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

:root {
  --primary: #4f46e5;
  --primary-light: #6366f1;
  --primary-dark: #4338ca;
  --success: #10b981;
  --bg: #0f172a;
  --surface: #ffffff;
  --text: #0f172a;
  --muted: #64748b;
  --border: #e2e8f0;
  --fill: #e2e8f0;
}

body {
  font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
  background: linear-gradient(135deg, #0f172a 0%, #1e1b4b 100%);
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1.5rem;
}

.container {
  background: var(--surface);
  width: 100%;
  max-width: 640px;
  border-radius: 20px;
  padding: 2.5rem 2rem;
  box-shadow: 0 25px 60px rgba(0, 0, 0, 0.45);
  text-align: center;
}

.title {
  font-size: 1.75rem;
  color: var(--text);
  margin-bottom: 0.25rem;
}

.subtitle {
  color: var(--muted);
  margin-bottom: 2.5rem;
  font-size: 0.95rem;
}

.progress-wrap {
  margin-bottom: 2.5rem;
}

.progress-track {
  position: relative;
  display: flex;
  justify-content: space-between;
  margin: 0 auto;
  max-width: 460px;
}

.progress-track::before {
  content: '';
  position: absolute;
  top: 24px;
  left: 0;
  right: 0;
  height: 4px;
  background: var(--fill);
  border-radius: 4px;
  transform: translateY(-50%);
}

.progress-fill {
  position: absolute;
  top: 24px;
  left: 0;
  width: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--primary-light), var(--success));
  border-radius: 4px;
  transform: translateY(-50%);
  transition: width 0.5s ease;
}

.step {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.6rem;
}

.step-number {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--surface);
  border: 3px solid var(--fill);
  color: var(--muted);
  font-weight: 700;
  font-size: 1.1rem;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.4s ease;
}

.step-label {
  font-size: 0.8rem;
  color: var(--muted);
  font-weight: 600;
  letter-spacing: 0.03em;
  transition: color 0.4s ease;
}

.step.active .step-number {
  border-color: var(--primary);
  background: var(--primary);
  color: #fff;
  box-shadow: 0 0 0 6px rgba(79, 70, 229, 0.18);
}

.step.done .step-number {
  border-color: var(--success);
  background: var(--success);
  color: #fff;
  box-shadow: 0 0 0 6px rgba(16, 185, 129, 0.16);
}

.step.done .step-label,
.step.active .step-label {
  color: var(--text);
}

.panel {
  display: none;
  padding: 1rem 0;
}

.panel.active {
  display: block;
  animation: fadeUp 0.4s ease;
}

.panel h2 {
  font-size: 1.35rem;
  color: var(--text);
  margin-bottom: 0.5rem;
}

.panel p {
  color: var(--muted);
  font-size: 0.95rem;
}

.buttons {
  display: flex;
  justify-content: center;
  gap: 1rem;
  margin-top: 2rem;
}

.btn {
  border: none;
  cursor: pointer;
  font-size: 0.95rem;
  font-weight: 600;
  padding: 0.8rem 2rem;
  border-radius: 12px;
  transition: all 0.25s ease;
}

.btn-primary {
  background: var(--primary);
  color: #fff;
  box-shadow: 0 8px 20px rgba(79, 70, 229, 0.35);
}

.btn-primary:hover:not(:disabled) {
  background: var(--primary-dark);
  transform: translateY(-2px);
}

.btn-outline {
  background: transparent;
  color: var(--primary);
  border: 2px solid var(--primary);
}

.btn-outline:hover:not(:disabled) {
  background: rgba(79, 70, 229, 0.08);
  transform: translateY(-2px);
}

.btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
  transform: none;
}

@keyframes fadeUp {
  from {
    opacity: 0;
    transform: translateY(12px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (max-width: 480px) {
  .container {
    padding: 1.75rem 1.25rem;
  }

  .step-number {
    width: 40px;
    height: 40px;
    font-size: 0.95rem;
  }

  .step-label {
    font-size: 0.7rem;
  }

  .progress-track::before,
  .progress-fill {
    top: 20px;
  }

  .btn {
    padding: 0.7rem 1.4rem;
    font-size: 0.9rem;
  }
}