #F3F6F9;
  --surface: #FFFFFF;
  --ink: #0B1420;
  --ink-soft: #3D4F63;
  --ink-faint: #7689A0;
  --line: #DCE6EF;
  --accent: #14507C;
  --frost: #9CC3E6;

  --font-sans: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, "SF Mono", "Cascadia Code", "JetBrains Mono", Menlo, Consolas, monospace;

  --container: 72rem;
  --gutter: clamp(1.25rem, 5vw, 3.5rem);
  --measure: 38rem;
  --header-h: 4rem;

  color-scheme: light;
}

[data-theme="dark"] {
  --bg: #080F1A;
  --surface: #0D1622;
  --ink: #E8EFF6;
  --ink-soft: #9DB0C6;
  --ink-faint: #5E7187;
  --line: #1B2738;
  --accent: #6CA0D8;
  --frost: #2E4D6E;
  color-scheme: dark;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) {
    --bg: #080F1A;
    --surface: #0D1622;
    --ink: #E8EFF6;
    --ink-soft: #9DB0C6;
    --ink-faint: #5E7187;
    --line: #1B2738;
    --accent: #6CA0D8;
    --frost: #2E4D6E;
    color-scheme: dark;
  }
}

/* ---------- Base ---------- */
html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 1rem);
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}

body {
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.6;
  font-variant-numeric: tabular-nums;
}

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

/* ---------- Skip link ---------- */
.skip {
  position: absolute;
  left: 0;
  top: 0;
  transform: translateY(-150%);
  background: var(--ink);
  color: var(--bg);
  padding: 0.625rem 1rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  z-index: 100;
  transition: transform 0.15s ease;
}
.skip:focus { transform: translateY(0); }

/* ---------- Crosshair ornament ---------- */
.crosshair {
  position: relative;
  display: inline-block;
  width: 9px;
  height: 9px;
  flex: none;
  color: var(--ink-faint);
}
.crosshair::before, .crosshair::after {
  content: "";
  position: absolute;
  background: currentColor;
}
.crosshair::before { left: 50%; top: 0; width: 1px; height: 100%; transform: translateX(-50%); }
.crosshair::after { top: 50%; left: 0; height: 1px; width: 100%; transform: translateY(-50%); }

/* ---------- Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--bg);
  border-bottom: 1px solid var(--line);
}
.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  height: var(--header-h);
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.625rem;
  font-weight: 600;
  letter-spacing: -0.01em;
}
.brand__mark { width: 22px; height: 22px; color: var(--accent); }
.brand__name { font-size: 0.9375rem; }

.site-nav { display: flex; gap: 1.5rem; }
.site-nav a {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink-soft);
  transition: color 0.15s ease;
}
.site-nav a:hover { color: var(--ink); }
.site-nav a[aria-current="true"] { color: var(--ink); }

.site-meta { display: flex; align-items: center; gap: 1rem; }
.clock {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  color: var(--ink-faint);
}
.theme-toggle {
  width: 32px;
  height: 32px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: var(--ink-soft);
  border: 1px solid var(--line);
  border-radius: 2px;
  transition: color 0.15s ease, border-color 0.15s ease;
}
.theme-toggle:hover { color: var(--ink); border-color: var(--ink-faint); }
.theme-toggle .icon { width: 16px; height: 16px; }
.theme-toggle .icon--moon { display: none; }
[data-theme="dark"] .theme-toggle .icon--sun { display: none; }
[data-theme="dark"] .theme-toggle .icon--moon { display: block; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) .theme-toggle .icon--sun { display: none; }
  :root:not([data-theme]) .theme-toggle .icon--moon { display: block; }
}

/* ---------- Hero ---------- */
.hero { position: relative; overflow: hidden; }
.hero__inner {
  position: relative;
  padding-block: clamp(4rem, 13vh, 8.5rem) clamp(3rem, 10vh, 6rem);
}

.compass {
  position: absolute;
  top: clamp(1rem, 5vh, 3.5rem);
  right: -4rem;
  width: clamp(240px, 34vw, 460px);
  height: auto;
  color: var(--frost);
  opacity: 0.65;
  pointer-events: none;
  z-index: 0;
}
.compass circle, .compass line, .compass path { fill: none; stroke: currentColor; stroke-width: 1; }
.compass__north, .compass__dot { fill: currentColor; stroke: none; }
.compass__ticks, .compass__north {
  transform-box: view-box;
  transform-origin: 120px 120px;
  animation: spin 90s linear infinite;
}
@media (prefers-reduced-motion: reduce) {
  .compass__ticks, .compass__north { animation: none; }
}
@keyframes spin { to { transform: rotate(360deg); } }

.hero__label, .hero__title, .hero__lede, .hero__foot { position: relative; z-index: 1; }

.hero__label {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--ink-faint);
  display: flex;
  flex-wrap: wrap;
  gap: 0;
}
.hero__label span { display: inline-flex; align-items: center; }
.hero__label span + span::before {
  content: "·";
  margin-inline: 0.875rem;
  opacity: 0.7;
}

.hero__title {
  font-size: clamp(3.5rem, 15vw, 11rem);
  line-height: 0.88;
  letter-spacing: -0.04em;
  font-weight: 600;
  margin-top: 2.5rem;
}
.hero__title .outline {
  color: transparent;
  -webkit-text-stroke: 2px var(--ink);
}

.hero__lede {
  max-width: 42rem;
  margin-top: 2.75rem;
  font-size: clamp(1.125rem, 2.2vw, 1.5rem);
  line-height: 1.45;
  letter-spacing: -0.01em;
  color: var(--ink-soft);
}

.hero__foot {
  margin-top: clamp(3rem, 8vh, 5rem);
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink-faint);
}
.hero__scroll { display: inline-flex; align-items: center; gap: 0.5rem; color: var(--ink-soft); transition: color 0.15s ease; }
.hero__scroll:hover { color: var(--ink); }

/* ---------- Sections ---------- */
.section { padding-block: clamp(4rem, 11vh, 7.5rem); border-top: 1px solid var(--line); }

.rail {
  display: grid;
  grid-template-columns: minmax(7rem, 11rem) 1fr;
  gap: 1.25rem 2rem;
  align-items: baseline;
}
.rail > * { grid-column: 2; }
.rail > .rail__kicker { grid-column: 1; }
@media (max-width: 640px) {
  .rail { grid-template-columns: 1fr; gap: 0.75rem; }
  .rail > *, .rail > .rail__kicker { grid-column: 1; }
}

.section__head { margin-bottom: clamp(2.5rem, 6vh, 4rem); }
.section__kicker {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-faint);
  display: inline-flex;
  align-items: center;
  gap: 0.625rem;
}
.section__title {
  font-size: clamp(1.75rem, 4.2vw, 2.75rem);
  line-height: 1.05;
  letter-spacing: -0.03em;
  font-weight: 600;
  max-width: 22ch;
}

/* About prose */
.prose-2 {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1.5rem 3rem;
}
.prose-2 p {
  color: var(--ink-soft);
  max-width: var(--measure);
}
.prose-2 p + p { margin-top: 0; }
@media (max-width: 640px) { .prose-2 { grid-template-columns: 1fr; gap: 1.25rem; } }

/* ---------- Principles ---------- */
.principles { border-top: 1px solid var(--line); }
.principles li {
  display: grid;
  grid-template-columns: 4.5rem 1fr;
  gap: 1.5rem;
  align-items: baseline;
  padding: 1.875rem 0;
  border-bottom: 1px solid var(--line);
}
.principles .num {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  letter-spacing: 0.1em;
  color: var(--ink-faint);
  transition: color 0.15s ease;
}
.principles .txt {
  font-size: clamp(1.25rem, 2.6vw, 1.75rem);
  line-height: 1.25;
  letter-spacing: -0.02em;
  color: var(--ink);
  max-width: 32ch;
}
.principles li:hover .num { color: var(--accent); }
@media (max-width: 640px) { .principles li { grid-template-columns: 3rem 1fr; gap: 1rem; padding: 1.5rem 0; } }

/* ---------- Domains ---------- */
.domains {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}
.domain {
  background: var(--bg);
  padding: 1.75rem;
  display: flex;
  flex-direction: column;
  gap: 0.875rem;
  min-height: 9rem;
  transition: background 0.2s ease;
}
.domain:hover { background: var(--surface); }
.domain__num {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.14em;
  color: var(--ink-faint);
  transition: color 0.15s ease;
}
.domain:hover .domain__num { color: var(--accent); }
.domain h3 { font-size: 1.5rem; letter-spacing: -0.02em; font-weight: 600; margin-top: auto; }
@media (max-width: 900px) { .domains { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 560px) { .domains { grid-template-columns: 1fr; } .domain { min-height: 0; padding: 1.75rem; } }

/* ---------- Footer ---------- */
.site-footer { border-top: 1px solid var(--line); padding-top: clamp(4rem, 11vh, 7.5rem); padding-bottom: 2rem; }

.footer-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
}
.footer-col { padding-inline: 1.75rem; }
@media (max-width: 900px) { .footer-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 560px) { .footer-grid { grid-template-columns: 1fr; } .footer-col { padding-inline: 0; } }

.footer-col h4 {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-faint);
  font-weight: 500;
  margin-bottom: 1rem;
}
.footer-col p { font-family: var(--font-mono); color: var(--ink-soft); font-size: 0.6875rem; line-height: 1.7; letter-spacing: 0.01em; }
.footer-col p + p { margin-top: 0.75rem; }
.footer-col a { transition: color 0.15s ease; }
.footer-col a:hover { color: var(--ink); }

.footer-bottom {
  margin-top: clamp(2.5rem, 6vh, 4rem);
  padding-top: 1.5rem;
  border-top: 1px solid var(--line);
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink-faint);
}
.footer-bottom a { color: var(--ink-soft); transition: color 0.15s ease; }
.footer-bottom a:hover { color: var(--ink); }

/* ---------- Entrance (CSS only, ends visible) ---------- */
@media (prefers-reduced-motion: no-preference) {
  .hero__label, .hero__title, .hero__lede, .hero__foot {
    opacity: 0;
    transform: translateY(16px);
    animation: rise 0.85s cubic-bezier(0.2, 0.7, 0.2, 1) forwards;
  }
  .hero__label { animation-delay: 0.05s; }
  .hero__title { animation-delay: 0.16s; animation-duration: 1s; }
  .hero__lede { animation-delay: 0.32s; }
  .hero__foot { animation-delay: 0.46s; }
}
@keyframes rise { to { opacity: 1; transform: none; } }

/* ---------- Responsive header ---------- */
@media (max-width: 720px) { .clock { display: none; } }
@media (max-width: 560px) {
  .site-nav { display: none; }
  .compass { right: -2rem; opacity: 0.4; }
}