* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: "Segoe UI", sans-serif;
  background: #f0f2f5;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
}

.container {
  background: #fff;
  border-radius: 12px;
  padding: 40px;
  width: 420px;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
  text-align: center;
}

h1 {
  font-size: 1.8rem;
  color: #1a1a2e;
  margin-bottom: 8px;
}

.subtitle {
  color: #666;
  font-size: 0.9rem;
  margin-bottom: 32px;
}

.card {
  display: flex;
  gap: 12px;
  justify-content: center;
  margin-bottom: 24px;
}

.btn {
  padding: 12px 24px;
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  cursor: pointer;
  transition: transform 0.1s, opacity 0.2s;
}

.btn:active {
  transform: scale(0.97);
}

.btn-primary {
  background: #4f46e5;
  color: #fff;
}

.btn-primary:hover {
  opacity: 0.88;
}

.btn-secondary {
  background: #e5e7eb;
  color: #1a1a2e;
}

.btn-secondary:hover {
  background: #d1d5db;
}

.result-box {
  background: #f8f9fa;
  border-radius: 8px;
  padding: 20px;
  min-height: 80px;
  text-align: left;
  font-family: monospace;
  font-size: 0.9rem;
  white-space: pre-wrap;
  border: 1px solid #e5e7eb;
  color: #444;
}

.result-box.success {
  border-color: #22c55e;
  background: #f0fdf4;
  color: #166534;
}

.result-box.error {
  border-color: #ef4444;
  background: #fef2f2;
  color: #991b1b;
}

.placeholder {
  color: #9ca3af;
  font-style: italic;
}