/* =========================================================================
   Atlas Frost - styles.css
   Single file, no external requests. System font stack (privacy + perf).
   Mobile-first. Icy / Nordic / Swiss-minimalist.
   ========================================================================= */

/* ---- Tokens ---------------------------------------------------------- */
:root {
  /* ink - polar night */
  --ink: #0a0e14;
  --ink-2: #141b26;
  --ink-3: #1f2836;

  /* paper - ice / snow */
  --paper: #f4f7fa;
  --paper-2: #eaeef4;
  --paper-3: #ffffff;

  /* frost accent - steel ice blue */
  --frost: #3e7cb1;
  --frost-deep: #2b5d87;

  /* muted text */
  --mute: #5c6b7a;
  --mute-2: #8794a3;

  /* hairlines */
  --rule: #d6dde5;
  --rule-dark: #2a3340;

  /* text on dark surfaces */
  --on-dark: #e6ecf2;
  --on-dark-mute: #9aa7b5;

  /* type */
  --sans: "Helvetica Neue", Helvetica, "Inter", system-ui, -apple-system, "Segoe UI", Roboto, Arial, sans-serif;
  --mono: "SF Mono", ui-monospace, "JetBrains Mono", "Menlo", Consolas, monospace;

  /* measure + rhythm */
  --measure: 70ch;
  --gutter: clamp(1.25rem, 5vw, 4rem);
  --section-y: clamp(4.5rem, 10vw, 8rem);
  --header-h: 64px;
}

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

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: var(--header-h);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: clamp(1rem, 0.97rem + 0.2vw, 1.0625rem);
  line-height: 1.6;
  font-weight: 400;
  letter-spacing: -0.005em;
}

img, svg { display: block; max-width: 100%; }

a { color: inherit; text-underline-offset: 0.18em; }

::selection { background: var(--frost); color: #fff; }

/* ---- Layout primitives ----------------------------------------------- */
.wrap {
  width: 100%;
  max-width: 1180px;
  margin-inline: auto;
  padding-inline: var(--gutter);
}

/* ---- Typography ------------------------------------------------------ */
h1, h2, h3 {
  margin: 0;
  font-weight: 500;
  line-height: 1.05;
  letter-spacing: -0.02em;
  color: var(--ink);
}

.display {
  font-size: clamp(2.75rem, 9vw, 5.5rem);
  line-height: 0.98;
  letter-spacing: -0.035em;
  font-weight: 500;
}

.eyebrow {
  margin: 0 0 1.5rem;
  font-size: 0.75rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.18em;
  color: var(--mute);
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
}

.eyebrow .dot {
  width: 7px; height: 7px;
  background: var(--frost);
  display: inline-block;
}

.lede {
  margin: 0;
  max-width: 52ch;
  font-size: clamp(1.05rem, 1rem + 0.4vw, 1.35rem);
  line-height: 1.5;
  color: var(--ink-2);
  font-weight: 400;
}

/* ---- Skip link + focus ----------------------------------------------- */
.skip {
  position: absolute;
  left: 0; top: 0;
  transform: translateY(-120%);
  background: var(--ink);
  color: var(--paper);
  padding: 0.6rem 1rem;
  font-size: 0.85rem;
  z-index: 100;
  transition: transform 0.15s ease;
}
.skip:focus { transform: translateY(0); }

:focus-visible {
  outline: 2px solid var(--frost);
  outline-offset: 3px;
}

/* ---- Header ---------------------------------------------------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--paper); /* solid fallback for no color-mix support */
  background: color-mix(in srgb, var(--paper) 88%, transparent);
  backdrop-filter: saturate(140%) blur(8px);
  -webkit-backdrop-filter: saturate(140%) blur(8px);
  border-bottom: 1px solid transparent;
  transition: border-color 0.2s ease, background 0.2s ease;
}
.site-header.is-scrolled { border-bottom-color: var(--rule); }

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  min-height: var(--header-h);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  text-decoration: none;
  color: var(--ink);
}
.brand .mark {
  color: var(--ink);
  /* the pair spans 22 of 48 viewBox units; a 3rem box puts the mark body at 2x the wordmark's caps */
  height: 3rem;
  width: auto;
}
.wordmark {
  font-size: 0.95rem;
  font-weight: 500;
  letter-spacing: 0.02em;
}

/* ---- Nav ------------------------------------------------------------- */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 0.5rem;
  background: none;
  border: 0;
  color: var(--ink);
  font-family: var(--sans);
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  padding: 0.5rem 0.25rem;
  cursor: pointer;
}
.nav-toggle-icon {
  width: 22px; height: 14px;
  position: relative;
}
.nav-toggle-icon::before,
.nav-toggle-icon::after {
  content: "";
  position: absolute; left: 0; right: 0;
  height: 1.5px; background: var(--ink);
  transition: transform 0.2s ease, top 0.2s ease;
}
.nav-toggle-icon::before { top: 2px; }
.nav-toggle-icon::after { top: 10px; }
.nav-toggle[aria-expanded="true"] .nav-toggle-icon::before { top: 6px; transform: rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle-icon::after { top: 6px; transform: rotate(-45deg); }

.nav ul {
  list-style: none;
  margin: 0; padding: 0;
  display: flex;
  gap: clamp(1.25rem, 3vw, 2.25rem);
}
.nav a {
  text-decoration: none;
  font-size: 0.9rem;
  letter-spacing: 0.01em;
  color: var(--ink-2);
  padding: 0.4rem 0;
  border-bottom: 1px solid transparent;
  transition: color 0.15s ease, border-color 0.15s ease;
}
.nav a:hover { color: var(--ink); border-bottom-color: var(--frost); }

/* Mobile nav. No-JS: links stack in flow, fully usable. JS: collapsible dropdown. */
@media (max-width: 719px) {
  .header-inner { flex-wrap: wrap; }

  .js .nav-toggle { display: inline-flex; }

  .nav ul {
    flex-direction: column;
    gap: 0;
  }
  .nav li { border-top: 1px solid var(--rule); }
  .nav a {
    display: block;
    padding: 0.85rem 0;
    font-size: 1rem;
  }

  /* JS-only: collapse into an absolute dropdown panel below the header. */
  .js .nav {
    position: absolute;
    top: 100%; left: 0; right: 0;
    background: var(--paper-3);
    border-bottom: 1px solid var(--rule);
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.25s ease;
  }
  .js .nav ul { padding: 0.5rem var(--gutter) 1.25rem; }
  .js .nav.is-open { max-height: 320px; }
}

/* ---- Hero ------------------------------------------------------------ */
.hero {
  position: relative;
  overflow: hidden;
  padding-block: clamp(4rem, 14vh, 8rem) clamp(4rem, 12vh, 7rem);
  border-bottom: 1px solid var(--rule);
}
.hero-grid {
  position: relative;
  z-index: 2;
  max-width: 1180px;
}
.hero-grid > * + * { margin-top: 1.75rem; }
.hero-meta {
  margin-top: 2.5rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 2rem;
  font-family: var(--mono);
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--mute);
}
.hero-meta span { white-space: nowrap; }

/* Geometric accent - bleeds off the right edge, very faint */
.hero-shape {
  position: absolute;
  top: 50%; right: -22vw;
  width: clamp(360px, 48vw, 620px);
  aspect-ratio: 1;
  transform: translateY(-50%);
  color: var(--rule);
  opacity: 0.9;
  z-index: 1;
  pointer-events: none;
}

/* ---- Section heads --------------------------------------------------- */
.section { padding-block: var(--section-y); border-bottom: 1px solid var(--rule); }

.section-head {
  display: grid;
  gap: 0.75rem 1.5rem;
  grid-template-columns: 1fr;
  margin-bottom: clamp(2.5rem, 5vw, 4rem);
}
.section-head .index {
  font-family: var(--mono);
  font-size: 0.8rem;
  color: var(--frost-deep);
  letter-spacing: 0.05em;
}
.section-head h2 {
  font-size: clamp(1.75rem, 4.5vw, 2.9rem);
  letter-spacing: -0.03em;
}
.section-kicker {
  margin: 0;
  max-width: 46ch;
  color: var(--mute);
  font-size: 1rem;
}

/* ---- Disciplines ----------------------------------------------------- */
.disciplines {
  list-style: none;
  margin: 0; padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  border-top: 1px solid var(--rule);
}
.discipline {
  display: grid;
  align-content: start;
  gap: 0.5rem;
  padding: clamp(1.5rem, 4vw, 2.5rem) 0;
  border-bottom: 1px solid var(--rule);
}
.discipline-num {
  font-family: var(--mono);
  font-size: 0.75rem;
  color: var(--frost-deep);
  letter-spacing: 0.05em;
}
.discipline h3 {
  font-size: clamp(1.2rem, 2.5vw, 1.5rem);
  letter-spacing: -0.02em;
}
.discipline p {
  margin: 0;
  max-width: 52ch;
  color: var(--ink-2);
}

@media (min-width: 720px) {
  .disciplines { grid-template-columns: 1fr 1fr; }
  .discipline { padding-inline: clamp(1.25rem, 3vw, 2rem); }
  .discipline:nth-child(odd) { border-right: 1px solid var(--rule); padding-left: 0; }
  .discipline:nth-child(even) { padding-right: 0; }
}

/* ---- Adjacent (3-col poster grid) ----------------------------------- */
.adjacent-grid {
  list-style: none;
  margin: 0; padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(2rem, 5vw, 3rem);
}
.adj-item {
  display: grid;
  align-content: start;
  gap: 0.75rem;
  padding-top: 1.25rem;
  border-top: 1px solid var(--rule);
}
.adj-num {
  font-family: var(--mono);
  font-size: 0.75rem;
  color: var(--frost-deep);
  letter-spacing: 0.05em;
}
.adj-name {
  margin: 0;
  font-size: clamp(1.5rem, 3vw, 2rem);
  letter-spacing: -0.03em;
  font-weight: 500;
  line-height: 1;
  color: var(--ink);
}
.adj-desc {
  margin: 0;
  max-width: 38ch;
  color: var(--ink-2);
  font-size: 0.95rem;
  line-height: 1.55;
}

@media (min-width: 720px) {
  .adjacent-grid {
    grid-template-columns: 1fr 1fr 1fr;
    gap: clamp(2rem, 4vw, 3.5rem);
  }
}

/* ---- Approach (dark, polar night) ------------------------------------ */
.section-quiet {
  background: var(--ink);
  color: var(--on-dark);
  border-bottom-color: var(--rule-dark);
}
.section-quiet .index { color: var(--frost); }
.section-quiet h2,
.section-quiet h3 { color: var(--paper); }
.section-quiet .section-kicker { color: var(--on-dark-mute); }

.approach-grid {
  display: grid;
  gap: clamp(2rem, 5vw, 4rem);
  grid-template-columns: 1fr;
}
.approach-body { max-width: 60ch; }
.approach-body > p {
  color: var(--on-dark);
  font-size: clamp(1.05rem, 1rem + 0.3vw, 1.2rem);
  line-height: 1.55;
}
.approach-body > p + p { margin-top: 1.25rem; }

.pullquote {
  margin: clamp(2rem, 5vw, 3rem) 0;
  padding-left: 1.25rem;
  border-left: 2px solid var(--frost);
}
.pullquote p {
  margin: 0;
  font-size: clamp(1.25rem, 2.5vw, 1.6rem);
  line-height: 1.35;
  letter-spacing: -0.02em;
  color: var(--paper);
  font-style: normal;
}

.approach-list {
  list-style: none;
  margin: clamp(2rem, 5vw, 3rem) 0 0;
  padding: 0;
  border-top: 1px solid var(--rule-dark);
}
.approach-list li {
  display: grid;
  grid-template-columns: 7rem 1fr;
  gap: 1rem;
  padding: 0.9rem 0;
  border-bottom: 1px solid var(--rule-dark);
}
.approach-list li > span:first-child {
  font-family: var(--mono);
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--frost);
  padding-top: 0.15rem;
}
.approach-list li > span:last-child {
  color: var(--on-dark-mute);
}

@media (min-width: 880px) {
  .approach-grid { grid-template-columns: 14rem 1fr; align-items: start; }
  .approach-list li { grid-template-columns: 8rem 1fr; }
}

/* ---- Work / engagements --------------------------------------------- */
.engagements {
  list-style: none;
  margin: 0; padding: 0;
  border-top: 1px solid var(--rule);
}
.engagement {
  display: grid;
  gap: 0.6rem;
  padding: clamp(1.25rem, 3vw, 1.75rem) 0;
  border-bottom: 1px solid var(--rule);
}
.eng-sector {
  font-family: var(--mono);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--mute);
}
.eng-result {
  margin: 0;
  font-size: clamp(1.05rem, 1rem + 0.3vw, 1.25rem);
  line-height: 1.4;
  color: var(--ink);
  max-width: 60ch;
}
.eng-tag {
  justify-self: start;
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--frost-deep);
  border: 1px solid var(--frost);
  padding: 0.2rem 0.55rem;
  margin-top: 0.25rem;
}

@media (min-width: 760px) {
  .engagement {
    grid-template-columns: 11rem 1fr 8rem;
    gap: clamp(1rem, 3vw, 2.5rem);
    align-items: baseline;
  }
  .eng-sector { padding-top: 0.2rem; }
  .eng-tag { justify-self: end; margin-top: 0; }
}

/* ---- Footer (dark) --------------------------------------------------- */
.site-footer {
  background: var(--ink);
  color: var(--on-dark);
  font-family: var(--mono);
  font-size: 0.72rem;
  padding-block: clamp(3rem, 7vw, 5rem);
}
.footer-grid {
  display: grid;
  gap: clamp(2rem, 5vw, 3rem);
  grid-template-columns: 1fr;
}
.footer-brand {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  color: var(--paper);
}
.footer-brand .mark {
  /* paper on the ink footer - the footer's version of --ink */
  color: var(--paper);
  height: 3rem;
  width: auto;
}
.footer-brand .wordmark { letter-spacing: 0.02em; }

.footer-col { max-width: 48ch; }
.footer-heading {
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.16em;
  color: var(--frost);
  margin-bottom: 1.25rem;
}
.footer-col p { margin: 0 0 0.75rem; color: var(--on-dark); }
.footer-col .muted { color: var(--on-dark-mute); line-height: 1.55; }
.footer-col a { color: var(--paper); }

.footer-base {
  grid-column: 1 / -1;
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 2rem;
  justify-content: space-between;
  padding-top: clamp(2rem, 5vw, 3rem);
  margin-top: clamp(1rem, 3vw, 2rem);
  border-top: 1px solid var(--rule-dark);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--on-dark-mute);
}

@media (min-width: 760px) {
  .footer-grid { grid-template-columns: 1fr 1fr 1.4fr; align-items: start; }
  .footer-brand { grid-column: 1 / -1; }
}

/* ---- Motion preferences --------------------------------------------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
}