:root {
  color-scheme: light dark;
  --ink: #172124;
  --muted: #566268;
  --paper: #f5f4ef;
  --paper-2: #e8e9e4;
  --night: #0d1719;
  --night-2: #14272a;
  --mint: #c9f2e7;
  --mint-strong: #73d8c0;
  --warm: #d8a85f;
  --line: rgba(23, 33, 36, 0.16);
  --max: 1180px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  background: var(--paper);
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.6;
  letter-spacing: 0;
}

a {
  color: inherit;
}

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

.site-header {
  position: sticky;
  z-index: 20;
  top: 0;
  min-height: 70px;
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 24px;
  padding: 10px max(24px, calc((100vw - var(--max)) / 2));
  color: #f7fbfa;
  background: rgba(13, 23, 25, 0.92);
  border-bottom: 1px solid rgba(255, 255, 255, 0.12);
  backdrop-filter: blur(18px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
}

.brand img {
  width: 44px;
  height: 44px;
  border-radius: 8px;
}

.brand span {
  display: flex;
  align-items: baseline;
  gap: 6px;
}

.brand small {
  color: var(--mint);
  font-size: 0.78rem;
}

.site-header nav {
  display: flex;
  justify-content: center;
  gap: 22px;
}

.site-header nav a {
  color: rgba(255, 255, 255, 0.76);
  text-decoration: none;
  font-size: 0.88rem;
}

.site-header nav a:hover,
.site-header nav a:focus-visible {
  color: #fff;
}

.header-cta,
.button {
  display: inline-flex;
  min-height: 42px;
  align-items: center;
  justify-content: center;
  padding: 0 18px;
  border-radius: 6px;
  text-decoration: none;
  font-weight: 700;
}

.header-cta {
  color: var(--night);
  background: var(--mint);
}

.hero {
  position: relative;
  min-height: min(850px, calc(100svh - 70px));
  display: flex;
  align-items: flex-end;
  overflow: hidden;
  color: #fff;
  background: var(--night);
}

.hero-image,
.hero-shade {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}

.hero-image {
  object-fit: cover;
  object-position: center 38%;
}

.hero-shade {
  background:
    linear-gradient(90deg, rgba(7, 14, 16, 0.94) 0%, rgba(7, 14, 16, 0.72) 42%, rgba(7, 14, 16, 0.16) 78%),
    linear-gradient(0deg, rgba(7, 14, 16, 0.70), transparent 52%);
}

.hero-copy {
  position: relative;
  z-index: 1;
  width: 100%;
  padding: 112px max(24px, calc((100vw - var(--max)) / 2)) 88px;
}

.hero-copy > * {
  max-width: 700px;
}

.eyebrow {
  margin: 0 0 10px;
  color: #337d6f;
  font-size: 0.76rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.hero .eyebrow,
.dark-section .eyebrow,
.assistive-section .eyebrow,
.final-cta .eyebrow {
  color: var(--mint-strong);
}

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

h1 {
  margin-bottom: 8px;
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(3.25rem, 8vw, 6.6rem);
  line-height: 0.96;
  font-weight: 500;
}

h2 {
  margin-bottom: 18px;
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(2rem, 4.8vw, 4.2rem);
  line-height: 1.06;
  font-weight: 500;
}

h3 {
  margin-bottom: 8px;
  font-size: 1.08rem;
  line-height: 1.3;
}

.hero-claim {
  margin-bottom: 2px;
  color: var(--mint);
  font-size: clamp(1.35rem, 2.4vw, 2.1rem);
  font-weight: 700;
}

.hero-claim-cn {
  margin-bottom: 22px;
  color: rgba(255, 255, 255, 0.72);
  font-size: 1rem;
}

.hero-summary {
  max-width: 620px;
  color: rgba(255, 255, 255, 0.84);
  font-size: 1.08rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 14px;
  margin-top: 30px;
}

.app-store-badge {
  display: inline-flex;
}

.app-store-badge img {
  width: 180px;
  height: auto;
}

.button.secondary {
  border: 1px solid rgba(255, 255, 255, 0.42);
  color: #fff;
  background: rgba(255, 255, 255, 0.08);
}

.answer-band {
  display: grid;
  grid-template-columns: minmax(280px, 0.75fr) minmax(0, 1.25fr);
  gap: 64px;
  align-items: start;
  padding: 68px max(24px, calc((100vw - var(--max)) / 2));
  background: var(--mint);
}

.answer-band h2 {
  margin-bottom: 0;
  font-size: clamp(1.9rem, 3.8vw, 3.2rem);
}

.answer-band > p {
  margin: 0;
  font-size: 1.15rem;
}

.section,
.gallery-section,
.formats-section,
.faq-section {
  padding: 110px max(24px, calc((100vw - var(--max)) / 2));
}

.section-heading {
  max-width: 800px;
  margin-bottom: 44px;
}

.section-heading > p:not(.eyebrow) {
  color: var(--muted);
  font-size: 1.08rem;
}

.principle-grid,
.format-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1px;
  border: 1px solid var(--line);
  background: var(--line);
}

.principle-grid article,
.format-grid article {
  padding: 28px;
  background: var(--paper);
}

.principle-grid article > span {
  display: block;
  margin-bottom: 42px;
  color: #337d6f;
  font-family: Georgia, "Times New Roman", serif;
  font-size: 1.5rem;
}

.principle-grid p,
.format-grid p {
  margin-bottom: 0;
  color: var(--muted);
}

.feature-section {
  display: grid;
  grid-template-columns: minmax(0, 0.84fr) minmax(0, 1.16fr);
  gap: 72px;
  align-items: center;
  padding: 110px max(24px, calc((100vw - var(--max)) / 2));
}

.dark-section {
  color: #f7fbfa;
  background: var(--night);
}

.sound-section {
  background: #ece9df;
}

.feature-copy > p:not(.eyebrow) {
  color: var(--muted);
}

.dark-section .feature-copy > p:not(.eyebrow) {
  color: rgba(255, 255, 255, 0.72);
}

.answer-first {
  font-size: 1.15rem;
  font-weight: 650;
}

.steps {
  margin: 34px 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid rgba(255, 255, 255, 0.16);
}

.steps li {
  display: grid;
  grid-template-columns: 34px 1fr;
  gap: 12px;
  padding: 18px 0;
  border-bottom: 1px solid rgba(255, 255, 255, 0.16);
}

.steps li > span {
  color: var(--mint-strong);
  font-weight: 800;
}

.steps p {
  margin: 2px 0 0;
  color: rgba(255, 255, 255, 0.62);
  font-size: 0.92rem;
}

.feature-media,
.gallery-grid figure,
.device-media {
  margin: 0;
}

.feature-media img,
.gallery-grid img,
.device-media img {
  width: 100%;
  height: auto;
  border-radius: 6px;
  box-shadow: 0 24px 64px rgba(0, 0, 0, 0.24);
}

figcaption {
  margin-top: 12px;
  color: var(--muted);
  font-size: 0.82rem;
}

.dark-section figcaption {
  color: rgba(255, 255, 255, 0.54);
}

.sound-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px;
  margin: 30px 0 16px;
}

.sound-grid span {
  padding: 10px 12px;
  border-left: 3px solid var(--mint-strong);
  background: rgba(255, 255, 255, 0.62);
  font-size: 0.9rem;
  font-weight: 700;
}

.note {
  font-size: 0.9rem;
}

.assistive-section {
  padding: 100px max(24px, calc((100vw - var(--max)) / 2));
  color: #f7fbfa;
  background: var(--night-2);
}

.assistive-section > div:first-child {
  max-width: 690px;
}

.assistive-flow {
  display: grid;
  grid-template-columns: 1fr auto 1fr auto 1fr;
  gap: 18px;
  align-items: center;
  margin-top: 42px;
}

.assistive-flow > div {
  min-height: 180px;
  padding: 24px;
  border: 1px solid rgba(255, 255, 255, 0.18);
}

.assistive-flow span {
  display: block;
  margin-bottom: 36px;
  color: var(--warm);
  font-size: 1.25rem;
}

.assistive-flow p {
  margin: 6px 0 0;
  color: rgba(255, 255, 255, 0.62);
  font-size: 0.92rem;
}

.assistive-flow i {
  color: var(--mint-strong);
  font-style: normal;
  font-size: 1.5rem;
}

.clarification {
  margin: 24px 0 0;
  color: var(--mint);
}

.gallery-section {
  background: #faf9f5;
}

.gallery-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}

.device-section {
  display: grid;
  grid-template-columns: minmax(0, 0.82fr) minmax(0, 1.18fr);
  gap: 72px;
  align-items: center;
  padding: 110px max(24px, calc((100vw - var(--max)) / 2));
  background: #dfe6e3;
}

.check-list {
  margin: 30px 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--line);
}

.check-list li {
  padding: 14px 0;
  border-bottom: 1px solid var(--line);
}

.device-media {
  position: relative;
}

.tap-guide {
  position: absolute;
  inset: 22% 28% 24%;
  display: grid;
  place-items: center;
  border: 2px dashed var(--mint-strong);
  background: rgba(13, 23, 25, 0.48);
}

.tap-guide span {
  max-width: 180px;
  color: #fff;
  text-align: center;
  font-size: 0.88rem;
  font-weight: 700;
}

.format-grid {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

.format-grid strong {
  display: block;
  margin-bottom: 28px;
  color: #216b5d;
  font-family: Georgia, "Times New Roman", serif;
  font-size: 1.4rem;
}

.faq-section {
  background: #faf9f5;
}

.faq-list {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0 48px;
  border-top: 1px solid var(--line);
}

.faq-list article {
  padding: 26px 0;
  border-bottom: 1px solid var(--line);
}

.faq-list p {
  margin-bottom: 0;
  color: var(--muted);
}

.final-cta {
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: 28px;
  align-items: center;
  padding: 64px max(24px, calc((100vw - var(--max)) / 2));
  color: #f7fbfa;
  background: var(--night);
}

.final-cta > img {
  border-radius: 8px;
}

.final-cta h2 {
  margin-bottom: 8px;
  font-size: clamp(2rem, 3.5vw, 3.2rem);
}

.final-cta p:last-child {
  margin-bottom: 0;
  color: rgba(255, 255, 255, 0.66);
}

footer {
  display: grid;
  grid-template-columns: 1fr auto auto;
  gap: 32px;
  align-items: center;
  padding: 42px max(24px, calc((100vw - var(--max)) / 2));
  color: rgba(255, 255, 255, 0.64);
  background: #071012;
  font-size: 0.86rem;
}

footer p {
  margin-bottom: 0;
}

footer nav {
  display: flex;
  flex-wrap: wrap;
  gap: 18px;
}

footer a {
  text-decoration: none;
}

@media (max-width: 960px) {
  .site-header {
    grid-template-columns: 1fr auto;
  }

  .site-header nav {
    display: none;
  }

  .hero {
    min-height: 760px;
  }

  .hero-copy {
    padding-top: 90px;
  }

  .answer-band,
  .feature-section,
  .device-section {
    grid-template-columns: 1fr;
    gap: 42px;
  }

  .principle-grid,
  .format-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .assistive-flow {
    grid-template-columns: 1fr;
  }

  .assistive-flow i {
    transform: rotate(90deg);
    text-align: center;
  }

  .assistive-flow > div {
    min-height: auto;
  }

  .assistive-flow span {
    margin-bottom: 18px;
  }

  footer {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 640px) {
  .site-header {
    min-height: 62px;
    padding: 8px 16px;
  }

  .brand small {
    display: none;
  }

  .header-cta {
    min-height: 38px;
    padding: 0 12px;
    font-size: 0.82rem;
  }

  .hero {
    min-height: 720px;
  }

  .hero-image {
    object-position: 60% center;
  }

  .hero-shade {
    background: linear-gradient(0deg, rgba(7, 14, 16, 0.96) 0%, rgba(7, 14, 16, 0.78) 62%, rgba(7, 14, 16, 0.30) 100%);
  }

  .hero-copy {
    padding: 80px 20px 48px;
  }

  h1 {
    font-size: clamp(3.2rem, 17vw, 4.8rem);
  }

  .answer-band,
  .section,
  .feature-section,
  .assistive-section,
  .gallery-section,
  .device-section,
  .formats-section,
  .faq-section {
    padding: 72px 20px;
  }

  .answer-band,
  .feature-section,
  .device-section {
    gap: 32px;
  }

  .principle-grid,
  .format-grid,
  .gallery-grid,
  .faq-list {
    grid-template-columns: 1fr;
  }

  .sound-grid {
    grid-template-columns: 1fr 1fr;
  }

  .final-cta {
    grid-template-columns: 1fr;
    padding: 54px 20px;
  }

  .final-cta > img {
    width: 72px;
    height: 72px;
  }

  footer {
    padding: 36px 20px;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
}