:root {
  --orange: #f3661f;
  --orange-dark: #d84d0a;
  --orange-soft: #fff0e8;
  --ink: #17191a;
  --graphite: #565c5f;
  --muted: #747a7d;
  --line: #dfe1df;
  --paper: #f6f5f1;
  --white: #fff;
  --shadow-soft: 0 16px 42px rgba(26, 31, 32, .09);
  --shadow-card: 0 24px 58px rgba(26, 31, 32, .13), 0 3px 9px rgba(26, 31, 32, .07);
  --shell: min(1120px, calc(100% - 48px));
  --ease: cubic-bezier(.2, .7, .2, 1);
  color-scheme: light;
  font-family: "Avenir Next", "Source Han Sans CN", "Noto Sans CJK SC", "Microsoft YaHei", Arial, sans-serif;
  color: var(--ink);
  background: var(--paper);
  font-synthesis: none;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  min-height: 100vh;
  margin: 0;
  background:
    radial-gradient(circle at 88% 6%, rgba(243, 102, 31, .12), transparent 26rem),
    radial-gradient(circle at 7% 86%, rgba(255, 255, 255, .96), transparent 32rem),
    var(--paper);
  overflow-x: hidden;
}
a { color: inherit; }
img { display: block; max-width: 100%; }
.shell { width: var(--shell); margin-inline: auto; }

.skip-link {
  position: fixed;
  z-index: 100;
  top: 8px;
  left: 8px;
  padding: 10px 14px;
  color: var(--white);
  background: var(--ink);
  transform: translateY(-140%);
}
.skip-link:focus { transform: translateY(0); }
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.site-header {
  position: fixed;
  z-index: 50;
  inset: 0 0 auto;
  border-bottom: 1px solid rgba(255, 255, 255, .86);
  background: rgba(255, 255, 255, .9);
  box-shadow: 0 10px 34px rgba(23, 25, 26, .065);
  backdrop-filter: blur(18px) saturate(130%);
}
.header-inner {
  min-height: 76px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}
.page-title {
  font-family: "YouYuan", "幼圆", "Arial Rounded MT Bold", "Microsoft YaHei", sans-serif;
  font-size: 22px;
  letter-spacing: .04em;
}
.back-link {
  min-height: 40px;
  padding: 0 14px;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  border: 1px solid rgba(23, 25, 26, .13);
  border-radius: 6px;
  color: #3e4244;
  background: rgba(255,255,255,.62);
  font-size: 13px;
  font-weight: 750;
  text-decoration: none;
  transition: color .25s, border-color .25s, background .25s, transform .25s var(--ease);
}
.back-link svg {
  width: 18px;
  height: 18px;
  fill: none;
  stroke: currentColor;
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke-width: 1.8;
}
.back-link:hover {
  color: var(--orange-dark);
  border-color: rgba(243, 102, 31, .35);
  background: var(--orange-soft);
  transform: translateX(-2px);
}

.tool-section {
  min-height: 100vh;
  padding: 132px 0 70px;
}
.tool-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  align-items: stretch;
  gap: 22px;
}
.tool-card {
  min-width: 0;
  padding: 34px;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: rgba(255,255,255,.95);
  box-shadow: var(--shadow-soft), inset 0 1px 0 rgba(255,255,255,.9);
  transition: border-color .3s, box-shadow .3s, transform .3s var(--ease);
}
.tool-card::before {
  content: "";
  height: 3px;
  margin: -34px -34px 30px;
  border-radius: 16px 16px 0 0;
  background: linear-gradient(90deg, var(--orange), transparent 76%);
}
.tool-card-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}
.tool-index {
  color: var(--orange-dark);
  font: 800 11px ui-monospace, SFMono-Regular, Consolas, monospace;
  letter-spacing: .14em;
}
.tool-card-top svg {
  width: 44px;
  height: 44px;
  fill: none;
  stroke: var(--orange);
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke-width: 1.6;
}
.tool-card h2 {
  margin: 26px 0 0;
  font-size: 31px;
  line-height: 1.15;
  letter-spacing: -.035em;
}
.tool-card p {
  margin: 17px 0 22px;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.85;
}
.tool-card ul {
  margin: 0 0 28px;
  padding: 0;
  display: grid;
  gap: 11px;
  list-style: none;
  color: #505658;
  font-size: 13px;
}
.tool-card li { position: relative; padding-left: 18px; }
.tool-card li::before {
  content: "";
  position: absolute;
  top: .55em;
  left: 0;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--orange);
  box-shadow: 0 0 0 4px var(--orange-soft);
}
.tool-button {
  min-height: 50px;
  padding: 0 21px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 14px;
  border: 1px solid transparent;
  border-radius: 7px;
  color: var(--white);
  background: linear-gradient(135deg, var(--orange), var(--orange-dark));
  box-shadow: 0 14px 28px rgba(197, 72, 9, .2), inset 0 1px 0 rgba(255,255,255,.25);
  font-size: 14px;
  font-weight: 750;
  text-decoration: none;
  transition: transform .25s var(--ease), box-shadow .25s var(--ease);
}
.tool-button:hover {
  box-shadow: 0 18px 34px rgba(197, 72, 9, .27), inset 0 1px 0 rgba(255,255,255,.25);
  transform: translateY(-2px);
}
.tool-web .tool-button { width: 100%; margin-top: auto; }

.app-download {
  margin-top: auto;
  display: grid;
  grid-template-columns: minmax(130px, 176px) minmax(180px, 1fr);
  align-items: end;
  gap: 22px;
}
.qr-link {
  padding: 12px;
  display: block;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--white);
  text-decoration: none;
  transition: border-color .25s, background .25s;
}
.qr-link img { width: 100%; height: auto; aspect-ratio: 1; image-rendering: pixelated; }
.qr-link:hover { border-color: rgba(243, 102, 31, .4); background: var(--orange-soft); }

.tool-usb {
  grid-column: 1 / -1;
  display: grid;
  grid-template-columns: minmax(280px, .78fr) minmax(540px, 1.42fr);
  align-items: center;
  gap: 48px;
}
.tool-usb::before { grid-column: 1 / -1; margin-bottom: 0; }
.tool-usb h2 { margin-top: 20px; }
.tool-usb p { margin-bottom: 0; }
.download-list { min-width: 0; }
.download-item {
  padding: 18px;
  display: grid;
  grid-template-columns: minmax(135px, .8fr) minmax(260px, 1.35fr) minmax(138px, .72fr);
  align-items: center;
  gap: 18px;
  border: 1px solid var(--line);
  border-radius: 11px;
  background: var(--paper);
}
.download-name { min-width: 0; display: grid; gap: 7px; }
.download-name span {
  color: var(--orange-dark);
  font: 800 9px ui-monospace, SFMono-Regular, Consolas, monospace;
  letter-spacing: .14em;
}
.download-name strong { font-size: 17px; overflow-wrap: anywhere; }
.download-meta {
  margin: 0;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
}
.download-meta div { padding: 4px 10px; text-align: center; }
.download-meta div + div { border-left: 1px solid var(--line); }
.download-meta dt { color: #999e9f; font-size: 9px; letter-spacing: .08em; }
.download-meta dd { margin: 5px 0 0; font-size: 12px; font-weight: 800; }
.download-button { min-height: 46px; padding-inline: 14px; }

a:focus-visible {
  outline: 3px solid rgba(243, 102, 31, .45);
  outline-offset: 4px;
}

@media (hover: hover) {
  .tool-card:hover {
    border-color: rgba(243, 102, 31, .35);
    box-shadow: var(--shadow-card);
    transform: translateY(-4px);
  }
}

@media (max-width: 960px) {
  :root { --shell: min(100% - 40px, 760px); }
  .tool-usb { grid-template-columns: 1fr; gap: 28px; }
  .download-item { grid-template-columns: minmax(130px, .8fr) minmax(260px, 1.35fr); }
  .download-button { grid-column: 1 / -1; }
}

@media (max-width: 720px) {
  :root { --shell: calc(100% - 28px); }
  .header-inner { min-height: 66px; }
  .page-title { font-size: 18px; }
  .back-link { min-height: 38px; padding-inline: 11px; }
  .tool-section { padding: 94px 0 38px; }
  .tool-grid { grid-template-columns: 1fr; gap: 16px; }
  .tool-card { padding: 25px; }
  .tool-card::before { margin: -25px -25px 24px; }
  .tool-card h2 { margin-top: 20px; font-size: 27px; }
  .app-download { grid-template-columns: minmax(120px, 168px) 1fr; gap: 16px; }
  .tool-usb { grid-column: auto; gap: 24px; }
  .tool-usb::before { margin-bottom: 0; }
  .download-item { grid-template-columns: 1fr; }
  .download-meta { padding: 12px 0; border-block: 1px solid var(--line); }
  .download-button { grid-column: auto; }
}

@media (max-width: 480px) {
  .page-title { font-size: 16px; }
  .back-link { gap: 5px; font-size: 12px; }
  .app-download { grid-template-columns: 1fr; }
  .qr-link { width: min(100%, 210px); margin-inline: auto; }
  .download-meta { grid-template-columns: 1fr; gap: 10px; }
  .download-meta div { display: flex; justify-content: space-between; gap: 18px; padding: 0; text-align: left; }
  .download-meta div + div { border-left: 0; }
  .download-meta dd { margin: 0; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: .01ms !important; transition-duration: .01ms !important; }
}