:root {
  --bg-color: #121212;
  --surface-color: #1e1e1e;
  --text-color: #f5f5f5;
  --muted-text-color: #b0b0b0;
  --primary-color: #e84393; /* vibrant pink accent */
  --secondary-color: #9c27b0; /* purple accent for subtle elements */
  --border-radius: 8px;
  --spacing-unit: 1rem;
  --max-width: 1200px;
}

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

body {
  font-family: 'Poppins', sans-serif;
  background-color: var(--bg-color);
  color: var(--text-color);
  line-height: 1.6;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.container {
  width: 90%;
  max-width: var(--max-width);
  margin: 0 auto;
}

/* Hero Section */
.hero {
  background: linear-gradient(180deg, var(--primary-color), var(--secondary-color));
  color: #fff;
  text-align: center;
  padding: calc(var(--spacing-unit) * 4) 0;
}

.hero-title {
  font-size: 2.5rem;
  margin-bottom: var(--spacing-unit);
  font-weight: 600;
}

.hero-subtitle {
  font-size: 1.2rem;
  margin-bottom: calc(var(--spacing-unit) * 2);
  font-weight: 400;
}

/* Buttons */
.btn {
  display: inline-block;
  padding: 0.75rem 2rem;
  font-size: 1rem;
  border-radius: var(--border-radius);
  text-decoration: none;
  cursor: pointer;
  transition: background 0.3s ease;
}

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

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

/* Section headings */
.section-title {
  font-size: 2rem;
  margin-bottom: calc(var(--spacing-unit) * 2);
  text-align: center;
  font-weight: 600;
}

/* Features grid */
.features {
  padding: calc(var(--spacing-unit) * 4) 0;
  background-color: var(--surface-color);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: calc(var(--spacing-unit) * 2);
}

.feature {
  background-color: var(--bg-color);
  padding: calc(var(--spacing-unit) * 2);
  border-radius: var(--border-radius);
  text-align: center;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.5);
  transition: transform 0.3s ease;
}

.feature:hover {
  transform: translateY(-5px);
}

.feature-icon {
  color: var(--primary-color);
  margin-bottom: var(--spacing-unit);
}

.feature h3 {
  font-size: 1.25rem;
  margin-bottom: 0.5rem;
}

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

/* Footer */
.footer {
  margin-top: auto;
  background-color: var(--surface-color);
  padding: calc(var(--spacing-unit) * 2) 0;
  text-align: center;
  color: var(--muted-text-color);
  font-size: 0.9rem;
}

/* Registration Page Styles */
.registration {
  padding: calc(var(--spacing-unit) * 4) 0;
  background-color: var(--surface-color);
  flex: 1;
}

.registration-form {
  background-color: var(--bg-color);
  padding: calc(var(--spacing-unit) * 3);
  border-radius: var(--border-radius);
  max-width: 600px;
  margin: 0 auto;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.5);
}

.registration-form .form-group {
  margin-bottom: calc(var(--spacing-unit) * 2);
}

.registration-form label {
  display: block;
  margin-bottom: 0.5rem;
  font-weight: 500;
}

.registration-form input {
  width: 100%;
  padding: 0.75rem 1rem;
  border: 2px solid var(--surface-color);
  border-radius: var(--border-radius);
  background-color: var(--surface-color);
  color: var(--text-color);
  font-size: 1rem;
}

.registration-form input:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

.registration-form .btn-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: calc(var(--spacing-unit) * 2);
}

.registration-form .detect-btn {
  flex-shrink: 0;
  background-color: var(--secondary-color);
  color: var(--bg-color);
  padding: 0.5rem 1rem;
  border: none;
  border-radius: var(--border-radius);
  cursor: pointer;
  transition: background 0.3s ease;
  font-size: 0.9rem;
}

.registration-form .detect-btn:hover {
  background-color: var(--primary-color);
}

.registration-form .submit-btn {
  display: block;
  width: 100%;
  padding: 0.75rem;
  background-color: var(--primary-color);
  color: var(--bg-color);
  border: none;
  border-radius: var(--border-radius);
  cursor: pointer;
  font-size: 1.1rem;
  transition: background 0.3s ease;
}

.registration-form .submit-btn:hover {
  background-color: var(--secondary-color);
}

.error-message {
  color: #e53935;
  font-size: 0.95em;
  margin-top: 4px;
  margin-left: 2px;
  min-height: 1.2em;
  font-weight: 500;
  letter-spacing: 0.01em;
  display: block;
}

/* Responsive typography */
@media (max-width: 768px) {
  .hero-title {
    font-size: 2rem;
  }
  .hero-subtitle {
    font-size: 1rem;
  }
  .section-title {
    font-size: 1.6rem;
  }
}

@media (max-width: 480px) {
  .hero-title {
    font-size: 1.6rem;
  }
  .hero-subtitle {
    font-size: 0.9rem;
  }
  .feature h3 {
    font-size: 1.1rem;
  }
  .feature p {
    font-size: 0.85rem;
  }
  .registration-form .btn-row {
    flex-direction: column;
    align-items: stretch;
    gap: 0.5rem;
  }
}