:root {
  color-scheme: light;
  --ink: #211f1a;
  --muted: #756b60;
  --paper: #fff6ed;
  --surface: rgba(255, 252, 246, 0.86);
  --line: rgba(92, 70, 45, 0.14);
  --accent: #1c8c6d;
  --accent-soft: #def5ec;
  --danger: #d9433f;
  --danger-soft: #fff0ed;
  --danger-line: #ffaaa3;
  --gold: #f2b84b;
  --shadow: 0 28px 90px rgba(84, 57, 28, 0.16);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Avenir Next", "Hiragino Sans", sans-serif;
  color: var(--ink);
  background:
    radial-gradient(circle at 12% 14%, rgba(217, 67, 63, 0.13), transparent 28%),
    radial-gradient(circle at 86% 10%, rgba(242, 184, 75, 0.23), transparent 24%),
    linear-gradient(145deg, #fff6ed, #fffaf2 48%, #eef7ef);
}

input {
  font: inherit;
}

.shell {
  width: min(1120px, calc(100% - 36px));
  margin: 0 auto;
  padding: 36px 0 44px;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(340px, 0.3fr);
  gap: 24px;
  align-items: end;
  margin-bottom: 22px;
}

.eyebrow {
  display: inline-flex;
  gap: 10px;
  align-items: center;
  margin-bottom: 16px;
  color: var(--accent);
  font-size: 13px;
  font-weight: 900;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.eyebrow::before {
  width: 10px;
  height: 10px;
  border-radius: 999px;
  background: var(--accent);
  box-shadow: 1px 1px 0 var(--danger);
  content: "";
}

h1 {
  margin: 0 0 14px;
  font-size: clamp(32px, 4.6vw, 43px);
}

.lead {
  margin: 0;
  color: var(--muted);
}

.code-card {
  min-width: 0;
  padding: 24px 26px;
  border-radius: 18px;
  background: #17251f;
  color: #e9fff5;
  box-shadow: var(--shadow);
}

.code-card span {
  display: block;
  margin-bottom: 10px;
  color: #a7d7c4;
  font-size: 12px;
  font-weight: 900;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

pre {
  margin: 0;
  overflow: auto;
  font-size: 13px;
  line-height: 1.65;
}

code {
  font-family: "SFMono-Regular", Consolas, monospace;
}

.form-demo {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
  padding: 24px;
  border: 1px solid rgba(255, 255, 255, 0.72);
  border-radius: 22px;
  background: var(--surface);
  box-shadow: var(--shadow);
  backdrop-filter: blur(18px);
}

.form-head {
  grid-column: 1 / -1;
  display: flex;
  justify-content: space-between;
  gap: 18px;
  align-items: start;
  padding: 2px 2px 12px;
}

.form-head span {
  display: block;
  margin-bottom: 7px;
  color: var(--accent);
  font-size: 12px;
  font-weight: 900;
  letter-spacing: 0.1em;
}

h2 {
  margin: 0;
  font-size: 26px;
  letter-spacing: -0.05em;
}

.form-head strong {
  flex: 0 0 auto;
  padding: 8px 11px;
  border-radius: 999px;
  background: #102c25;
  color: #c7ffe9;
  font-size: 13px;
}

.field-card {
  position: relative;
  display: grid;
  align-content: start;
  gap: 18px;
  min-width: 0;
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: #fffdf8;
  transition:
    border-color 180ms ease,
    background 180ms ease,
    box-shadow 180ms ease,
    transform 180ms ease;
}

.field-card::after {
  position: absolute;
  inset: 14px 14px auto auto;
  display: grid;
  place-items: center;
  width: 30px;
  height: 30px;
  border-radius: 999px;
  background: #e8f6ef;
  color: var(--accent);
  font-weight: 900;
  content: "✓";
}

.field-card:has(input:invalid) {
  border-color: var(--danger-line);
  background:
    radial-gradient(circle at 0 0, rgba(217, 67, 63, 0.1), transparent 45%),
    var(--danger-soft);
  box-shadow: 0 18px 50px rgba(217, 67, 63, 0.12);
  transform: translateY(-2px);
}

.field-card:has(input:invalid)::after {
  background: var(--danger);
  color: #fff;
  content: "!";
}

.field-copy {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 12px;
  min-width: 0;
  padding-right: 38px;
}

.number {
  display: grid;
  place-items: center;
  width: 28px;
  height: 28px;
  border-radius: 10px;
  background: #f1eadf;
  color: var(--muted);
  font-size: 13px;
  font-weight: 900;
}

.field-card:has(input:invalid) .number {
  background: #ffd9d4;
  color: #a42b28;
}

h3 {
  margin: 0 0 4px;
  font-size: 17px;
  letter-spacing: -0.03em;
}

.field-copy p,
.error-message,
.success-message,
.tips p {
  margin: 0;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.6;
}

label {
  display: grid;
  gap: 9px;
  color: var(--muted);
  font-size: 12px;
  font-weight: 800;
}

input {
  width: 100%;
  min-width: 0;
  min-height: 52px;
  padding: 0 16px;
  border: 1px solid #e4d8c5;
  border-radius: 12px;
  outline: none;
  background: #fffaf2;
  color: var(--ink);
}

input:focus-visible {
  border-color: var(--accent);
  box-shadow: 0 0 0 4px rgba(28, 140, 109, 0.12);
}

input:invalid {
  border-color: var(--danger-line);
}

.error-message,
.success-message {
  display: block;
  min-height: 1.6em;
  font-weight: 800;
}

.error-message {
  display: none;
  color: #ad302c;
}

.success-message {
  color: var(--accent);
}

.field-card:has(input:invalid) .error-message {
  display: block;
}

.field-card:has(input:invalid) .success-message {
  display: none;
}

.tips {
  display: flex;
  gap: 14px;
  align-items: center;
  margin-top: 20px;
  padding: 20px 22px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: rgba(255, 252, 246, 0.7);
}

.tips span {
  flex: 0 0 auto;
  padding: 8px 10px;
  border-radius: 999px;
  background: #102c25;
  color: #c7ffe9;
  font-size: 12px;
  font-weight: 900;
}

@media (max-width: 940px) {
  .hero,
  .form-demo {
    grid-template-columns: 1fr;
  }

  h1 {
    max-width: 14ch;
  }
}

@media (max-width: 560px) {
  .shell {
    width: min(100% - 22px, 1120px);
    padding-top: 24px;
  }

  .hero {
    gap: 20px;
  }

  h1 {
    font-size: clamp(32px, 10.4vw, 44px);
  }

  .lead {
    font-size: 15px;
    line-height: 1.78;
  }

  .form-demo {
    gap: 14px;
    padding: 14px;
    border-radius: 18px;
  }

  .form-head {
    display: grid;
  }

  .form-head strong {
    width: max-content;
  }

  .field-card {
    gap: 14px;
    padding: 16px;
    border-radius: 14px;
  }

  .tips {
    align-items: start;
    flex-direction: column;
  }

  pre {
    font-size: 12px;
  }
}