* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif;
  background: #f6f8fb;
  color: #0f172a;
}

.container {
  max-width: 720px;
  margin: 6rem auto;
  padding: 2rem;
  background: #fff;
  border-radius: 14px;
  box-shadow: 0 8px 24px rgba(2, 6, 23, .08);
}

h1 { margin: 0 0 1.25rem; }

.field { margin-bottom: 1rem; }

label {
  display: inline-block;
  margin-bottom: .5rem;
  font-weight: 600;
}

input, textarea {
  width: 100%;
  padding: .75rem .9rem;
  border: 1px solid #cbd5e1;
  border-radius: 8px;
  font: inherit;
  background: #fff;
  color: inherit;
}

input:focus, textarea:focus {
  outline: 3px solid #a5b4fc;
  border-color: #6366f1;
}

.error {
  min-height: 1.1em;           /* reserve space; prevents layout jump */
  color: #b91c1c;
  margin-top: .35rem;
  font-size: .9rem;
}

.invalid {
  border-color: #ef4444 !important;
  background: #fff5f5;
}

.btn {
  padding: .8rem 1.2rem;
  background: #2563eb;
  color: #fff;
  border: 0;
  border-radius: 9px;
  font-weight: 700;
  cursor: pointer;
}
.btn:hover { background: #1d4ed8; }

/* Inline result message */
.result {
  display: none;
  margin-top: 1rem;
  padding: .9rem 1rem;
  border-radius: 10px;
  font-weight: 600;
}
.result.show    { display: block; }
.result.success { background: #ecfdf5; color: #065f46; border: 1px solid #10b981; }
.result.error   { background: #fef2f2; color: #7f1d1d; border: 1px solid #ef4444; }