:root {
  --header: #303030;
  --header-deep: #262626;
  --notice: #4a4a4a;
  --hero: #020706;
  --green: #79efc4;
  --green-strong: #25d99b;
  --green-dark: #0da876;
  --text: #151b19;
  --muted: #68746f;
  --white: #ffffff;
  --soft: #f5f6f5;
  --line: #e7ebe9;
  --warning-bg: #fff0ee;
  --warning: #f15b49;
  --shell: 1160px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-width: 320px;
  color: var(--text);
  background: #fff;
  font-family:
    Inter,
    "PingFang SC",
    "Microsoft YaHei",
    Arial,
    sans-serif;
  -webkit-font-smoothing: antialiased;
}

body,
button,
a {
  font: inherit;
}

img {
  display: block;
  max-width: 100%;
  height: auto;
  transform: none !important;
}

a {
  color: inherit;
}

button {
  color: inherit;
}

.page-shell {
  width: min(var(--shell), calc(100% - 40px));
  margin: 0 auto;
}

/* Header */

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  min-height: 68px;
  background: var(--header);
}

.header-inner {
  width: min(var(--shell), calc(100% - 40px));
  min-height: 68px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  gap: 42px;
}

.brand {
  display: inline-flex;
  align-items: center;
  margin-right: auto;
  text-decoration: none;
}

.brand img {
  width: auto;
  max-width: 155px;
  max-height: 40px;
  object-fit: contain;
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 36px;
}

.main-nav a {
  color: #f6f6f6;
  font-size: 14px;
  font-weight: 700;
  text-decoration: none;
}

.main-nav a:hover {
  color: var(--green);
}

.header-download {
  min-height: 38px;
  padding: 0 23px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: #08241a;
  background: var(--green);
  border-radius: 999px;
  font-size: 14px;
  font-weight: 900;
  text-decoration: none;
}

.mobile-menu-button {
  display: none;
  width: 42px;
  height: 42px;
  padding: 9px;
  background: transparent;
  border: 0;
  cursor: pointer;
}

.mobile-menu-button span {
  display: block;
  height: 2px;
  margin: 5px 0;
  background: #fff;
  border-radius: 2px;
}

/* Warning */

.channel-warning {
  position: relative;
  z-index: 20;
  background: var(--notice);
}

.warning-inner {
  width: min(var(--shell), calc(100% - 40px));
  min-height: 39px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 20px;
}

.warning-inner p {
  margin: 0;
  color: #f7f7f7;
  font-size: 13px;
  font-weight: 600;
  text-align: center;
}

.warning-inner button {
  margin-left: auto;
  padding: 0;
  color: #ddd;
  background: transparent;
  border: 0;
  font-size: 24px;
  line-height: 1;
  cursor: pointer;
}

/* Hero */

.hero-section {
  overflow: hidden;
  background:
    radial-gradient(circle at 56% 49%, rgba(26, 210, 142, 0.16), transparent 30%),
    var(--hero);
}

.hero-stage {
  width: min(1440px, 100%);
  margin: 0 auto;
  padding: 28px 0 14px;
}

.hero-picture {
  width: min(1180px, calc(100% - 30px));
  margin: 0 auto;
}

.hero-picture img {
  width: 100%;
  height: auto;
  max-height: 640px;
  margin: 0 auto;
  object-fit: contain;
  object-position: center;
}

.hero-downloads {
  position: relative;
  z-index: 5;
  width: min(720px, calc(100% - 34px));
  margin: -86px auto 0;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
}

.platform-button {
  min-height: 64px;
  padding: 9px 23px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 13px;
  color: #081b15;
  background: var(--green);
  border: 1px solid rgba(255, 255, 255, 0.6);
  border-radius: 999px;
  text-decoration: none;
  box-shadow: 0 15px 34px rgba(0, 0, 0, 0.24);
  transition:
    transform 180ms ease,
    background 180ms ease;
}

.platform-button:hover {
  background: #98f7d4;
  transform: translateY(-3px);
}

.platform-symbol {
  width: 34px;
  height: 34px;
  flex: 0 0 34px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.platform-symbol svg {
  width: 31px;
  height: 31px;
  fill: currentColor;
  stroke: currentColor;
  stroke-width: 1;
}

.platform-symbol-web svg {
  fill: none;
  stroke-width: 1.7;
}

.platform-button small,
.platform-button strong {
  display: block;
}

.platform-button small {
  margin-bottom: 2px;
  font-size: 10px;
  font-weight: 600;
  opacity: 0.7;
}

.platform-button strong {
  font-size: 17px;
}

.version-line {
  width: min(760px, calc(100% - 30px));
  min-height: 36px;
  margin: 8px auto 0;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 9px;
}

.version-status {
  width: 7px;
  height: 7px;
  flex: 0 0 7px;
  background: var(--green);
  border-radius: 50%;
  box-shadow: 0 0 12px var(--green);
}

.version-line p {
  margin: 0;
  color: #d2d9d6;
  font-size: 11px;
  text-align: center;
}

.version-line p span {
  margin: 0 5px;
  color: #69756f;
}

.version-line strong {
  color: var(--green);
}

/* Guide */

.guide-section {
  padding: 24px 0 64px;
  background: #fff;
}

.download-notice {
  padding: 14px 20px;
  color: var(--warning);
  background: var(--warning-bg);
  border-radius: 18px;
}

.download-notice p {
  margin: 3px 0;
  font-size: 13px;
  line-height: 1.65;
}

.guide-tabs {
  margin: 20px 0 0;
  padding: 6px;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  background: #f7f8f7;
  border: 1px solid #eef0ef;
  border-radius: 999px;
}

.guide-tab {
  min-height: 57px;
  padding: 8px 15px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 13px;
  color: #68706d;
  background: transparent;
  border: 0;
  border-radius: 999px;
  font-weight: 700;
  cursor: pointer;
}

.guide-tab.is-active {
  color: #101513;
  background: #fff;
  box-shadow: 0 7px 24px rgba(23, 37, 31, 0.08);
}

.tab-icon {
  width: 30px;
  height: 30px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.tab-icon svg {
  width: 28px;
  height: 28px;
  fill: currentColor;
  stroke: currentColor;
}

.tab-icon-android svg {
  fill: none;
  stroke-width: 1.8;
}

.guide-panel {
  padding-top: 46px;
}

.panel-heading {
  max-width: 680px;
  margin: 0 auto 46px;
  text-align: center;
}

.panel-heading > span {
  color: var(--green-dark);
  font-size: 11px;
  font-weight: 900;
  letter-spacing: 0.16em;
}

.panel-heading h2 {
  margin: 9px 0 0;
  font-size: clamp(30px, 4vw, 46px);
  line-height: 1.15;
  letter-spacing: -0.045em;
}

.panel-heading p {
  margin: 14px 0 0;
  color: var(--muted);
  line-height: 1.7;
}

/* Step grid */

.step-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  column-gap: 34px;
  row-gap: 55px;
}

.step-item {
  position: relative;
  min-width: 0;
  text-align: center;
}

.step-number {
  position: absolute;
  z-index: 0;
  left: 50%;
  bottom: 58px;
  transform: translateX(-50%);
  color: #f0f2f1;
  font-size: 92px;
  font-weight: 900;
  line-height: 1;
  letter-spacing: -0.08em;
}

.step-item figure {
  position: relative;
  z-index: 2;
  height: 390px;
  margin: 0;
  display: flex;
  align-items: flex-end;
  justify-content: center;
}

.step-item img {
  width: auto;
  max-width: 100%;
  max-height: 380px;
  object-fit: contain;
  object-position: center bottom;
  filter: drop-shadow(0 12px 16px rgba(22, 30, 27, 0.13));
}

.step-item h3 {
  position: relative;
  z-index: 3;
  margin: 21px 0 0;
  font-size: 16px;
}

.step-item p {
  position: relative;
  z-index: 3;
  margin: 8px auto 0;
  max-width: 240px;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.65;
}

.step-grid-ios .step-item:last-child {
  grid-column: 2 / 4;
}

.step-grid-compact {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.step-grid-compact .step-item:nth-child(4) {
  grid-column: 1 / 2;
  margin-left: 50%;
}

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

.step-grid-android .step-item:nth-child(5) {
  grid-column: 1 / 2;
  margin-left: 50%;
}

/* Bottom buttons */

.bottom-downloads {
  width: min(690px, 100%);
  margin: 60px auto 0;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
}

.bottom-downloads a {
  min-height: 57px;
  padding: 0 20px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 11px;
  color: #071c14;
  background: var(--green);
  border-radius: 999px;
  font-weight: 800;
  text-decoration: none;
}

.bottom-downloads a:hover {
  background: #98f7d4;
}

.mini-platform-icon {
  font-size: 22px;
}

/* Information */

.information-section {
  padding: 52px 0;
  background: #f5f7f6;
  border-top: 1px solid var(--line);
}

.information-layout {
  display: grid;
  grid-template-columns: minmax(320px, 0.85fr) minmax(0, 1.15fr);
  gap: 70px;
  align-items: center;
}

.certification {
  display: flex;
  align-items: center;
  gap: 24px;
}

.certification figure {
  width: 180px;
  min-height: 105px;
  margin: 0;
  padding: 13px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: #fff;
  border-radius: 14px;
}

.certification img {
  width: auto;
  max-width: 100%;
  max-height: 78px;
  object-fit: contain;
}

.certification span {
  color: var(--green-dark);
  font-size: 10px;
  font-weight: 900;
  letter-spacing: 0.14em;
}

.certification h2 {
  margin: 8px 0 0;
  font-size: 26px;
  line-height: 1.25;
}

.information-list {
  display: grid;
}

.information-list p {
  margin: 0;
  padding: 13px 0;
  color: var(--muted);
  border-bottom: 1px solid #dfe5e2;
  line-height: 1.65;
}

.information-list p:last-child {
  border-bottom: 0;
}

/* Footer */

.site-footer {
  padding: 28px 0;
  background: var(--header-deep);
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 35px;
}

.footer-inner img {
  width: auto;
  max-width: 145px;
  max-height: 36px;
  object-fit: contain;
}

.footer-inner p {
  max-width: 700px;
  margin: 0;
  color: #a6aeaa;
  font-size: 12px;
  line-height: 1.7;
  text-align: right;
}

[hidden] {
  display: none !important;
}

/* Responsive */

@media (max-width: 980px) {
  .main-nav {
    gap: 20px;
  }

  .hero-downloads {
    margin-top: -40px;
  }

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

  .step-grid-ios .step-item:last-child,
  .step-grid-compact .step-item:nth-child(4),
  .step-grid-android .step-item:nth-child(5) {
    grid-column: auto;
    margin-left: 0;
  }

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

  .information-layout {
    grid-template-columns: 1fr;
    gap: 35px;
  }
}

@media (max-width: 760px) {
  .page-shell,
  .header-inner,
  .warning-inner {
    width: min(100% - 28px, var(--shell));
  }

  .site-header,
  .header-inner {
    min-height: 62px;
  }

  .brand img {
    max-width: 135px;
    max-height: 34px;
  }

  .main-nav {
    position: absolute;
    top: 62px;
    left: 0;
    right: 0;
    padding: 17px 20px;
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    background: #303030;
    border-top: 1px solid #444;
  }

  .main-nav.is-open {
    display: flex;
  }

  .main-nav a {
    padding: 12px 0;
    border-bottom: 1px solid #444;
  }

  .header-download {
    margin-left: auto;
    min-height: 36px;
    padding: 0 15px;
    font-size: 12px;
  }

  .mobile-menu-button {
    display: block;
  }

  .warning-inner {
    padding: 7px 0;
  }

  .warning-inner p {
    font-size: 11px;
    line-height: 1.5;
  }

  .hero-stage {
    padding-top: 14px;
  }

  .hero-picture {
    width: 100%;
  }

  .hero-downloads {
    width: min(100% - 28px, 560px);
    margin: -8px auto 0;
    grid-template-columns: 1fr;
    gap: 10px;
  }

  .platform-button {
    min-height: 58px;
  }

  .version-line {
    padding: 8px 0 4px;
  }

  .version-line p {
    line-height: 1.55;
  }

  .guide-section {
    padding-top: 18px;
  }

  .guide-tabs {
    padding: 5px;
    grid-template-columns: 1fr;
    border-radius: 18px;
  }

  .guide-tab {
    min-height: 50px;
    border-radius: 14px;
  }

  .step-grid,
  .step-grid-compact,
  .step-grid-android {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: 18px;
    row-gap: 44px;
  }

  .step-item figure {
    height: 320px;
  }

  .step-item img {
    max-height: 310px;
  }

  .step-number {
    bottom: 61px;
    font-size: 72px;
  }

  .bottom-downloads {
    grid-template-columns: 1fr;
    gap: 10px;
  }

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

  .footer-inner {
    align-items: flex-start;
    flex-direction: column;
  }

  .footer-inner p {
    text-align: left;
  }
}

@media (max-width: 520px) {
  .header-download {
    display: none;
  }

  .hero-picture img {
    width: 118%;
    max-width: none;
    margin-left: -9%;
  }

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

  .step-grid,
  .step-grid-compact,
  .step-grid-android {
    grid-template-columns: 1fr;
  }

  .step-item figure {
    height: auto;
    min-height: 390px;
  }

  .step-item img {
    max-height: 430px;
  }

  .step-number {
    bottom: 62px;
    font-size: 86px;
  }

  .download-notice {
    padding: 13px 15px;
  }
}