:root {
  color-scheme: light;
  --ink: #20262b;
  --muted: #747d85;
  --tomato: #ff422c;
  --line: #dce0e4;
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--ink);
  background: #fff;
  font-synthesis: none;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; }
a { color: inherit; text-decoration: none; }
img { display: block; max-width: 100%; }
h1, h2, h3, p { margin: 0; }
a:focus-visible { outline: 3px solid var(--tomato); outline-offset: 7px; border-radius: 4px; }
/* Desktop content keeps its scale; wider viewports add equal outer margins. */
.container { width: min(calc(100% - 64px), 1040px); margin-inline: auto; }
.section-rule { position: relative; }
.section-rule::after {
  content: "";
  display: block;
  height: 1px;
  background: var(--line);
  width: min(calc(100% - 64px), 1120px);
  margin-inline: auto;
}
.skip-link {
  position: absolute;
  top: 12px;
  left: 12px;
  padding: 10px 16px;
  background: #fff;
  z-index: 5;
  transform: translateY(-200%);
}
.skip-link:focus { transform: translateY(0); }

.site-header { display: flex; align-items: center; justify-content: space-between; padding-top: 28px; }
.brand { display: inline-flex; align-items: center; gap: 12px; font-size: 28px; line-height: 1.2; font-weight: 750; }
.brand img { width: 52px; height: 52px; }
.nav-link { display: inline-block; padding: 12px 0 12px 12px; font-size: 16px; font-weight: 500; color: #626c75; }
.nav-link:hover { color: var(--tomato); }

.hero-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 300px;
  gap: 80px;
  align-items: center;
  padding-top: 72px;
  padding-bottom: 88px;
}
h1 { font-size: 64px; line-height: 1.25; font-weight: 800; letter-spacing: -0.012em; }
h1 span { display: block; color: var(--tomato); }
.hero-subtitle { margin-top: 24px; font-size: 24px; line-height: 1.65; font-weight: 600; color: var(--muted); }
.feature-line { margin-top: 12px; font-size: 20px; line-height: 1.6; color: var(--muted); letter-spacing: 0.035em; }
.scan-entry { display: flex; align-items: center; gap: 28px; margin-top: 44px; }
.miniapp-code { flex: 0 0 164px; }
.miniapp-code img { width: 164px; height: auto; }
.scan-title { color: var(--tomato); font-size: 22px; line-height: 1.5; font-weight: 650; }
.scan-hint { color: var(--muted); font-size: 18px; line-height: 1.6; margin-top: 6px; }

/* The frame is the approved raster asset. Original 1:2 screenshots fit in its
   measured clear area, below Dynamic Island and above the home indicator. */
.phone { position: relative; aspect-ratio: 852 / 1846; }
.phone-frame { width: 100%; height: auto; }
.phone-screen {
  position: absolute;
  left: calc(66 / 852 * 100%);
  top: calc(200 / 1846 * 100%);
  width: calc(720 / 852 * 100%);
  height: auto;
}
.hero-phone { width: 300px; }

.how-it-works { scroll-margin-top: 36px; }
.how-it-works > .container { padding-top: 88px; padding-bottom: 88px; }
h2 { font-size: 40px; line-height: 1.4; font-weight: 800; letter-spacing: -0.025em; text-align: center; }
.learning-layout { display: grid; grid-template-columns: 340px minmax(0, 1fr); gap: 96px; align-items: center; margin-top: 64px; }
.study-phone { width: 260px; justify-self: center; }
.learning-path h3 { font-size: 28px; line-height: 1.5; font-weight: 750; letter-spacing: -0.025em; }
.learning-path p { font-size: 20px; line-height: 1.85; color: var(--muted); margin-top: 14px; }
.learning-path + .learning-path { border-top: 1px solid var(--line); padding-top: 36px; margin-top: 36px; }
.review-note { color: var(--muted); font-size: 18px; line-height: 1.8; margin-top: 48px; }
.site-footer { padding: 30px 24px; text-align: center; font-size: 14px; line-height: 1.6; color: var(--muted); }
.icp-link { display: inline-block; margin-top: 8px; text-underline-offset: 3px; }
.icp-link:hover { color: var(--ink); text-decoration: underline; }

@media (max-width: 900px) {
  .container { width: min(calc(100% - 48px), 600px); }
  .section-rule::after { width: calc(100% - 48px); }
  .site-header { padding-top: 20px; }
  .brand { gap: 8px; font-size: 24px; }
  .brand img { width: 44px; height: 44px; }
  .nav-link { padding-block: 12px; font-size: 15px; }
  .hero-layout { grid-template-columns: minmax(0, 1fr); gap: 48px; padding-top: 66px; padding-bottom: 64px; }
  h1 { font-size: 48px; letter-spacing: -0.025em; }
  .hero-subtitle { margin-top: 20px; font-size: 18px; line-height: 1.8; white-space: normal; }
  .feature-line { margin-top: 14px; font-size: 17px; }
  .scan-entry { margin-top: 30px; gap: 18px; }
  .miniapp-code { flex-basis: 124px; }
  .miniapp-code img { width: 124px; }
  .scan-title { font-size: 18px; white-space: normal; }
  .scan-hint { font-size: 15px; margin-top: 4px; }
  .hero-phone { width: min(100%, 280px); justify-self: center; }
  .how-it-works > .container { padding-top: 62px; padding-bottom: 60px; }
  h2 { font-size: 30px; line-height: 1.5; letter-spacing: -0.03em; text-align: left; }
  .learning-layout { grid-template-columns: minmax(0, 1fr); gap: 42px; margin-top: 38px; }
  .learning-copy { grid-row: 1; }
  .study-phone { width: min(100%, 260px); }
  .learning-path h3 { font-size: 24px; }
  .learning-path p { font-size: 18px; line-height: 1.9; margin-top: 12px; }
  .learning-path + .learning-path { padding-top: 26px; margin-top: 26px; }
  .review-note { margin-top: 30px; font-size: 17px; line-height: 1.9; white-space: normal; }
  .site-footer { padding: 28px 24px; font-size: 14px; }
}

@media (max-width: 600px) {
  h1 { font-size: 40px; }
}

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