* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  min-width: 320px;
  color: #15342d;
  background: #f6f2e9;
  font-family: var(--font-sans, "Noto Sans CJK SC", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
button, input { font: inherit; }
button { color: inherit; }
a { color: inherit; text-decoration: none; }
button:focus-visible, a:focus-visible {
  outline: 3px solid rgba(23, 107, 87, .28);
  outline-offset: 4px;
}
.noise {
  position: fixed;
  z-index: 20;
  inset: 0;
  pointer-events: none;
  opacity: .025;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 180 180' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.8' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='.8'/%3E%3C/svg%3E");
}
.shell {
  width: min(calc(100% - 44px), clamp(1180px, 72vw, 1520px));
  margin: 0 auto;
}
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin: 0 0 18px;
  color: #176b57;
  font-size: 13px;
  font-weight: 850;
  letter-spacing: .12em;
}
.eyebrow::before { content: ""; width: 22px; height: 2px; background: #ff8057; border-radius: 2px; }
.display {
  margin: 0;
  font-size: clamp(44px, 6.2vw, 88px);
  line-height: 1.02;
  letter-spacing: -.065em;
  font-weight: 950;
}
.section-title {
  margin: 0;
  max-width: 820px;
  font-size: clamp(34px, 4.6vw, 62px);
  line-height: 1.08;
  letter-spacing: -.05em;
  font-weight: 930;
}
.section-lead { max-width: 650px; margin: 22px 0 0; color: #668079; font-size: 18px; line-height: 1.8; }
.accent { color: #ff7047; }
.marker {
  position: relative;
  white-space: nowrap;
}
.marker::after {
  content: "";
  position: absolute;
  z-index: -1;
  left: -.03em;
  right: -.06em;
  bottom: .04em;
  height: .28em;
  border-radius: 99px;
  background: #ffd85a;
  transform: rotate(-1deg);
}

/* navigation */
.nav {
  position: fixed;
  z-index: 100;
  top: 0;
  left: 0;
  right: 0;
  height: 72px;
  transition: background .25s ease, box-shadow .25s ease, height .25s ease;
}
.nav.scrolled { height: 62px; background: rgba(246, 242, 233, .86); backdrop-filter: blur(18px); box-shadow: 0 1px 0 rgba(21,52,45,.08); }
.nav-inner { height: 100%; display: flex; align-items: center; justify-content: space-between; }
.brand { display: flex; align-items: center; gap: 11px; font-size: 19px; font-weight: 900; letter-spacing: -.04em; }
.brand-logo {
  display: block;
  flex: 0 0 auto;
  width: 42px;
  height: 42px;
  object-fit: contain;
  filter: drop-shadow(0 8px 14px rgba(23,107,87,.14));
}
.nav-links { display: flex; align-items: center; gap: 27px; color: #5f7770; font-size: 14px; font-weight: 720; }
.nav-links a { transition: color .15s ease; }
.nav-links a:hover { color: #176b57; }
.nav-cta {
  border: 0;
  border-radius: 999px;
  padding: 11px 18px;
  color: #fff;
  background: #173f35;
  cursor: pointer;
  font-size: 13px;
  font-weight: 800;
  transition: transform .15s ease, background .15s ease;
}
.nav-cta:hover { transform: translateY(-2px); background: #176b57; }

/* hero */
.hero {
  position: relative;
  min-height: 820px;
  padding: 136px 0 82px;
  overflow: hidden;
}
.hero::before {
  content: "ENGLISH";
  position: absolute;
  top: 87px;
  left: 50%;
  color: rgba(23,107,87,.038);
  font: 950 clamp(120px, 23vw, 330px)/1 system-ui, sans-serif;
  letter-spacing: -.09em;
  transform: translateX(-50%);
  pointer-events: none;
}
.hero-grid { position: relative; z-index: 2; display: grid; grid-template-columns: 1.04fr .96fr; gap: 48px; align-items: center; }
.pilot-pill {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  margin-bottom: 24px;
  padding: 8px 13px;
  border: 1px solid rgba(23,107,87,.13);
  border-radius: 999px;
  background: rgba(255,255,255,.58);
  color: #517069;
  font-size: 12px;
  font-weight: 780;
}
.pilot-pill i { width: 7px; height: 7px; border-radius: 50%; background: #55aa7f; box-shadow: 0 0 0 5px rgba(85,170,127,.12); }
.hero-copy .display span { display: block; }
.hero-copy .display .line-2 { margin-top: 4px; color: #176b57; }
.hero-desc { max-width: 585px; margin: 27px 0 0; color: #607a72; font-size: clamp(17px, 2vw, 20px); line-height: 1.8; }
.hero-actions { display: flex; flex-wrap: wrap; align-items: center; gap: 13px; margin-top: 34px; }
.primary-btn, .secondary-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-height: 54px;
  padding: 0 23px;
  border-radius: 999px;
  cursor: pointer;
  font-weight: 850;
  transition: transform .18s ease, box-shadow .18s ease, background .18s ease;
}
.primary-btn { border: 0; color: #fff; background: #ff7047; box-shadow: 0 14px 30px rgba(255,112,71,.25); }
.primary-btn:hover { transform: translateY(-3px); background: #f3623a; box-shadow: 0 18px 36px rgba(255,112,71,.31); }
.primary-btn svg { width: 18px; height: 18px; }
.secondary-btn { border: 1px solid rgba(23,63,53,.15); background: rgba(255,255,255,.56); }
.secondary-btn:hover { transform: translateY(-3px); background: #fff; }
.hero-proof { display: flex; flex-wrap: wrap; gap: 22px; margin-top: 32px; color: #6b827c; font-size: 12px; font-weight: 680; }
.hero-proof span { display: flex; align-items: center; gap: 7px; }
.hero-proof span::before { content: "✓"; display: grid; place-items: center; width: 18px; height: 18px; border-radius: 50%; color: #176b57; background: #dfeee7; font-size: 11px; font-weight: 900; }

/* hero product model */
.demo-stage {
  position: relative;
  min-width: 0;
  min-height: 650px;
  display: grid;
  align-items: center;
  scroll-margin-top: 88px;
}
.hero-companion-card {
  width: 100%;
  max-width: 580px;
  margin-inline: auto;
}
.hero-companion-card .companion-stage-meta {
  min-height: 50px;
  padding-inline: 18px;
}
.hero-companion-card .companion-stage {
  height: clamp(420px, 36vw, 440px);
}
.hero-companion-card .companion-controlbar {
  grid-template-columns: 1fr;
  gap: 10px;
  min-height: 0;
  padding: 14px 18px 16px;
}
.hero-companion-card .companion-controls {
  justify-content: flex-start;
}

/* story ribbon */
.story-ribbon { position: relative; z-index: 4; margin-top: -18px; }
.ribbon-inner { display: grid; grid-template-columns: repeat(5, 1fr); overflow: hidden; border: 1px solid rgba(23,52,45,.09); border-radius: 22px; background: rgba(255,255,255,.72); box-shadow: 0 18px 45px rgba(30,62,53,.08); backdrop-filter: blur(14px); }
.ribbon-step { position: relative; padding: 23px 19px; }
.ribbon-step:not(:last-child)::after { content: "→"; position: absolute; top: 50%; right: -7px; z-index: 2; color: #9aaba6; transform: translateY(-50%); }
.ribbon-step small { display: block; color: #ff7047; font-size: 9px; font-weight: 900; letter-spacing: .08em; }
.ribbon-step strong { display: block; margin-top: 6px; font-size: 13px; }

/* sections */
.section { padding: 122px 0; }
.section-head { display: flex; align-items: end; justify-content: space-between; gap: 32px; margin-bottom: 56px; }
.section-head .section-lead { margin: 0; max-width: 410px; font-size: 16px; }
.problem-grid { display: grid; grid-template-columns: 1.07fr .93fr; gap: 22px; }
.parent-scene { position: relative; min-height: 520px; overflow: hidden; border-radius: 34px; background: #173f35; color: #fff; }
.parent-scene::before { content: ""; position: absolute; width: 430px; height: 430px; right: -150px; top: -150px; border: 1px solid rgba(255,255,255,.12); border-radius: 50%; box-shadow: 0 0 0 55px rgba(255,255,255,.025), 0 0 0 110px rgba(255,255,255,.018); }
.scene-copy { position: relative; z-index: 2; padding: 44px; max-width: 520px; }
.scene-copy .eyebrow { color: #c7e2d9; }
.scene-copy h3 { margin: 0; font-size: clamp(33px, 4vw, 54px); line-height: 1.12; letter-spacing: -.055em; }
.scene-copy p { max-width: 450px; margin: 19px 0 0; color: #b8d0c8; font-size: 15px; line-height: 1.8; }
.chat-stack { position: absolute; right: 25px; bottom: 27px; width: min(395px, calc(100% - 50px)); }
.chat { width: fit-content; max-width: 88%; margin-top: 9px; padding: 12px 15px; border-radius: 16px 16px 16px 5px; color: #21423a; background: #fff; font-size: 12px; line-height: 1.55; box-shadow: 0 10px 25px rgba(0,0,0,.13); }
.chat.me { margin-left: auto; border-radius: 16px 16px 5px 16px; background: #d8f1e6; }
.chat.ai { display: flex; gap: 9px; align-items: flex-start; }
.chat.ai i { display: grid; place-items: center; flex: 0 0 auto; width: 25px; height: 25px; border-radius: 9px; color: white; background: #176b57; font-style: normal; }
.problem-side { display: grid; gap: 22px; }
.quote-card, .truth-card { position: relative; overflow: hidden; border-radius: 30px; padding: 36px; }
.quote-card { min-height: 250px; background: #ff7047; color: #fff; }
.quote-mark { position: absolute; right: 25px; top: 6px; color: rgba(255,255,255,.16); font: 950 110px/1 Georgia, serif; }
.quote-card blockquote { position: relative; z-index: 2; margin: 0; font-size: 27px; line-height: 1.45; letter-spacing: -.035em; font-weight: 880; }
.quote-card footer { margin-top: 21px; color: #ffe0d6; font-size: 12px; font-weight: 700; }
.truth-card { min-height: 248px; border: 1px solid rgba(23,52,45,.08); background: #fff; }
.truth-card small { color: #6d837d; font-size: 11px; font-weight: 780; }
.truth-equation { display: flex; align-items: center; gap: 13px; margin-top: 24px; font-size: clamp(24px, 3vw, 40px); font-weight: 950; letter-spacing: -.05em; }
.truth-equation .strike { position: relative; color: #93a19d; }
.truth-equation .strike::after { content: ""; position: absolute; left: -3px; right: -3px; top: 50%; height: 4px; border-radius: 4px; background: #ff7047; transform: rotate(-8deg); }
.truth-card p { margin: 18px 0 0; color: #6b817a; font-size: 13px; line-height: 1.7; }

.loop-section { background: #fffdf8; }
.loop-track { position: relative; display: grid; grid-template-columns: repeat(5, 1fr); gap: 15px; }
.loop-track::before { content: ""; position: absolute; left: 8%; right: 8%; top: 42px; height: 2px; background: repeating-linear-gradient(90deg, #bed7ce 0 9px, transparent 9px 17px); }
.loop-card { position: relative; z-index: 2; min-height: 266px; padding: 24px 20px; border: 1px solid rgba(23,52,45,.08); border-radius: 24px; background: #fff; transition: transform .22s ease, box-shadow .22s ease; }
.loop-card:hover { transform: translateY(-8px); box-shadow: 0 22px 45px rgba(23,52,45,.1); }
.loop-number { display: grid; place-items: center; width: 38px; height: 38px; margin-bottom: 26px; border-radius: 13px; color: #fff; background: #176b57; box-shadow: 0 0 0 8px #fff; font-size: 11px; font-weight: 900; }
.loop-card:nth-child(2) .loop-number { background: #ff7047; }
.loop-card:nth-child(3) .loop-number { background: #6f79d8; }
.loop-card:nth-child(4) .loop-number { color: #523e00; background: #ffd85a; }
.loop-card:nth-child(5) .loop-number { background: #3e9170; }
.loop-card h3 { margin: 0; font-size: 18px; letter-spacing: -.03em; }
.loop-card p { margin: 12px 0 0; color: #71857f; font-size: 12px; line-height: 1.7; }
.loop-tag { display: inline-flex; margin-top: 18px; padding: 6px 9px; border-radius: 99px; color: #4f6b63; background: #eff5f2; font-size: 8px; font-weight: 850; }

.ai-section { position: relative; overflow: hidden; color: #fff; background: #142f29; }
.ai-section::after { content: "AI"; position: absolute; right: -40px; bottom: -125px; color: rgba(255,255,255,.025); font: 950 390px/1 system-ui; letter-spacing: -.1em; }
.ai-section .eyebrow { color: #9cd3c1; }
.ai-section .section-lead { color: #9fbab2; }
.ai-grid { position: relative; z-index: 2; display: grid; grid-template-columns: repeat(3, 1fr); border-top: 1px solid rgba(255,255,255,.1); border-left: 1px solid rgba(255,255,255,.1); }
.ai-card { min-height: 280px; padding: 31px; border-right: 1px solid rgba(255,255,255,.1); border-bottom: 1px solid rgba(255,255,255,.1); transition: background .2s ease; }
.ai-card:hover { background: rgba(255,255,255,.045); }
.ai-icon { display: grid; place-items: center; width: 47px; height: 47px; margin-bottom: 35px; border-radius: 16px; color: #17352d; background: #ffd85a; font-size: 19px; font-weight: 900; }
.ai-card:nth-child(2) .ai-icon, .ai-card:nth-child(5) .ai-icon { color: #fff; background: #ff7047; }
.ai-card:nth-child(3) .ai-icon, .ai-card:nth-child(6) .ai-icon { color: #fff; background: #6f79d8; }
.ai-card h3 { margin: 0; font-size: 21px; letter-spacing: -.035em; }
.ai-card p { margin: 12px 0 0; color: #a3bcb5; font-size: 13px; line-height: 1.75; }
.ai-card b { color: #fff; }

.pronunciation-grid { display: grid; grid-template-columns: .85fr 1.15fr; gap: 70px; align-items: center; }
.speech-panel { position: relative; min-height: 530px; overflow: hidden; padding: 32px; border-radius: 34px; color: #fff; background: #6f79d8; box-shadow: 0 28px 70px rgba(82,92,180,.22); }
.speech-panel::after { content: "r"; position: absolute; right: -12px; bottom: -85px; color: rgba(255,255,255,.08); font: 950 330px/1 Georgia, serif; }
.speech-top { position: relative; z-index: 2; display: flex; align-items: center; justify-content: space-between; }
.speech-top span { font-size: 11px; font-weight: 850; }
.listening-pill { display: flex; align-items: center; gap: 6px; padding: 7px 10px; border-radius: 99px; background: rgba(255,255,255,.13); font-size: 9px !important; }
.listening-pill i { width: 6px; height: 6px; border-radius: 50%; background: #8ff0c4; box-shadow: 0 0 0 5px rgba(143,240,196,.1); }
.speech-sentence { position: relative; z-index: 2; margin-top: 72px; font-size: clamp(37px, 5vw, 62px); line-height: 1.12; letter-spacing: -.05em; font-weight: 930; }
.speech-sentence span { position: relative; display: inline-block; }
.speech-sentence span::after { content: ""; position: absolute; left: 0; right: 0; bottom: -8px; height: 5px; border-radius: 5px; background: #ffd85a; }
.speech-bars { position: relative; z-index: 2; display: flex; align-items: center; gap: 6px; height: 62px; margin-top: 56px; }
.speech-bars i { flex: 1; max-width: 9px; border-radius: 99px; background: rgba(255,255,255,.72); animation: wave 1.4s ease-in-out infinite; }
.speech-bars i:nth-child(3n) { animation-delay: -.3s; }
.speech-bars i:nth-child(2n) { animation-delay: -.6s; }
.speech-note { position: relative; z-index: 2; margin-top: 42px; padding: 17px; border-radius: 18px; background: rgba(20,25,80,.18); backdrop-filter: blur(10px); }
.speech-note small { color: #d7daf9; font-size: 9px; font-weight: 760; }
.speech-note strong { display: block; margin-top: 6px; font-size: 14px; line-height: 1.5; }
.rule-list { display: grid; gap: 20px; margin-top: 38px; }
.rule { display: grid; grid-template-columns: 34px 1fr; gap: 14px; align-items: start; }
.rule i { display: grid; place-items: center; width: 34px; height: 34px; border-radius: 12px; color: #176b57; background: #e2f0e9; font-size: 12px; font-style: normal; font-weight: 900; }
.rule h3 { margin: 0; font-size: 16px; }
.rule p { margin: 5px 0 0; color: #70847e; font-size: 12px; line-height: 1.7; }

.evidence-section { background: #ffd85a; }
.evidence-section .eyebrow { color: #684f00; }
.evidence-section .eyebrow::before { background: #173f35; }
.evidence-ladder { display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px; margin-top: 54px; }
.ladder-step { position: relative; min-height: 250px; padding: 25px; border-radius: 24px; background: rgba(255,255,255,.65); }
.ladder-step::after { content: "→"; position: absolute; top: 50%; right: -12px; z-index: 2; font-size: 20px; font-weight: 900; transform: translateY(-50%); }
.ladder-step:last-child::after { display: none; }
.ladder-step small { color: #745f18; font-size: 9px; font-weight: 900; letter-spacing: .08em; }
.ladder-step h3 { margin: 31px 0 0; font-size: 22px; letter-spacing: -.04em; }
.ladder-step p { margin: 11px 0 0; color: #725f20; font-size: 12px; line-height: 1.65; }
.ladder-step.final { color: #fff; background: #173f35; }
.ladder-step.final small, .ladder-step.final p { color: #b9d1c9; }

.roles-grid { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 18px; }
.role-card { min-height: 390px; overflow: hidden; border: 1px solid rgba(23,52,45,.08); border-radius: 30px; background: #fff; transition: transform .2s ease, box-shadow .2s ease; }
.role-card:hover { transform: translateY(-7px); box-shadow: 0 24px 54px rgba(23,52,45,.1); }
.role-visual { position: relative; height: 185px; overflow: hidden; padding: 24px; }
.role-card:nth-child(1) .role-visual { background: #e7f3ed; }
.role-card:nth-child(2) .role-visual { background: #fff0e8; }
.role-card:nth-child(3) .role-visual { background: #eeeefe; }
.role-big { position: absolute; right: -10px; bottom: -44px; color: rgba(23,52,45,.06); font-size: 140px; font-weight: 950; }
.role-ui { position: relative; z-index: 2; margin-top: 18px; padding: 13px; border-radius: 15px; background: rgba(255,255,255,.78); box-shadow: 0 12px 30px rgba(23,52,45,.09); font-size: 10px; font-weight: 800; }
.role-ui div { display: flex; justify-content: space-between; margin-top: 8px; color: #70847e; font-size: 8px; }
.role-copy { padding: 27px; }
.role-copy small { color: #ff7047; font-size: 9px; font-weight: 900; letter-spacing: .08em; }
.role-copy h3 { margin: 8px 0 0; font-size: 23px; }
.role-copy p { margin: 12px 0 0; color: #71857f; font-size: 12px; line-height: 1.75; }
.role-copy ul { margin: 17px 0 0; padding: 0; list-style: none; color: #526c65; font-size: 11px; line-height: 1.8; }
.role-copy li::before { content: "•"; margin-right: 8px; color: #ff7047; font-weight: 900; }

.principles { padding-top: 20px; }
.principle-bar { display: grid; grid-template-columns: 1fr 1fr 1fr; overflow: hidden; border-radius: 28px; background: #173f35; color: #fff; }
.principle { padding: 32px; }
.principle:not(:last-child) { border-right: 1px solid rgba(255,255,255,.1); }
.principle strong { display: block; font-size: 20px; }
.principle p { margin: 9px 0 0; color: #b4ccc4; font-size: 12px; line-height: 1.7; }

.closing { position: relative; overflow: hidden; padding: 120px 0; color: #fff; background: #ff7047; }
.closing::before { content: "Hello!"; position: absolute; right: -35px; top: 15px; color: rgba(255,255,255,.08); font: 950 clamp(110px, 20vw, 280px)/1 system-ui; letter-spacing: -.08em; transform: rotate(-5deg); }
.closing-grid { position: relative; z-index: 2; display: grid; grid-template-columns: 1fr auto; gap: 50px; align-items: end; }
.closing h2 { max-width: 780px; margin: 0; font-size: clamp(42px, 6vw, 78px); line-height: 1.06; letter-spacing: -.06em; }
.closing p { max-width: 600px; margin: 22px 0 0; color: #ffe3db; font-size: 16px; line-height: 1.8; }
.closing-btn { min-width: 190px; min-height: 58px; border: 0; border-radius: 999px; color: #173f35; background: #ffd85a; cursor: pointer; font-weight: 900; box-shadow: 0 17px 38px rgba(100,38,16,.18); transition: transform .18s ease; }
.closing-btn:hover { transform: translateY(-4px) rotate(-1deg); }
.footer { padding: 30px 0; color: #72857f; background: #f6f2e9; font-size: 11px; }
.footer-inner { display: flex; align-items: center; justify-content: space-between; gap: 20px; }
.footer .brand { color: #173f35; font-size: 15px; }
.footer .brand-logo { width: 32px; height: 32px; }
.footer-filing { display: flex; align-items: center; justify-content: center; width: 100%; gap: 6px; margin-top: 16px; font-size: 11px; line-height: 16px; }
.footer-filing-icon { flex: 0 0 auto; width: 13px; height: 14px; object-fit: contain; }
.footer-filing-separator { color: #a7b5b0; }
.footer-filing a { color: #72857f; text-decoration: none; }
.footer-filing a:hover { color: #173f35; text-decoration: underline; }
.footer-filing a:focus-visible { outline: 2px solid #4b8f7a; outline-offset: 3px; border-radius: 2px; }

.toast { position: fixed; z-index: 300; left: 50%; bottom: 28px; min-width: 250px; padding: 14px 18px; border-radius: 14px; color: #fff; background: #173f35; box-shadow: 0 18px 45px rgba(23,52,45,.25); font-size: 12px; font-weight: 750; text-align: center; opacity: 0; pointer-events: none; transform: translate(-50%, 18px); transition: opacity .25s ease, transform .25s ease; }
.toast.show { opacity: 1; transform: translate(-50%, 0); }
.reveal { opacity: 0; transform: translateY(26px); transition: opacity .65s ease, transform .65s cubic-bezier(.22,1,.36,1); }
.reveal.visible { opacity: 1; transform: none; }

@keyframes wave { 0%,100% { transform: scaleY(.38); } 50% { transform: scaleY(1); } }

@media (min-width: 1640px) {
  .display { font-size: clamp(88px, 4.6vw, 96px); }
  .hero-grid { gap: clamp(56px, 3.8vw, 76px); }
  .hero-desc { max-width: 650px; }
  .demo-stage { min-height: 700px; }
  .hero-companion-card { max-width: 660px; }
  .hero-companion-card .companion-stage { height: clamp(460px, 24vw, 500px); }
  .ribbon-step { padding: 25px 23px; }
  .ribbon-step strong { font-size: 14px; }
}

@media (max-width: 980px) {
  .hero-grid, .problem-grid, .pronunciation-grid, .closing-grid { grid-template-columns: 1fr; }
  .hero-copy { text-align: center; }
  .hero-copy .hero-desc { margin-left: auto; margin-right: auto; }
  .hero-actions, .hero-proof { justify-content: center; }
  .demo-stage {
    width: min(100%, 820px);
    min-height: 0;
    margin: 26px auto 0;
  }
  .loop-track { grid-template-columns: repeat(2, 1fr); }
  .loop-track::before { display: none; }
  .loop-card:last-child { grid-column: 1 / -1; min-height: 210px; }
  .ai-grid { grid-template-columns: repeat(2, 1fr); }
  .roles-grid { grid-template-columns: 1fr 1fr; }
  .role-card:last-child { grid-column: 1 / -1; }
  .evidence-ladder { grid-template-columns: repeat(2, 1fr); }
  .ladder-step:nth-child(2)::after { display: none; }
  .principle-bar { grid-template-columns: 1fr; }
  .principle:not(:last-child) { border-right: 0; border-bottom: 1px solid rgba(255,255,255,.1); }
  .closing-grid { align-items: start; }
  .companion-stage { height: 570px; }
  .companion-controlbar { grid-template-columns: 1fr; }
  .companion-controls { justify-content: flex-start; }
}
@media (max-width: 720px) {
  .shell { width: min(100% - 30px, 1180px); }
  .nav { height: 62px; }
  .nav-links a { display: none; }
  .nav-links { gap: 0; }
  .hero { min-height: auto; padding: 108px 0 64px; }
  .display { font-size: clamp(42px, 13.4vw, 65px); }
  .hero-desc { font-size: 16px; }
  .hero-actions { display: grid; grid-template-columns: 1fr; }
  .primary-btn, .secondary-btn { width: 100%; }
  .demo-stage {
    width: 100%;
    min-height: 0;
    margin: 24px 0 0;
    transform: none;
  }
  .hero-companion-card { max-width: none; }
  .hero-companion-card .companion-stage { height: 500px; }
  .story-ribbon { margin-top: 0; }
  .ribbon-inner { grid-template-columns: 1fr; }
  .ribbon-step { display: grid; grid-template-columns: 52px 1fr; align-items: center; padding: 13px 17px; }
  .ribbon-step small { grid-row: 1; }
  .ribbon-step strong { grid-column: 2; grid-row: 1; margin: 0; }
  .ribbon-step:not(:last-child)::after { top: auto; left: 24px; right: auto; bottom: -10px; transform: rotate(90deg); }
  .section { padding: 86px 0; }
  .section-title { font-size: clamp(33px, 10vw, 48px); }
  .section-head { display: block; margin-bottom: 38px; }
  .section-head .section-lead { margin-top: 18px; }
  .parent-scene { min-height: 560px; }
  .scene-copy { padding: 31px 27px; }
  .scene-copy h3 { font-size: 36px; }
  .quote-card, .truth-card { padding: 27px; }
  .loop-track, .ai-grid, .roles-grid, .evidence-ladder { grid-template-columns: 1fr; }
  .loop-card:last-child, .role-card:last-child { grid-column: auto; }
  .ai-card { min-height: 235px; }
  .ladder-step::after { top: auto; right: 50%; bottom: -17px; transform: translateX(50%) rotate(90deg); }
  .ladder-step:nth-child(2)::after { display: block; }
  .speech-panel { min-height: 500px; padding: 25px; }
  .closing { padding: 88px 0; }
  .closing h2 { font-size: 44px; }
  .closing-btn { width: 100%; }
  .footer-inner { align-items: flex-start; flex-direction: column; }
  .footer-filing { justify-content: center; }
  .companion-model-card { border-radius: 23px; box-shadow: 8px 10px 0 rgba(23,52,45,.07); }
  .companion-stage-meta { min-height: 52px; padding: 0 16px; font-size: 8px; }
  .companion-stage { height: 530px; }
  .companion-stage::after { inset: 14px; }
  .companion-stage-guide { left: 18px; bottom: 17px; font-size: 8px; }
  .poster-book { width: 174px; height: 256px; padding: 28px 23px; }
  .poster-book img { width: 58px; height: 58px; }
  .poster-book strong { margin-top: 28px; font-size: 26px; }
  .companion-controlbar { min-height: 0; padding: 17px; }
  .companion-control-copy strong { font-size: 17px; }
  .companion-controls { display: grid; grid-template-columns: 1fr 1fr; width: 100%; }
  .companion-controls .companion-primary { grid-column: 1 / -1; grid-row: 1; width: 100%; }
  .companion-controls button { width: 100%; }
  .companion-stage canvas { cursor: pointer; }
}
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; animation-duration: .01ms !important; animation-iteration-count: 1 !important; transition-duration: .01ms !important; }
}