* { box-sizing: border-box; }

body {
  font-family: system-ui, Arial, sans-serif;
  margin: 0;
  padding: 24px;
  background: #fafafa;
  color: #111;
}

.wrap {
  max-width: 520px;
  margin: 0 auto;
}

h1 { margin: 0 0 16px; font-size: 1.4rem; }

fieldset {
  border: 1px solid #ddd;
  border-radius: 10px;
  padding: 18px;
  background: #fff;
}

legend { padding: 0 8px; font-weight: 600; }

.hint { margin: 8px 0 16px; color: #444; font-size: 0.95rem; }

.required { color: #c00; font-weight: 700; }

.field { margin-bottom: 14px; }

label { display: block; margin-bottom: 6px; font-weight: 600; }

input {
  width: 100%;
  padding: 10px;
  border: 1px solid #bbb;
  border-radius: 8px;
  outline: none;
}

input:focus { border-color: #666; }

input.is-invalid { border-color: #c00; }
input.is-valid   { border-color: #0a7; }

.error {
  display: block;
  min-height: 18px;
  margin-top: 6px;
  color: #c00;
  font-size: 0.9rem;
}

button {
  width: 100%;
  padding: 10px 12px;
  border: 0;
  border-radius: 8px;
  background: #111;
  color: #fff;
  cursor: pointer;
  font-weight: 600;
}

button:disabled { opacity: 0.6; cursor: not-allowed; }

.success {
  margin-top: 12px;
  color: #0a7;
  font-weight: 600;
  min-height: 20px;
}