body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: #f8fafc;
  margin: 0;
  padding: 0;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
}
.container {
  background: white;
  padding: 2rem;
  border-radius: 16px;
  box-shadow: 0 4px 20px rgba(0,0,0,0.08);
  text-align: center;
  max-width: 500px;
  width: 90%;
}
h1 {
  color: #1e293b;
  margin-bottom: 1.5rem;
}
input[type="file"] {
  margin-bottom: 1rem;
  font-size: 1rem;
}
button {
  background: #3b82f6;
  color: white;
  border: none;
  padding: 0.75rem 1.5rem;
  border-radius: 8px;
  cursor: pointer;
  font-size: 1rem;
  transition: background 0.2s;
}
button:hover {
  background: #2563eb;
}
#countdown {
  color: #64748b;
  font-size: 1rem;
}