* {
  box-sizing: border-box;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
}

body {
  margin: 0;
  background: #f5f7fa;
  color: #1f2933;
}

header {
  background: #0f172a;
  color: white;
  padding: 2rem;
  text-align: center;
}

main {
  max-width: 900px;
  margin: 2rem auto;
  padding: 1rem;
}

.input-section {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

textarea {
  min-height: 200px;
  padding: 1rem;
  font-size: 1rem;
  border-radius: 8px;
  border: 1px solid #cbd5e1;
}

button {
  padding: 0.8rem;
  background: #2563eb;
  color: white;
  font-size: 1rem;
  border: none;
  border-radius: 8px;
  cursor: pointer;
}

button:hover {
  background: #1d4ed8;
}

.card {
  background: white;
  padding: 1.2rem;
  margin-top: 1rem;
  border-radius: 10px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.06);
}

.hidden {
  display: none;
}

.timestamp {
  margin-top: 1rem;
  font-size: 0.85rem;
  color: #64748b;
}

footer {
  text-align: center;
  padding: 1.5rem;
  color: #64748b;
}