:root {
  color-scheme: light;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans JP", sans-serif;
  color: #16342e;
  background: #eef5f2;
}

* { box-sizing: border-box; }

body {
  min-height: 100vh;
  margin: 0;
  background:
    radial-gradient(circle at 15% 10%, rgba(49, 179, 147, .17), transparent 34rem),
    linear-gradient(145deg, #f7faf9, #e3f0eb);
}

.demo-shell {
  width: min(960px, calc(100% - 32px));
  min-height: 100vh;
  margin: 0 auto;
  padding: max(36px, 7vh) 0;
  display: grid;
  grid-template-columns: 1.02fr .98fr;
  gap: 24px;
  align-items: center;
}

.hero-card, .auth-card {
  border-radius: 24px;
  box-shadow: 0 22px 60px rgba(12, 63, 51, .12);
}

.hero-card {
  padding: 46px;
  color: #fff;
  background: linear-gradient(150deg, #073b31, #0a5848);
}

.brand { display: flex; gap: 16px; align-items: center; }
.brand img { border-radius: 14px; }
.eyebrow { margin: 0 0 4px; font-weight: 800; letter-spacing: .04em; color: #a7ecda; }
h1 { margin: 0; font-size: clamp(30px, 4vw, 46px); line-height: 1.18; letter-spacing: -.03em; }
.lead { margin: 28px 0; font-size: 16px; line-height: 1.9; color: #d8eee8; }
.feature-list { margin: 0; padding: 0; list-style: none; display: grid; gap: 13px; }
.feature-list li { position: relative; padding-left: 28px; line-height: 1.65; }
.feature-list li::before { content: "✓"; position: absolute; left: 0; color: #58d6b6; font-weight: 900; }

.auth-card { padding: 38px; background: #fff; }
.step-label { margin: 0 0 6px; color: #16816b; font-size: 12px; font-weight: 900; letter-spacing: .12em; }
h2 { margin: 0; font-size: 26px; color: #0a3c32; }
.description { margin: 8px 0 24px; color: #61736e; line-height: 1.65; }
form { display: grid; gap: 17px; }
label { display: grid; gap: 7px; font-size: 14px; font-weight: 700; }
label > span { color: #b74d39; font-size: 11px; }
input {
  width: 100%;
  min-height: 48px;
  padding: 10px 13px;
  border: 1px solid #c9d8d3;
  border-radius: 10px;
  background: #fbfdfc;
  color: #16342e;
  font: inherit;
}
input:focus { outline: 3px solid rgba(29, 153, 126, .17); border-color: #16816b; }
.check-row { grid-template-columns: 22px 1fr; gap: 9px; align-items: start; font-weight: 500; line-height: 1.55; }
.check-row input { min-height: 0; width: 18px; height: 18px; margin-top: 2px; accent-color: #16816b; }
.check-row span { color: #3f514d; font-size: 13px; }
.check-row a { color: #0a715d; }
.required-check { margin-top: 2px; }
.primary-button {
  min-height: 52px;
  border: 0;
  border-radius: 11px;
  background: #12856e;
  color: #fff;
  font: inherit;
  font-weight: 800;
  cursor: pointer;
  box-shadow: 0 8px 20px rgba(18, 133, 110, .19);
}
.primary-button:disabled { cursor: wait; opacity: .62; }
.text-button { border: 0; background: transparent; color: #48645d; text-decoration: underline; cursor: pointer; }
.code-input { text-align: center; font-size: 28px; font-weight: 800; letter-spacing: .3em; }
.message { min-height: 24px; margin: 18px 0 0; color: #b23d32; font-size: 13px; line-height: 1.55; }
.message.is-success { color: #0a715d; }
.development-code { padding: 10px; border-radius: 8px; background: #fff6ce; color: #745c00; text-align: center; }

@media (max-width: 740px) {
  .demo-shell { width: min(100% - 20px, 520px); grid-template-columns: 1fr; padding: 18px 0 28px; }
  .hero-card { padding: 26px 24px; border-radius: 19px; }
  .hero-card .lead { margin: 18px 0; }
  .auth-card { padding: 26px 22px; border-radius: 19px; }
  h1 { font-size: 30px; }
}