/* =========================================================
   Human × AI — collaboration constellation
   ========================================================= */

.hxai-section {
  position: relative;
  width: min(94%, var(--container));
  margin: 0 auto;
  padding: clamp(3.5rem, 7vw, 5.5rem) 0;
  overflow: hidden;
}

.hxai-intro {
  text-align: center;
  max-width: 38rem;
  margin: 0 auto 2.5rem;
}

.hxai-lede {
  margin-top: 1rem;
  color: var(--muted);
  font-size: 1.02rem;
  line-height: 1.7;
}

/* ---------- Desktop system ---------- */
.hxai-system {
  position: relative;
  display: none;
  height: clamp(480px, 62vh, 560px);
  padding: 0 0 6.5rem;
  isolation: isolate;
}

@media (min-width: 900px) {
  .hxai-system {
    display: block;
  }

  .hxai-mobile {
    display: none !important;
  }
}

.hxai-system__grid {
  position: absolute;
  inset: 0 0 5.5rem;
  z-index: 0;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(34, 211, 238, 0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(34, 211, 238, 0.035) 1px, transparent 1px);
  background-size: 48px 48px;
  mask-image: radial-gradient(ellipse 70% 65% at 50% 45%, black 20%, transparent 75%);
  opacity: 0.85;
}

.hxai-wires {
  position: absolute;
  inset: 0 0 5.5rem;
  width: 100%;
  height: calc(100% - 5.5rem);
  z-index: 1;
  pointer-events: none;
  overflow: visible;
}

.hxai-wire {
  opacity: 0.22;
  stroke-dasharray: 6 8;
  transition: opacity 0.45s var(--ease), stroke-width 0.35s ease;
}

.hxai-system[data-phase="1"] .hxai-wire[data-from="human"],
.hxai-system[data-phase="1"] .hxai-wire[data-cap="strategy"],
.hxai-system[data-phase="1"] .hxai-wire[data-cap="judgment"],
.hxai-system[data-phase="1"] .hxai-wire[data-cap="creativity"],
.hxai-system[data-phase="1"] .hxai-wire[data-cap="decision"] {
  opacity: 0.55;
}

.hxai-system[data-phase="2"] .hxai-wire[data-from="human"],
.hxai-system[data-phase="2"] .hxai-wire[data-from="ai"],
.hxai-system[data-phase="3"] .hxai-wire,
.hxai-system[data-phase="4"] .hxai-wire {
  opacity: 0.5;
}

.hxai-system.is-signaling .hxai-wire.is-active {
  opacity: 0.95;
  stroke-width: 1.8;
  stroke-dasharray: none;
}

.hxai-packet {
  filter: drop-shadow(0 0 6px rgba(34, 211, 238, 0.75));
}

.hxai-pole {
  position: absolute;
  z-index: 2;
  top: 0;
  bottom: 5.5rem;
  width: 22%;
  opacity: 0;
  transition: opacity 0.7s var(--ease), transform 0.7s var(--ease);
}

.hxai-pole--human {
  left: 0;
  transform: translateX(-18px);
}

.hxai-pole--ai {
  right: 0;
  transform: translateX(18px);
}

.hxai-system[data-phase="1"] .hxai-pole--human,
.hxai-system[data-phase="2"] .hxai-pole--human,
.hxai-system[data-phase="3"] .hxai-pole--human,
.hxai-system[data-phase="4"] .hxai-pole--human,
.hxai-system[data-phase="3"] .hxai-pole--ai,
.hxai-system[data-phase="4"] .hxai-pole--ai {
  opacity: 1;
  transform: none;
}

.hxai-hub {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  display: grid;
  place-items: center;
  width: 92px;
  height: 92px;
  border-radius: 50%;
  border: 1px solid rgba(148, 163, 184, 0.28);
  background:
    radial-gradient(circle at 40% 35%, rgba(34, 211, 238, 0.08), transparent 55%),
    rgba(13, 19, 32, 0.72);
  color: var(--accent);
  letter-spacing: 0.2em;
  font-size: 0.72rem;
  font-weight: 600;
  transition: border-color 0.35s ease, box-shadow 0.35s ease;
}

.hxai-hub__ring {
  position: absolute;
  inset: -8px;
  border-radius: 50%;
  border: 1px solid rgba(34, 211, 238, 0.18);
  animation: hxaiRingPulse 4.5s ease-in-out infinite;
  pointer-events: none;
}

.hxai-hub:hover,
.hxai-hub[aria-pressed="true"],
.hxai-hub.is-lit {
  border-color: rgba(34, 211, 238, 0.55);
  box-shadow: 0 0 0 1px rgba(34, 211, 238, 0.12), 0 0 28px rgba(34, 211, 238, 0.12);
}

.hxai-hub:hover,
.hxai-hub.is-lit {
  transform: translate(-50%, -50%) scale(1.04);
}

.hxai-hub__label {
  position: relative;
  z-index: 1;
}

.hxai-caps {
  position: absolute;
  inset: 0;
  list-style: none;
}

.hxai-caps li {
  position: absolute;
  left: 0;
  right: 0;
}

.hxai-pole--human .hxai-caps li:nth-child(1) { top: 14%; }
.hxai-pole--human .hxai-caps li:nth-child(2) { top: 28%; }
.hxai-pole--human .hxai-caps li:nth-child(3) { top: 62%; }
.hxai-pole--human .hxai-caps li:nth-child(4) { top: 76%; }

.hxai-pole--ai .hxai-caps li:nth-child(1) { top: 14%; }
.hxai-pole--ai .hxai-caps li:nth-child(2) { top: 28%; }
.hxai-pole--ai .hxai-caps li:nth-child(3) { top: 62%; }
.hxai-pole--ai .hxai-caps li:nth-child(4) { top: 76%; }

.hxai-cap {
  display: inline-flex;
  align-items: center;
  gap: 0.65rem;
  padding: 0.35rem 0.15rem;
  color: var(--muted-strong);
  font-family: var(--font-serif);
  font-size: clamp(1.05rem, 1.4vw, 1.2rem);
  letter-spacing: -0.01em;
  text-align: left;
  background: transparent;
  border: none;
  border-bottom: 1px solid transparent;
  transition: color 0.3s ease, border-color 0.3s ease, transform 0.3s var(--ease);
}

.hxai-pole--ai .hxai-cap {
  flex-direction: row-reverse;
  text-align: right;
  float: right;
}

.hxai-cap__dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  border: 1px solid rgba(34, 211, 238, 0.45);
  background: transparent;
  flex-shrink: 0;
  transition: background 0.3s ease, box-shadow 0.3s ease, border-color 0.3s ease;
}

.hxai-cap:hover,
.hxai-cap.is-active,
.hxai-cap:focus-visible {
  color: var(--white);
  border-bottom-color: rgba(34, 211, 238, 0.28);
  outline: none;
}

.hxai-cap:hover .hxai-cap__dot,
.hxai-cap.is-active .hxai-cap__dot,
.hxai-cap:focus-visible .hxai-cap__dot {
  background: var(--accent);
  border-color: var(--accent);
  box-shadow: 0 0 10px rgba(34, 211, 238, 0.55);
}

.hxai-cap.is-active {
  transform: translateX(4px);
}

.hxai-pole--ai .hxai-cap.is-active {
  transform: translateX(-4px);
}

/* Core — strongest focal point */
.hxai-core {
  position: absolute;
  z-index: 3;
  left: 50%;
  top: calc(50% - 2.75rem);
  transform: translate(-50%, -50%) scale(0.86);
  display: grid;
  place-items: center;
  width: min(28%, 240px);
  aspect-ratio: 1;
  opacity: 0;
  transition: opacity 0.75s var(--ease), transform 0.75s var(--ease);
}

.hxai-system[data-phase="2"] .hxai-core,
.hxai-system[data-phase="3"] .hxai-core,
.hxai-system[data-phase="4"] .hxai-core {
  opacity: 1;
  transform: translate(-50%, -50%);
}

.hxai-core__aura {
  position: absolute;
  inset: -8%;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(34, 211, 238, 0.16), transparent 68%);
  filter: blur(2px);
  opacity: 0.55;
  transition: opacity 0.5s ease, transform 0.5s var(--ease);
}

.hxai-system[data-phase="4"] .hxai-core__aura,
.hxai-system.is-signaling .hxai-core__aura {
  opacity: 0.95;
  transform: scale(1.08);
}

.hxai-core__orbit {
  position: absolute;
  inset: 4%;
  border-radius: 50%;
  border: 1px dashed rgba(34, 211, 238, 0.28);
  animation: hxaiOrbitSpin 28s linear infinite;
}

.hxai-core__orbit--slow {
  inset: -6%;
  border-style: solid;
  border-color: rgba(148, 163, 184, 0.14);
  animation-duration: 48s;
  animation-direction: reverse;
}

.hxai-core__orbit::before,
.hxai-core__orbit--slow::after {
  content: "";
  position: absolute;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--accent);
  top: -3px;
  left: 50%;
  box-shadow: 0 0 8px rgba(34, 211, 238, 0.7);
}

.hxai-core__node {
  position: relative;
  z-index: 1;
  display: grid;
  place-items: center;
  text-align: center;
  width: 100%;
  height: 100%;
  border-radius: 50%;
  border: 1px solid rgba(34, 211, 238, 0.42);
  background:
    radial-gradient(circle at 50% 40%, rgba(34, 211, 238, 0.14), transparent 55%),
    linear-gradient(160deg, rgba(18, 26, 43, 0.95), rgba(7, 11, 20, 0.92));
  box-shadow:
    0 0 0 1px rgba(7, 11, 20, 0.6),
    0 18px 48px rgba(0, 0, 0, 0.35),
    inset 0 1px 0 rgba(255, 255, 255, 0.04);
  padding: 1.25rem;
  transition: border-color 0.4s ease, box-shadow 0.4s ease;
}

.hxai-system.is-signaling .hxai-core__node,
.hxai-system[data-phase="4"] .hxai-core__node {
  border-color: rgba(34, 211, 238, 0.7);
  box-shadow:
    0 0 0 1px rgba(34, 211, 238, 0.12),
    0 0 40px rgba(34, 211, 238, 0.16),
    0 18px 48px rgba(0, 0, 0, 0.35);
}

.hxai-core__brand {
  font-family: var(--font-serif);
  font-size: clamp(1.25rem, 2vw, 1.65rem);
  color: var(--white);
  letter-spacing: -0.02em;
  line-height: 1.15;
}

.hxai-core__formula {
  margin-top: 0.55rem;
  font-size: 0.68rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--accent-strong);
  max-width: 14ch;
  line-height: 1.45;
}

.hxai-detail {
  position: absolute;
  left: 50%;
  bottom: 0;
  transform: translateX(-50%) translateY(10px);
  z-index: 2;
  text-align: center;
  max-width: 34rem;
  width: min(92%, 34rem);
  min-height: 5rem;
  opacity: 0;
  transition: opacity 0.55s var(--ease), transform 0.55s var(--ease);
}

.hxai-system[data-phase="4"] .hxai-detail,
.hxai-system.is-signaling .hxai-detail {
  opacity: 1;
  transform: translateX(-50%);
}

.hxai-detail__eyebrow {
  font-size: 0.68rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 0.4rem;
}

.hxai-detail__title {
  font-family: var(--font-serif);
  font-size: 1.35rem;
  color: var(--white);
  margin-bottom: 0.4rem;
}

.hxai-detail__text {
  color: var(--muted);
  font-size: 0.95rem;
  line-height: 1.65;
}

@keyframes hxaiRingPulse {
  0%, 100% { opacity: 0.35; transform: scale(1); }
  50% { opacity: 0.85; transform: scale(1.06); }
}

@keyframes hxaiOrbitSpin {
  to { transform: rotate(360deg); }
}

/* ---------- Mobile vertical flow ---------- */
.hxai-mobile {
  display: flex;
  flex-direction: column;
  align-items: stretch;
  gap: 0;
  padding: 0;
  max-width: 100%;
}

.hxai-m-block {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity 0.55s var(--ease), transform 0.55s var(--ease);
}

.hxai-mobile.is-alive .hxai-m-block,
.hxai-mobile.is-alive .hxai-m-core {
  opacity: 1;
  transform: none;
}

.hxai-mobile.is-alive .hxai-m-block--ai {
  transition-delay: 0.2s;
}

.hxai-mobile.is-alive .hxai-m-core {
  transition-delay: 0.1s;
}

.hxai-m-hub {
  position: relative;
  display: grid;
  place-items: center;
  width: 64px;
  height: 64px;
  margin: 0 auto 0.65rem;
  border-radius: 50%;
  border: 1px solid rgba(148, 163, 184, 0.28);
  background: rgba(13, 19, 32, 0.8);
  color: var(--accent);
  font-size: 0.62rem;
  letter-spacing: 0.16em;
  font-weight: 600;
}

.hxai-m-hub__ring {
  position: absolute;
  inset: -5px;
  border-radius: 50%;
  border: 1px solid rgba(34, 211, 238, 0.2);
  animation: hxaiRingPulse 4.5s ease-in-out infinite;
}

.hxai-m-hub--ai {
  margin: 0.65rem auto 0;
}

.hxai-m-block--ai {
  display: flex;
  flex-direction: column;
}

.hxai-m-caps {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.4rem;
  width: 100%;
  margin: 0;
  padding: 0;
  list-style: none;
}

.hxai-m-caps li {
  min-width: 0;
}

.hxai-m-cap {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  min-height: 42px;
  padding: 0.55rem 0.5rem;
  border: 1px solid var(--navy-border);
  border-radius: var(--radius-sm);
  background: rgba(13, 19, 32, 0.55);
  color: var(--muted-strong);
  font-family: var(--font-serif);
  font-size: 0.92rem;
  transition: border-color 0.3s ease, color 0.3s ease, background 0.3s ease, box-shadow 0.3s ease;
}

.hxai-m-cap.is-active,
.hxai-m-cap:focus-visible {
  color: var(--white);
  border-color: rgba(34, 211, 238, 0.45);
  background: rgba(34, 211, 238, 0.08);
  box-shadow: 0 0 0 1px rgba(34, 211, 238, 0.1);
  outline: none;
}

.hxai-m-flow {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.2rem;
  padding: 0.4rem 0;
  flex-shrink: 0;
}

.hxai-m-flow span {
  width: 2px;
  height: 6px;
  border-radius: 2px;
  background: rgba(34, 211, 238, 0.4);
  opacity: 0.4;
}

.hxai-mobile.is-alive .hxai-m-flow span {
  animation: hxaiFlowDrop 1.4s var(--ease) infinite;
}

.hxai-mobile.is-alive .hxai-m-flow span:nth-child(2) { animation-delay: 0.2s; }
.hxai-mobile.is-alive .hxai-m-flow span:nth-child(3) { animation-delay: 0.4s; }

@keyframes hxaiFlowDrop {
  0%, 100% { opacity: 0.2; transform: scaleY(0.7); }
  50% { opacity: 1; transform: scaleY(1.15); background: var(--accent); }
}

.hxai-m-core {
  position: relative;
  text-align: center;
  padding: 1rem 0.85rem;
  border: 1px solid rgba(34, 211, 238, 0.35);
  border-radius: 50%;
  width: min(58%, 168px);
  aspect-ratio: 1;
  margin: 0 auto;
  display: grid;
  place-content: center;
  background:
    radial-gradient(circle at 50% 40%, rgba(34, 211, 238, 0.14), transparent 60%),
    rgba(13, 19, 32, 0.9);
  box-shadow: 0 0 28px rgba(34, 211, 238, 0.1);
  opacity: 0;
  transform: scale(0.92);
  transition: opacity 0.6s var(--ease), transform 0.6s var(--ease), box-shadow 0.4s ease;
}

.hxai-mobile.is-signaling .hxai-m-core {
  box-shadow: 0 0 36px rgba(34, 211, 238, 0.22);
  border-color: rgba(34, 211, 238, 0.6);
}

.hxai-m-core__aura {
  position: absolute;
  inset: -8px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(34, 211, 238, 0.12), transparent 70%);
  pointer-events: none;
}

.hxai-m-core__brand {
  position: relative;
  font-family: var(--font-serif);
  font-size: 1.1rem;
  color: var(--white);
  line-height: 1.15;
}

.hxai-m-core__formula {
  position: relative;
  margin-top: 0.35rem;
  font-size: 0.58rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--accent-strong);
  max-width: 14ch;
  margin-left: auto;
  margin-right: auto;
  line-height: 1.35;
}

.hxai-m-detail {
  margin-top: 0.9rem;
  text-align: center;
  min-height: 0;
  padding: 0 0.15rem;
}

.hxai-m-detail__title {
  font-family: var(--font-serif);
  font-size: 1.05rem;
  color: var(--white);
  margin-bottom: 0.25rem;
}

.hxai-m-detail__text {
  color: var(--muted);
  font-size: 0.86rem;
  line-height: 1.5;
}

@media (max-width: 899px) {
  .hxai-section {
    padding: 2.5rem 0 2.25rem;
  }

  .hxai-intro {
    margin-bottom: 1.25rem;
    text-align: left;
  }

  .hxai-lede {
    font-size: 0.92rem;
    margin-top: 0.65rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  .hxai-hub__ring,
  .hxai-core__orbit,
  .hxai-m-hub__ring,
  .hxai-m-flow span {
    animation: none !important;
  }

  .hxai-pole,
  .hxai-core,
  .hxai-detail,
  .hxai-m-block,
  .hxai-m-core {
    opacity: 1 !important;
    transition: none !important;
  }

  .hxai-pole--human,
  .hxai-pole--ai {
    transform: none !important;
  }

  .hxai-core {
    transform: translate(-50%, -50%) !important;
  }

  .hxai-detail {
    transform: translateX(-50%) !important;
  }
}