/* ==========================================================================
   LLM Systems — landing page
   Implemented from design_handoff_landing_page/LLM Systems Landing v2.dc.html
   ========================================================================== */

:root {
  /* Surfaces */
  --bg:            #FFFFFF;
  --surface:       #FAFAFB;
  --band:          #F4F4F5;
  --deep:          #EDEDEF;

  /* Ink */
  --ink:           #141518;
  --ink-hover:     #2E2F33;

  /* Text scale */
  --t-primary:     #141518;
  --t-body:        #2A2B2E;
  --t-secondary:   #4A4B4F;
  --t-muted:       #77787B;
  --t-faint:       #8E8F93;
  --t-line:        #A9AAAD;
  --t-hair:        #C4C5C8;

  /* Borders */
  --b-hair:        rgba(20, 21, 24, 0.08);
  --b-card:        rgba(20, 21, 24, 0.10);
  --b-chip:        rgba(20, 21, 24, 0.12);
  --b-emph:        rgba(20, 21, 24, 0.25);
  --b-strong:      rgba(20, 21, 24, 0.35);

  /* Type */
  --f-head:  'Space Grotesk', ui-sans-serif, system-ui, sans-serif;
  --f-mono:  'IBM Plex Mono', ui-monospace, SFMono-Regular, Menlo, monospace;
  --f-body:  'IBM Plex Sans', ui-sans-serif, system-ui, -apple-system, sans-serif;

  /* Layout */
  --wrap:    1140px;
  --radius:  16px;
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  /* keep anchored sections clear of the sticky nav */
  scroll-padding-top: 88px;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--bg);
  background-image: radial-gradient(circle at 1px 1px, rgba(20, 21, 24, 0.05) 1px, transparent 0);
  background-size: 34px 34px;
  color: var(--t-body);
  font-family: var(--f-body);
  min-height: 100vh;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

::selection { background: rgba(20, 21, 24, 0.12); }

img { max-width: 100%; }

a:focus-visible,
summary:focus-visible {
  outline: 2px solid var(--ink);
  outline-offset: 3px;
  border-radius: 4px;
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  z-index: 100;
  background: var(--ink);
  color: #fff;
  font-family: var(--f-mono);
  font-size: 13.5px;
  padding: 12px 18px;
  border-radius: 0 0 8px 0;
  text-decoration: none;
}
.skip-link:focus { left: 0; }

/* --------------------------------------------------------------------------
   Shared primitives
   -------------------------------------------------------------------------- */

.wrap {
  max-width: var(--wrap);
  margin: 0 auto;
  padding-left: 32px;
  padding-right: 32px;
}

.band {
  background: var(--band);
  border-top: 1px solid var(--b-hair);
  border-bottom: 1px solid var(--b-hair);
}

.eyebrow {
  font-family: var(--f-mono);
  font-size: 12.5px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink);
  margin-bottom: 18px;
}

h2 {
  font-family: var(--f-head);
  font-weight: 600;
  font-size: clamp(28px, 4vw, 44px);
  line-height: 1.08;
  letter-spacing: -0.02em;
  margin: 0;
  color: var(--t-primary);
}
h2.h2--lg { font-size: clamp(30px, 4vw, 46px); }

.lede {
  font-family: var(--f-body);
  font-size: 17px;
  line-height: 1.6;
  color: var(--t-muted);
  margin: 0;
}

.head--center {
  text-align: center;
  margin-left: auto;
  margin-right: auto;
}

.card {
  border: 1px solid var(--b-card);
  background: var(--surface);
  border-radius: var(--radius);
}

.grid { display: grid; gap: 20px; }
.grid--2 { grid-template-columns: repeat(2, 1fr); gap: 18px; }
.grid--3 { grid-template-columns: repeat(3, 1fr); }
.grid--4 { grid-template-columns: repeat(4, 1fr); gap: 18px; }

.chip {
  font-family: var(--f-mono);
  font-size: 13px;
  color: var(--t-secondary);
  border: 1px solid var(--b-chip);
  background: rgba(20, 21, 24, 0.04);
  padding: 9px 15px;
  border-radius: 8px;
  white-space: nowrap;
}

/* Buttons */
.btn {
  display: inline-block;
  font-family: var(--f-mono);
  font-weight: 500;
  text-decoration: none;
  text-align: center;
  border-radius: 8px;
  transition: background-color 0.18s ease, border-color 0.18s ease, color 0.18s ease;
}
.btn--primary {
  color: #FFFFFF;
  background: var(--ink);
  border: 1px solid var(--ink);
}
.btn--primary:hover { background: var(--ink-hover); border-color: var(--ink-hover); }

.btn--ghost {
  color: var(--t-body);
  background: transparent;
  border: 1px solid rgba(20, 21, 24, 0.18);
}
.btn--ghost:hover {
  background: rgba(20, 21, 24, 0.05);
  border-color: rgba(20, 21, 24, 0.32);
}

.btn--lg  { font-size: 14.5px; padding: 14px 26px; }
.btn--xl  { font-size: 15px;   padding: 15px 32px; border-radius: 9px; }
.btn--nav { font-size: 13.5px; padding: 10px 18px; border-radius: 7px; }
.btn--block { display: block; font-size: 14px; padding: 13px; border-radius: 9px; }

/* --------------------------------------------------------------------------
   Nav
   -------------------------------------------------------------------------- */

.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding: 18px 40px;
  border-bottom: 1px solid var(--b-hair);
  background: rgba(255, 255, 255, 0.82);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
}
.brand img { height: 34px; display: block; }
.brand span {
  font-family: var(--f-head);
  font-weight: 600;
  font-size: 19px;
  letter-spacing: -0.01em;
  color: var(--t-primary);
}

.nav__links {
  display: flex;
  align-items: center;
  gap: 38px;
}
.nav__link {
  font-family: var(--f-mono);
  font-size: 13.5px;
  letter-spacing: 0.01em;
  color: var(--t-muted);
  text-decoration: none;
  transition: color 0.18s ease;
}
.nav__link:hover { color: var(--t-body); }

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

.hero {
  position: relative;
  text-align: center;
  padding: 108px 32px 96px;
  max-width: 1080px;
  margin: 0 auto;
}
.hero__glow {
  position: absolute;
  top: -40px;
  left: 50%;
  transform: translateX(-50%);
  width: 760px;
  height: 520px;
  max-width: 100%;
  background: radial-gradient(ellipse at center, rgba(20, 21, 24, 0.05), transparent 65%);
  filter: blur(20px);
  pointer-events: none;
  z-index: 0;
}
.hero__inner { position: relative; z-index: 1; }

.hero h1 {
  font-family: var(--f-head);
  font-weight: 600;
  font-size: clamp(30px, 4.6vw, 52px);
  line-height: 1.12;
  letter-spacing: -0.02em;
  margin: 0 0 8px;
  color: var(--t-primary);
}
.hero h1 span { display: block; }

.hero__sub {
  font-family: var(--f-body);
  font-size: clamp(15px, 1.6vw, 18px);
  line-height: 1.6;
  color: var(--t-muted);
  max-width: 560px;
  margin: 14px auto 0;
}

.figure {
  position: relative;
  display: inline-block;
  max-width: 100%;
  margin: 56px 0 10px;
}
.figure__circuit {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  max-width: 115%;
  height: auto;
  opacity: 0.55;
  pointer-events: none;
  z-index: 0;
}
.figure__chip {
  position: absolute;
  top: -6px;
  left: -26px;
  font-family: var(--f-mono);
  font-size: 12px;
  color: var(--t-secondary);
  border: 1px solid rgba(20, 21, 24, 0.3);
  background: rgba(255, 255, 255, 0.92);
  padding: 7px 12px;
  border-radius: 8px;
  z-index: 2;
}
.figure__chip b { color: var(--ink); font-weight: 400; }

.figure__row {
  position: relative;
  display: flex;
  align-items: baseline;
  justify-content: center;
  gap: 26px;
  flex-wrap: wrap;
  z-index: 1;
}
.figure__num {
  font-family: var(--f-mono);
  font-weight: 600;
  font-size: clamp(140px, 24vw, 300px);
  line-height: 0.82;
  letter-spacing: -0.05em;
  color: var(--ink);
  display: inline-block;
}
.figure__label {
  text-align: left;
  font-family: var(--f-mono);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  font-size: clamp(16px, 2.4vw, 26px);
  line-height: 1.15;
  color: var(--t-secondary);
}

.cta-row {
  display: flex;
  gap: 14px;
  justify-content: center;
  flex-wrap: wrap;
  margin-top: 38px;
}

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

.section { max-width: var(--wrap); margin: 0 auto; }
.section--cost         { padding: 110px 32px 96px; }
.section--how          { padding: 110px 32px; }
.section--platform     { padding: 128px 32px 40px; }
.section--proof        { padding: 110px 32px 30px; }
.section--pricing      { padding: 120px 32px 40px; }
.section--faq          { padding: 110px 32px; max-width: 880px; }
.section--cta          { padding: 80px 32px 120px; }

/* Cost / chart */
.chart-card {
  margin-top: 22px;
  border: 1px solid var(--b-card);
  background: var(--surface);
  border-radius: 18px;
  padding: 34px 30px 26px;
  box-shadow: 0 30px 80px -40px rgba(20, 21, 24, 0.1);
}
.chart-scroll { overflow-x: auto; overflow-y: hidden; }
.chart-scroll svg {
  display: block;
  width: 100%;
  min-width: 620px;
  height: auto;
  font-family: var(--f-mono);
}

.chart-card__footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
  margin-top: 18px;
  padding-top: 18px;
  border-top: 1px solid var(--b-hair);
}
.legend { display: flex; gap: 22px; flex-wrap: wrap; }
.legend span {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--f-mono);
  font-size: 12.5px;
  color: var(--t-secondary);
}
.legend span + span { color: var(--t-muted); }
.legend i { display: block; width: 14px; border-radius: 2px; }
.legend .swatch--ink  { height: 4px; background: var(--ink); }
.legend .swatch--gray { height: 3px; background: var(--t-line); }

.chart-live {
  font-family: var(--f-mono);
  font-size: 12.5px;
  color: var(--t-secondary);
}
.chart-live strong { color: var(--ink); font-weight: 600; }

/* Comparison strip */
.compare { margin-top: 18px; }
.compare__title {
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--t-faint);
}
.compare__list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-top: 14px;
  padding: 0;
  list-style: none;
}
.compare__list li {
  font-family: var(--f-body);
  font-size: 14px;
  line-height: 1.5;
  color: var(--t-secondary);
  display: flex;
  gap: 10px;
}
.compare__list li span { flex: none; }
.compare__card { padding: 26px 28px; }
.compare__card--us {
  border-color: var(--b-emph);
  background: var(--bg);
}
.compare__card--us .compare__title { color: var(--ink); }
.compare__card--us .compare__list li { color: var(--t-primary); }
.mark--no  { color: var(--t-line); }
.mark--yes { color: var(--ink); }

/* How it works */
.step-card { padding: 30px 26px; }
.step-card__num {
  font-family: var(--f-mono);
  font-size: 13px;
  font-weight: 600;
  color: #FFFFFF;
  background: var(--ink);
  width: 34px;
  height: 34px;
  border-radius: 9px;
  display: flex;
  align-items: center;
  justify-content: center;
}
.step-card__layer {
  font-family: var(--f-mono);
  font-size: 11.5px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--t-faint);
  margin-top: 18px;
}
.step-card__title {
  font-family: var(--f-head);
  font-weight: 600;
  font-size: 20px;
  color: var(--t-primary);
  margin: 6px 0 8px;
}
.step-card p {
  font-family: var(--f-body);
  font-size: 14.5px;
  line-height: 1.6;
  color: var(--t-muted);
  margin: 0;
}

/* Platform architecture */
.layers {
  display: flex;
  flex-direction: column;
  gap: 18px;
  margin-top: 56px;
}
.layer {
  display: flex;
  align-items: center;
  gap: 28px;
  padding: 26px 30px;
  border-radius: 14px;
  border: 1px solid var(--b-card);
  background: var(--surface);
  flex-wrap: wrap;
}
.layer--deep { background: var(--deep); }
.layer--emph {
  border-color: var(--b-emph);
  background: linear-gradient(180deg, rgba(20, 21, 24, 0.06), rgba(20, 21, 24, 0.02));
}
.layer__id {
  display: flex;
  align-items: center;
  gap: 18px;
  min-width: 268px;
  flex: 1;
}
.layer__icon {
  flex: none;
  width: 54px;
  height: 54px;
  border-radius: 50%;
  border: 1.5px solid var(--t-line);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--t-secondary);
}
.layer--emph .layer__icon { border-color: var(--ink); color: var(--ink); }
.layer__title {
  font-family: var(--f-head);
  font-weight: 600;
  font-size: 21px;
  color: var(--t-primary);
  line-height: 1.15;
}
.layer__tag {
  font-family: var(--f-mono);
  font-size: 12px;
  color: var(--t-faint);
  margin-top: 4px;
}
.layer--emph .layer__tag { color: var(--ink); }
.layer__chips {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  flex: 1.4;
}
.layer--emph .layer__chips .chip {
  color: var(--t-body);
  border-color: var(--b-strong);
  background: rgba(20, 21, 24, 0.06);
}
.layer__fee {
  font-family: var(--f-body);
  font-size: 13.5px;
  line-height: 1.5;
  color: var(--t-muted);
  min-width: 170px;
  max-width: 200px;
  flex: 1;
}

/* Proof band */
.stat { padding: 26px 24px; }
.stat__figure {
  font-family: var(--f-mono);
  font-weight: 600;
  font-size: 34px;
  color: var(--ink);
  letter-spacing: -0.02em;
}
.stat__label {
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--t-faint);
  margin-top: 6px;
}
.stat__copy {
  font-family: var(--f-body);
  font-size: 13.5px;
  line-height: 1.5;
  color: var(--t-muted);
  margin-top: 8px;
}

.security {
  margin-top: 18px;
  background: var(--band);
  padding: 24px 30px;
  display: flex;
  align-items: center;
  gap: 26px;
  flex-wrap: wrap;
  justify-content: space-between;
}
.security__copy {
  font-family: var(--f-body);
  font-size: 14px;
  line-height: 1.5;
  color: var(--t-muted);
  max-width: 300px;
}
.security__chips { display: flex; gap: 10px; flex-wrap: wrap; }
.security__chips .chip {
  font-size: 12.5px;
  padding: 9px 14px;
  background: rgba(20, 21, 24, 0.03);
}

/* Pricing */
.price-grid {
  margin: 54px auto 0;
  align-items: stretch;
  gap: 20px;
}
.price-card {
  display: flex;
  flex-direction: column;
  padding: 32px 28px;
}
.price-card__layer {
  font-family: var(--f-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--t-faint);
}
.price-card__name {
  font-family: var(--f-head);
  font-weight: 600;
  font-size: 21px;
  color: var(--t-primary);
  margin-top: 10px;
}
.price-card__amount {
  font-family: var(--f-mono);
  font-weight: 600;
  font-size: 42px;
  color: var(--ink);
  letter-spacing: -0.02em;
  margin-top: 24px;
}
.price-card__unit {
  font-family: var(--f-mono);
  font-size: 13px;
  color: var(--t-muted);
  margin-top: 6px;
}
.price-card p {
  font-family: var(--f-body);
  font-size: 14px;
  line-height: 1.55;
  color: var(--t-muted);
  margin: 18px 0 0;
}
.price-card hr {
  height: 1px;
  border: 0;
  background: var(--b-hair);
  margin: 24px 0;
}
.price-card ul {
  display: flex;
  flex-direction: column;
  gap: 11px;
  flex: 1;
  margin: 0;
  padding: 0;
  list-style: none;
}
.price-card li {
  font-family: var(--f-body);
  font-size: 14px;
  line-height: 1.5;
  color: var(--t-secondary);
  display: flex;
  gap: 10px;
}
.price-card li span { flex: none; }
.price-card .btn { margin-top: 26px; }

.price-foot {
  text-align: center;
  font-family: var(--f-mono);
  font-size: 13px;
  color: var(--t-faint);
  margin-top: 30px;
}
.price-foot span { color: var(--ink); }

/* FAQ */
.faq-list { display: flex; flex-direction: column; gap: 12px; }
.faq {
  border: 1px solid var(--b-card);
  background: var(--surface);
  border-radius: 12px;
}
.faq > summary {
  cursor: pointer;
  padding: 20px 24px;
  font-family: var(--f-head);
  font-weight: 500;
  font-size: 17px;
  color: var(--t-primary);
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  list-style: none;
}
.faq > summary::-webkit-details-marker { display: none; }
.faq__ic {
  color: var(--ink);
  font-family: var(--f-mono);
  font-size: 22px;
  line-height: 1;
  transition: transform 0.25s ease;
  flex: none;
}
.faq[open] .faq__ic { transform: rotate(45deg); }
.faq__body {
  padding: 0 24px 22px;
  font-family: var(--f-body);
  font-size: 15px;
  line-height: 1.65;
  color: var(--t-muted);
}

/* Final CTA */
.cta-panel {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--b-emph);
  border-radius: 20px;
  background: linear-gradient(180deg, rgba(20, 21, 24, 0.06), rgba(244, 244, 245, 0.6));
  padding: 72px 40px;
  text-align: center;
}
.cta-panel__glow {
  position: absolute;
  bottom: -120px;
  left: 50%;
  transform: translateX(-50%);
  width: 600px;
  height: 300px;
  background: radial-gradient(ellipse at center, rgba(20, 21, 24, 0.1), transparent 70%);
  filter: blur(20px);
  pointer-events: none;
}
.cta-panel__inner { position: relative; }
.cta-panel h2 {
  font-size: clamp(30px, 4.5vw, 52px);
  line-height: 1.05;
  margin: 0 0 14px;
}
.cta-panel p {
  font-family: var(--f-body);
  font-size: 18px;
  line-height: 1.6;
  color: var(--t-muted);
  max-width: 520px;
  margin: 0 auto 32px;
}

/* Footer */
.footer {
  border-top: 1px solid var(--b-hair);
  background: var(--band);
}
.footer__inner {
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 48px 32px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 24px;
}
.footer .brand img { height: 28px; }
.footer .brand span { font-size: 16px; }
.footer__links { display: flex; gap: 30px; flex-wrap: wrap; }
.footer__links a {
  font-family: var(--f-mono);
  font-size: 13px;
  color: var(--t-faint);
  text-decoration: none;
  transition: color 0.18s ease;
}
.footer__links a:hover { color: var(--t-secondary); }
.footer__legal {
  font-family: var(--f-mono);
  font-size: 12px;
  color: var(--t-hair);
}

/* --------------------------------------------------------------------------
   Reveal system — only hides content when JS is running
   -------------------------------------------------------------------------- */

.js [data-reveal] {
  opacity: 0;
  transform: translateY(26px);
  transition: opacity 0.7s ease-out, transform 0.7s ease-out;
}
.js [data-reveal].is-visible {
  opacity: 1;
  transform: none;
}

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

@media (max-width: 1000px) {
  .grid--4 { grid-template-columns: repeat(2, 1fr); }
  .layer__fee { max-width: none; flex-basis: 100%; }
}

@media (max-width: 880px) {
  .grid--3, .grid--2 { grid-template-columns: 1fr; }
  .layer { gap: 20px; }
  .layer__id { min-width: 100%; }
  .layer__chips { flex: 1 1 100%; }
}

@media (max-width: 820px) {
  .nav { padding: 14px 20px; }
  .nav__links { gap: 20px; }
  .nav__links .nav__link { display: none; }
  .brand img { height: 30px; }
  .brand span { font-size: 17px; }
}

@media (max-width: 700px) {
  .wrap { padding-left: 20px; padding-right: 20px; }
  .hero { padding: 72px 20px 64px; }
  .figure { margin-top: 40px; }
  .figure__chip { left: -6px; }
  .section--cost         { padding: 80px 20px 72px; }
  .section--how          { padding: 80px 20px; }
  .section--platform     { padding: 88px 20px 32px; }
  .section--proof        { padding: 80px 20px 24px; }
  .section--pricing      { padding: 88px 20px 32px; }
  .section--faq          { padding: 80px 20px; }
  .section--cta          { padding: 56px 20px 88px; }
  .chart-card { padding: 24px 18px 20px; }
  .cta-panel { padding: 56px 24px; }
  .footer__inner { padding: 40px 20px; }
  .layer { padding: 22px 20px; }
}

@media (max-width: 560px) {
  .grid--4 { grid-template-columns: 1fr; }
  .figure__row { gap: 14px; }
  .price-card__amount { font-size: 36px; }
}

/* --------------------------------------------------------------------------
   Reduced motion
   -------------------------------------------------------------------------- */

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .js [data-reveal] { opacity: 1; transform: none; transition: none; }
  .faq__ic { transition: none; }
  * { scroll-behavior: auto !important; }
}