:root {
  --bg: #0f172a;
  --card: #111827;
  --text: #e5e7eb;
  --muted: #94a3b8;
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --border: #1f2937;
  --success: #10b981;
  --error: #ef4444;
  --white: #ffffff;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: Arial, Helvetica, sans-serif;
  background: linear-gradient(135deg, #0b1120, #111827);
  color: var(--text);
  min-height: 100vh;
}

.app {
  width: min(1100px, 92%);
  margin: 0 auto;
  padding: 32px 0;
  display: grid;
  gap: 24px;
}

.card {
  background: rgba(17, 24, 39, 0.96);
  border: 1px solid var(--border);
  border-radius: 18px;
  padding: 24px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.25);
}

.header h1,
.result-header h2 {
  margin: 0 0 8px;
  line-height: 1.2;
}

.header p {
  margin: 0;
  color: var(--muted);
}

.form {
  margin-top: 24px;
}

.field {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 18px;
}

label {
  font-weight: 700;
  font-size: 0.95rem;
}

select,
input {
  width: 100%;
  padding: 14px 16px;
  border-radius: 12px;
  border: 1px solid #334155;
  background: #0b1220;
  color: var(--text);
  outline: none;
}

select:focus,
input:focus {
  border-color: var(--primary);
}

.grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.actions {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin-top: 8px;
}

button {
  border: none;
  border-radius: 12px;
  padding: 14px 18px;
  font-weight: 700;
  cursor: pointer;
  background: var(--primary);
  color: var(--white);
  transition: 0.2s ease;
}

button:hover {
  background: var(--primary-hover);
}

button.secondary {
  background: #334155;
}

button.secondary:hover {
  background: #475569;
}

button:disabled {
  opacity: 0.55;
  cursor: not-allowed;
}

.message {
  margin-top: 14px;
  min-height: 22px;
  color: var(--muted);
}

.message.error {
  color: var(--error);
}

.message.success {
  color: var(--success);
}

.result-card {
  min-height: 320px;
}

.result-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 16px;
}

.result {
  white-space: pre-wrap;
  line-height: 1.7;
  color: #e2e8f0;
  background: #0b1220;
  border: 1px solid #243041;
  border-radius: 14px;
  padding: 20px;
  min-height: 240px;
}

.loader {
  width: 20px;
  height: 20px;
  border: 3px solid rgba(255, 255, 255, 0.2);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

.hidden {
  display: none;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

@media (max-width: 720px) {
  .grid {
    grid-template-columns: 1fr;
  }

  .card {
    padding: 18px;
  }

  .actions {
    flex-direction: column;
  }

  button {
    width: 100%;
  }
}