:root {
  font-family: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background-color: #f9fafb;
  color: #1f2933;
}

body, html {
  margin: 0;
  padding: 0;
}

main {
  max-width: 640px;
  margin: 2rem auto;
  background: #ffffff;
  padding: 2rem;
  border-radius: 12px;
  box-shadow: 0 10px 30px rgba(15, 23, 42, 0.12);
}

h1, h2 {
  margin-top: 0;
  font-weight: 600;
}

form {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.field-group {
  display: flex;
  flex-direction: column;
}

.field-group.inline {
  flex-direction: row;
  flex-wrap: wrap;
  gap: 1rem;
}

.field-group.inline > div {
  flex: 1;
  display: flex;
  flex-direction: column;
}

label {
  font-size: 0.95rem;
  margin-bottom: 0.25rem;
}

input, textarea {
  width: 100%;
  box-sizing: border-box;
  border-radius: 8px;
  border: 1px solid #cbd5e1;
  padding: 0.75rem;
  font-size: 1rem;
}

button {
  padding: 0.85rem 1.2rem;
  border: none;
  border-radius: 999px;
  background: #2563eb;
  color: white;
  font-size: 1rem;
  cursor: pointer;
  font-weight: 600;
  transition: background 0.2s ease;
}

button:hover {
  background: #1d4ed8;
}

#result {
  margin-top: 2rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

#proof-image {
  max-width: 100%;
  border-radius: 12px;
  border: 1px solid #e2e8f0;
  background: #f1f5f9;
}

#pdf-link {
  align-self: flex-start;
  color: #2563eb;
}

#error {
  margin-top: 1.5rem;
  color: #dc2626;
}

.hidden {
  display: none;
}

@media (max-width: 600px) {
  main {
    margin: 1rem;
    padding: 1.5rem;
  }

  .field-group.inline {
    flex-direction: column;
  }
}