:root {
  --ink: #1b1d20;
  --muted: #606366;
  --sep: #d0d3d6;
  --line: #f1f5f9;
  --paper: #ffffff;
  --bg: #f8fafc;
  --btn: #24272c;
  --btn-border: #383c44;
  --btn-hover: #2a2e34;
  --btn-sub: #8e9299;
  --peek: #b5babf;
  --peek-bar: #e2e7fe;
  --brand: #3a82f7;
  --card: #f3f4fa;
  --font: "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --safe-top: env(safe-area-inset-top, 0px);
  --safe-bottom: env(safe-area-inset-bottom, 0px);
  --header-h: 42px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  min-height: 100vh;
  min-height: 100dvh;
  font-family: var(--font);
  color: var(--ink);
  background: var(--bg);
  line-height: 1.5;
  overflow-x: clip;
  -webkit-tap-highlight-color: transparent;
}

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

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

.page-bg {
  pointer-events: none;
  position: absolute;
  top: var(--header-h);
  left: 0;
  right: 0;
  bottom: 0;
  overflow: hidden;
  z-index: 0;
}

.page-bg img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.bg-h5 {
  object-position: top center;
}

.bg-pc {
  display: none;
}

.topbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 30;
  padding: 0 1rem;
  padding-top: var(--safe-top);
  height: calc(var(--header-h) + var(--safe-top));
  display: flex;
  align-items: center;
  background: var(--paper);
  border-bottom: 1px solid var(--line);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.015);
  user-select: none;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
}

.brand img {
  width: 24px;
  height: 24px;
  object-fit: contain;
  border-radius: 6px;
}

.brand span {
  font-weight: 700;
  font-size: 14px;
  letter-spacing: 0.04em;
  color: var(--ink);
}

.main {
  position: relative;
  z-index: 10;
  margin-top: calc(var(--header-h) + var(--safe-top));
}

.hero {
  position: relative;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.hero-inner {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 2.5rem 1.5rem 3rem;
  text-align: center;
  animation: fade-up 0.7s ease both;
}

.hero-title {
  margin: 0;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 0;
  font-size: 23px;
  font-weight: 400;
  letter-spacing: 0.04em;
  line-height: 1.3;
  color: var(--ink);
}

.hero-title .em {
  font-weight: 800;
}

.spark {
  width: 1.25rem;
  height: 1.25rem;
  margin: 0 0.35rem;
  color: var(--ink);
  flex-shrink: 0;
}

.hero-sub {
  margin: 0.75rem 0 0;
  max-width: 22rem;
  font-size: 13px;
  font-weight: 400;
  letter-spacing: 0.03em;
  line-height: 1.6;
  color: var(--muted);
}

.hero-sub .em {
  font-weight: 800;
  color: var(--ink);
}

.hero-sub .sep {
  color: var(--sep);
  margin: 0 0.25rem;
}

.desktop-only {
  display: none;
}

.mobile-only {
  display: block;
}

.dl-mobile {
  width: 100%;
  max-width: 297px;
  margin: 3.5rem auto 0;
  display: flex;
  flex-direction: column;
  gap: 0.875rem;
  animation: fade-up 0.9s ease both;
}

.dl-desktop {
  display: none;
}

.dl-btn {
  width: 100%;
  height: 54px;
  padding: 0.25rem 1rem;
  background: var(--btn);
  border: 1px solid var(--btn-border);
  border-radius: 14px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
  transition: transform 0.15s ease;
}

.dl-btn:active {
  transform: scale(0.98);
}

.dl-btn.is-preferred {
  outline: 2px solid rgba(58, 130, 247, 0.55);
  outline-offset: 2px;
}

.dl-row {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  user-select: none;
}

.dl-row img {
  width: 20px;
  height: 20px;
  object-fit: contain;
}

.dl-row strong {
  color: #fff;
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.04em;
  line-height: 1;
}

.dl-btn small {
  margin-top: 2px;
  color: var(--btn-sub);
  font-size: 9px;
  font-weight: 500;
  letter-spacing: 0.04em;
  line-height: 1;
  user-select: none;
}

.tutorial-wrap {
  position: relative;
  background: var(--paper);
  overflow: hidden;
  z-index: 20;
}

.tutorial {
  padding: 1.25rem 1rem 2rem;
  max-width: 720px;
  margin: 0 auto;
}

.tutorial-head {
  text-align: center;
  margin-bottom: 1.25rem;
}

.tutorial-head h2 {
  margin: 0;
  font-size: 1.15rem;
  font-weight: 800;
  letter-spacing: 0.02em;
}

.tutorial-head p {
  margin: 0.4rem 0 0;
  font-size: 0.85rem;
  color: var(--muted);
}

.tutorial-head a {
  color: var(--brand);
  font-weight: 700;
}

.guide-card {
  position: relative;
  margin-top: 1.5rem;
  padding: 2.1rem 1.1rem 1.25rem;
  background: var(--card);
  border-radius: 22px;
}

.guide-tab {
  position: absolute;
  top: 0;
  left: 1rem;
  transform: translateY(-45%);
  padding: 0.45rem 0.95rem;
  background: var(--ink);
  color: #fff;
  font-size: 0.82rem;
  font-weight: 800;
  letter-spacing: 0.02em;
  border-radius: 999px;
  box-shadow: 0 6px 16px rgba(27, 29, 32, 0.18);
}

.steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.85rem;
}

.steps li {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0.7rem;
  align-items: start;
}

.steps .num {
  width: 1.65rem;
  height: 1.65rem;
  border-radius: 50%;
  display: grid;
  place-items: center;
  background: #fff;
  color: var(--brand);
  font-size: 0.82rem;
  font-weight: 800;
  box-shadow: 0 2px 8px rgba(58, 130, 247, 0.18);
  flex-shrink: 0;
}

.steps p {
  margin: 0.1rem 0 0;
  font-size: 0.9rem;
  color: #3a3d42;
  line-height: 1.65;
  text-align: left;
}

.tutorial-visual {
  margin-top: 1.5rem;
  border-radius: 16px;
  overflow: hidden;
  background: #eef5ff;
}

.tutorial-visual img {
  width: 100%;
  height: auto;
}

.footer {
  position: relative;
  z-index: 10;
  padding: 0 1rem calc(1.5rem + var(--safe-bottom));
  text-align: center;
  background: var(--paper);
  color: var(--peek);
  font-size: 0.78rem;
}

.footer p {
  margin: 0.2rem 0;
}

.footer a {
  color: var(--brand);
  font-weight: 700;
}

@keyframes fade-up {
  from {
    opacity: 0;
    transform: translateY(14px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes bounce-down {
  0%,
  100% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(4px);
  }
}

@keyframes fade-in {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

@media (min-width: 768px) {
  :root {
    --header-h: 84px;
  }

  .bg-h5 {
    display: none;
  }

  .bg-pc {
    display: block;
  }

  .topbar {
    padding: 0 3rem;
  }

  .brand img {
    width: 48px;
    height: 48px;
    border-radius: 12px;
  }

  .brand span {
    font-size: 1.25rem;
  }

  .hero-inner {
    padding: 3rem 1.5rem 4rem;
  }

  .hero-title {
    font-size: 48px;
  }

  .spark {
    width: 2rem;
    height: 2rem;
    margin: 0 0.75rem;
  }

  .hero-sub {
    max-width: 42rem;
    margin-top: 1rem;
    font-size: 18px;
    line-height: 1.5;
  }

  .mobile-only {
    display: none;
  }

  .desktop-only {
    display: inline;
  }

  .dl-mobile {
    display: none;
  }

  .dl-desktop {
    display: flex;
    flex-wrap: wrap;
    align-items: flex-end;
    justify-content: center;
    gap: 1.5rem;
    margin-top: 4rem;
    min-height: 192px;
    animation: fade-up 0.9s ease both;
  }

  .dl-card {
    position: relative;
    width: 262px;
    height: 108px;
    background: var(--btn);
    border: 1px solid var(--btn-border);
    border-radius: 20px;
    overflow: hidden;
    cursor: pointer;
    transition: height 0.3s ease, background 0.3s ease, box-shadow 0.3s ease;
  }

  .dl-card:hover,
  .dl-card.is-open {
    height: 192px;
    background: var(--btn-hover);
    box-shadow: 0 16px 36px rgba(0, 0, 0, 0.3);
  }

  .dl-card-default,
  .dl-card-hover {
    position: absolute;
    inset: 0;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 1rem;
    text-align: center;
    transition: opacity 0.3s ease;
  }

  .dl-card-default {
    opacity: 1;
    pointer-events: none;
  }

  .dl-card-hover {
    opacity: 0;
    pointer-events: none;
  }

  .dl-card:hover .dl-card-default,
  .dl-card.is-open .dl-card-default {
    opacity: 0;
  }

  .dl-card:hover .dl-card-hover,
  .dl-card.is-open .dl-card-hover {
    opacity: 1;
    pointer-events: auto;
    animation: fade-in 0.25s ease both;
  }

  .dl-card-face {
    display: inline-flex;
    align-items: center;
    gap: 0.75rem;
  }

  .dl-card-face img {
    width: 42px;
    height: 42px;
    object-fit: contain;
  }

  .dl-card-face strong,
  .dl-card-bigicon strong {
    color: #fff;
    font-size: 19px;
    font-weight: 700;
    letter-spacing: 0.04em;
  }

  .dl-card-bigicon strong {
    font-size: 16px;
    margin-top: 0.35rem;
  }

  .dl-card-desc {
    color: var(--btn-sub);
    font-size: 11px;
    font-weight: 500;
    letter-spacing: 0.03em;
    line-height: 1;
    user-select: none;
  }

  .qr-box {
    width: 110px;
    height: 110px;
    border-radius: 12px;
    background: #fff;
    padding: 8px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
  }

  .qr-box img {
    width: 100%;
    height: 100%;
    object-fit: contain;
  }

  .dl-card-bigicon img {
    width: 80px;
    height: 80px;
    object-fit: contain;
  }

  .dl-card-mac {
    gap: 0.5rem;
    padding: 0.75rem 1rem;
  }

  .mac-chip {
    width: 100%;
    max-width: 210px;
    height: 60px;
    padding: 0.5rem 1rem;
    border-radius: 16px;
    background: #fff;
    color: var(--ink);
    display: flex;
    align-items: center;
    justify-content: space-between;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
    transition: background 0.15s ease;
  }

  .mac-chip:hover {
    background: #f1f5ff;
  }

  .mac-chip-left {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
  }

  .mac-chip-left img {
    width: 24px;
    height: 24px;
    object-fit: contain;
  }

  .mac-chip-left em {
    font-style: normal;
    font-size: 13px;
    font-weight: 700;
  }

  .mac-chip-go {
    font-size: 12px;
    font-weight: 700;
    color: var(--brand);
  }

  .tutorial-wrap {
    margin-top: 0;
    border-radius: 0;
    max-width: 960px;
    margin-left: auto;
    margin-right: auto;
    background: transparent;
    padding: 0 1.5rem 3rem;
    overflow: visible;
  }

  .tutorial-peek {
    display: none;
  }

  .tutorial {
    padding: 2rem;
    background: var(--paper);
    border-radius: 24px;
    box-shadow: 0 12px 40px rgba(15, 28, 51, 0.06);
    max-width: none;
  }

  .guide-card {
    padding: 2.4rem 1.6rem 1.5rem;
  }

  .steps {
    gap: 1rem;
  }

  .steps p {
    font-size: 0.98rem;
  }

  .tutorial-visual {
    margin-top: 2rem;
    border-radius: 20px;
  }

  .footer {
    background: transparent;
    padding-bottom: 2rem;
  }
}

@media (min-width: 1200px) {
  .dl-desktop {
    flex-wrap: nowrap;
  }
}

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

  *,
  *::before,
  *::after {
    animation: none !important;
    transition: none !important;
  }
}