* {
  box-sizing: border-box;
}

/* Garante que o atributo "hidden" sempre vença outras regras de display
   (ex.: img#qr-image abaixo), senão elementos ficam "escondidos" mas visíveis. */
[hidden] {
  display: none !important;
}

body {
  font-family: system-ui, -apple-system, Segoe UI, Roboto, sans-serif;
  background: #f2f2f2;
  display: flex;
  justify-content: center;
  padding: 40px 16px;
  margin: 0;
  color: #222;
}

.card {
  background: #fff;
  border-radius: 8px;
  padding: 24px 32px;
  max-width: 420px;
  width: 100%;
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.1);
}

.topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

h1 {
  font-size: 1.25rem;
  margin: 0 0 16px;
}

label {
  display: block;
  margin-bottom: 12px;
  font-size: 0.9rem;
}

input {
  width: 100%;
  padding: 8px;
  margin-top: 4px;
  border: 1px solid #ccc;
  border-radius: 4px;
  font-size: 1rem;
}

button {
  padding: 8px 16px;
  border: none;
  border-radius: 4px;
  background: #128c7e;
  color: #fff;
  cursor: pointer;
  font-size: 0.95rem;
}

button:hover {
  background: #0f7469;
}

button.link-button {
  background: none;
  color: #128c7e;
  padding: 0;
  text-decoration: underline;
  font-size: 0.85rem;
}

img#qr-image {
  display: block;
  max-width: 100%;
  margin: 16px auto;
  border: 1px solid #eee;
}

p {
  margin: 8px 0;
}

.error {
  color: #c0392b;
  margin-top: 12px;
  font-size: 0.9rem;
}

.muted {
  color: #777;
  font-size: 0.85rem;
}