:root {
  color-scheme: light;
  --ink: #18233d;
  --muted: #66718b;
  --blue: #335cff;
  --blue-dark: #2346dc;
  --purple: #8b5cf6;
  --mint: #51d7b7;
  --line: rgba(24, 35, 61, 0.12);
  --surface: rgba(255, 255, 255, 0.78);
  --shadow: 0 24px 70px rgba(49, 66, 122, 0.13);
  --radius-large: 32px;
  --radius-medium: 22px;
  font-family: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-synthesis: none;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-width: 320px;
  overflow-x: hidden;
  color: var(--ink);
  background:
    radial-gradient(circle at 50% -10%, rgba(95, 122, 255, 0.14), transparent 30rem),
    #f7f8fc;
}

button,
textarea {
  font: inherit;
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

a {
  color: inherit;
  text-decoration: none;
}

button {
  color: inherit;
}

.page-glow {
  position: fixed;
  z-index: -1;
  width: 32rem;
  height: 32rem;
  border-radius: 50%;
  filter: blur(100px);
  opacity: 0.18;
  pointer-events: none;
}

.page-glow-one {
  top: 25rem;
  right: -16rem;
  background: #8b5cf6;
}

.page-glow-two {
  top: 78rem;
  left: -18rem;
  background: #45cdb8;
}

.section-shell,
.site-header {
  width: min(1180px, calc(100% - 48px));
  margin-inline: auto;
}

.header-actions { display: flex; align-items: center; gap: 10px; }
.language-switch { display: inline-flex; padding: 3px; border: 1px solid var(--line); border-radius: 999px; background: rgba(255,255,255,.72); }
.language-switch button { min-width: 37px; padding: 5px 8px; border: 0; border-radius: 999px; color: #7a8499; background: transparent; cursor: pointer; font-size: 9px; font-weight: 800; }
.language-switch button.active { color: #fff; background: var(--blue); }

.site-header {
  position: relative;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 84px;
  border-bottom: 1px solid var(--line);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 17px;
  font-weight: 760;
  letter-spacing: -0.02em;
}

.brand-mark {
  position: relative;
  display: inline-grid;
  place-items: center;
  width: 30px;
  height: 30px;
}

.brand-mark::after {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--blue);
  box-shadow: 0 0 14px rgba(51, 92, 255, 0.7);
  content: "";
}

.brand-mark span {
  position: absolute;
  width: 28px;
  height: 10px;
  border: 1px solid rgba(51, 92, 255, 0.7);
  border-radius: 50%;
}

.brand-mark span:nth-child(2) {
  transform: rotate(60deg);
}

.brand-mark span:nth-child(3) {
  transform: rotate(-60deg);
}

nav {
  display: flex;
  align-items: center;
  gap: 34px;
  color: #505b75;
  font-size: 14px;
  font-weight: 600;
}

nav a,
.text-link {
  transition: color 180ms ease;
}

nav a:hover,
.text-link:hover {
  color: var(--blue);
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-height: 48px;
  padding: 0 22px;
  border: 1px solid transparent;
  border-radius: 999px;
  cursor: pointer;
  font-size: 14px;
  font-weight: 700;
  transition: transform 180ms ease, box-shadow 180ms ease, background 180ms ease;
}

.button:hover {
  transform: translateY(-2px);
}

.button-primary {
  color: #fff;
  background: var(--blue);
  box-shadow: 0 14px 30px rgba(51, 92, 255, 0.24);
}

.button-primary:hover {
  background: var(--blue-dark);
  box-shadow: 0 18px 36px rgba(51, 92, 255, 0.3);
}

.button-secondary,
.button-ghost {
  border-color: var(--line);
  background: rgba(255, 255, 255, 0.58);
}

.button-small {
  min-height: 38px;
  padding-inline: 17px;
  font-size: 13px;
}

.hero {
  display: grid;
  grid-template-columns: 1.02fr 0.98fr;
  align-items: center;
  gap: 54px;
  min-height: 680px;
  padding-block: 68px 88px;
}

.eyebrow {
  display: flex;
  align-items: center;
  gap: 9px;
  margin: 0 0 20px;
  color: var(--blue);
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.eyebrow > span {
  width: 18px;
  height: 1px;
  background: currentColor;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  max-width: 620px;
  margin-bottom: 24px;
  font-size: clamp(3.45rem, 6.6vw, 5.8rem);
  font-weight: 720;
  letter-spacing: -0.072em;
  line-height: 0.98;
}

h1 em {
  display: block;
  color: var(--blue);
  font-family: Georgia, "Times New Roman", serif;
  font-weight: 500;
}

.hero-description {
  max-width: 570px;
  margin-bottom: 32px;
  color: var(--muted);
  font-size: 18px;
  line-height: 1.72;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.hero-notes {
  display: flex;
  flex-wrap: wrap;
  gap: 22px;
  margin-top: 34px;
  color: #7b849b;
  font-size: 12px;
  font-weight: 650;
}

.hero-notes span::before {
  display: inline-block;
  width: 5px;
  height: 5px;
  margin-right: 8px;
  border-radius: 50%;
  background: var(--mint);
  vertical-align: 2px;
  content: "";
}

.quantum-visual {
  position: relative;
  display: grid;
  place-items: center;
  width: 100%;
  aspect-ratio: 1;
  max-width: 560px;
  margin-left: auto;
  overflow: hidden;
  border: 1px solid rgba(255, 255, 255, 0.8);
  border-radius: 46px;
  background:
    linear-gradient(rgba(255, 255, 255, 0.14) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.14) 1px, transparent 1px),
    linear-gradient(145deg, #e7ebff 0%, #d6dffb 45%, #e5ddfb 100%);
  background-size: 36px 36px, 36px 36px, auto;
  box-shadow: var(--shadow);
}

.quantum-visual::before {
  position: absolute;
  width: 55%;
  height: 55%;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.8);
  filter: blur(60px);
  content: "";
}

.orbit {
  position: absolute;
  width: 69%;
  height: 27%;
  border: 1.5px solid rgba(56, 78, 170, 0.35);
  border-radius: 50%;
  animation: orbitPulse 5s ease-in-out infinite;
}

.orbit-two {
  transform: rotate(60deg);
  animation-delay: -1.6s;
}

.orbit-three {
  transform: rotate(-60deg);
  animation-delay: -3.2s;
}

.orbit i {
  position: absolute;
  top: 50%;
  right: -5px;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--blue);
  box-shadow: 0 0 16px rgba(51, 92, 255, 0.75);
}

.orbit-two i {
  background: var(--purple);
}

.orbit-three i {
  background: var(--mint);
}

.quantum-core {
  position: relative;
  display: grid;
  place-items: center;
  width: 96px;
  height: 96px;
  border: 1px solid rgba(255, 255, 255, 0.8);
  border-radius: 50%;
  color: white;
  background: linear-gradient(145deg, #456cf9, #7d5dea);
  box-shadow: 0 18px 50px rgba(70, 75, 190, 0.35), inset 0 1px 10px rgba(255, 255, 255, 0.38);
}

.quantum-core span {
  font-family: Georgia, serif;
  font-size: 42px;
}

.visual-card {
  position: absolute;
  z-index: 2;
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 13px 16px;
  border: 1px solid rgba(255, 255, 255, 0.85);
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.68);
  box-shadow: 0 12px 28px rgba(54, 70, 130, 0.1);
  backdrop-filter: blur(14px);
}

.visual-card strong {
  font-size: 12px;
}

.visual-card span {
  color: var(--muted);
  font-size: 10px;
}

.visual-card-one {
  top: 15%;
  left: 8%;
}

.visual-card-two {
  right: 7%;
  bottom: 25%;
}

.visual-caption {
  position: absolute;
  bottom: 26px;
  left: 28px;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.visual-caption span {
  color: var(--blue);
  font-size: 9px;
  font-weight: 800;
  letter-spacing: 0.14em;
}

.visual-caption strong {
  font-size: 13px;
}

@keyframes orbitPulse {
  0%, 100% { opacity: 0.62; }
  50% { opacity: 1; }
}

.labs-section,
.process-section,
.tutor-section {
  padding-block: 100px;
}

.section-heading {
  display: grid;
  grid-template-columns: 1fr minmax(260px, 430px);
  align-items: end;
  gap: 42px;
  margin-bottom: 46px;
}

.section-heading h2,
.tutor-intro h2 {
  margin-bottom: 0;
  font-size: clamp(2.3rem, 4.5vw, 4rem);
  letter-spacing: -0.055em;
  line-height: 1.03;
}

.section-heading > p,
.tutor-intro > p {
  margin-bottom: 4px;
  color: var(--muted);
  line-height: 1.7;
}

.lab-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
}

.lab-card {
  position: relative;
  min-height: 390px;
  padding: 28px;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: var(--radius-medium);
  background: var(--surface);
  box-shadow: 0 16px 50px rgba(47, 60, 110, 0.07);
}

.lab-card-featured {
  display: grid;
  grid-template-rows: 190px auto;
  padding: 0;
}

.lab-content {
  position: relative;
  padding: 26px 28px 28px;
}

.lab-number {
  position: absolute;
  top: 25px;
  right: 28px;
  color: #a7aec0;
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.12em;
}

.lab-status {
  margin-bottom: 12px;
  color: var(--blue);
  font-size: 10px;
  font-weight: 800;
  letter-spacing: 0.11em;
  text-transform: uppercase;
}

.lab-card h3 {
  max-width: 300px;
  margin-bottom: 14px;
  font-size: 24px;
  letter-spacing: -0.035em;
}

.lab-card > p:not(.lab-status),
.lab-content > p:not(.lab-status) {
  color: var(--muted);
  font-size: 14px;
  line-height: 1.65;
}

.text-link {
  padding: 0;
  border: 0;
  color: var(--ink);
  background: none;
  cursor: pointer;
  font-size: 12px;
  font-weight: 780;
}

.lab-art {
  position: relative;
  overflow: hidden;
  background: linear-gradient(135deg, #edf1ff, #e4e9fa);
}

.double-slit-art .source-dot {
  position: absolute;
  top: calc(50% - 6px);
  left: 15%;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--blue);
  box-shadow: 0 0 22px rgba(51, 92, 255, 0.8);
}

.slit-bar {
  position: absolute;
  left: 40%;
  width: 6px;
  height: 43%;
  border-radius: 5px;
  background: #697696;
}

.slit-bar-one {
  top: 0;
}

.slit-bar-two {
  bottom: 0;
}

.wave {
  position: absolute;
  top: 50%;
  left: 42%;
  border: 1px solid rgba(51, 92, 255, 0.37);
  border-left: 0;
  border-radius: 0 100% 100% 0;
  transform: translateY(-50%);
}

.wave-one { width: 18%; height: 36%; }
.wave-two { width: 35%; height: 65%; }
.wave-three { width: 53%; height: 96%; }

.lab-icon {
  position: relative;
  width: 100%;
  height: 142px;
  margin: 20px 0 35px;
}

.lab-icon-vector::before,
.lab-icon-vector::after {
  position: absolute;
  bottom: 18px;
  left: 14px;
  width: 75%;
  height: 3px;
  border-radius: 5px;
  background: var(--blue);
  transform: rotate(-28deg);
  transform-origin: left center;
  content: "";
}

.lab-icon-vector::after {
  width: 52%;
  background: var(--purple);
  transform: rotate(-66deg);
}

.lab-icon-vector span,
.lab-icon-vector i {
  position: absolute;
  border: solid transparent;
  border-width: 7px 0 7px 12px;
  border-left-color: var(--blue);
  transform: rotate(-28deg);
}

.lab-icon-vector span { top: 24px; right: 13px; }
.lab-icon-vector i { top: 8px; left: 46%; border-left-color: var(--purple); transform: rotate(-66deg); }

.lab-icon-energy {
  margin-top: 26px;
  transform: perspective(350px) rotateX(57deg) rotateZ(-12deg);
}

.lab-icon-energy::before,
.lab-icon-energy span,
.lab-icon-energy i,
.lab-icon-energy b {
  position: absolute;
  inset: 10px 5%;
  border: 2px solid rgba(51, 92, 255, 0.42);
  border-radius: 50%;
  content: "";
}

.lab-icon-energy span { inset: 27px 18%; border-color: rgba(139, 92, 246, 0.48); }
.lab-icon-energy i { inset: 43px 30%; border-color: rgba(81, 215, 183, 0.7); }
.lab-icon-energy b { inset: 57px 42%; background: var(--blue); border: 0; box-shadow: 0 0 18px rgba(51, 92, 255, 0.65); }

.lab-icon-superposition {
  display: grid;
  place-items: center;
}

.lab-icon-entanglement::before,
.lab-icon-entanglement::after {
  position: absolute;
  top: 28px;
  width: 84px;
  height: 84px;
  border: 1.5px solid rgba(139,92,246,.48);
  border-radius: 50%;
  background: radial-gradient(circle at 35% 30%, rgba(255,255,255,.92), rgba(139,92,246,.13));
  box-shadow: 0 16px 30px rgba(90,65,170,.11);
  content: "";
}
.lab-icon-entanglement::before { left: 9%; }
.lab-icon-entanglement::after { right: 9%; }
.lab-icon-entanglement span { position: absolute; top: 69px; left: 31%; right: 31%; height: 2px; border-top: 2px dashed rgba(51,92,255,.62); }
.lab-icon-entanglement i,
.lab-icon-entanglement b { position: absolute; z-index: 1; top: 62px; width: 14px; height: 14px; border-radius: 50%; background: var(--mint); box-shadow: 0 0 16px rgba(81,215,183,.75); }
.lab-icon-entanglement i { left: calc(9% + 35px); }
.lab-icon-entanglement b { right: calc(9% + 35px); }

.lab-icon-photoelectric::before { position: absolute; top: 13px; bottom: 13px; left: 58%; width: 10px; border-radius: 7px; background: linear-gradient(#8fa0c7,#3c4b70); box-shadow: 12px 0 25px rgba(51,92,255,.12); content: ""; }
.lab-icon-photoelectric span { position: absolute; top: 30px; left: 8%; width: 48%; height: 58px; clip-path: polygon(0 38%,100% 0,100% 100%,0 62%); background: linear-gradient(90deg,rgba(139,92,246,.08),rgba(51,92,255,.38)); }
.lab-icon-photoelectric i,
.lab-icon-photoelectric b { position: absolute; width: 11px; height: 11px; border-radius: 50%; background: var(--mint); box-shadow: 0 0 14px rgba(81,215,183,.75); }
.lab-icon-photoelectric i { top: 43px; left: 72%; }
.lab-icon-photoelectric b { top: 88px; left: 83%; }

.mini-sphere {
  position: absolute;
  width: 122px;
  height: 122px;
  border: 1.5px solid rgba(51, 92, 255, 0.42);
  border-radius: 50%;
  background: radial-gradient(circle at 35% 28%, rgba(255, 255, 255, 0.92), rgba(113, 143, 255, 0.13) 48%, rgba(139, 92, 246, 0.06));
  box-shadow: 0 18px 38px rgba(51, 92, 255, 0.12);
}

.mini-sphere::before,
.mini-sphere::after {
  position: absolute;
  inset: 12px 47px;
  border: 1px solid rgba(51, 92, 255, 0.3);
  border-radius: 50%;
  content: "";
}

.mini-sphere::after {
  inset: 47px 9px;
}

.mini-equator {
  position: absolute;
  width: 124px;
  height: 38px;
  border: 1px solid rgba(139, 92, 246, 0.48);
  border-radius: 50%;
  transform: rotate(-12deg);
}

.mini-vector {
  position: absolute;
  width: 3px;
  height: 79px;
  border-radius: 3px;
  background: linear-gradient(var(--mint), var(--blue));
  box-shadow: 0 0 12px rgba(81, 215, 183, 0.5);
  transform: translate(21px, -22px) rotate(32deg);
  transform-origin: bottom center;
}

.mini-vector::before {
  position: absolute;
  top: -6px;
  left: -4px;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--mint);
  box-shadow: 0 0 14px rgba(81, 215, 183, 0.8);
  content: "";
}

.process-section {
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.compact-heading {
  grid-template-columns: 1fr;
}

.process-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 26px;
}

.process-grid article {
  padding-top: 26px;
  border-top: 2px solid rgba(51, 92, 255, 0.18);
}

.process-grid article > span {
  display: inline-grid;
  place-items: center;
  width: 32px;
  height: 32px;
  margin-bottom: 24px;
  border-radius: 50%;
  color: var(--blue);
  background: #e8edff;
  font-size: 11px;
  font-weight: 800;
}

.process-grid h3 {
  margin-bottom: 10px;
  font-size: 18px;
}

.process-grid p {
  max-width: 310px;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.7;
}

.tutor-section {
  display: grid;
  grid-template-columns: 0.82fr 1.18fr;
  align-items: center;
  gap: 70px;
}

.tutor-intro h2 {
  margin-bottom: 20px;
}

.tutor-intro > p {
  max-width: 470px;
}

.tutor-principles {
  display: grid;
  gap: 15px;
  margin-top: 36px;
}

.tutor-principles > div {
  display: grid;
  grid-template-columns: 32px 1fr;
  gap: 12px;
  align-items: start;
}

.tutor-principles span {
  padding-top: 3px;
  color: var(--blue);
  font-size: 10px;
  font-weight: 800;
}

.tutor-principles p {
  margin: 0;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.45;
}

.tutor-principles strong {
  display: block;
  color: var(--ink);
  font-size: 14px;
}
.tutor-principles em { font-style: normal; }

.chat-shell {
  overflow: hidden;
  border: 1px solid rgba(255, 255, 255, 0.9);
  border-radius: var(--radius-large);
  background: rgba(255, 255, 255, 0.82);
  box-shadow: var(--shadow);
  backdrop-filter: blur(24px);
}

.chat-header {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 19px 22px;
  border-bottom: 1px solid var(--line);
}

.tutor-avatar {
  display: grid;
  place-items: center;
  width: 38px;
  height: 38px;
  border-radius: 13px;
  color: #fff;
  background: linear-gradient(145deg, var(--blue), var(--purple));
  font-size: 10px;
  font-weight: 850;
  letter-spacing: 0.06em;
}

.chat-header strong,
.chat-header span {
  display: block;
}

.chat-header strong {
  margin-bottom: 4px;
  font-size: 13px;
}

.chat-header span {
  color: var(--muted);
  font-size: 10px;
}

.chat-header span i {
  display: inline-block;
  width: 6px;
  height: 6px;
  margin-right: 5px;
  border-radius: 50%;
  background: #a5adbd;
}

.chat-header span.connected i {
  background: #36bf87;
  box-shadow: 0 0 8px rgba(54, 191, 135, 0.5);
}

.chat-header span.demo i {
  background: #f4a340;
}

.chat-messages {
  display: flex;
  flex-direction: column;
  gap: 14px;
  height: 325px;
  padding: 22px;
  overflow-y: auto;
  scroll-behavior: smooth;
}

.message {
  max-width: 84%;
  padding: 13px 15px;
  border-radius: 16px;
  font-size: 13px;
  line-height: 1.58;
}

.message p {
  margin: 0;
  white-space: pre-wrap;
}

.message-author {
  display: block;
  margin-bottom: 4px;
  color: #8b93a7;
  font-size: 9px;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.assistant-message {
  align-self: flex-start;
  border: 1px solid var(--line);
  border-bottom-left-radius: 5px;
  background: #f7f8fc;
}

.user-message {
  align-self: flex-end;
  border-bottom-right-radius: 5px;
  color: white;
  background: var(--blue);
}

.user-message .message-author {
  color: rgba(255, 255, 255, 0.7);
}

.typing-message p::after {
  display: inline-block;
  width: 18px;
  animation: typingDots 1.2s infinite;
  content: "…";
}

@keyframes typingDots {
  0%, 20% { opacity: 0.2; }
  50% { opacity: 1; }
  80%, 100% { opacity: 0.2; }
}

.lab-suggestion {
  margin-top: 11px;
  padding-top: 11px;
  border-top: 1px solid var(--line);
}

.lab-suggestion a {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--blue);
  font-size: 11px;
  font-weight: 800;
}

.suggestion-row {
  display: flex;
  gap: 7px;
  padding: 0 22px 13px;
  overflow-x: auto;
}

.suggestion-row button {
  flex: 0 0 auto;
  padding: 7px 10px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: #687188;
  background: #fff;
  cursor: pointer;
  font-size: 9px;
  font-weight: 700;
}

.suggestion-row button:hover {
  border-color: rgba(51, 92, 255, 0.35);
  color: var(--blue);
}

.chat-form {
  display: flex;
  gap: 10px;
  align-items: flex-end;
  margin: 0 16px;
  padding: 9px 9px 9px 15px;
  border: 1px solid rgba(51, 92, 255, 0.18);
  border-radius: 18px;
  background: #fff;
  box-shadow: 0 8px 24px rgba(53, 67, 120, 0.06);
}

.chat-form:focus-within {
  border-color: rgba(51, 92, 255, 0.48);
  box-shadow: 0 0 0 3px rgba(51, 92, 255, 0.08);
}

.chat-form textarea {
  flex: 1;
  max-height: 120px;
  resize: none;
  border: 0;
  outline: 0;
  color: var(--ink);
  background: transparent;
  font-size: 13px;
  line-height: 1.5;
}

.chat-form textarea::placeholder {
  color: #9aa1b1;
}

.chat-form button {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  min-height: 37px;
  padding: 0 12px 0 14px;
  border: 0;
  border-radius: 12px;
  color: white;
  background: var(--blue);
  cursor: pointer;
  font-size: 11px;
  font-weight: 800;
}

.chat-form button:disabled {
  cursor: wait;
  opacity: 0.55;
}

.chat-form button i {
  font-size: 15px;
  font-style: normal;
}

.chat-disclaimer {
  margin: 10px 20px 15px;
  color: #9aa1b1;
  font-size: 8px;
  text-align: center;
}

.site-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 120px;
  border-top: 1px solid var(--line);
  color: #7e879b;
  font-size: 11px;
}

.site-footer p {
  margin: 0;
}

.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;
}

@media (max-width: 980px) {
  nav { display: none; }
  .hero { grid-template-columns: 1fr; padding-top: 80px; }
  .hero-copy { text-align: center; }
  .hero-description { margin-inline: auto; }
  .eyebrow, .hero-actions, .hero-notes { justify-content: center; }
  .quantum-visual { width: min(600px, 100%); margin: 20px auto 0; }
  .lab-grid { grid-template-columns: 1fr 1fr; }
  .lab-card-featured { grid-column: 1 / -1; grid-template-columns: 0.9fr 1.1fr; grid-template-rows: auto; min-height: 310px; }
  .tutor-section { grid-template-columns: 1fr; }
  .tutor-intro { text-align: center; }
  .tutor-intro .eyebrow { justify-content: center; }
  .tutor-intro > p { margin-inline: auto; }
  .tutor-principles { max-width: 520px; margin-inline: auto; text-align: left; }
}

@media (max-width: 680px) {
  .section-shell, .site-header { width: min(100% - 28px, 1180px); }
  .site-header .button { display: none; }
  .hero { min-height: auto; padding-block: 62px 70px; }
  h1 { font-size: clamp(3rem, 15vw, 4.6rem); }
  .hero-description { font-size: 16px; }
  .hero-actions { flex-direction: column; }
  .button { width: 100%; }
  .quantum-visual { border-radius: 30px; }
  .visual-card { display: none; }
  .section-heading { grid-template-columns: 1fr; gap: 18px; }
  .labs-section, .process-section, .tutor-section { padding-block: 74px; }
  .lab-grid, .process-grid { grid-template-columns: 1fr; }
  .lab-card-featured { grid-column: auto; grid-template-columns: 1fr; grid-template-rows: 170px auto; }
  .lab-card { min-height: 350px; }
  .process-grid { gap: 32px; }
  .chat-messages { height: 360px; padding-inline: 15px; }
  .suggestion-row { padding-inline: 15px; }
  .chat-form { margin-inline: 10px; }
  .chat-form button span { display: none; }
  .message { max-width: 92%; }
  .site-footer { flex-direction: column; justify-content: center; gap: 12px; padding-block: 26px; text-align: center; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: 0.01ms !important; animation-iteration-count: 1 !important; }
}