:root {
  --ink: #16252b;
  --muted: #566970;
  --line: #dbe3e2;
  --paper: #ffffff;
  --stone: #f4f6f3;
  --petrol: #0b6573;
  --petrol-dark: #084a55;
  --lemon: #e8c94d;
  --dark: #173137;
  --shadow: 0 18px 45px rgba(22, 53, 59, 0.11);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "微软雅黑", Arial, Helvetica, sans-serif;
  line-height: 1.72;
}

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

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

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  width: 100%;
  background: rgba(255, 255, 255, 0.96);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(14px);
}

.header-inner,
.hero-inner,
.section-inner,
.subhero-inner,
.article-layout,
.faq-layout,
.footer-inner {
  width: min(1180px, calc(100% - 48px));
  margin: 0 auto;
}

.header-inner {
  min-height: 72px;
  display: flex;
  align-items: center;
  gap: 28px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 11px;
  flex: 0 0 auto;
  font-weight: 800;
  color: var(--petrol-dark);
}

.brand img,
.footer-brand img {
  border-radius: 8px;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-left: auto;
}

.site-nav a {
  padding: 8px 12px;
  color: #40545b;
  font-size: 15px;
  border-bottom: 2px solid transparent;
}

.site-nav a:hover,
.site-nav a.active {
  color: var(--petrol);
  border-bottom-color: var(--petrol);
}

.header-actions,
.hero-actions,
.download-actions,
.subhero-actions,
.article-download > div {
  display: flex;
  align-items: center;
  gap: 10px;
}

.button {
  min-height: 46px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0 23px;
  border: 1px solid var(--petrol);
  border-radius: 6px;
  background: var(--petrol);
  color: #ffffff;
  font-weight: 750;
  line-height: 1;
  transition: background 0.2s ease, border-color 0.2s ease, transform 0.2s ease;
}

.button:hover {
  background: var(--petrol-dark);
  border-color: var(--petrol-dark);
  transform: translateY(-1px);
}

.button-small {
  min-height: 38px;
  padding: 0 15px;
  font-size: 14px;
}

.button-secondary {
  background: transparent;
  color: var(--petrol-dark);
}

.button-secondary:hover {
  color: #ffffff;
}

.menu-toggle {
  display: none;
  width: 42px;
  height: 42px;
  padding: 10px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: #ffffff;
}

.menu-toggle span {
  display: block;
  height: 2px;
  margin: 4px 0;
  background: var(--ink);
}

.hero {
  background: var(--stone);
  border-bottom: 1px solid var(--line);
  overflow: hidden;
}

.hero-inner {
  min-height: 620px;
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(460px, 0.92fr);
  align-items: center;
  gap: 64px;
  padding: 58px 0 48px;
}

.eyebrow {
  display: inline-block;
  margin-bottom: 17px;
  color: var(--petrol-dark);
  font-size: 14px;
  font-weight: 800;
  letter-spacing: 0;
}

.hero h1,
.subhero h1 {
  margin: 0;
  color: var(--ink);
  font-size: 50px;
  line-height: 1.14;
  letter-spacing: 0;
}

.hero-copy > p,
.subhero p {
  max-width: 620px;
  margin: 22px 0 28px;
  color: var(--muted);
  font-size: 17px;
}

.compatibility-list {
  margin: 28px 0 0;
  padding-top: 20px;
  border-top: 1px solid #cbd7d5;
}

.compatibility-list > div {
  display: grid;
  grid-template-columns: 82px 1fr;
  gap: 12px;
  padding: 5px 0;
}

.compatibility-list dt {
  color: var(--muted);
}

.compatibility-list dd {
  margin: 0;
  font-weight: 700;
}

.hero-media {
  position: relative;
  min-height: 510px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.screen-bookmark {
  position: absolute;
  width: 226px;
  margin: 0;
  padding: 10px 10px 38px;
  background: #ffffff;
  border: 1px solid #d7dfdd;
  border-radius: 7px;
  box-shadow: var(--shadow);
}

.screen-bookmark img {
  width: 100%;
  max-width: 400px;
  border-radius: 4px;
}

.screen-bookmark figcaption {
  position: absolute;
  left: 13px;
  bottom: 8px;
  color: var(--petrol-dark);
  font-size: 13px;
  font-weight: 800;
}

.screen-bookmark-main {
  z-index: 3;
  left: 42px;
  transform: rotate(-2deg);
}

.screen-bookmark-back {
  z-index: 2;
  right: 20px;
  top: 34px;
  transform: rotate(3deg);
}

.screen-bookmark-note {
  z-index: 1;
  right: 62px;
  bottom: 5px;
  transform: rotate(7deg);
}

.section {
  padding: 82px 0;
}

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

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

.section-heading {
  margin-bottom: 34px;
}

.section-heading h2,
.download-band h2,
.article-download h2 {
  margin: 0;
  font-size: 34px;
  line-height: 1.25;
  letter-spacing: 0;
}

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

.feature-ledger article {
  display: grid;
  grid-template-columns: 72px 250px 1fr;
  align-items: start;
  gap: 26px;
  padding: 27px 0;
  border-bottom: 1px solid var(--line);
}

.ledger-index {
  color: var(--petrol);
  font-weight: 850;
}

.feature-ledger h3,
.feature-ledger p {
  margin: 0;
}

.feature-ledger h3 {
  font-size: 19px;
}

.feature-ledger p {
  color: var(--muted);
}

.preview-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 24px;
}

.preview-grid figure {
  margin: 0;
  padding: 22px;
  background: #ffffff;
  border: 1px solid var(--line);
  border-radius: 7px;
}

.preview-grid img {
  width: auto;
  max-width: 100%;
  max-height: 480px;
  margin: 0 auto;
  border-radius: 5px;
}

.preview-grid figcaption {
  display: grid;
  gap: 5px;
  margin-top: 18px;
}

.preview-grid figcaption span {
  color: var(--muted);
  font-size: 14px;
}

.checkpoint-layout {
  display: grid;
  grid-template-columns: 1.35fr 0.65fr;
  gap: 70px;
  align-items: start;
}

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

.checkpoint-list li {
  position: relative;
  padding: 22px 0 22px 54px;
  border-bottom: 1px solid var(--line);
  counter-increment: checkpoint;
}

.checkpoint-list {
  counter-reset: checkpoint;
}

.checkpoint-list li::before {
  content: counter(checkpoint, decimal-leading-zero);
  position: absolute;
  left: 0;
  top: 23px;
  color: var(--petrol);
  font-weight: 850;
}

.checkpoint-list span {
  font-weight: 800;
}

.checkpoint-list p {
  margin: 5px 0 0;
  color: var(--muted);
}

.note-panel {
  padding: 30px;
  background: #f9f7e9;
  border: 1px solid #ddd4a3;
  border-radius: 7px;
}

.note-label {
  color: #6d5d13;
  font-weight: 800;
}

.note-panel h3 {
  margin: 10px 0;
  font-size: 22px;
}

.note-panel p {
  color: #4c5557;
}

.text-link {
  color: var(--petrol);
  font-weight: 800;
  border-bottom: 1px solid currentColor;
}

.section-dark .section-heading {
  margin-bottom: 24px;
}

.caution-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: rgba(255, 255, 255, 0.18);
  border: 1px solid rgba(255, 255, 255, 0.18);
}

.caution-grid article {
  padding: 27px;
  background: var(--dark);
}

.caution-grid h3 {
  margin: 0 0 8px;
  color: #f6dc68;
  font-size: 18px;
}

.caution-grid p {
  margin: 0;
  color: #d5e1e1;
}

.faq-preview-layout {
  display: grid;
  grid-template-columns: 0.8fr 1.2fr;
  gap: 70px;
}

.large-copy {
  color: var(--muted);
  font-size: 17px;
}

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

.faq-preview-list a {
  display: flex;
  justify-content: space-between;
  gap: 24px;
  padding: 20px 0;
  border-bottom: 1px solid var(--line);
}

.faq-preview-list strong {
  color: var(--petrol);
}

.download-band {
  padding: 54px 0;
  background: var(--petrol);
  color: #ffffff;
}

.download-band-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 32px;
}

.download-band span {
  color: #cde7e8;
  font-weight: 700;
}

.download-band h2 {
  margin-top: 6px;
  font-size: 28px;
}

.button-light {
  background: #ffffff;
  border-color: #ffffff;
  color: var(--petrol-dark);
}

.button-outline-light {
  background: transparent;
  border-color: #d5eeee;
  color: #ffffff;
}

.button-light:hover,
.button-outline-light:hover {
  background: var(--dark);
  border-color: var(--dark);
  color: #ffffff;
}

.site-footer {
  padding: 45px 0;
  background: #10252a;
  color: #d3dfe0;
}

.footer-inner {
  text-align: center;
}

.footer-brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: #ffffff;
  font-weight: 800;
}

.site-footer nav {
  display: flex;
  justify-content: center;
  gap: 24px;
  margin: 22px 0;
}

.site-footer a:hover {
  color: #ffffff;
}

.site-footer p {
  max-width: 760px;
  margin: 10px auto 0;
  color: #b7c8ca;
  font-size: 13px;
  text-align: center;
}

.subhero {
  background: var(--stone);
  border-bottom: 1px solid var(--line);
}

.subhero-inner {
  min-height: 350px;
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: center;
  gap: 60px;
  padding: 56px 0;
}

.subhero h1 {
  font-size: 42px;
}

.subhero p {
  margin-bottom: 0;
}

.article-section,
.faq-section {
  padding: 68px 0 90px;
}

.article-layout {
  display: grid;
  grid-template-columns: 220px minmax(0, 780px);
  justify-content: space-between;
  gap: 70px;
  align-items: start;
}

.article-index,
.faq-aside {
  position: sticky;
  top: 100px;
  display: grid;
  gap: 7px;
  padding: 24px;
  background: var(--stone);
  border: 1px solid var(--line);
  border-radius: 7px;
}

.article-index,
.article-content,
.faq-aside,
.faq-list {
  width: 100%;
  min-width: 0;
}

.article-index strong,
.faq-aside strong {
  margin-bottom: 8px;
  color: var(--petrol-dark);
}

.article-index a {
  padding: 5px 0;
  color: var(--muted);
}

.article-index a:hover {
  color: var(--petrol);
}

.article-content > section {
  position: relative;
  padding: 0 0 48px 60px;
  border-left: 1px solid var(--line);
}

.article-content > section:last-of-type {
  padding-bottom: 20px;
}

.step-number {
  position: absolute;
  left: -24px;
  top: -2px;
  width: 47px;
  height: 32px;
  display: grid;
  place-items: center;
  background: #ffffff;
  border: 1px solid var(--petrol);
  border-radius: 5px;
  color: var(--petrol);
  font-weight: 850;
}

.article-content h2 {
  margin: 0 0 16px;
  font-size: 28px;
}

.article-content p {
  margin: 0 0 16px;
  color: #40545b;
}

.article-content p a {
  color: var(--petrol);
  font-weight: 750;
  border-bottom: 1px solid currentColor;
}

.article-callout {
  display: grid;
  grid-template-columns: 90px 1fr;
  gap: 16px;
  margin-top: 22px;
  padding: 18px;
  background: #f9f7e9;
  border-left: 3px solid var(--lemon);
}

.article-figure {
  max-width: 360px;
  margin: 28px 0 10px;
  padding: 18px;
  background: var(--stone);
  border: 1px solid var(--line);
  border-radius: 7px;
}

.article-figure img {
  max-width: 400px;
  margin: 0 auto;
}

.article-figure figcaption {
  margin-top: 12px;
  color: var(--muted);
  font-size: 13px;
}

.article-download {
  margin-top: 38px;
  padding: 30px;
  background: var(--stone);
  border: 1px solid var(--line);
  border-radius: 7px;
}

.article-download h2 {
  font-size: 25px;
}

.article-download p {
  margin: 8px 0 20px;
}

.faq-layout {
  display: grid;
  grid-template-columns: 240px minmax(0, 820px);
  justify-content: space-between;
  gap: 70px;
  align-items: start;
}

.faq-aside ol {
  margin: 0 0 12px;
  padding-left: 22px;
  color: var(--muted);
}

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

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

.faq-item button {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 22px 0;
  border: 0;
  background: transparent;
  color: var(--ink);
  font: inherit;
  font-size: 17px;
  font-weight: 800;
  text-align: left;
  cursor: pointer;
}

.faq-item i {
  position: relative;
  width: 22px;
  height: 22px;
  flex: 0 0 22px;
}

.faq-item i::before,
.faq-item i::after {
  content: "";
  position: absolute;
  background: var(--petrol);
}

.faq-item i::before {
  width: 16px;
  height: 2px;
  left: 3px;
  top: 10px;
}

.faq-item i::after {
  width: 2px;
  height: 16px;
  left: 10px;
  top: 3px;
  transition: transform 0.2s ease;
}

.faq-item button[aria-expanded="true"] i::after {
  transform: rotate(90deg);
}

.faq-answer {
  display: grid;
  grid-template-rows: 0fr;
  transition: grid-template-rows 0.25s ease;
}

.faq-answer p {
  min-height: 0;
  overflow: hidden;
  margin: 0;
  color: var(--muted);
}

.faq-item.open .faq-answer {
  grid-template-rows: 1fr;
}

.faq-item.open .faq-answer p {
  padding: 0 44px 24px 0;
}

@media (max-width: 1040px) {
  .header-actions {
    display: none;
  }

  .hero-inner {
    grid-template-columns: 1fr 430px;
    gap: 30px;
  }

  .screen-bookmark {
    width: 205px;
  }
}

@media (max-width: 820px) {
  .header-inner,
  .hero-inner,
  .section-inner,
  .subhero-inner,
  .article-layout,
  .faq-layout,
  .footer-inner {
    width: calc(100% - 32px);
    max-width: 680px;
  }

  .header-inner {
    min-height: 64px;
  }

  .menu-toggle {
    display: block;
    margin-left: auto;
  }

  .site-nav {
    position: absolute;
    left: 16px;
    right: 16px;
    top: 63px;
    display: none;
    padding: 10px;
    background: #ffffff;
    border: 1px solid var(--line);
    box-shadow: var(--shadow);
  }

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

  .site-nav a {
    padding: 11px 12px;
    border-bottom: 0;
  }

  .hero-inner {
    min-height: auto;
    grid-template-columns: 1fr;
    gap: 28px;
    padding: 42px 0 32px;
  }

  .hero h1 {
    font-size: 40px;
  }

  .hero-media {
    min-height: 480px;
    order: 2;
  }

  .screen-bookmark-main {
    left: 18%;
  }

  .screen-bookmark-back {
    right: 13%;
  }

  .screen-bookmark-note {
    right: 27%;
  }

  .feature-ledger article {
    grid-template-columns: 54px 1fr;
  }

  .feature-ledger p {
    grid-column: 2;
  }

  .preview-grid,
  .caution-grid {
    grid-template-columns: 1fr;
  }

  .preview-grid figure {
    display: grid;
    grid-template-columns: minmax(150px, 0.7fr) 1fr;
    gap: 20px;
    align-items: center;
  }

  .checkpoint-layout,
  .faq-preview-layout {
    grid-template-columns: 1fr;
    gap: 42px;
  }

  .download-band-inner,
  .subhero-inner {
    display: grid;
    grid-template-columns: 1fr;
  }

  .article-layout,
  .faq-layout {
    grid-template-columns: 1fr;
    gap: 34px;
  }

  .article-index,
  .faq-aside {
    position: static;
  }
}

@media (max-width: 520px) {
  .section {
    padding: 58px 0;
  }

  .brand img {
    width: 42px;
    height: 42px;
  }

  .hero h1,
  .subhero h1 {
    font-size: 32px;
    line-height: 1.2;
  }

  .hero-copy > p,
  .subhero p {
    font-size: 15px;
  }

  .hero-inner {
    gap: 12px;
    padding: 30px 0 20px;
  }

  .eyebrow {
    margin-bottom: 10px;
  }

  .hero-copy > p {
    margin: 14px 0 18px;
    line-height: 1.62;
  }

  .hero-actions,
  .subhero-actions,
  .download-actions,
  .article-download > div {
    width: 100%;
    align-items: stretch;
  }

  .hero-actions .button,
  .subhero-actions .button,
  .download-actions .button,
  .article-download .button {
    flex: 1;
    padding: 0 12px;
  }

  .compatibility-list > div {
    grid-template-columns: 76px 1fr;
    padding: 2px 0;
    font-size: 14px;
  }

  .compatibility-list {
    margin-top: 16px;
    padding-top: 12px;
  }

  .hero-media {
    min-height: 248px;
  }

  .screen-bookmark {
    width: 116px;
    padding: 5px 5px 25px;
  }

  .screen-bookmark-main {
    left: 8%;
  }

  .screen-bookmark-back {
    right: 5%;
    top: 4px;
  }

  .screen-bookmark-note {
    right: 33%;
    bottom: 0;
  }

  .screen-bookmark figcaption {
    left: 8px;
    bottom: 5px;
    font-size: 11px;
  }

  .section-heading h2 {
    font-size: 28px;
  }

  .feature-ledger article {
    grid-template-columns: 42px 1fr;
    gap: 14px;
  }

  .preview-grid figure {
    grid-template-columns: 1fr;
  }

  .preview-grid img {
    max-height: 520px;
  }

  .subhero-inner {
    min-height: 0;
    gap: 28px;
    padding: 42px 0;
  }

  .article-content > section {
    padding-left: 28px;
  }

  .step-number {
    left: -14px;
    width: 38px;
  }

  .article-callout {
    grid-template-columns: 1fr;
  }

  .site-footer nav {
    flex-wrap: wrap;
    gap: 12px 20px;
  }
}