/* =========================================================
   Clearline — Stylesheet
   Aesthetic: matches NexLayer Labs — clean white, sans-serif,
              blue accent, hairline dividers, generous whitespace
   ========================================================= */

@import url('https://fonts.googleapis.com/css2?family=Geist:wght@300;400;500;600;700;800&family=Geist+Mono:wght@400;500&display=swap');

:root {
  --white:      #FFFFFF;
  --paper:      #FFFFFF;
  --paper-2:    #FAFAFA;
  --surface:    #FFFFFF;
  --ink:        #0A0A0A;
  --ink-2:      #555555;
  --ink-3:      #888888;
  --rule:       #E5E5E5;
  --rule-soft:  #F0F0F0;
  --accent:     #1F5FE0;
  --accent-2:   #1A4FBF;
  --accent-bg:  #EEF3FE;
  --accent-soft:#5A8AE8;

  --sans:   'Geist', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --mono:   'Geist Mono', ui-monospace, SFMono-Regular, Menlo, monospace;

  --measure: 70ch;
  --gutter: 2rem;
  --max:    1100px;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--white);
  color: var(--ink-2);
  font-family: var(--sans);
  font-weight: 400;
  font-size: 17px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

main, header, footer, nav { position: relative; z-index: 1; }

/* ===== Typography ===== */
h1, h2, h3, h4 {
  font-family: var(--sans);
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--ink);
  margin: 0;
  line-height: 1.15;
}

h1 {
  font-size: clamp(2.5rem, 5.4vw, 4.2rem);
  font-weight: 800;
  letter-spacing: -0.035em;
  line-height: 1.05;
}

h2 {
  font-size: clamp(1.6rem, 2.6vw, 2.1rem);
  font-weight: 700;
  letter-spacing: -0.025em;
  line-height: 1.2;
}

h3 {
  font-size: 1.2rem;
  font-weight: 600;
  letter-spacing: -0.015em;
  line-height: 1.35;
}

h4 {
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent);
}

p { margin: 0 0 1.1em; max-width: var(--measure); color: var(--ink-2); }
p.lead {
  font-size: 1.15rem;
  line-height: 1.6;
  color: var(--ink-2);
  max-width: 60ch;
  font-weight: 400;
}

a {
  color: var(--ink);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
  text-decoration-color: var(--rule);
  transition: text-decoration-color 0.15s ease, color 0.15s ease;
}
a:hover { color: var(--accent); text-decoration-color: var(--accent); }

strong { font-weight: 600; color: var(--ink); }
em { font-style: italic; }

code, .mono {
  font-family: var(--mono);
  font-size: 0.92em;
  background: var(--paper-2);
  padding: 0.08em 0.4em;
  border-radius: 3px;
  color: var(--ink);
}

ul, ol { margin: 0 0 1.2em; padding-left: 1.4em; max-width: var(--measure); }
li { margin-bottom: 0.4em; color: var(--ink-2); }

hr { border: 0; border-top: 1px solid var(--rule); margin: 3rem 0; }

/* ===== Layout ===== */
.shell {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 var(--gutter);
}
.shell-narrow {
  max-width: 800px;
  margin: 0 auto;
  padding: 0 var(--gutter);
}

/* ===== Top Bar ===== */
.topbar {
  border-bottom: 1px solid var(--rule);
  background: var(--white);
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(8px);
}

.topbar-inner {
  max-width: var(--max);
  margin: 0 auto;
  padding: 1.4rem var(--gutter);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.7rem;
  text-decoration: none;
  color: var(--ink);
}
.brand:hover { color: var(--ink); }
.brand-mark { width: 32px; height: 32px; flex-shrink: 0; }
.brand-text { display: flex; flex-direction: column; line-height: 1; }
.brand-name {
  font-size: 1.05rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--ink);
}
.brand-sub {
  font-size: 0.65rem;
  font-weight: 600;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent);
  margin-top: 4px;
}

.nav {
  display: flex;
  align-items: center;
  gap: 2.2rem;
  font-size: 0.95rem;
  font-weight: 500;
}
.nav a { color: var(--ink); text-decoration: none; transition: color 0.15s ease; }
.nav a:hover, .nav a[aria-current="page"] { color: var(--accent); }
.nav a.cta {
  background: var(--ink);
  color: var(--white);
  padding: 0.55em 1.2em;
  border-radius: 4px;
  font-weight: 500;
  font-size: 0.92rem;
}
.nav a.cta:hover { background: var(--accent); color: var(--white); }

@media (max-width: 820px) {
  .nav { display: none; }
  .nav.mobile-open {
    display: flex; flex-direction: column;
    align-items: flex-start; gap: 1rem;
    position: absolute; top: 100%; left: 0; right: 0;
    background: var(--white); padding: 1.5rem 2rem;
    border-bottom: 1px solid var(--rule);
  }
  .menu-toggle { display: inline-block; }
}
.menu-toggle {
  display: none; background: none; border: 1px solid var(--rule);
  padding: 0.5em 0.9em; font-family: var(--sans); font-size: 0.85rem;
  cursor: pointer; color: var(--ink); border-radius: 4px;
}

/* ===== Eyebrow ===== */
.eyebrow {
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 1.4rem;
  display: inline-block;
}

.section-num {
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--ink-3);
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

/* ===== Hero ===== */
.hero { padding: 6rem 0 5rem; border-bottom: 1px solid var(--rule); }
.hero h1 { max-width: 16ch; margin-bottom: 1.8rem; }
.hero .lead { margin-bottom: 2rem; color: var(--ink-2); }
.hero-actions { display: flex; gap: 1rem; flex-wrap: wrap; margin-top: 2.2rem; }

/* ===== Buttons ===== */
.btn {
  display: inline-block;
  font-family: var(--sans);
  font-size: 0.95rem;
  font-weight: 500;
  padding: 0.85em 1.7em;
  background: var(--ink);
  color: var(--white);
  text-decoration: none;
  border: 1px solid var(--ink);
  border-radius: 4px;
  transition: background 0.15s ease, color 0.15s ease, border-color 0.15s ease;
}
.btn:hover { background: var(--accent); border-color: var(--accent); color: var(--white); }
.btn.ghost { background: transparent; color: var(--ink); }
.btn.ghost:hover { background: var(--ink); color: var(--white); border-color: var(--ink); }
.btn.accent { background: var(--accent); border-color: var(--accent); }
.btn.accent:hover { background: var(--accent-2); border-color: var(--accent-2); }

/* ===== Sections ===== */
.section { padding: 5rem 0; border-bottom: 1px solid var(--rule); }
.section:last-child { border-bottom: none; }
.section-head { margin-bottom: 3rem; }
.section-head h2 { max-width: 24ch; margin-bottom: 1.2rem; margin-top: 1rem; }

/* ===== Two-column ===== */
.two-col { display: grid; grid-template-columns: 1fr 2fr; gap: 4rem; align-items: start; }
.two-col .col-label h4 { position: sticky; top: 6rem; }
@media (max-width: 820px) { .two-col { grid-template-columns: 1fr; gap: 1.5rem; } }

/* ===== Three-column ===== */
.three-col { display: grid; grid-template-columns: repeat(3, 1fr); gap: 2.5rem; margin-top: 2rem; }
@media (max-width: 820px) { .three-col { grid-template-columns: 1fr; gap: 2rem; } }

.tile { border-top: 2px solid var(--ink); padding-top: 1.4rem; }
.tile h3 { margin-bottom: 0.6rem; color: var(--ink); }
.tile p { color: var(--ink-2); font-size: 0.97rem; }
.tile .tile-num {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--accent);
  display: block;
  margin-bottom: 0.6rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}
.tile a.tile-link {
  font-size: 0.92rem;
  font-weight: 500;
  text-decoration: none;
  color: var(--accent);
  display: inline-block;
  margin-top: 1rem;
}
.tile a.tile-link:hover { color: var(--accent-2); text-decoration: underline; text-underline-offset: 3px; }

/* ===== Tables ===== */
table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.95rem;
  margin: 1.5rem 0 2rem;
  background: var(--white);
}
thead th {
  text-align: left;
  font-weight: 600;
  font-size: 0.78rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--ink-2);
  padding: 1rem 1rem;
  border-bottom: 1px solid var(--ink);
}
tbody td {
  padding: 1rem 1rem;
  border-bottom: 1px solid var(--rule-soft);
  vertical-align: top;
  color: var(--ink-2);
}
tbody tr:last-child td { border-bottom: none; }
tbody td:first-child { font-weight: 500; color: var(--ink); }

/* ===== Tier columns ===== */
.tier-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0;
  border: 1px solid var(--rule);
  border-radius: 6px;
  background: var(--white);
  margin: 2rem 0;
  overflow: hidden;
}
.tier { padding: 2.5rem 2.2rem; border-right: 1px solid var(--rule); }
.tier:last-child { border-right: none; }
.tier .tier-label {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 0.7rem;
}
.tier h3 {
  font-size: 1.7rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
  letter-spacing: -0.025em;
}
.tier .tier-tag { font-size: 0.92rem; color: var(--ink-3); margin-bottom: 1.6rem; }
.tier > p { color: var(--ink-2); }
.tier ul { list-style: none; padding: 0; margin: 1.5rem 0; }
.tier ul li {
  padding: 0.6rem 0 0.6rem 1.5rem;
  border-bottom: 1px solid var(--rule-soft);
  font-size: 0.95rem;
  color: var(--ink-2);
  position: relative;
}
.tier ul li::before {
  content: "";
  position: absolute;
  left: 0; top: 1.05rem;
  width: 8px; height: 1px;
  background: var(--accent);
}
@media (max-width: 820px) {
  .tier-grid { grid-template-columns: 1fr; }
  .tier { border-right: none; border-bottom: 1px solid var(--rule); }
  .tier:last-child { border-bottom: none; }
}

.tier-grid.tier-grid-3 { grid-template-columns: repeat(3, 1fr); }
@media (max-width: 820px) { .tier-grid.tier-grid-3 { grid-template-columns: 1fr; } }

/* ===== Definition list ===== */
dl.terms { margin: 2rem 0; display: grid; grid-template-columns: 1fr 2fr; gap: 0; }
dl.terms dt {
  font-size: 1rem;
  font-weight: 600;
  color: var(--ink);
  padding: 1.3rem 1.5rem 1.3rem 0;
  border-top: 1px solid var(--rule);
}
dl.terms dd {
  margin: 0;
  padding: 1.3rem 0;
  color: var(--ink-2);
  border-top: 1px solid var(--rule);
  font-size: 0.95rem;
}
dl.terms dt:last-of-type, dl.terms dd:last-of-type { border-bottom: 1px solid var(--rule); }
@media (max-width: 820px) {
  dl.terms { grid-template-columns: 1fr; }
  dl.terms dd { border-top: none; padding-top: 0.4rem; padding-bottom: 1.3rem; }
}

/* ===== FAQ ===== */
.faq-item { border-bottom: 1px solid var(--rule); padding: 1.6rem 0; }
.faq-item summary {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--ink);
  cursor: pointer;
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: "+";
  color: var(--accent);
  font-size: 1.4rem;
  font-weight: 400;
  flex-shrink: 0;
}
.faq-item[open] summary::after { content: "−"; }
.faq-item .faq-body { padding-top: 1rem; color: var(--ink-2); font-size: 0.97rem; }

/* ===== Pull quote / call out ===== */
.callout {
  background: var(--accent-bg);
  border-left: 3px solid var(--accent);
  padding: 1.5rem 1.8rem;
  margin: 2rem 0;
  font-size: 1.05rem;
  font-weight: 500;
  color: var(--ink);
  max-width: var(--measure);
  border-radius: 0 4px 4px 0;
}

.note {
  background: var(--paper-2);
  padding: 1.2rem 1.5rem;
  border-left: 2px solid var(--ink-3);
  font-size: 0.92rem;
  color: var(--ink-2);
  margin: 1.5rem 0;
  max-width: var(--measure);
  border-radius: 0 4px 4px 0;
}

/* ===== Form ===== */
.form { max-width: 580px; margin: 2rem 0; }
.form label {
  display: block;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--ink);
  margin-bottom: 0.4rem;
  margin-top: 1.2rem;
}
.form input, .form textarea, .form select {
  width: 100%;
  font-family: var(--sans);
  font-size: 1rem;
  padding: 0.75rem 0.9rem;
  background: var(--white);
  border: 1px solid var(--rule);
  color: var(--ink);
  border-radius: 4px;
}
.form input:focus, .form textarea:focus, .form select:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-bg);
}
.form textarea { min-height: 140px; resize: vertical; }
.form button { margin-top: 1.5rem; cursor: pointer; }

/* ===== Footer ===== */
.footer {
  border-top: 1px solid var(--rule);
  padding: 4rem 0 2.5rem;
  margin-top: 4rem;
  background: var(--paper-2);
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 3rem;
  margin-bottom: 3rem;
}
@media (max-width: 820px) { .footer-grid { grid-template-columns: 1fr 1fr; gap: 2rem; } }
.footer h4 {
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-2);
  margin-bottom: 1rem;
}
.footer ul { list-style: none; padding: 0; margin: 0; }
.footer ul li { margin-bottom: 0.55rem; }
.footer a { font-size: 0.92rem; text-decoration: none; color: var(--ink-2); }
.footer a:hover { color: var(--accent); }
.footer .brand-name { font-size: 1.05rem; }
.footer-bottom {
  border-top: 1px solid var(--rule);
  padding-top: 1.5rem;
  display: flex;
  justify-content: space-between;
  font-size: 0.85rem;
  color: var(--ink-3);
  flex-wrap: wrap;
  gap: 1rem;
}
.footer-bottom .legal-line { max-width: 60ch; }
.footer-bottom a { color: var(--ink-3); }
.footer-bottom a:hover { color: var(--accent); }

/* ===== Page header ===== */
.page-head { padding: 5rem 0 3.5rem; border-bottom: 1px solid var(--rule); }
.page-head h1 {
  max-width: 22ch;
  font-size: clamp(2.1rem, 4.4vw, 3.4rem);
  margin-bottom: 1.4rem;
}
.page-head .lead { margin-top: 1rem; }

/* ===== Numbered legal-style sections ===== */
.legal-section {
  display: grid;
  grid-template-columns: 5rem 1fr;
  gap: 2.5rem;
  margin-bottom: 3.5rem;
  align-items: start;
}
.legal-section .num {
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--accent);
  letter-spacing: 0.08em;
  padding-top: 0.35rem;
  border-top: 1px solid var(--accent);
  text-transform: uppercase;
}
.legal-section .body h3 { margin-bottom: 0.7rem; color: var(--ink); }
@media (max-width: 700px) {
  .legal-section { grid-template-columns: 1fr; gap: 0.7rem; }
  .legal-section .num { border-top: none; padding-top: 0; padding-bottom: 0.4rem; }
}

/* ===== Audience strip ===== */
.audience { display: grid; grid-template-columns: repeat(4, 1fr); gap: 2rem; margin: 2rem 0; }
.audience .a-card { border-top: 1px solid var(--rule); padding-top: 1.2rem; }
.audience .a-card h4 { margin-bottom: 0.5rem; color: var(--ink); }
.audience .a-card p { font-size: 0.92rem; color: var(--ink-2); }
@media (max-width: 820px) { .audience { grid-template-columns: 1fr 1fr; } }
@media (max-width: 500px) { .audience { grid-template-columns: 1fr; } }

/* ===== Stack diagram ===== */
.stack { display: grid; gap: 0.7rem; margin: 2.5rem 0; max-width: 540px; }
.stack .layer {
  border: 1px solid var(--rule);
  background: var(--white);
  padding: 1.1rem 1.4rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.95rem;
  font-weight: 500;
  border-radius: 4px;
  color: var(--ink);
}
.stack .layer span:last-child { color: var(--ink-3); font-weight: 400; font-size: 0.88rem; }
.stack .layer .layer-num {
  color: var(--accent);
  margin-right: 0.9em;
  font-family: var(--mono);
  font-size: 0.85rem;
  font-weight: 500;
}
.stack .layer.top { border-top: 3px solid var(--accent); }
.stack .layer.bottom { border-bottom: 3px solid var(--ink); }

/* ===== Resources index ===== */
.resource-list { margin: 2rem 0; }
.resource-row {
  display: grid;
  grid-template-columns: 8rem 1fr 6rem;
  align-items: center;
  gap: 2rem;
  padding: 1.4rem 0;
  border-bottom: 1px solid var(--rule);
  text-decoration: none;
  color: var(--ink);
  transition: padding-left 0.15s ease, background 0.15s ease;
}
.resource-row:hover { padding-left: 0.8rem; background: var(--paper-2); }
.resource-row .res-tag {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--accent);
}
.resource-row .res-title { font-size: 1.05rem; font-weight: 600; color: var(--ink); }
.resource-row .res-meta { font-size: 0.85rem; color: var(--ink-3); text-align: right; }
@media (max-width: 700px) {
  .resource-row { grid-template-columns: 1fr; gap: 0.3rem; }
  .resource-row .res-meta { text-align: left; }
}

/* ===== Tag ===== */
.tag {
  display: inline-block;
  font-size: 0.74rem;
  font-weight: 500;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  background: var(--paper-2);
  color: var(--ink-2);
  padding: 0.3em 0.7em;
  margin-right: 0.4em;
  border-radius: 3px;
}

/* ===== CTA band ===== */
.cta-band { background: var(--ink); color: var(--white); padding: 5rem 0; margin-top: 0; }
.cta-band h2 { color: var(--white); max-width: 24ch; margin-bottom: 1.1rem; }
.cta-band p { color: rgba(255,255,255,0.72); max-width: 60ch; margin-bottom: 2rem; }
.cta-band .btn { background: var(--white); color: var(--ink); border-color: var(--white); }
.cta-band .btn:hover { background: var(--accent); color: var(--white); border-color: var(--accent); }
.cta-band a { color: var(--white); text-decoration-color: rgba(255,255,255,0.4); }
.cta-band a:hover { color: var(--accent-soft); text-decoration-color: var(--accent-soft); }

/* ===== Print ===== */
@media print {
  .topbar, .footer, .cta-band { display: none; }
  body { color: var(--ink); }
}