/* Tessera marketing site. Vanilla CSS, no build step, no external assets.
   Colour tokens follow the Aicons brand palette (blue and anthracite family).
   Tessera carries its own mosaic-tile mark; the palette is Aicons' system,
   the identity on this page is Tessera's own. */

:root {
  --ai-anthracite: #192024;
  --ai-anthracite-800: #222D33;
  --ai-steel-700: #47617A;
  --ai-steel-500: #6A859C;
  --ai-steel-300: #A9B6C4;
  --ai-blue-700: #0B63B8;
  --ai-blue-500: #2E9DFF;
  --ai-blue-300: #69B9FF;
  --ai-blue-900: #08477F;
  --ai-signal-700: #9A4A2E;
  --ai-signal-600: #B05636;
  --ai-signal-500: #C96442;
  --ai-signal-300: #E08A64;
  --ai-bg: #EDEFF2;
  --ai-surface: #FFFFFF;
  --ai-surface-alt: #F7F9FC;
  --ai-hairline: #D4DAE2;
  --ai-hairline-dark: #2E3C44;

  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 24px;
  --space-6: 32px;
  --space-7: 40px;
  --space-8: 56px;
  --space-9: 80px;

  /* Radius and shadow scale matched to the Aicons cockpit "Cowork" design
     system (ai/css/cockpit.css) -- the most recent, most polished, most
     accessibility-audited Aicons visual language on file (WCAG-AA pass,
     260825/260912). Tessera's own signal colour (--ai-signal-600) is the
     same hex as the cockpit's canonical --accent, confirming the two are
     already one palette. */
  --radius-2xs: 2px;
  --radius-xs: 4px;
  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-lg: 10px;
  --shadow-sm: 0 1px 3px 0 rgba(0,0,0,0.1), 0 1px 2px -1px rgba(0,0,0,0.1);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -2px rgba(0,0,0,0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1), 0 4px 6px -4px rgba(0,0,0,0.1);

  --ease-in: cubic-bezier(0.2, 0, 0, 1);
  --ease-out: cubic-bezier(0.4, 0, 1, 1);
}

* { box-sizing: border-box; }

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

body {
  margin: 0;
  font-family: 'Open Sans', 'Helvetica Neue', Arial, sans-serif;
  font-weight: 400;
  font-size: 16px;
  line-height: 1.55;
  color: var(--ai-steel-700);
  background: var(--ai-bg);
}

a { color: var(--ai-blue-700); text-decoration: none; }
a:hover { text-decoration: underline; }
a:focus-visible,
button:focus-visible {
  outline: 2px solid var(--ai-blue-700);
  outline-offset: 2px;
}

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

.sr-only {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-6);
}

h1, h2, h3 { color: var(--ai-anthracite); font-weight: 600; margin: 0; }

.eyebrow {
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ai-blue-700);
  margin: 0 0 var(--space-3);
}

.eyebrow--on-dark { color: var(--ai-blue-300); }

h2.section-title {
  font-size: 16px;
  letter-spacing: 0.10em;
  text-transform: uppercase;
}

.section-lede {
  font-size: 20px;
  line-height: 1.5;
  color: var(--ai-anthracite);
  max-width: 720px;
  margin: var(--space-3) 0 0;
}

p { max-width: 720px; }

hr.divider {
  border: none;
  border-top: 1px solid var(--ai-hairline);
  margin: 0;
}

/* Nav */

.nav {
  background: var(--ai-surface);
  border-bottom: 1px solid var(--ai-hairline);
  position: sticky;
  top: 0;
  z-index: 20;
}

.nav__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.nav__brand {
  font-family: 'Open Sans', sans-serif;
  font-weight: 600;
  font-size: 20px;
  letter-spacing: 0.30em;
  color: var(--ai-anthracite);
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
}

.nav__mark { width: 22px; height: 22px; }

.nav__toggle {
  display: none;
  background: none;
  border: none;
  color: var(--ai-anthracite);
  cursor: pointer;
  padding: var(--space-2);
}

.nav__toggle svg { width: 24px; height: 24px; }

.nav__menu {
  list-style: none;
  display: flex;
  align-items: center;
  gap: var(--space-6);
  margin: 0;
  padding: 0;
}

.nav__link {
  font-size: 14px;
  font-weight: 600;
  color: var(--ai-steel-700);
}

.nav__link:hover { color: var(--ai-blue-700); text-decoration: none; }

.nav__cta {
  background: var(--ai-signal-600);
  color: #FFFFFF;
  font-size: 14px;
  font-weight: 600;
  padding: var(--space-2) var(--space-5);
  border-radius: var(--radius-sm);
  transition: background-color 180ms var(--ease-in), box-shadow 180ms var(--ease-in);
}

.nav__cta:hover { box-shadow: var(--shadow-sm); }

.nav__cta:hover {
  background: var(--ai-signal-700);
  text-decoration: none;
}

/* Hero */

.hero {
  /* Cowork login-screen gradient (ai/css/cockpit.css .login-screen): the
     cockpit's own signature dark surface, reused here for the same brand
     recognition instead of a flat fill. */
  background: linear-gradient(135deg, #0C1014 0%, #192024 60%, #1E2A35 100%);
  color: #FFFFFF;
  padding: var(--space-9) 0;
}

.hero__inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-8);
  align-items: center;
}

.hero__title {
  font-size: 44px;
  font-weight: 600;
  letter-spacing: 0.02em;
  color: var(--ai-blue-300);
  margin: 0 0 var(--space-4);
}

.hero__subtitle {
  font-size: 20px;
  line-height: 1.5;
  color: #D9E2EA;
  max-width: 560px;
  margin: 0 0 var(--space-6);
}

.hero__actions {
  display: flex;
  gap: var(--space-4);
  align-items: center;
  flex-wrap: wrap;
}

.btn-primary {
  background: var(--ai-signal-600);
  color: #FFFFFF;
  font-size: 15px;
  font-weight: 600;
  padding: var(--space-3) var(--space-6);
  border-radius: var(--radius-sm);
  display: inline-block;
  transition: background-color 180ms var(--ease-in), box-shadow 180ms var(--ease-in);
}

.btn-primary:hover { box-shadow: var(--shadow-md); }

.btn-primary:hover {
  background: var(--ai-signal-700);
  text-decoration: none;
}

.btn-ghost {
  color: var(--ai-blue-300);
  font-size: 15px;
  font-weight: 600;
}

.hero__mosaic { justify-self: center; }

.tile { transition: opacity 260ms var(--ease-in); }

/* Sections */

.section { padding: var(--space-9) 0; }
.section-alt { background: var(--ai-surface); }

.section-head { margin-bottom: var(--space-7); }

/* Flow (how it works) */

.flow {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-5);
  margin-top: var(--space-7);
}

.flow__step {
  background: var(--ai-surface);
  border: 1px solid var(--ai-hairline);
  border-top: 3px solid var(--ai-hairline);
  border-radius: var(--radius-sm);
  padding: var(--space-5);
  transition: border-color 150ms var(--ease-in), box-shadow 150ms var(--ease-in), transform 150ms var(--ease-in);
}

.flow__step:hover {
  border-color: var(--ai-blue-700);
  border-top-color: var(--ai-blue-700);
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.flow__index {
  font-size: 13px;
  font-weight: 600;
  color: var(--ai-blue-700);
  letter-spacing: 0.08em;
  margin: 0 0 var(--space-3);
}

.flow__title {
  font-size: 17px;
  font-weight: 600;
  color: var(--ai-anthracite);
  margin: 0 0 var(--space-2);
}

.flow__body {
  font-size: 14px;
  margin: 0;
}

/* Prompt demo */

.prompt-demo {
  margin-top: var(--space-7);
  background: var(--ai-anthracite-800);
  border: 1px solid var(--ai-hairline-dark);
  border-radius: var(--radius-md);
  padding: var(--space-6);
}

.prompt-demo__head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  flex-wrap: wrap;
}

.prompt-demo__title {
  color: #FFFFFF;
  font-size: 15px;
  font-weight: 600;
  margin: 0;
}

.prompt-demo__toggle {
  background: var(--ai-blue-700);
  color: #FFFFFF;
  border: none;
  font-size: 13px;
  font-weight: 600;
  padding: var(--space-2) var(--space-4);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: background-color 180ms var(--ease-in);
}

.prompt-demo__toggle:hover { background: var(--ai-blue-500); }

.prompt-demo__body {
  margin-top: var(--space-4);
  display: none;
}

.prompt-demo__body[data-open="true"] { display: block; }

.prompt-demo__code {
  background: var(--ai-anthracite);
  color: #C6D2DB;
  font-family: 'SFMono-Regular', 'Courier New', monospace;
  font-size: 13px;
  line-height: 1.6;
  padding: var(--space-5);
  border: 1px solid var(--ai-hairline-dark);
  border-radius: var(--radius-xs);
  white-space: pre-wrap;
  word-break: break-word;
  margin: 0 0 var(--space-4);
}

.prompt-demo__actions {
  display: flex;
  gap: var(--space-4);
}

.prompt-demo__send,
.prompt-demo__abort {
  font-size: 13px;
  font-weight: 600;
  padding: var(--space-2) var(--space-5);
  border-radius: var(--radius-sm);
  border: none;
  cursor: default;
}

.prompt-demo__send { background: var(--ai-blue-700); color: #FFFFFF; }
.prompt-demo__abort { background: transparent; color: var(--ai-signal-300); border: 1px solid var(--ai-signal-300); }

.prompt-demo__note {
  font-size: 12px;
  color: var(--ai-steel-500);
  margin: var(--space-3) 0 0;
}

/* Pillars (why Tessera) */

.pillars {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-5);
  margin-top: var(--space-7);
}

.pillar {
  background: var(--ai-surface);
  border: 1px solid var(--ai-hairline);
  border-top: 3px solid var(--ai-blue-700);
  border-radius: var(--radius-sm);
  padding: var(--space-5);
  transition: box-shadow 150ms var(--ease-in), transform 150ms var(--ease-in);
}

.pillar:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.pillar__title {
  font-size: 15px;
  font-weight: 600;
  color: var(--ai-anthracite);
  margin: 0 0 var(--space-2);
}

.pillar__body { font-size: 14px; margin: 0; }

/* Trust */

.trust {
  background: var(--ai-anthracite);
  color: #D9E2EA;
}

.trust h2 { color: var(--ai-blue-300); }

.trust .section-lede { color: #D9E2EA; }

.trust__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-5);
  margin-top: var(--space-7);
}

.trust__item {
  border-top: 1px solid var(--ai-hairline-dark);
  padding-top: var(--space-4);
}

.trust__item-title {
  font-size: 14px;
  font-weight: 600;
  color: #FFFFFF;
  margin: 0 0 var(--space-2);
  letter-spacing: 0.02em;
}

.trust__item-body {
  font-size: 14px;
  color: #B7C4CD;
  margin: 0;
}

/* CTA */

.cta {
  background: var(--ai-blue-900);
  color: #FFFFFF;
  text-align: center;
}

.cta h2 { color: #FFFFFF; }

.cta .section-lede {
  color: #D9E2EA;
  margin-left: auto;
  margin-right: auto;
}

.cta__actions {
  margin-top: var(--space-6);
  display: flex;
  justify-content: center;
  gap: var(--space-4);
  flex-wrap: wrap;
}

.cta__note {
  font-size: 13px;
  color: #9FB3C2;
  margin: var(--space-5) auto 0;
  max-width: 560px;
}

/* Footer */

.footer {
  background: var(--ai-surface);
  border-top: 1px solid var(--ai-hairline);
  padding: var(--space-6) 0;
}

.footer__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  flex-wrap: wrap;
}

.footer__origin {
  font-size: 9pt;
  letter-spacing: 0.30em;
  text-transform: uppercase;
  color: var(--ai-steel-500);
}

.footer__legal {
  font-size: 12px;
  color: var(--ai-steel-500);
}

.footer__legal a { color: var(--ai-steel-500); }

@media (max-width: 900px) {
  .hero__inner { grid-template-columns: 1fr; }
  .hero__mosaic { justify-self: start; width: 220px; }
  .flow, .pillars { grid-template-columns: repeat(2, 1fr); }
  .trust__grid { grid-template-columns: 1fr; }
}

@media (max-width: 640px) {
  .container { padding: 0 var(--space-5); }
  .nav__menu {
    display: none;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: var(--ai-surface);
    border-bottom: 1px solid var(--ai-hairline);
    flex-direction: column;
    align-items: flex-start;
    padding: var(--space-5);
    gap: var(--space-4);
  }
  .nav__menu[data-open="true"] { display: flex; }
  .nav__toggle { display: inline-flex; }
  .hero__title { font-size: 32px; }
  .flow, .pillars { grid-template-columns: 1fr; }
  .footer__inner { flex-direction: column; align-items: flex-start; }
}

@media (prefers-reduced-motion: reduce) {
  * { transition-duration: 80ms !important; }
}