/* ================= tokens ================= */
:root{
  /* dark = "blueprint" (default) */
  --bg: #0A2044;
  --bg-soft: #0D2750;
  --ink: #EAF2FF;
  --ink-soft: #C3D3EC;
  --muted: #82A0C7;
  --line: rgba(234,242,255,0.16);
  --line-strong: rgba(234,242,255,0.30);
  --accent: #F0A93B;
  --accent-soft: rgba(240,169,59,0.14);
  --on-accent: #0A2044;
  --grid-dot: rgba(234,242,255,0.07);
  --shadow-glow: rgba(240,169,59,0.35);

  --font-display: 'Space Grotesk', sans-serif;
  --font-body: 'Inter', sans-serif;
  --font-mono: 'IBM Plex Mono', monospace;
  --maxw: 780px;
}

[data-theme="light"]{
  /* light = "blueline / diazo print" */
  --bg: #F3F6FC;
  --bg-soft: #E8EEF9;
  --ink: #12294D;
  --ink-soft: #2C4470;
  --muted: #5B7396;
  --line: rgba(18,41,77,0.14);
  --line-strong: rgba(18,41,77,0.26);
  --accent: #C9820E;
  --accent-soft: rgba(201,130,14,0.12);
  --on-accent: #FFFFFF;
  --grid-dot: rgba(18,41,77,0.08);
  --shadow-glow: rgba(201,130,14,0.25);
}

*{ box-sizing: border-box; }
html{ scroll-behavior: smooth; }

body{
  margin: 0;
  background-color: var(--bg);
  background-image: radial-gradient(var(--grid-dot) 1px, transparent 1px);
  background-size: 26px 26px;
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  transition: background-color 0.3s ease, color 0.3s ease;
}

h1, h2, h3{
  font-family: var(--font-display);
  font-weight: 600;
  color: var(--ink);
  margin: 0 0 0.4em;
  letter-spacing: -0.01em;
}

a{ color: inherit; }

.skip-link{
  position: absolute; left: -999px; top: 0;
  background: var(--accent); color: var(--on-accent);
  padding: 10px 16px; z-index: 200;
  font-family: var(--font-mono); font-size: 14px;
}
.skip-link:focus{ left: 12px; top: 12px; }

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

/* ================= top nav ================= */
.topnav{
  position: sticky; top: 0; z-index: 100;
  display: flex; align-items: center; justify-content: space-between;
  gap: 16px;
  padding: 16px 32px;
  background: color-mix(in srgb, var(--bg) 86%, transparent);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
}
.brand{ text-decoration: none; }
.brand-mark{
  font-family: var(--font-mono); font-weight: 500; font-size: 15px;
  border: 1.5px solid var(--accent); color: var(--accent);
  border-radius: 999px; padding: 5px 11px;
}
.toplinks{ display: flex; gap: 22px; overflow-x: auto; scrollbar-width: none; max-width: 56vw; }
.toplinks::-webkit-scrollbar{ display: none; }
.toplinks a{
  text-decoration: none; font-size: 14.5px; color: var(--ink-soft);
  white-space: nowrap; transition: color 0.15s ease;
}
.toplinks a:hover{ color: var(--accent); }

.theme-toggle{
  display: flex; align-items: center; justify-content: center;
  width: 36px; height: 36px; border-radius: 50%;
  border: 1.5px solid var(--line-strong);
  background: var(--bg-soft);
  color: var(--accent);
  cursor: pointer;
  flex-shrink: 0;
  transition: border-color 0.15s ease, transform 0.15s ease;
}
.theme-toggle:hover{ border-color: var(--accent); transform: rotate(12deg); }
.icon-sun, .icon-moon{ display: none; }
[data-theme="dark"] .icon-sun{ display: block; }
[data-theme="light"] .icon-moon{ display: block; }

/* ================= state track ================= */
.state-track{
  position: fixed; left: 28px; top: 50%; transform: translateY(-50%);
  display: flex; flex-direction: column; align-items: flex-start; gap: 22px;
  z-index: 90;
}
.track-line{ position: absolute; left: 5px; top: 6px; bottom: 6px; width: 1px; background: var(--line); z-index: -1; }
.state-node{ background: none; border: none; display: flex; align-items: center; gap: 10px; cursor: pointer; padding: 2px 0; font-family: var(--font-mono); }
.dot{
  width: 11px; height: 11px; border-radius: 50%;
  border: 2px solid var(--muted); background: var(--bg);
  transition: border-color 0.2s ease, background 0.2s ease, transform 0.2s ease, box-shadow 0.2s ease;
  flex-shrink: 0;
}
.state-node.accepting .dot{ box-shadow: 0 0 0 2.5px var(--bg), 0 0 0 4px var(--muted); }
.state-node.is-active .dot, .state-node:hover .dot{
  border-color: var(--accent); background: var(--accent); transform: scale(1.15);
  box-shadow: 0 0 10px var(--shadow-glow);
}
.state-node.is-active.accepting .dot, .state-node.accepting:hover .dot{
  box-shadow: 0 0 0 2.5px var(--bg), 0 0 0 4px var(--accent), 0 0 10px var(--shadow-glow);
}
.node-label{
  font-size: 12.5px; color: var(--ink-soft); opacity: 0; transform: translateX(-6px);
  transition: opacity 0.2s ease, transform 0.2s ease; pointer-events: none; white-space: nowrap;
}
.state-node.is-active .node-label, .state-node:hover .node-label, .state-node:focus-visible .node-label{ opacity: 1; transform: translateX(0); }

@media (max-width: 999px){ .state-track{ display: none; } }

/* ================= layout helpers ================= */
.section{ padding: 96px 32px; }
.section-inner{ max-width: var(--maxw); margin: 0 auto; }
.band{ background: var(--bg-soft); }

.eyebrow{ font-family: var(--font-mono); font-size: 13px; color: var(--accent); letter-spacing: 0.02em; margin: 0 0 14px; }
.eyebrow-tag{
  display: inline-block; border: 1px solid var(--line-strong); border-radius: 4px;
  padding: 5px 10px; cursor: help;
}
.tagline{ font-size: 19px; color: var(--ink-soft); max-width: 620px; margin: 0 0 18px; }
.prose p{ color: var(--ink-soft); max-width: 660px; }
.prose p + p{ margin-top: 1em; }

.reveal{ opacity: 0; transform: translateY(10px); transition: opacity 0.6s ease, transform 0.6s ease; }
.reveal.in-view{ opacity: 1; transform: translateY(0); }

@media (prefers-reduced-motion: reduce){
  html{ scroll-behavior: auto; }
  .reveal{ opacity: 1; transform: none; transition: none; }
  .dot, .node-label, .theme-toggle{ transition: none; }
}

/* ================= hero ================= */
.hero{ padding-top: 64px; padding-bottom: 80px; overflow: hidden; }
.hero-grid{
  max-width: 1100px; margin: 0 auto; padding: 0 32px;
  display: grid; grid-template-columns: 1.15fr 1fr; gap: 30px; align-items: center;
}
.hero h1{ font-size: clamp(40px, 6vw, 60px); line-height: 1.05; margin-bottom: 16px; }
.hero h1 .word{ display: inline-block; }
.meta-row{ font-family: var(--font-mono); font-size: 13.5px; color: var(--muted); margin: 0 0 30px; }

.hero-mark{ position: relative; max-width: 420px; margin: 0 auto; }
.mark-glow{
  position: absolute; left: 8%; top: 12%; width: 44%; height: 60%;
  background: radial-gradient(circle, var(--shadow-glow) 0%, transparent 70%);
  filter: blur(18px); pointer-events: none;
}

#hero-trace{ position: relative; }
#hero-trace .trace-line{ fill: none; stroke: var(--accent); stroke-width: 2; stroke-linecap: round; }
#hero-trace .trace-line.dashed-tail{ stroke-dasharray: 4 7 !important; opacity: 0.55; }
#hero-trace .arrowhead{ fill: var(--accent); opacity: 0; transition: opacity 0.3s ease 0.15s; }
#hero-trace .arrowhead.in{ opacity: 1; }
#hero-trace .node-circle{ fill: var(--bg); stroke: var(--accent); stroke-width: 3; transform-origin: center; }
#hero-trace .node-circle.big{ transform: scale(0.6); opacity: 0; transition: transform 0.5s cubic-bezier(.2,1.4,.4,1), opacity 0.4s ease; }
#hero-trace .node-text{
  font-family: var(--font-display); font-weight: 600; font-size: 30px;
  fill: var(--ink); text-anchor: middle; opacity: 0; transition: opacity 0.4s ease 0.1s;
}
#hero-trace .node-group.in .node-circle.big{ transform: scale(1); opacity: 1; }
#hero-trace .node-group.in .node-text{ opacity: 1; }
#hero-trace .node-dot{ fill: var(--accent); transform: scale(0); opacity: 0; transform-origin: center; transition: transform 0.4s cubic-bezier(.2,1.4,.4,1), opacity 0.3s ease; }
#hero-trace .node-dot.in{ transform: scale(1); opacity: 1; }
#hero-trace .node-dot.fade{ opacity: 0.6; }
#hero-trace .node-dot.fade.in{ opacity: 0.6; }

@media (max-width: 860px){
  .hero-grid{ grid-template-columns: 1fr; text-align: left; }
  .hero-mark{ order: -1; max-width: 280px; }
  .section{ padding: 72px 22px; }
}

/* --- hero entrance choreography (motion allowed) --- */
@media (prefers-reduced-motion: no-preference){
  .eyebrow-tag{ opacity: 0; animation: fadeUp 0.6s ease 0.05s forwards; }
  .hero h1 .word{ opacity: 0; filter: blur(6px); animation: materialize 0.7s cubic-bezier(.2,.7,.3,1) forwards; }
  .hero h1 .word:nth-child(1){ animation-delay: 0.15s; }
  .hero h1 .word:nth-child(2){ animation-delay: 0.30s; }
  .hero .reveal-in{ opacity: 0; animation: fadeUp 0.6s ease forwards; }
  .hero .tagline.reveal-in{ animation-delay: 0.55s; }
  .hero .meta-row.reveal-in{ animation-delay: 0.68s; }
  .hero .btn.reveal-in{ animation-delay: 0.8s; }
  .hero .btn.reveal-in:nth-of-type(2){ animation-delay: 0.9s; }
  .hero .btn.reveal-in:nth-of-type(3){ animation-delay: 1.0s; }
  .mark-glow{ opacity: 0; animation: glowIn 1.2s ease 0.3s forwards, breathe 4.5s ease-in-out 2s infinite; }
}

@keyframes fadeUp{ from{ opacity: 0; transform: translateY(14px); } to{ opacity: 1; transform: translateY(0); } }
@keyframes materialize{ from{ opacity: 0; filter: blur(6px); transform: translateY(10px); } to{ opacity: 1; filter: blur(0); transform: translateY(0); } }
@keyframes glowIn{ from{ opacity: 0; } to{ opacity: 1; } }
@keyframes breathe{ 0%,100%{ opacity: 0.7; } 50%{ opacity: 1; } }

/* ================= buttons ================= */
.cta-row{ display: flex; flex-wrap: wrap; gap: 12px; align-items: center; }
.btn{
  display: inline-block; text-decoration: none; font-size: 14.5px; font-weight: 500;
  padding: 12px 20px; border-radius: 8px;
  transition: background 0.15s ease, color 0.15s ease, border-color 0.15s ease, box-shadow 0.2s ease, transform 0.15s ease;
}
.btn-primary{ background: var(--accent); color: var(--on-accent); }
.btn-primary:hover{ box-shadow: 0 0 22px var(--shadow-glow); transform: translateY(-1px); }
.btn-outline{ border: 1.5px solid var(--line-strong); color: var(--ink); }
.btn-outline:hover{ border-color: var(--accent); color: var(--accent); box-shadow: 0 0 16px var(--shadow-glow); }
.btn-text{ padding: 12px 4px; color: var(--accent); text-decoration: none; }
.btn-text:hover{ text-decoration: underline; }

.link-arrow{ display: inline-block; margin-top: 22px; color: var(--accent); text-decoration: none; font-weight: 500; }
.link-arrow:hover{ text-decoration: underline; }

/* ================= pipeline (research) ================= */
.pipeline{ list-style: none; margin: 28px 0 0; padding: 0; max-width: 560px; }
.pipeline li{ display: flex; align-items: center; gap: 12px; padding: 10px 0; border-bottom: 1px solid var(--line); font-size: 15px; color: var(--muted); }
.pipeline li.done{ color: var(--ink); }
.pipeline .tag{
  font-family: var(--font-mono); font-size: 11px; text-transform: uppercase; letter-spacing: 0.04em;
  padding: 3px 8px; border-radius: 5px; background: var(--line); color: var(--muted); flex-shrink: 0; width: 52px; text-align: center;
}
.pipeline li.done .tag{ background: var(--accent-soft); color: var(--accent); }

.tech-tags{ display: flex; flex-wrap: wrap; gap: 8px; margin-top: 22px; }
.tech-tags span{ font-family: var(--font-mono); font-size: 12.5px; color: var(--ink-soft); border: 1px solid var(--line-strong); border-radius: 999px; padding: 5px 12px; }

/* ================= cards ================= */
.card-grid{ max-width: 1080px; margin: 40px auto 0; padding: 0 32px; display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px; }
.card-grid.three{ grid-template-columns: repeat(3, 1fr); }
.card{
  border: 1px solid var(--line); border-radius: 12px; padding: 26px; background: var(--bg-soft);
  display: flex; flex-direction: column;
  transition: border-color 0.15s ease, transform 0.15s ease, box-shadow 0.2s ease;
}
.card:hover{ border-color: var(--accent); transform: translateY(-3px); box-shadow: 0 10px 30px -14px var(--shadow-glow); }
.card h3{ font-size: 19px; margin-bottom: 10px; display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.card p{ color: var(--ink-soft); font-size: 15px; flex-grow: 1; margin: 0; }
.card-foot{ margin-top: 18px; display: flex; align-items: center; justify-content: space-between; font-size: 13.5px; }
.card-foot .tech{ font-family: var(--font-mono); color: var(--muted); }
.card-foot a{ color: var(--accent); text-decoration: none; font-weight: 500; }
.card-foot a:hover{ text-decoration: underline; }
.card-idea{ background: var(--accent-soft); border-color: var(--accent-soft); }
.tag.idea{ font-family: var(--font-mono); font-size: 10.5px; text-transform: uppercase; background: var(--bg); color: var(--accent); padding: 3px 8px; border-radius: 999px; }

@media (max-width: 760px){ .card-grid, .card-grid.three{ grid-template-columns: 1fr; } }

/* ================= timeline ================= */
.timeline{ list-style: none; margin: 30px 0 0; padding: 0; max-width: 640px; }
.timeline li{ display: flex; align-items: baseline; justify-content: space-between; gap: 16px; padding: 18px 0; border-bottom: 1px solid var(--line); }
.timeline li:first-child{ padding-top: 0; }
.timeline-main h3{ font-size: 17px; margin-bottom: 3px; }
.timeline-main p{ margin: 0; color: var(--muted); font-size: 14.5px; }
.timeline .tag{ font-family: var(--font-mono); font-size: 11.5px; color: var(--accent); background: var(--accent-soft); padding: 4px 10px; border-radius: 999px; white-space: nowrap; }

/* ================= contact ================= */
.direct-contact{ display: flex; flex-wrap: wrap; gap: 22px; margin-top: 26px; }
.direct-contact a{
  display: inline-flex; align-items: center; gap: 8px;
  font-family: var(--font-mono); font-size: 14px; color: var(--ink-soft);
  text-decoration: none; transition: color 0.15s ease;
}
.direct-contact a:hover{ color: var(--accent); }
.direct-contact svg{ flex-shrink: 0; }

/* ================= footer ================= */
.site-footer{ text-align: center; padding: 32px; font-family: var(--font-mono); font-size: 12.5px; color: var(--muted); border-top: 1px solid var(--line); }