:root {
  --ink: #17191f;
  --paper: #fffdf8;
  --paper-soft: #f5f2ea;
  --coral: #ff4f78;
  --teal: #20b8a8;
  --yellow: #ffd166;
  --blue: #3f7cff;
  --muted: #656a75;
  --line: #dcd7cb;
  --white: #ffffff;
  --shadow: 8px 8px 0 var(--ink);
  --radius: 6px;
  --container: 1180px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: "Microsoft YaHei", "PingFang SC", Arial, sans-serif;
  line-height: 1.75;
}

body::before {
  position: fixed;
  inset: 0;
  z-index: -1;
  content: "";
  pointer-events: none;
  opacity: 0.22;
  background-image: radial-gradient(var(--ink) 0.6px, transparent 0.6px);
  background-size: 18px 18px;
}

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

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

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

.container {
  width: min(calc(100% - 36px), var(--container));
  margin-inline: auto;
}

.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 1000;
  padding: 8px 12px;
  color: var(--white);
  background: var(--ink);
  transform: translateY(-160%);
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  border-bottom: 3px solid var(--ink);
  background: rgba(255, 253, 248, 0.96);
  backdrop-filter: blur(12px);
}

.nav-wrap {
  min-height: 74px;
  display: flex;
  align-items: center;
  gap: 28px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 11px;
  flex: 0 0 auto;
  font-size: 1.2rem;
  font-weight: 900;
}

.brand img {
  width: 44px;
  height: 44px;
}

.brand span {
  letter-spacing: 0;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 26px;
  margin-left: auto;
  font-size: 0.95rem;
  font-weight: 700;
}

.site-nav a:not(.button):hover,
.site-nav a[aria-current="page"] {
  color: var(--coral);
}

.nav-toggle {
  display: none;
  width: 44px;
  height: 44px;
  padding: 0;
  border: 2px solid var(--ink);
  color: var(--ink);
  background: var(--yellow);
  cursor: pointer;
}

.nav-toggle span,
.nav-toggle::before,
.nav-toggle::after {
  width: 20px;
  height: 2px;
  margin: 5px auto;
  display: block;
  content: "";
  background: currentColor;
  transition: transform 0.2s ease;
}

.button {
  min-height: 46px;
  padding: 10px 20px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  border: 2px solid var(--ink);
  border-radius: var(--radius);
  color: var(--white);
  background: var(--coral);
  box-shadow: 4px 4px 0 var(--ink);
  font-weight: 900;
  transition: transform 0.16s ease, box-shadow 0.16s ease;
}

.button:hover {
  transform: translate(2px, 2px);
  box-shadow: 2px 2px 0 var(--ink);
}

.button:focus-visible,
.nav-toggle:focus-visible,
summary:focus-visible,
a:focus-visible {
  outline: 3px solid var(--blue);
  outline-offset: 3px;
}

.button.dark {
  background: var(--ink);
}

.button.teal {
  background: var(--teal);
}

.eyebrow {
  margin: 0 0 12px;
  color: var(--coral);
  font-size: 0.78rem;
  font-weight: 900;
  text-transform: uppercase;
}

.eyebrow span {
  padding: 5px 9px;
  border: 2px solid var(--ink);
  color: var(--ink);
  background: var(--yellow);
}

.hero {
  position: relative;
  overflow: hidden;
  padding: 72px 0 78px;
  border-bottom: 3px solid var(--ink);
}

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(340px, 0.95fr);
  align-items: center;
  gap: 72px;
}

.hero h1 {
  max-width: 720px;
  margin: 0;
  font-size: clamp(2.7rem, 7vw, 5rem);
  line-height: 0.98;
  letter-spacing: 0;
}

.hero h1 + p {
  max-width: 690px;
  margin: 26px 0 0;
  color: #3d414b;
  font-size: 1.08rem;
}

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

.proof-strip {
  margin-top: 36px;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.proof-strip span {
  padding: 6px 10px;
  border: 2px solid var(--ink);
  background: var(--white);
  font-size: 0.84rem;
  font-weight: 800;
}

.hero-visual {
  min-height: 570px;
  position: relative;
  display: grid;
  place-items: center;
}

.phone-frame {
  width: min(315px, 78vw);
  padding: 14px;
  position: relative;
  z-index: 2;
  border: 4px solid var(--ink);
  border-radius: 34px;
  background: var(--ink);
  box-shadow: 14px 14px 0 var(--teal);
  transform: rotate(2deg);
}

.phone-frame::before {
  width: 74px;
  height: 8px;
  margin: 0 auto 12px;
  display: block;
  border-radius: 8px;
  content: "";
  background: #555b65;
}

.phone-frame img {
  width: 100%;
  max-width: 297px;
  margin: auto;
  border-radius: 18px;
}

.speech-note {
  width: 190px;
  padding: 15px 18px;
  position: absolute;
  border: 3px solid var(--ink);
  background: var(--yellow);
  box-shadow: 6px 6px 0 var(--ink);
  font-weight: 900;
}

.speech-note.one {
  top: 35px;
  left: 0;
  transform: rotate(-5deg);
}

.speech-note.two {
  right: -12px;
  bottom: 54px;
  color: var(--white);
  background: var(--coral);
  transform: rotate(4deg);
}

.section {
  padding: 90px 0;
}

.section.alt {
  border-block: 3px solid var(--ink);
  background: var(--paper-soft);
}

.section.dark {
  color: var(--white);
  background: var(--ink);
}

.section-head {
  margin-bottom: 42px;
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 24px;
}

.section-head h2 {
  max-width: 760px;
  margin: 0;
  font-size: clamp(2rem, 4.5vw, 3.7rem);
  line-height: 1.1;
  letter-spacing: 0;
}

.section-index {
  flex: 0 0 auto;
  color: var(--coral);
  font-size: 1rem;
  font-weight: 900;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 18px;
}

.feature-card,
.review-card,
.step-card,
.info-panel {
  border: 3px solid var(--ink);
  border-radius: var(--radius);
  background: var(--white);
  box-shadow: 6px 6px 0 var(--ink);
}

.feature-card {
  min-height: 285px;
  padding: 24px;
  display: flex;
  flex-direction: column;
}

.feature-card:nth-child(2) {
  background: #e8fbf8;
}

.feature-card:nth-child(3) {
  background: #fff2f5;
}

.feature-card:nth-child(4) {
  background: #fff8dc;
}

.feature-icon {
  width: 54px;
  height: 54px;
  display: grid;
  place-items: center;
  border: 2px solid var(--ink);
  border-radius: 50%;
  background: var(--yellow);
  font-size: 1.45rem;
  font-weight: 900;
}

.feature-card h3 {
  margin: 22px 0 9px;
  font-size: 1.22rem;
}

.feature-card p {
  margin: 0;
  color: var(--muted);
  font-size: 0.94rem;
}

.feature-card b {
  margin-top: auto;
  padding-top: 18px;
  color: var(--coral);
  font-size: 0.8rem;
}

.screens-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  align-items: end;
  gap: 22px;
}

.screen-shot {
  margin: 0;
}

.screen-shot:nth-child(even) {
  transform: translateY(28px);
}

.screen-shot img {
  width: 100%;
  max-width: 297px;
  margin: 0 auto;
  border: 3px solid var(--ink);
  border-radius: 22px;
  background: var(--white);
  box-shadow: 8px 8px 0 var(--coral);
}

.screen-shot figcaption {
  margin-top: 14px;
  text-align: center;
  font-weight: 800;
}

.path-grid {
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: 52px;
  align-items: center;
}

.path-list {
  display: grid;
  gap: 18px;
}

.path-item {
  padding: 18px 20px;
  display: grid;
  grid-template-columns: 48px 1fr;
  gap: 16px;
  border-left: 5px solid var(--coral);
  background: rgba(255, 255, 255, 0.06);
}

.path-item span {
  width: 44px;
  height: 44px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  color: var(--ink);
  background: var(--yellow);
  font-weight: 900;
}

.path-item h3,
.path-item p {
  margin: 0;
}

.path-item p {
  margin-top: 4px;
  color: #c7c9ce;
}

.path-copy h2 {
  margin: 0 0 22px;
  font-size: clamp(2rem, 4vw, 3.5rem);
  line-height: 1.1;
}

.path-copy .section-copy p {
  margin: 0 0 26px;
  color: #d4d5d9;
}

.review-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.review-card {
  padding: 24px;
}

.review-card .stars {
  color: #ef9b00;
  font-size: 1.1rem;
}

.review-card blockquote {
  margin: 18px 0;
  font-size: 1rem;
}

.review-card cite {
  color: var(--muted);
  font-size: 0.86rem;
  font-style: normal;
  font-weight: 700;
}

.faq-list {
  border-top: 3px solid var(--ink);
}

.faq-list details {
  border-bottom: 3px solid var(--ink);
  background: var(--white);
}

.faq-list summary {
  min-height: 74px;
  padding: 18px 62px 18px 18px;
  position: relative;
  display: flex;
  align-items: center;
  gap: 16px;
  cursor: pointer;
  list-style: none;
  font-weight: 900;
}

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

.faq-list summary::after {
  width: 34px;
  height: 34px;
  position: absolute;
  right: 16px;
  display: grid;
  place-items: center;
  border: 2px solid var(--ink);
  content: "+";
  background: var(--yellow);
  font-size: 1.3rem;
}

.faq-list details[open] summary::after {
  content: "-";
  background: var(--teal);
}

.faq-list details p {
  max-width: 900px;
  margin: 0;
  padding: 0 68px 24px 34px;
  color: var(--muted);
}

.home-faq {
  display: grid;
  grid-template-columns: 0.8fr 1.2fr;
  gap: 50px;
}

.home-faq h2 {
  margin-top: 0;
  font-size: clamp(2rem, 4vw, 3.6rem);
  line-height: 1.08;
}

.home-faq-copy p {
  color: var(--muted);
}

.download-band {
  padding: 58px 0;
  border-block: 3px solid var(--ink);
  background: var(--yellow);
}

.download-band .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 30px;
}

.download-band h2 {
  margin: 0;
  font-size: clamp(1.8rem, 4vw, 3.3rem);
  line-height: 1.1;
}

.download-band p {
  margin: 9px 0 0;
}

.page-hero {
  padding: 76px 0 64px;
  border-bottom: 3px solid var(--ink);
  background: linear-gradient(90deg, var(--paper) 0 72%, var(--yellow) 72% 100%);
}

.page-hero h1 {
  max-width: 880px;
  margin: 0;
  font-size: clamp(2.6rem, 6vw, 5rem);
  line-height: 1.04;
  letter-spacing: 0;
}

.page-hero p {
  max-width: 760px;
  margin: 22px 0 0;
  color: var(--muted);
  font-size: 1.06rem;
}

.crumbs {
  margin-bottom: 24px;
  color: var(--muted);
  font-size: 0.86rem;
}

.crumbs a:hover {
  color: var(--coral);
}

.guide-layout {
  display: grid;
  grid-template-columns: 1fr 300px;
  gap: 52px;
  align-items: start;
}

.guide-steps {
  display: grid;
  gap: 28px;
}

.step-card {
  padding: 28px;
  display: grid;
  grid-template-columns: 70px 1fr;
  gap: 22px;
}

.step-number {
  width: 64px;
  height: 64px;
  display: grid;
  place-items: center;
  border: 3px solid var(--ink);
  border-radius: 50%;
  background: var(--coral);
  color: var(--white);
  font-size: 1.25rem;
  font-weight: 900;
}

.step-card:nth-child(even) .step-number {
  color: var(--ink);
  background: var(--teal);
}

.step-card h2 {
  margin: 0 0 10px;
  font-size: 1.42rem;
}

.step-card p {
  margin: 8px 0;
  color: #4f545e;
}

.step-card ul,
.feature-detail ul {
  padding-left: 20px;
}

.guide-aside {
  position: sticky;
  top: 102px;
}

.info-panel {
  padding: 24px;
  background: #fff8dc;
}

.info-panel h2,
.info-panel h3 {
  margin-top: 0;
}

.info-panel ul {
  padding-left: 19px;
}

.info-panel + .info-panel {
  margin-top: 22px;
  background: #e8fbf8;
}

.inline-screen {
  width: 100%;
  max-width: 297px;
  margin: 26px auto 8px;
  border: 3px solid var(--ink);
  border-radius: 20px;
  box-shadow: 7px 7px 0 var(--teal);
}

.article-section {
  margin-top: 56px;
}

.article-section h2 {
  margin: 0 0 20px;
  font-size: clamp(1.8rem, 4vw, 2.7rem);
}

.article-section p {
  max-width: 900px;
  color: #4f545e;
}

.feature-detail-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 22px;
}

.feature-detail {
  padding: 26px;
  border: 3px solid var(--ink);
  background: var(--white);
  box-shadow: 6px 6px 0 var(--ink);
}

.feature-detail:nth-child(2n) {
  background: #e8fbf8;
}

.feature-detail h2 {
  margin: 0 0 12px;
  font-size: 1.38rem;
}

.feature-detail p {
  margin: 8px 0;
  color: #4f545e;
}

.trouble-table {
  width: 100%;
  border-collapse: collapse;
  border: 3px solid var(--ink);
  background: var(--white);
}

.trouble-table th,
.trouble-table td {
  padding: 16px;
  border: 2px solid var(--ink);
  text-align: left;
  vertical-align: top;
}

.trouble-table th {
  background: var(--yellow);
}

.site-footer {
  padding: 48px 0 26px;
  color: #d8dae0;
  background: var(--ink);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr 1fr;
  gap: 42px;
}

.footer-brand .brand {
  color: var(--white);
}

.footer-brand p,
.disclaimer {
  color: #aeb1ba;
  font-size: 0.85rem;
}

.footer-nav h2 {
  margin-top: 0;
  color: var(--white);
  font-size: 1rem;
}

.footer-nav a {
  margin: 8px 0;
  display: block;
}

.footer-nav a:hover {
  color: var(--yellow);
}

.copyright {
  margin-top: 34px;
  padding-top: 22px;
  display: flex;
  justify-content: space-between;
  gap: 20px;
  border-top: 1px solid #3b3f49;
  color: #90949e;
  font-size: 0.78rem;
}

[data-reveal] {
  opacity: 1;
  transform: none;
}

[data-reveal].visible {
  opacity: 1;
  transform: translateY(0);
}

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

  [data-reveal] {
    opacity: 1;
    transform: none;
    transition: none;
  }
}

@media (max-width: 980px) {
  .nav-toggle {
    margin-left: auto;
    display: block;
  }

  .site-nav {
    width: 100%;
    padding: 18px;
    position: absolute;
    top: 74px;
    left: 0;
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 4px;
    border-bottom: 3px solid var(--ink);
    background: var(--paper);
  }

  .site-nav.open {
    display: flex;
  }

  .site-nav a:not(.button) {
    padding: 10px 4px;
  }

  .hero-grid,
  .path-grid,
  .home-faq,
  .guide-layout {
    grid-template-columns: 1fr;
  }

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

  .feature-card {
    min-height: 240px;
  }

  .guide-aside {
    position: static;
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
  }

  .info-panel + .info-panel {
    margin-top: 0;
  }
}

@media (max-width: 720px) {
  .container {
    width: min(calc(100% - 26px), var(--container));
  }

  .hero,
  .section {
    padding-block: 58px;
  }

  .hero {
    padding-block: 40px;
  }

  .hero-grid {
    gap: 22px;
  }

  .hero h1 {
    font-size: 3rem;
  }

  .hero-visual {
    min-height: 285px;
  }

  .phone-frame {
    width: min(165px, 44vw);
    padding: 10px;
    border-radius: 26px;
    box-shadow: 9px 9px 0 var(--teal);
  }

  .speech-note {
    width: 118px;
    padding: 11px 13px;
    font-size: 0.82rem;
  }

  .speech-note.one {
    top: 28px;
    left: 5%;
  }

  .speech-note.two {
    right: 3%;
    bottom: 38px;
  }

  .section-head {
    align-items: flex-start;
    flex-direction: column;
  }

  .feature-grid,
  .screens-grid,
  .review-grid,
  .feature-detail-grid,
  .footer-grid,
  .guide-aside {
    grid-template-columns: 1fr;
  }

  .screen-shot:nth-child(even) {
    transform: none;
  }

  .screen-shot img {
    width: min(86vw, 297px);
  }

  .download-band .container,
  .copyright {
    align-items: flex-start;
    flex-direction: column;
  }

  .step-card {
    padding: 22px;
    grid-template-columns: 1fr;
  }

  .trouble-table,
  .trouble-table tbody,
  .trouble-table tr,
  .trouble-table th,
  .trouble-table td {
    display: block;
    width: 100%;
  }

  .trouble-table th {
    border-bottom: 0;
  }

  .trouble-table tr + tr {
    border-top: 3px solid var(--ink);
  }
}

@media (max-width: 430px) {
  .brand span {
    font-size: 1rem;
  }

  .hero h1 {
    font-size: 2.52rem;
  }

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

  .phone-frame {
    width: min(165px, 44vw);
  }

  .speech-note.one {
    left: -4px;
  }

  .speech-note.two {
    right: -3px;
  }
}