:root {
  color-scheme: light;
  --bg: #f4f5f7;
  --card-bg: #ffffff;
  --text: #1f2430;
  --muted: #5b6270;
  --accent: #2563eb;
  --border: #d9dce3;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Kaku Gothic ProN", sans-serif;
  padding: 24px;
}

.card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 32px;
  max-width: 480px;
  width: 100%;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.06);
}

h1 {
  font-size: 1.3rem;
  margin: 0 0 12px;
}

.lead {
  color: var(--muted);
  font-size: 0.9rem;
  line-height: 1.6;
  margin-bottom: 24px;
}

label {
  display: block;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 6px;
  margin-top: 16px;
}

input {
  width: 100%;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 1rem;
}

button {
  margin-top: 24px;
  width: 100%;
  padding: 12px;
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
}

button:hover { background: #1d4ed8; }

.hint {
  margin-top: 20px;
  font-size: 0.8rem;
  color: var(--muted);
}

code {
  background: #eef0f4;
  padding: 2px 6px;
  border-radius: 4px;
}