:root {
  --primary-color: #0056b3;
  --primary-hover: #004494;
  --secondary-color: #6c757d;
  --text-color: #333;
  --text-muted: #666;
  --bg-color: #fff;
  --bg-alt: #f8f9fa;
  --border-color: #dee2e6;
  --error-color: #dc3545;
  --success-color: #28a745;
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --max-width: 1200px;
  --container-narrow: 600px;
  --spacing: 1rem;
  --border-radius: 4px;
}

/* Base Styles */
* {
  box-sizing: border-box;
}

body {
  margin: 0;
  padding: 0;
  font-family: var(--font-family);
  font-size: 16px;
  line-height: 1.6;
  color: var(--text-color);
  background-color: var(--bg-color);
}

img {
  max-width: 100%;
  height: auto;
}

a {
  color: var(--primary-color);
  text-decoration: none;
  transition: color 0.3s ease;
}

a:hover {
  text-decoration: underline;
}

/* Layout */
header {
  padding: calc(var(--spacing) * 1.5) var(--spacing);
  border-bottom: 1px solid var(--border-color);
  background: var(--bg-color);
}

.logo-link {
  display: flex;
  align-items: center;
  gap: var(--spacing);
  color: var(--text-color);
  font-weight: 700;
  font-size: 1.5rem;
  letter-spacing: -0.02em;
  text-decoration: none;
}

.logo-link:hover {
  text-decoration: none;
  color: var(--primary-color);
}

.logo {
  height: 5rem;
  width: auto;
}

main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: calc(var(--spacing) * 2) var(--spacing);
}

section {
  margin-bottom: calc(var(--spacing) * 4);
}

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

.container.narrow {
  max-width: var(--container-narrow);
}

/* Components: Card Grid */
.card-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: calc(var(--spacing) * 2);
  margin-bottom: calc(var(--spacing) * 4);
}

/* Components: Card */
.card {
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  padding: calc(var(--spacing) * 1.5);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  background: var(--bg-color);
  display: flex;
  flex-direction: column;
}

.card:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}

.card .meta {
  font-size: 0.8rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: calc(var(--spacing) / 2);
}

.card h3 {
  margin: 0 0 calc(var(--spacing) / 2);
  font-size: 1.25rem;
}

.card p {
  margin-bottom: var(--spacing);
  flex-grow: 1;
}

.card-link {
  font-weight: 600;
  display: inline-block;
}

/* Section Registration */
.section-registration {
  background-color: var(--bg-alt);
  padding: calc(var(--spacing) * 3) var(--spacing);
  border-radius: var(--border-radius);
}

.section-registration h2 {
  text-align: center;
  margin-top: 0;
}

.section-registration p {
  text-align: center;
}

/* Forms */
.register-form {
  margin-top: calc(var(--spacing) * 2);
}

.form-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing);
  margin-bottom: var(--spacing);
}

.form-field {
  display: flex;
  flex-direction: column;
}

.form-field span {
  font-size: 0.9rem;
  font-weight: 600;
  margin-bottom: calc(var(--spacing) / 4);
}

.form-field input[type="text"],
.form-field input[type="email"] {
  padding: 0.75rem;
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  font-size: 1rem;
  width: 100%;
}

.form-field input:focus {
  outline: none;
  border-color: var(--primary-color);
  box-shadow: 0 0 0 2px rgba(0, 86, 179, 0.1);
}

.form-full {
  grid-column: span 2;
}

.checkbox {
  display: flex;
  align-items: flex-start;
  gap: 0.5rem;
  cursor: pointer;
  margin-bottom: var(--spacing);
}

.checkbox input {
  margin-top: 0.3rem;
}

.checkbox span {
  font-size: 0.9rem;
  color: var(--text-muted);
}

.form-note {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: var(--spacing);
}

.form-error {
  color: var(--error-color);
  background: #f8d7da;
  border: 1px solid #f5c6cb;
  padding: 0.75rem;
  border-radius: var(--border-radius);
  margin-top: var(--spacing);
}

.form-success {
  color: var(--success-color);
  background: #d4edda;
  border: 1px solid #c3e6cb;
  padding: 0.75rem;
  border-radius: var(--border-radius);
  margin-top: var(--spacing);
}

.cta-button {
  display: block;
  width: 100%;
  padding: 1rem;
  background-color: var(--primary-color);
  color: white;
  border: none;
  border-radius: var(--border-radius);
  font-size: 1rem;
  font-weight: 700;
  cursor: pointer;
  transition: background-color 0.3s ease;
}

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

/* Footer */
footer {
  margin-top: calc(var(--spacing) * 4);
  padding: calc(var(--spacing) * 2) var(--spacing);
  border-top: 1px solid var(--border-color);
  text-align: center;
  font-size: 0.9rem;
  color: var(--text-muted);
}

footer a {
  color: var(--text-muted);
  margin: 0 0.25rem;
}

footer a:hover {
  color: var(--primary-color);
}

/* Mobile adjustments */
@media (max-width: 600px) {
  .form-grid {
    grid-template-columns: 1fr;
  }

  .form-full {
    grid-column: span 1;
  }

  .card-grid {
    grid-template-columns: 1fr;
  }

  .logo-link {
    font-size: 1.25rem;
    flex-direction: column;
    text-align: center;
    gap: calc(var(--spacing) / 2);
  }

  .logo {
    height: 60px;
  }
}