/* NextEntropy — site styles
   Editorial, restrained: off-white ground, near-black ink, one accent. */

:root {
  --bg: #f5f2ec;
  --card: #fbfaf6;
  --ink: #15140f;
  --muted: #6b675e;
  --line: #dcd7cb;
  --accent: #0e5a47;
  --accent-soft: #e2ebe5;
  --fail: #c9573a;
  --pass: #7fbf9f;

  --serif: "Newsreader", "Iowan Old Style", Georgia, serif;
  --sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --mono: "IBM Plex Mono", ui-monospace, "SF Mono", Menlo, monospace;

  --wrap: 1120px;
  --gutter: 24px;
}

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

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 1.0625rem;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

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

a {
  color: inherit;
  text-decoration-color: var(--line);
  text-underline-offset: 0.2em;
  transition: text-decoration-color 0.15s ease, color 0.15s ease;
}

a:hover {
  text-decoration-color: var(--ink);
}

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

.wrap {
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 0 var(--gutter);
}

/* ---------- Type ---------- */

h1,
h2,
h3 {
  font-family: var(--serif);
  font-weight: 400;
  letter-spacing: -0.02em;
  margin: 0;
}

h1 {
  font-size: clamp(2.6rem, 6.4vw, 4.9rem);
  line-height: 1.02;
}

h2 {
  font-size: clamp(1.8rem, 3.4vw, 2.6rem);
  line-height: 1.1;
}

h3 {
  font-size: 1.35rem;
  line-height: 1.25;
  letter-spacing: -0.01em;
}

p {
  margin: 0 0 1em;
}

p:last-child {
  margin-bottom: 0;
}

.eyebrow {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--muted);
}

.lede {
  font-size: clamp(1.15rem, 1.9vw, 1.4rem);
  line-height: 1.45;
  color: #3a382f;
  max-width: 38em;
}

.muted {
  color: var(--muted);
}

.small {
  font-size: 0.9rem;
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: rgba(245, 242, 236, 0.88);
  backdrop-filter: saturate(1.4) blur(10px);
  -webkit-backdrop-filter: saturate(1.4) blur(10px);
  border-bottom: 1px solid var(--line);
}

.bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 68px;
  gap: 24px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--serif);
  font-size: 1.5rem;
  letter-spacing: -0.02em;
  text-decoration: none;
}

.brand::before {
  content: "";
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--accent);
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 28px;
}

.site-nav a {
  font-size: 0.94rem;
  text-decoration: none;
  color: #3a382f;
}

.site-nav a:hover,
.site-nav a[aria-current="page"] {
  color: var(--ink);
}

.site-nav a[aria-current="page"] {
  box-shadow: 0 1px 0 var(--ink);
}

.nav-toggle {
  display: none;
  font: inherit;
  font-size: 0.94rem;
  background: none;
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 6px 14px;
  color: var(--ink);
  cursor: pointer;
}

/* ---------- Buttons ---------- */

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--sans);
  font-size: 0.98rem;
  font-weight: 500;
  line-height: 1;
  padding: 15px 22px;
  border-radius: 999px;
  border: 1px solid var(--ink);
  background: var(--ink);
  color: var(--bg);
  text-decoration: none;
  transition: background 0.15s ease, color 0.15s ease, border-color 0.15s ease;
}

.btn:hover {
  background: var(--accent);
  border-color: var(--accent);
}

.btn-ghost {
  background: transparent;
  color: var(--ink);
}

.btn-ghost:hover {
  background: var(--ink);
  border-color: var(--ink);
  color: var(--bg);
}

.site-nav .btn {
  padding: 10px 16px;
  font-size: 0.9rem;
  color: var(--bg);
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 36px;
}

.arrow-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-weight: 500;
  text-decoration: none;
  border-bottom: 1px solid var(--ink);
  padding-bottom: 2px;
}

.arrow-link::after {
  content: "→";
  transition: transform 0.15s ease;
}

.arrow-link:hover::after {
  transform: translateX(3px);
}

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

.hero {
  padding: clamp(72px, 12vw, 148px) 0 clamp(56px, 8vw, 96px);
}

.hero h1 {
  max-width: 14em;
}

.hero .lede {
  margin-top: 28px;
}

.page-hero {
  padding: clamp(64px, 9vw, 120px) 0 clamp(48px, 6vw, 80px);
}

.page-hero .eyebrow {
  display: block;
  margin-bottom: 22px;
}

.page-hero h1 {
  font-size: clamp(2.3rem, 5.4vw, 4.1rem);
  max-width: 15em;
}

.page-hero .lede {
  margin-top: 24px;
}

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

.section {
  padding: clamp(56px, 8vw, 104px) 0;
  border-top: 1px solid var(--line);
}

.row {
  display: grid;
  grid-template-columns: 200px minmax(0, 1fr);
  gap: 48px;
}

.row > .eyebrow {
  padding-top: 0.55em;
}

.row h2 {
  max-width: 18em;
}

.row h2 + p,
.row h2 + .lede,
.row h2 + .prose {
  margin-top: 20px;
}

.prose {
  max-width: 40em;
}

.prose p {
  color: #3a382f;
}

/* ---------- Three-line model strip ---------- */

.strip {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  border-top: 1px solid var(--ink);
}

.strip > div {
  padding: 26px 28px 30px 0;
}

.strip > div + div {
  padding-left: 28px;
  border-left: 1px solid var(--line);
}

.strip .eyebrow {
  display: block;
  margin-bottom: 14px;
}

.strip p {
  font-family: var(--serif);
  font-size: clamp(1.3rem, 2.2vw, 1.7rem);
  line-height: 1.2;
  letter-spacing: -0.015em;
}

/* ---------- Definition-style lists ---------- */

.deflist {
  margin: 36px 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--line);
}

.deflist li {
  display: grid;
  grid-template-columns: minmax(0, 15em) minmax(0, 1fr);
  gap: 24px;
  padding: 20px 0;
  border-bottom: 1px solid var(--line);
}

.deflist strong {
  font-weight: 600;
}

.deflist span {
  color: #3a382f;
}

.ticks {
  margin: 28px 0 0;
  padding: 0;
  list-style: none;
}

.ticks li {
  position: relative;
  padding: 12px 0 12px 30px;
  border-top: 1px solid var(--line);
}

.ticks li:last-child {
  border-bottom: 1px solid var(--line);
}

.ticks li::before {
  content: "";
  position: absolute;
  left: 2px;
  top: 1.35em;
  width: 12px;
  height: 1px;
  background: var(--accent);
}

/* ---------- Steps ---------- */

.steps {
  margin: 36px 0 0;
  padding: 0;
  list-style: none;
  counter-reset: step;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
  gap: 0;
  border-top: 1px solid var(--ink);
}

.steps li {
  counter-increment: step;
  padding: 24px 24px 8px 0;
}

.steps li::before {
  content: "0" counter(step);
  display: block;
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  color: var(--muted);
  margin-bottom: 14px;
}

.steps h3 {
  margin-bottom: 8px;
}

.steps p {
  color: #3a382f;
  font-size: 0.98rem;
}

/* ---------- Two-door cards ---------- */

.doors {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
  margin-top: 36px;
}

.door {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  min-height: 260px;
  padding: 32px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 6px;
  text-decoration: none;
  transition: border-color 0.15s ease, transform 0.15s ease;
}

.door:hover {
  border-color: var(--ink);
  transform: translateY(-2px);
}

.door h3 {
  font-size: clamp(1.5rem, 2.4vw, 1.9rem);
  margin: 16px 0 12px;
}

.door p {
  color: #3a382f;
  max-width: 26em;
}

.door .arrow-link {
  align-self: flex-start;
  margin-top: 28px;
}

/* ---------- Task card (the one concrete artefact) ---------- */

.task {
  margin-top: 36px;
  background: var(--ink);
  color: #ece8dd;
  border-radius: 8px;
  overflow: hidden;
  font-family: var(--mono);
  font-size: 0.86rem;
  line-height: 1.55;
}

.task-head {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  padding: 14px 22px;
  border-bottom: 1px solid #34322a;
  color: #a39f92;
  font-size: 0.74rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.task dl {
  margin: 0;
}

.task-row {
  display: grid;
  grid-template-columns: 120px minmax(0, 1fr);
  gap: 20px;
  padding: 16px 22px;
  border-bottom: 1px solid #2a2821;
}

.task-row:last-child {
  border-bottom: 0;
}

.task dt {
  color: #a39f92;
  font-size: 0.74rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding-top: 2px;
}

.task dd {
  margin: 0;
}

.task .quote {
  font-family: var(--serif);
  font-size: 1.2rem;
  line-height: 1.35;
  color: #fff;
}

.task .fail {
  color: var(--fail);
  font-weight: 500;
}

.task .ok {
  color: var(--pass);
}

.task .miss {
  color: var(--fail);
}

.caption {
  margin-top: 14px;
  font-size: 0.86rem;
  color: var(--muted);
}

/* ---------- Diagram ---------- */

.diagram {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 110px minmax(0, 1.5fr) 110px minmax(0, 1fr);
  align-items: center;
  margin-top: 40px;
}

.node {
  padding: 20px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 6px;
}

.node strong {
  display: block;
  font-family: var(--serif);
  font-size: 1.25rem;
  font-weight: 400;
  letter-spacing: -0.01em;
  margin: 6px 0 4px;
}

.node p {
  font-size: 0.9rem;
  color: var(--muted);
}

.node.solid {
  background: var(--ink);
  border-color: var(--ink);
  color: var(--bg);
}

.node.solid p {
  color: #b9b5a8;
}

.boundary {
  position: relative;
  display: grid;
  gap: 12px;
  padding: 40px 18px 18px;
  border: 1.5px dashed var(--accent);
  border-radius: 10px;
  background: var(--accent-soft);
}

.boundary-label {
  position: absolute;
  top: 12px;
  left: 18px;
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
}

.flow {
  position: relative;
  text-align: center;
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--muted);
  padding: 0 8px 22px;
}

.flow::after {
  content: "";
  position: absolute;
  left: 10px;
  right: 10px;
  bottom: 8px;
  height: 1px;
  background: var(--ink);
}

.flow::before {
  content: "";
  position: absolute;
  right: 10px;
  bottom: 4px;
  width: 8px;
  height: 8px;
  border-top: 1px solid var(--ink);
  border-right: 1px solid var(--ink);
  transform: rotate(45deg);
}

/* ---------- Environment card ---------- */

.envcard {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 24px;
  align-items: end;
  margin-top: 36px;
  padding: 32px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 6px;
}

.envcard h3 {
  font-size: clamp(1.6rem, 2.6vw, 2.1rem);
  margin: 12px 0 10px;
}

.envcard p {
  color: #3a382f;
  max-width: 32em;
}

.status {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 7px 12px;
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--accent);
  white-space: nowrap;
}

.status::before {
  content: "";
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
}

/* ---------- FAQ ---------- */

.faq {
  margin-top: 32px;
  border-top: 1px solid var(--line);
}

.faq details {
  border-bottom: 1px solid var(--line);
}

.faq summary {
  display: flex;
  justify-content: space-between;
  gap: 24px;
  padding: 20px 0;
  font-family: var(--serif);
  font-size: 1.25rem;
  letter-spacing: -0.01em;
  cursor: pointer;
  list-style: none;
}

.faq summary::-webkit-details-marker {
  display: none;
}

.faq summary::after {
  content: "+";
  font-family: var(--mono);
  color: var(--muted);
}

.faq details[open] summary::after {
  content: "–";
}

.faq details p {
  padding: 0 0 22px;
  max-width: 40em;
  color: #3a382f;
}

/* ---------- Essay (Thesis) ---------- */

.essay {
  max-width: 44rem;
}

.essay section {
  padding: 44px 0;
  border-top: 1px solid var(--line);
}

.essay section:first-child {
  border-top: 1px solid var(--ink);
}

.essay h2 {
  font-family: var(--mono);
  font-size: 0.72rem;
  font-weight: 400;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 20px;
}

.essay p {
  font-family: var(--serif);
  font-size: clamp(1.2rem, 1.9vw, 1.42rem);
  line-height: 1.5;
  letter-spacing: -0.005em;
}

.essay sup a {
  font-family: var(--mono);
  font-size: 0.6em;
  text-decoration: none;
  color: var(--accent);
  padding: 0 1px;
}

.notes {
  margin: 0;
  padding: 0 0 0 1.2em;
  font-size: 0.88rem;
  color: var(--muted);
}

.notes li {
  padding: 4px 0;
}

/* ---------- Team and contact ---------- */

.team {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(230px, 1fr));
  gap: 20px;
  margin-top: 36px;
}

.person {
  padding: 24px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 6px;
}

.person .avatar {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--accent-soft);
  margin-bottom: 18px;
}

.person h3 {
  font-size: 1.2rem;
}

.person .role {
  display: block;
  margin: 4px 0 12px;
}

.person p {
  font-size: 0.94rem;
  color: #3a382f;
}

.routes {
  margin: 36px 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--ink);
}

.routes li {
  border-bottom: 1px solid var(--line);
}

.routes a {
  display: grid;
  grid-template-columns: minmax(0, 14em) minmax(0, 1fr) auto;
  gap: 24px;
  align-items: baseline;
  padding: 22px 0;
  text-decoration: none;
}

.routes strong {
  font-family: var(--serif);
  font-size: 1.3rem;
  font-weight: 400;
  letter-spacing: -0.01em;
}

.routes span {
  color: #3a382f;
}

.routes em {
  font-style: normal;
  font-weight: 500;
  white-space: nowrap;
}

.routes a:hover strong {
  color: var(--accent);
}

/* ---------- Closing band ---------- */

.closing {
  padding: clamp(64px, 9vw, 120px) 0;
  border-top: 1px solid var(--line);
}

.closing h2 {
  font-size: clamp(2rem, 4.4vw, 3.4rem);
  max-width: 16em;
}

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

.site-footer {
  border-top: 1px solid var(--ink);
  padding: 48px 0 56px;
  font-size: 0.92rem;
}

.foot {
  display: grid;
  grid-template-columns: minmax(0, 1.4fr) repeat(2, minmax(0, 1fr));
  gap: 40px;
}

.foot p {
  color: var(--muted);
  max-width: 26em;
  margin-top: 14px;
}

.foot ul {
  margin: 12px 0 0;
  padding: 0;
  list-style: none;
}

.foot li {
  padding: 4px 0;
}

.foot a {
  text-decoration: none;
  color: #3a382f;
}

.foot a:hover {
  color: var(--ink);
}

.legal {
  margin-top: 44px;
  padding-top: 20px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.84rem;
}

/* ---------- Responsive ---------- */

@media (max-width: 900px) {
  .row {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  .row > .eyebrow {
    padding-top: 0;
  }

  .diagram {
    grid-template-columns: 1fr;
  }

  .flow {
    padding: 14px 0 14px 34px;
    text-align: left;
  }

  .flow::after {
    left: 14px;
    right: auto;
    top: 6px;
    bottom: 6px;
    width: 1px;
    height: auto;
  }

  .flow::before {
    left: 10px;
    right: auto;
    bottom: 6px;
    transform: rotate(135deg);
  }
}

@media (max-width: 760px) {
  .nav-toggle {
    display: inline-block;
  }

  .site-nav {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: flex-start;
    gap: 0;
    padding: 8px var(--gutter) 20px;
    background: var(--bg);
    border-bottom: 1px solid var(--line);
  }

  .site-nav.open {
    display: flex;
  }

  .site-nav a {
    width: 100%;
    padding: 12px 0;
    font-size: 1.05rem;
    border-bottom: 1px solid var(--line);
  }

  .site-nav a[aria-current="page"] {
    box-shadow: none;
    font-weight: 600;
  }

  .site-nav .btn {
    width: auto;
    margin-top: 16px;
    padding: 12px 18px;
    border-bottom: 1px solid var(--ink);
  }

  .strip {
    grid-template-columns: 1fr;
  }

  .strip > div,
  .strip > div + div {
    padding: 20px 0;
    border-left: 0;
  }

  .strip > div + div {
    border-top: 1px solid var(--line);
  }

  .doors {
    grid-template-columns: 1fr;
  }

  .door {
    min-height: 0;
    padding: 24px;
  }

  .deflist li {
    grid-template-columns: 1fr;
    gap: 4px;
  }

  .envcard {
    grid-template-columns: 1fr;
    padding: 24px;
  }

  .task-row {
    grid-template-columns: 1fr;
    gap: 6px;
  }

  .routes a {
    grid-template-columns: 1fr;
    gap: 4px;
  }

  .foot {
    grid-template-columns: 1fr;
    gap: 28px;
  }
}

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