:root {
  --canvas: #ffffff;
  --ink: #182129;
  --muted: #65717b;
  --line: #e5e9e8;
  --soft: #f7faf8;
  --green: #16835d;
  --green-dark: #106846;
  --coral: #ee695f;
  --max-width: 1440px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  background: var(--canvas);
  color: var(--ink);
  font-family: Inter, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  margin: 0;
  min-width: 320px;
}
a { color: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
.skip-link { background: var(--ink); color: #fff; left: 16px; padding: 10px 14px; position: fixed; top: -64px; z-index: 10; }
.skip-link:focus { top: 16px; }

.site-header {
  align-items: center;
  border-bottom: 1px solid var(--line);
  display: flex;
  height: 58px;
  justify-content: flex-start;
  padding: 0 clamp(24px, 4vw, 76px);
}
.brand { align-items: center; display: inline-flex; font-size: 17px; font-weight: 740; gap: 9px; letter-spacing: 0; text-decoration: none; }
.brand img { border-radius: 9px; height: 27px; object-fit: cover; width: 27px; }
.hero {
  align-items: center;
  display: grid;
  gap: clamp(44px, 6vw, 96px);
  grid-template-columns: minmax(340px, .72fr) minmax(500px, 1.28fr);
  margin: 0 auto;
  max-width: 1480px;
  min-height: calc(100vh - 119px);
  padding: 56px clamp(24px, 4vw, 76px) 48px;
}
.hero-copy { max-width: 445px; }
h1, h2, h3, p { margin-top: 0; }
h1 { font-size: clamp(42px, 3.5vw, 54px); font-weight: 770; letter-spacing: 0; line-height: 1.21; margin-bottom: 24px; }
.hero-summary { color: #5c6872; font-size: 17px; line-height: 1.8; margin-bottom: 30px; max-width: 410px; }
.download-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-bottom: 12px; }
.download-button {
  align-items: center;
  background: var(--green);
  border: 1px solid var(--green);
  border-radius: 7px;
  color: #fff;
  cursor: pointer;
  display: inline-flex;
  font: inherit;
  font-size: 15px;
  font-weight: 650;
  gap: 9px;
  min-height: 48px;
  padding: 0 20px;
  transition: background-color 160ms ease, border-color 160ms ease, transform 160ms ease;
}
.download-button:not(:disabled):hover { background: var(--green-dark); border-color: var(--green-dark); transform: translateY(-1px); }
.download-button:disabled { cursor: wait; opacity: .58; }
.download-button:focus-visible, .site-footer a:focus-visible { outline: 2px solid var(--coral); outline-offset: 3px; }
.download-notes { color: #5d666c; font-size: 12px; line-height: 1.5; }
.download-notes p { margin: 0 0 4px; }

.hero-product { border: 1px solid #e2e7e5; border-radius: 8px; box-shadow: 0 18px 44px rgba(22, 43, 35, .1), 0 4px 12px rgba(22, 43, 35, .06); justify-self: end; max-width: 760px; overflow: hidden; }
.hero-product img { display: block; height: auto; width: 100%; }
.site-footer { align-items: center; border-top: 1px solid var(--line); color: #5d666c; display: flex; font-size: 12px; gap: 22px; justify-content: space-between; padding: 24px clamp(24px, 4vw, 76px); }
.site-footer div { display: flex; flex-wrap: wrap; gap: 20px; }
.site-footer a { text-decoration: none; }
.site-footer a:hover { color: var(--green); text-decoration: underline; }

@media (min-width: 1100px) {
  h1 { font-size: clamp(44px, 3.05vw, 48px); white-space: nowrap; }
}

@media (max-width: 1120px) {
  .hero { gap: 45px; grid-template-columns: minmax(316px, .75fr) minmax(420px, 1.12fr); min-height: 640px; }
  h1 { font-size: clamp(40px, 4.6vw, 54px); }
}
@media (max-width: 840px) {
  .hero { gap: 42px; grid-template-columns: 1fr; padding-top: 64px; }
  .hero-copy { max-width: 580px; }
  .hero-summary { max-width: 550px; }
  .hero-product { justify-self: start; max-width: 680px; }
}
@media (max-width: 620px) {
  .site-header { height: 56px; padding: 0 20px; }
  .brand { font-size: 15px; }
  .brand img { height: 25px; width: 25px; }
  .hero { min-height: auto; padding: 52px 20px 40px; }
  h1 { font-size: 36px; line-height: 1.24; margin-bottom: 19px; }
  .hero-summary { font-size: 16px; line-height: 1.72; margin-bottom: 25px; }
  .download-actions { display: grid; grid-template-columns: 1fr; }
  .download-button { justify-content: center; width: 100%; }
  .hero-product { border-radius: 12px; }
  .site-footer { align-items: flex-start; flex-direction: column; gap: 13px; padding: 22px 20px; }
  .site-footer div { gap: 14px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .download-button { transition: none; }
}