:root {
  --paper: #fff8ee;
  --ink: #211f1a;
  --muted: #756d61;
  --line: rgb(33 31 26 / 12%);
  --brand: #0f9f73;
  --brand-soft: color-mix(in oklch, var(--brand) 12%, white);
  --brand-border: color-mix(in oklch, var(--brand) 34%, white);
  --brand-shadow: color-mix(in oklch, var(--brand) 20%, transparent);
  --danger: #dc4a55;
  --danger-soft: color-mix(in oklch, var(--danger) 12%, white);
  --danger-border: color-mix(in oklch, var(--danger) 38%, white);
  --danger-shadow: color-mix(in oklch, var(--danger) 18%, transparent);
  --idle: #8c7b68;
  --idle-soft: color-mix(in oklch, var(--idle) 11%, white);
  --orange: #ec8b34;
  --shadow: 0 30px 90px rgb(92 62 27 / 15%);
  color-scheme: light;
  font-family: "Avenir Next", "Hiragino Sans", "Yu Gothic", sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  min-height: 100vh;
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at 13% 10%, rgb(15 159 115 / 18%), transparent 28rem),
    radial-gradient(circle at 88% 12%, rgb(220 74 85 / 15%), transparent 30rem),
    linear-gradient(135deg, #fff4e6 0%, var(--paper) 52%, #eee6d8 100%);
  overflow-x: hidden;
}

input {
  font: inherit;
}

.page {
  width: min(1200px, calc(100% - 48px));
  margin: 0 auto;
  padding: 38px 0;
}

.page > *,
.demo-shell,
.stage,
.field-grid,
.field-card,
.code-card,
.takeaway {
  min-width: 0;
  max-width: 100%;
}

h1,
p,
pre {
  margin: 0;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin: 0 0 16px;
  color: var(--brand);
  font-size: 13px;
  font-weight: 900;
  letter-spacing: 0.14em;
}

.eyebrow::before {
  width: 10px;
  height: 10px;
  border-radius: 999px;
  background: currentColor;
  box-shadow: 2px 2px 0 var(--orange);
  content: "";
}

h1 {
  font-size: clamp(28px, 4.4vw, 50px);
  line-height: 1.12;
  overflow-wrap: anywhere;
}

.lead {
  margin-top: 16px;
  color: var(--muted);
  font-size: clamp(16px, 1.7vw, 18px);
  font-weight: 800;
  line-height: 1.75;
  overflow-wrap: anywhere;
}

.demo-shell {
  margin-top: 24px;
  border: 1px solid var(--line);
  border-radius: 30px;
  background: rgb(255 248 238 / 78%);
  box-shadow: var(--shadow);
  overflow: hidden;
}

.demo-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  padding: 20px 22px;
  border-bottom: 1px solid var(--line);
}

.demo-head span,
.code-card span,
.field-kicker {
  color: var(--brand);
  font-size: 12px;
  font-weight: 900;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.demo-head strong {
  display: block;
  margin-top: 4px;
  font-size: 20px;
  line-height: 1.35;
  letter-spacing: -0.04em;
  overflow-wrap: anywhere;
}

.code-pill {
  flex: 0 0 auto;
  padding: 10px 14px;
  border-radius: 999px;
  color: var(--brand);
  background: var(--brand-soft);
}

.stage {
  display: grid;
  gap: 18px;
  padding: 22px;
  background:
    linear-gradient(rgb(33 31 26 / 5%) 1px, transparent 1px),
    linear-gradient(90deg, rgb(33 31 26 / 5%) 1px, transparent 1px),
    var(--paper);
  background-size: 34px 34px;
}

.field-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
}

.field-card {
  --state: var(--idle);
  --state-soft: var(--idle-soft);
  --state-border: var(--line);
  --state-shadow: rgb(33 31 26 / 8%);
  position: relative;
  display: grid;
  gap: 12px;
  min-height: 292px;
  padding: 26px;
  border: 2px solid var(--state-border);
  border-radius: 28px;
  background:
    radial-gradient(circle at 100% 0%, var(--state-soft), transparent 210px),
    rgb(255 255 255 / 90%);
  box-shadow: 0 18px 48px var(--state-shadow);
  transition:
    background 180ms ease,
    border-color 180ms ease,
    box-shadow 180ms ease,
    translate 180ms ease;
}

.field-card:hover {
  translate: 0 -3px;
}

.field-card:has(input:placeholder-shown) {
  --state: var(--idle);
  --state-soft: var(--idle-soft);
  --state-border: rgb(33 31 26 / 14%);
}

.field-card:has(input:valid:not(:placeholder-shown)) {
  --state: var(--brand);
  --state-soft: var(--brand-soft);
  --state-border: var(--brand);
  --state-shadow: var(--brand-shadow);
}

.field-card:has(input:invalid:not(:placeholder-shown)) {
  --state: var(--danger);
  --state-soft: var(--danger-soft);
  --state-border: var(--danger-border);
  --state-shadow: var(--danger-shadow);
}

.state-badge {
  display: inline-grid;
  width: 46px;
  height: 46px;
  place-items: center;
  border-radius: 999px;
  color: white;
  background: var(--state);
  font-weight: 900;
}

.state-badge::before {
  content: "…";
}

.field-card:has(input:valid:not(:placeholder-shown)) .state-badge::before {
  content: "OK";
}

.field-card:has(input:invalid:not(:placeholder-shown)) .state-badge::before {
  content: "!";
}

.field-kicker {
  color: var(--state);
}

.field-card strong {
  font-size: clamp(25px, 2.8vw, 34px);
  line-height: 1.08;
  letter-spacing: -0.07em;
}

.field-card input {
  width: 100%;
  min-height: 58px;
  padding: 0 16px;
  border: 1px solid color-mix(in oklch, var(--state) 34%, white);
  border-radius: 18px;
  color: var(--ink);
  background: rgb(255 255 255 / 84%);
  font-size: 16px;
  font-weight: 900;
  outline: none;
  transition:
    border-color 180ms ease,
    box-shadow 180ms ease,
    background 180ms ease;
}

.field-card input:focus-visible {
  border-color: var(--state);
  box-shadow: 0 0 0 4px color-mix(in oklch, var(--state) 18%, transparent);
}

.field-card input::placeholder {
  color: rgb(117 109 97 / 62%);
}

.hint {
  display: none;
  color: var(--state);
  font-size: 14px;
  font-weight: 900;
  line-height: 1.5;
}

.field-card:has(input:placeholder-shown) .hint.empty,
.field-card:has(input:valid:not(:placeholder-shown)) .hint.ok,
.field-card:has(input:invalid:not(:placeholder-shown)) .hint.error {
  display: block;
}

.code-card {
  display: grid;
  gap: 12px;
  padding: 22px;
  border-radius: 24px;
  color: white;
  background: #0d3f32;
  box-shadow: 0 20px 50px rgb(15 79 61 / 16%);
}

.code-card span {
  color: #9ce7c5;
}

.code-card pre {
  overflow-x: auto;
}

.code-card code {
  display: block;
  color: #fff8ee;
  font-size: 15px;
  font-weight: 900;
  line-height: 1.65;
  white-space: pre;
}

.takeaway {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  margin-top: 18px;
  padding: 16px 18px;
  border: 1px solid var(--line);
  border-radius: 24px;
  background: rgb(255 255 255 / 70%);
}

.takeaway span {
  flex: 0 0 auto;
  padding: 8px 12px;
  border-radius: 999px;
  color: white;
  background: var(--brand);
  font-size: 12px;
  font-weight: 900;
}

.takeaway p {
  color: var(--muted);
  font-weight: 800;
  line-height: 1.7;
}

@media (max-width: 900px) {
  .page {
    width: min(100% - 28px, 640px);
    padding: 24px 0;
  }

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

  .field-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 520px) {
  .page {
    width: min(100% - 20px, 420px);
  }

  h1 {
    font-size: 30px;
  }

  .lead {
    font-size: 15px;
  }

  .demo-head,
  .stage {
    padding: 14px;
  }

  .field-card {
    min-height: auto;
    padding: 22px;
  }

  .code-card code {
    font-size: 12px;
    overflow-wrap: anywhere;
    white-space: pre-wrap;
  }
}