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

:root {
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --background: #ffffff;
  --surface: #f8fafc;
  --surface-hover: #f1f5f9;
  --text: #0f172a;
  --text-secondary: #64748b;
  --border: #e2e8f0;
  --success: #22c55e;
  --error: #ef4444;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
  background: var(--background);
  color: var(--text);
  min-height: 100vh;
  line-height: 1.6;
}

.container {
  max-width: 1000px;
  margin: 0 auto;
  padding: 2rem 1.5rem;
}

header {
  text-align: center;
  margin-bottom: 2.5rem;
}

h1 {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 0.5rem;
  letter-spacing: -0.02em;
}

.subtitle {
  color: var(--text-secondary);
  font-size: 1.1rem;
}

main {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.input-section,
.output-section {
  background: var(--surface);
  border-radius: 16px;
  padding: 1.5rem;
  border: 1px solid var(--border);
}

label {
  display: block;
  font-weight: 600;
  margin-bottom: 0.75rem;
  font-size: 1rem;
  color: var(--text);
}

textarea {
  width: 100%;
  background: var(--background);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1rem;
  font-size: 1rem;
  color: var(--text);
  resize: vertical;
  font-family: inherit;
  transition: border-color 0.2s, box-shadow 0.2s;
}

textarea:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

textarea::placeholder {
  color: var(--text-secondary);
  opacity: 0.7;
}

textarea[readonly] {
  background: var(--surface-hover);
  cursor: default;
}

.button-group {
  display: flex;
  gap: 0.75rem;
  margin-top: 1rem;
}

.btn {
  padding: 0.85rem 1.75rem;
  border-radius: 10px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: all 0.2s;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  min-width: 130px;
}

.btn.primary {
  background: var(--primary);
  color: white;
}

.btn.primary:hover:not(:disabled) {
  background: var(--primary-hover);
  transform: translateY(-1px);
}

.btn.primary:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

.btn.secondary {
  background: var(--background);
  color: var(--text);
  border: 1px solid var(--border);
}

.btn.secondary:hover {
  background: var(--surface);
}

.btn.hidden {
  display: none;
}

.output-section .btn {
  margin-top: 1rem;
  width: 100%;
}

footer {
  text-align: center;
  margin-top: 2rem;
  color: var(--text-secondary);
  font-size: 0.875rem;
}

/* Loading track animation */
.loading-track {
  flex: 1;
  height: 50px;
  background: #ffffff;
  border-radius: 10px;
  position: relative;
  overflow: hidden;
  border: 1px solid var(--border);
}

.capybara-rider {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  width: 48px;
  height: 48px;
  object-fit: contain;
  left: -50px;
}

@keyframes ride-across {
  0% { left: -50px; }
  100% { left: calc(100% + 50px); }
}

/* Toast notification */
.toast {
  position: fixed;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%) translateY(100px);
  background: var(--text);
  color: var(--background);
  padding: 0.875rem 1.5rem;
  border-radius: 10px;
  font-weight: 500;
  opacity: 0;
  transition: all 0.3s ease;
  z-index: 1000;
}

.toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* Accessibility */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* Responsive */
@media (max-width: 640px) {
  .container {
    padding: 1rem;
  }

  h1 {
    font-size: 1.75rem;
  }

  .subtitle {
    font-size: 0.95rem;
  }

  .button-group {
    flex-direction: column;
  }

  .btn {
    width: 100%;
  }
}