:root {
  --ink: #102b42;
  --ink-soft: #49616f;
  --accent: #138f70;
  --accent-deep: #08765c;
  --accent-pale: #dff5ed;
  --paper: #f4f8f7;
  --surface: #ffffff;
  --line: #d9e5e1;
  --shadow: 0 24px 80px rgba(20, 64, 54, 0.12);
  --radius: 18px;
  --shell: min(1180px, calc(100vw - 40px));
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 88px;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: "Noto Sans SC", "Microsoft YaHei", "PingFang SC", system-ui, sans-serif;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -2;
  pointer-events: none;
  background:
    radial-gradient(circle at 78% 4%, rgba(19, 143, 112, 0.09), transparent 29rem),
    linear-gradient(rgba(16, 43, 66, 0.025) 1px, transparent 1px),
    linear-gradient(90deg, rgba(16, 43, 66, 0.025) 1px, transparent 1px);
  background-size: auto, 72px 72px, 72px 72px;
  mask-image: linear-gradient(to bottom, black, transparent 70%);
}

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

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

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

.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 100;
  transform: translateY(-150%);
  padding: 8px 12px;
  border-radius: 8px;
  background: var(--ink);
  color: white;
}

.skip-link:focus {
  transform: translateY(0);
}

.shell {
  width: var(--shell);
  margin-inline: auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 30;
  border-bottom: 1px solid transparent;
  transition: background 180ms ease, border-color 180ms ease, box-shadow 180ms ease;
}

.site-header.is-scrolled {
  border-color: rgba(16, 43, 66, 0.08);
  background: rgba(244, 248, 247, 0.88);
  box-shadow: 0 8px 30px rgba(16, 43, 66, 0.04);
  backdrop-filter: blur(18px);
}

.nav {
  height: 76px;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 28px;
}

.brand {
  width: max-content;
}

.brand img {
  height: 38px;
  width: auto;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 30px;
  font-size: 14px;
  color: var(--ink-soft);
}

.nav-links a {
  position: relative;
}

.nav-links a::after {
  content: "";
  position: absolute;
  right: 0;
  bottom: -7px;
  left: 0;
  height: 1px;
  background: var(--accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 180ms ease;
}

.nav-links a:hover::after,
.nav-links a:focus-visible::after {
  transform: scaleX(1);
}

.nav > .button {
  justify-self: end;
}

.button {
  min-height: 50px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  padding: 0 22px;
  border: 1px solid transparent;
  border-radius: 12px;
  font-size: 15px;
  font-weight: 700;
  white-space: nowrap;
  transition: transform 160ms ease, box-shadow 160ms ease, border-color 160ms ease, background 160ms ease;
}

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

.button:active {
  transform: translateY(1px);
}

.button:focus-visible,
.nav-links a:focus-visible,
summary:focus-visible {
  outline: 3px solid rgba(19, 143, 112, 0.25);
  outline-offset: 3px;
}

.button-primary {
  color: #fff;
  background: var(--accent);
  box-shadow: 0 14px 34px rgba(19, 143, 112, 0.22);
}

.button-primary:hover {
  background: var(--accent-deep);
  box-shadow: 0 18px 42px rgba(19, 143, 112, 0.28);
}

.button-secondary {
  border-color: var(--line);
  background: rgba(255, 255, 255, 0.66);
}

.button-secondary:hover,
.button-ghost:hover {
  border-color: rgba(19, 143, 112, 0.42);
  background: #fff;
}

.button-small {
  min-height: 40px;
  padding-inline: 16px;
  font-size: 14px;
  border-radius: 10px;
}

.button-ghost {
  border-color: var(--line);
  background: transparent;
}

.hero {
  position: relative;
  min-height: calc(100dvh - 76px);
  display: grid;
  align-items: center;
  overflow: hidden;
  padding: 48px 0 82px;
}

.hero-orbit {
  position: absolute;
  right: -16vw;
  top: 2%;
  width: min(760px, 70vw);
  aspect-ratio: 1;
  border: 1px solid rgba(19, 143, 112, 0.12);
  border-radius: 50%;
  box-shadow:
    0 0 0 90px rgba(19, 143, 112, 0.025),
    0 0 0 180px rgba(19, 143, 112, 0.018);
  pointer-events: none;
}

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(380px, 0.95fr);
  gap: clamp(50px, 8vw, 110px);
  align-items: center;
}

.eyebrow {
  margin: 0 0 22px;
  color: var(--accent-deep);
  font-size: 14px;
  font-weight: 800;
  letter-spacing: 0.08em;
}

h1,
h2,
h3,
p {
  text-wrap: pretty;
}

h1 {
  max-width: 760px;
  margin: 0;
  font-size: clamp(44px, 5.7vw, 76px);
  line-height: 1.08;
  letter-spacing: -0.055em;
  font-weight: 820;
}

h1 strong {
  position: relative;
  color: var(--accent);
  font-weight: inherit;
}

h1 strong::after {
  content: "";
  position: absolute;
  right: 0;
  bottom: -7px;
  left: 0;
  height: 7px;
  border-radius: 50%;
  background: rgba(19, 143, 112, 0.22);
  transform: rotate(-1deg);
}

.hero-lede {
  max-width: 26em;
  margin: 30px 0 0;
  color: var(--ink-soft);
  font-size: clamp(17px, 2vw, 20px);
}

.hero-actions {
  display: flex;
  gap: 14px;
  margin-top: 36px;
}

.hero-product {
  position: relative;
  min-height: 650px;
  display: grid;
  place-items: center;
}

.device-shadow {
  position: absolute;
  width: 80%;
  height: 30%;
  bottom: 4%;
  border-radius: 50%;
  background: rgba(13, 69, 55, 0.2);
  filter: blur(50px);
  transform: rotate(-7deg);
}

.device {
  position: relative;
  z-index: 2;
  width: min(356px, 82vw);
  height: 620px;
  overflow: hidden;
  border: 8px solid #fff;
  border-radius: 28px;
  background: #fff;
  box-shadow: var(--shadow);
  transform: rotate(2deg);
}

.device-bar {
  height: 30px;
  display: flex;
  align-items: center;
  gap: 5px;
  padding: 0 12px;
  border-bottom: 1px solid #e6ecea;
  background: #f8faf9;
}

.device-bar span {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: #c7d3cf;
}

.device img {
  width: 100%;
}

.memory-note {
  position: absolute;
  z-index: 3;
  display: grid;
  gap: 2px;
  min-width: 150px;
  padding: 15px 18px;
  border: 1px solid rgba(19, 143, 112, 0.16);
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.86);
  box-shadow: 0 14px 40px rgba(16, 43, 66, 0.1);
  backdrop-filter: blur(12px);
}

.note-one {
  top: 16%;
  right: -4%;
}

.note-two {
  bottom: 15%;
  left: -7%;
}

.note-label {
  color: var(--ink-soft);
  font-size: 12px;
}

.memory-note strong {
  font-size: 17px;
}

.proof-strip {
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.44);
}

.proof-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
}

.proof-grid p {
  margin: 0;
  padding: 24px 26px;
  border-right: 1px solid var(--line);
}

.proof-grid p:first-child {
  padding-left: 0;
}

.proof-grid p:last-child {
  border-right: 0;
}

.proof-grid strong,
.proof-grid span {
  display: block;
}

.proof-grid strong {
  font-size: 15px;
}

.proof-grid span {
  margin-top: 2px;
  color: var(--ink-soft);
  font-size: 12px;
}

.section {
  padding: 132px 0;
}

.section-heading {
  max-width: 790px;
  margin-bottom: 76px;
}

.section-heading.compact {
  max-width: 680px;
  margin-bottom: 52px;
}

.section-heading h2,
.privacy-copy h2,
.final-cta h2 {
  margin: 0;
  font-size: clamp(34px, 5vw, 58px);
  line-height: 1.13;
  letter-spacing: -0.045em;
}

.section-heading > p:last-child {
  max-width: 640px;
  margin: 24px 0 0;
  color: var(--ink-soft);
  font-size: 17px;
}

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

.method-flow li {
  display: grid;
  grid-template-columns: 110px minmax(0, 1fr);
  gap: 30px;
  padding: 34px 0;
  border-bottom: 1px solid var(--line);
}

.method-flow li > div {
  display: grid;
  grid-template-columns: minmax(180px, 0.35fr) minmax(0, 0.65fr);
  gap: 60px;
  align-items: baseline;
}

.step-index {
  color: var(--accent);
  font-size: 13px;
  font-weight: 800;
}

.method-flow h3 {
  margin: 0;
  font-size: 25px;
}

.method-flow p {
  max-width: 590px;
  margin: 0;
  color: var(--ink-soft);
}

.features {
  padding-top: 104px;
}

.feature-grid {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 18px;
}

.feature {
  position: relative;
  overflow: hidden;
  min-height: 360px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: rgba(255, 255, 255, 0.76);
}

.feature-copy {
  position: relative;
  z-index: 2;
  max-width: 560px;
  padding: 38px;
}

.feature-number {
  display: block;
  margin-bottom: 20px;
  color: var(--accent-deep);
  font-size: 13px;
  font-weight: 800;
}

.feature h3 {
  max-width: 19em;
  margin: 0;
  font-size: clamp(24px, 3vw, 36px);
  line-height: 1.22;
  letter-spacing: -0.03em;
}

.feature p {
  max-width: 34em;
  margin: 18px 0 0;
  color: var(--ink-soft);
}

.feature-report {
  min-height: 620px;
  grid-row: span 2;
  background:
    radial-gradient(circle at 70% 72%, rgba(19, 143, 112, 0.11), transparent 52%),
    #fff;
}

.report-crop {
  position: absolute;
  right: 7%;
  bottom: -155px;
  width: 58%;
  height: 480px;
  overflow: hidden;
  border: 7px solid #fff;
  border-radius: 23px 23px 0 0;
  box-shadow: 0 22px 70px rgba(16, 43, 66, 0.14);
}

.report-crop img {
  width: 100%;
}

.feature-local {
  min-height: 300px;
  background: linear-gradient(145deg, #e8f8f2, #f8fbfa);
}

.local-visual {
  position: absolute;
  right: -5%;
  bottom: -18%;
  width: 220px;
  aspect-ratio: 1;
  display: grid;
  place-items: center;
}

.local-visual img {
  position: relative;
  z-index: 2;
  width: 88px;
  border-radius: 20px;
  box-shadow: 0 15px 38px rgba(16, 43, 66, 0.13);
}

.ring {
  position: absolute;
  border: 1px solid rgba(19, 143, 112, 0.28);
  border-radius: 50%;
}

.ring-a {
  width: 160px;
  height: 160px;
}

.ring-b {
  width: 220px;
  height: 220px;
}

.feature-import {
  min-height: 300px;
}

.format-list {
  position: absolute;
  right: 28px;
  bottom: 26px;
  left: 38px;
  display: flex;
  flex-wrap: wrap;
  gap: 9px;
}

.format-list span {
  padding: 9px 13px;
  border: 1px solid var(--line);
  border-radius: 9px;
  background: #f5f8f7;
  color: var(--ink);
  font-family: ui-monospace, SFMono-Regular, Consolas, monospace;
  font-size: 12px;
  font-weight: 700;
}

.feature-walkman {
  min-height: 300px;
  background:
    repeating-linear-gradient(90deg, transparent 0 29px, rgba(19, 143, 112, 0.04) 30px),
    #fff;
}

.sound-lines {
  position: absolute;
  right: 30px;
  bottom: 34px;
  display: flex;
  align-items: end;
  gap: 8px;
  height: 78px;
}

.sound-lines i {
  width: 7px;
  border-radius: 8px;
  background: var(--accent);
  animation: sound 1.8s ease-in-out infinite alternate;
}

.sound-lines i:nth-child(1),
.sound-lines i:nth-child(7) { height: 24%; }
.sound-lines i:nth-child(2),
.sound-lines i:nth-child(6) { height: 52%; animation-delay: 160ms; }
.sound-lines i:nth-child(3),
.sound-lines i:nth-child(5) { height: 78%; animation-delay: 320ms; }
.sound-lines i:nth-child(4) { height: 100%; animation-delay: 480ms; }

.feature-data {
  min-height: 540px;
  background: #fff;
}

.feature-data img {
  position: absolute;
  right: 7%;
  bottom: -180px;
  width: 47%;
  border: 7px solid #fff;
  border-radius: 22px 22px 0 0;
  box-shadow: 0 22px 70px rgba(16, 43, 66, 0.14);
}

.privacy {
  padding-top: 100px;
}

.privacy-layout {
  display: grid;
  grid-template-columns: 0.75fr 1.25fr;
  gap: clamp(60px, 10vw, 140px);
  align-items: center;
  padding: clamp(44px, 7vw, 90px);
  border: 1px solid rgba(19, 143, 112, 0.17);
  border-radius: var(--radius);
  background:
    radial-gradient(circle at 15% 22%, rgba(19, 143, 112, 0.16), transparent 30%),
    rgba(255, 255, 255, 0.68);
}

.privacy-mark {
  position: relative;
  display: grid;
  place-items: center;
  min-height: 360px;
}

.privacy-mark::before,
.privacy-mark::after {
  content: "";
  position: absolute;
  border: 1px solid rgba(19, 143, 112, 0.2);
  border-radius: 50%;
}

.privacy-mark::before {
  width: 280px;
  height: 280px;
}

.privacy-mark::after {
  width: 360px;
  height: 360px;
}

.privacy-mark img {
  position: relative;
  z-index: 2;
  width: 130px;
  border-radius: 28px;
  box-shadow: var(--shadow);
}

.privacy-copy h2 {
  max-width: 700px;
}

.privacy-copy > p:not(.eyebrow) {
  max-width: 650px;
  margin: 24px 0 0;
  color: var(--ink-soft);
  font-size: 17px;
}

.privacy-points {
  margin: 38px 0 0;
  padding: 0;
  list-style: none;
}

.privacy-points li {
  display: grid;
  grid-template-columns: 44px 1fr;
  gap: 12px;
  padding: 14px 0;
  border-bottom: 1px solid var(--line);
  font-weight: 700;
}

.privacy-points span {
  color: var(--accent);
  font-size: 12px;
}

.downloads {
  padding-top: 100px;
}

.download-list {
  border-top: 1px solid var(--line);
}

.download-row {
  min-height: 112px;
  display: grid;
  grid-template-columns: 64px minmax(240px, 1fr) 140px auto;
  gap: 24px;
  align-items: center;
  border-bottom: 1px solid var(--line);
}

.platform-mark {
  width: 50px;
  height: 50px;
  display: grid;
  place-items: center;
  border: 1px solid rgba(19, 143, 112, 0.2);
  border-radius: 13px;
  background: rgba(255, 255, 255, 0.74);
  color: var(--accent-deep);
  font-family: ui-monospace, SFMono-Regular, Consolas, monospace;
  font-size: 11px;
  font-weight: 800;
}

.platform-copy h3,
.platform-copy p {
  margin: 0;
}

.platform-copy h3 {
  font-size: 20px;
}

.platform-copy p {
  margin-top: 3px;
  color: var(--ink-soft);
  font-size: 13px;
}

.release-state {
  color: var(--ink-soft);
  font-size: 13px;
}

.release-state.ready {
  color: var(--accent-deep);
  font-weight: 800;
}

.release-state.preview {
  color: #8a5a00;
  font-weight: 800;
}

.button.is-disabled {
  color: #788b93;
  background: #edf2f0;
  cursor: not-allowed;
  pointer-events: none;
}

.question-layout {
  display: grid;
  grid-template-columns: 0.8fr 1.2fr;
  gap: clamp(50px, 9vw, 120px);
}

.faq {
  border-top: 1px solid var(--line);
}

.faq details {
  border-bottom: 1px solid var(--line);
}

.faq summary {
  position: relative;
  padding: 26px 42px 26px 0;
  cursor: pointer;
  list-style: none;
  font-size: 18px;
  font-weight: 750;
}

.faq summary::-webkit-details-marker {
  display: none;
}

.faq summary::after {
  content: "+";
  position: absolute;
  right: 2px;
  top: 22px;
  color: var(--accent);
  font-size: 24px;
  font-weight: 400;
  transition: transform 180ms ease;
}

.faq details[open] summary::after {
  transform: rotate(45deg);
}

.faq p {
  max-width: 640px;
  margin: -6px 0 26px;
  color: var(--ink-soft);
}

.final-cta {
  padding: 10px 0 120px;
}

.final-cta-inner {
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: 30px;
  align-items: center;
  padding: 46px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fff;
  box-shadow: 0 18px 60px rgba(16, 43, 66, 0.07);
}

.final-cta img {
  width: 58px;
}

.final-cta h2 {
  font-size: clamp(28px, 4vw, 42px);
}

.final-cta p {
  margin: 8px 0 0;
  color: var(--ink-soft);
}

.final-actions {
  display: flex;
  gap: 10px;
}

footer {
  border-top: 1px solid var(--line);
}

.footer-inner {
  min-height: 150px;
  display: grid;
  grid-template-columns: auto 1fr auto auto;
  gap: 30px;
  align-items: center;
}

.footer-inner > img {
  height: 34px;
  width: auto;
}

.footer-inner > p {
  margin: 0;
  color: var(--ink-soft);
  font-size: 13px;
}

.footer-links {
  display: flex;
  gap: 22px;
  color: var(--ink-soft);
  font-size: 13px;
}

.footer-links a:hover {
  color: var(--accent-deep);
}

.copyright a:hover {
  color: var(--accent-deep);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.reveal {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 620ms ease, transform 620ms cubic-bezier(0.2, 0.8, 0.2, 1);
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

@keyframes sound {
  to { transform: scaleY(0.58); opacity: 0.66; }
}

@media (max-width: 980px) {
  .nav {
    grid-template-columns: 1fr auto;
  }

  .nav-links {
    display: none;
  }

  .hero {
    min-height: auto;
    padding-top: 70px;
  }

  .hero-grid,
  .privacy-layout,
  .question-layout {
    grid-template-columns: 1fr;
  }

  .hero-copy {
    max-width: 760px;
  }

  .hero-product {
    min-height: 660px;
  }

  .proof-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .proof-grid p {
    border-bottom: 1px solid var(--line);
  }

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

  .feature-report {
    min-height: 600px;
    grid-row: auto;
  }

  .feature-data {
    min-height: 520px;
  }

  .privacy-mark {
    min-height: 260px;
  }

  .privacy-mark::before {
    width: 200px;
    height: 200px;
  }

  .privacy-mark::after {
    width: 260px;
    height: 260px;
  }

  .final-cta-inner {
    grid-template-columns: auto 1fr;
  }

  .final-actions {
    grid-column: 1 / -1;
  }

  .footer-inner {
    grid-template-columns: auto 1fr;
    padding: 34px 0;
  }

  .footer-links,
  .copyright {
    justify-self: start;
  }
}

@media (max-width: 680px) {
  :root {
    --shell: min(100% - 28px, 1180px);
    --radius: 15px;
  }

  .nav {
    height: 66px;
  }

  .brand img {
    height: 32px;
  }

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

  .hero {
    padding: 54px 0 60px;
  }

  .hero-grid {
    gap: 38px;
  }

  h1 {
    font-size: clamp(38px, 11vw, 54px);
    letter-spacing: -0.06em;
  }

  .hero-lede {
    margin-top: 24px;
  }

  .hero-actions,
  .final-actions {
    display: grid;
    grid-template-columns: 1fr;
  }

  .hero-actions .button,
  .final-actions .button {
    width: 100%;
  }

  .hero-product {
    min-height: 570px;
  }

  .device {
    height: 535px;
  }

  .memory-note {
    min-width: 132px;
    padding: 12px 14px;
  }

  .note-one {
    right: 0;
  }

  .note-two {
    left: 0;
  }

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

  .proof-grid p,
  .proof-grid p:first-child {
    padding: 18px 12px;
  }

  .section {
    padding: 88px 0;
  }

  .section-heading {
    margin-bottom: 48px;
  }

  .section-heading h2,
  .privacy-copy h2 {
    font-size: 36px;
  }

  .method-flow li {
    grid-template-columns: 48px 1fr;
    gap: 12px;
    padding: 27px 0;
  }

  .method-flow li > div {
    grid-template-columns: 1fr;
    gap: 8px;
  }

  .method-flow h3 {
    font-size: 21px;
  }

  .feature {
    min-height: 320px;
  }

  .feature-copy {
    padding: 28px;
  }

  .feature-report {
    min-height: 560px;
  }

  .report-crop {
    right: 8%;
    bottom: -190px;
    width: 75%;
  }

  .feature-data {
    min-height: 490px;
  }

  .feature-data img {
    right: 8%;
    bottom: -155px;
    width: 70%;
  }

  .download-row {
    grid-template-columns: 54px minmax(0, 1fr) auto;
    gap: 14px;
    padding: 18px 0;
  }

  .download-row .release-state {
    display: none;
  }

  .privacy-layout {
    gap: 20px;
    padding: 34px 24px;
  }

  .privacy-mark {
    min-height: 230px;
  }

  .final-cta-inner {
    grid-template-columns: 1fr;
    padding: 34px 24px;
  }

  .download-row {
    grid-template-columns: 48px minmax(0, 1fr);
  }

  .download-row .button {
    grid-column: 1 / -1;
    width: 100%;
  }

  .final-actions {
    grid-column: auto;
  }

  .footer-inner {
    grid-template-columns: 1fr;
    gap: 14px;
  }

  .footer-links {
    flex-wrap: wrap;
  }
}

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

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }

  .reveal {
    opacity: 1;
    transform: none;
  }
}