:root {
  color-scheme: light;
  font-family: "Geist", "Microsoft YaHei UI", "PingFang SC", system-ui, sans-serif;
  color: #182b29;
  background: #f5f8f6;
  font-synthesis: none;
  --ink: #182b29;
  --secondary: #526561;
  --line: #dce6e1;
  --accent: #145c4b;
  --accent-dark: #10483c;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
}

[hidden] { display: none !important; }

.site-header {
  background: #fff;
  border-bottom: 1px solid var(--line);
}

.site-header-inner {
  width: min(calc(100% - 3rem), 68rem);
  min-height: 4.5rem;
  margin: 0 auto;
  display: flex;
  align-items: center;
  gap: .75rem;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 2.15rem;
  height: 2.15rem;
  border-radius: .65rem;
  background: var(--accent);
  color: white;
  font-size: .85rem;
  font-weight: 750;
}

.brand-name {
  font-size: 1.02rem;
  font-weight: 750;
}

.site-name {
  padding-inline-start: .75rem;
  border-inline-start: 1px solid var(--line);
  color: var(--secondary);
  font-size: .85rem;
}

.layout {
  width: min(calc(100% - 3rem), 64rem);
  margin: 0 auto;
  padding: clamp(3.5rem, 9vw, 7.75rem) 0 4rem;
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.08fr);
  grid-template-areas: "intro card" "guide card";
  column-gap: clamp(2.5rem, 8vw, 7rem);
  row-gap: 2.25rem;
  align-items: start;
}

.intro { grid-area: intro; }

.intro h1 {
  margin: 0 0 1rem;
  font-size: clamp(2rem, 4.4vw, 3.45rem);
  line-height: 1.14;
  letter-spacing: -.035em;
}

.intro > p {
  max-width: 31ch;
  margin: 0;
  color: var(--secondary);
  line-height: 1.8;
}

.guide {
  grid-area: guide;
  border-top: 1px solid var(--line);
  padding-top: 1.25rem;
}

.guide h2 {
  margin: 0 0 1rem;
  font-size: .875rem;
  color: var(--secondary);
}

.guide ol {
  margin: 0;
  padding: 0 0 0 1.45rem;
}

.guide li {
  padding-inline-start: .35rem;
  margin-block: .8rem;
  line-height: 1.55;
  font-size: .88rem;
}

.guide li::marker { color: var(--accent); font-weight: 750; }
.guide p { margin: .2rem 0 0; color: var(--secondary); }

.activation-card {
  grid-area: card;
  padding: clamp(1.4rem, 3.5vw, 2.3rem);
  background: white;
  border: 1px solid var(--line);
  border-radius: 1.25rem;
  box-shadow: 0 1.15rem 3rem rgba(30, 61, 48, .07);
}

.activation-card h2 {
  margin: 0 0 1.6rem;
  font-size: 1.25rem;
}

form {
  display: grid;
  gap: 1.25rem;
}

.field { min-width: 0; }

.field label {
  display: block;
  margin: 0 0 .55rem;
  font-size: .91rem;
  font-weight: 700;
}

.field input {
  width: 100%;
  min-height: 3.15rem;
  padding: .7rem .85rem;
  border: 1px solid #b9cac2;
  border-radius: .65rem;
  background: #fbfdfc;
  color: var(--ink);
  font: 1rem "IBM Plex Mono", Consolas, "Microsoft YaHei UI", monospace;
}

.field input::placeholder { color: #687b74; }
.field input[aria-invalid="true"] { border-color: #b04439; }
.field input[readonly] { background: #f0f4f1; }
.field p { margin: .45rem 0 0; color: var(--secondary); font-size: .79rem; line-height: 1.5; }

button,
.download-link {
  min-height: 3.15rem;
  border: 1px solid transparent;
  border-radius: .65rem;
  padding: .7rem 1rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: .7rem;
  font-family: inherit;
  font-size: .93rem;
  font-weight: 700;
  line-height: 1.4;
  text-align: start;
}

button {
  margin-top: .25rem;
  color: white;
  background: var(--accent);
  cursor: pointer;
}

button:hover:not(:disabled) { background: var(--accent-dark); }
button:disabled { cursor: wait; opacity: .65; }
button span, .download-link span { font-size: 1.15rem; }

.download-link {
  color: var(--accent-dark);
  background: #e7f4ed;
  border-color: #b8d9c9;
  text-decoration: none;
}

.download-link:hover { background: #d7ebdf; }

:where(input, button, a):focus-visible {
  outline: 2px solid #176e59;
  outline-offset: 3px;
}

.form-status {
  margin: -.35rem 0 0;
  color: var(--secondary);
  font-size: .86rem;
  line-height: 1.6;
}

.form-status:empty { margin: 0; height: 0; position: absolute; }
.form-status[data-state="success"] { color: var(--accent-dark); }
.form-status[data-state="error"] { color: #952f25; }

@media (max-width: 44rem) {
  .layout {
    grid-template-columns: minmax(0, 1fr);
    grid-template-areas: "intro" "card" "guide";
    row-gap: 1.6rem;
    padding-top: 2.3rem;
  }

  .site-header-inner { min-height: 3.8rem; }
}

@media (max-width: 25rem) {
  .site-header-inner, .layout { width: calc(100% - 2rem); }
}