:root {
  --primary: #3498db;
  --secondary: #2ecc71;
  --dark: #2c3e50;
  --light: #ecf0f1;
  --accent: #e74c3c;
  --warning: #f39c12;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

/* Terms of Service Checkbox Styling */
.terms-agreement {
  margin: 1.5rem 0;
  padding: 1rem;
  background: rgba(52, 152, 219, 0.05);
  border-radius: 8px;
  border: 1px solid rgba(52, 152, 219, 0.2);
}

.checkbox-container {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
}

.checkbox-container input[type="checkbox"] {
  margin-top: 0.2rem;
  width: 18px;
  height: 18px;
  cursor: pointer;
  accent-color: var(--primary);
}

.checkbox-container label {
  cursor: pointer;
  line-height: 1.5;
  font-size: 0.95rem;
  color: var(--dark);
}

.checkbox-container label a {
  color: var(--primary);
  text-decoration: none;
  font-weight: 500;
}

.checkbox-container label a:hover {
  text-decoration: underline;
}

body {
  background-color: var(--light);
  color: var(--dark);
  line-height: 1.6;
}

header {
  background-color: var(--primary);
  color: white;
  padding: 1rem 0;
  box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
}

.logo {
  font-size: 1.8rem;
  font-weight: 700;
  display: flex;
  align-items: center;
}

.logo-icon {
  margin-right: 10px;
  font-size: 2rem;
}

.nav-links {
  display: flex;
  list-style: none;
}

.nav-links li {
  margin-left: 2rem;
}

.nav-links a {
  color: white;
  text-decoration: none;
  font-weight: 500;
  transition: color 0.3s;
}

.nav-links a:hover {
  color: var(--light);
}

.hero-signup {
  background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
  color: white;
  padding: 4rem 2rem;
  text-align: center;
}

.hero-content {
  max-width: 800px;
  margin: 0 auto;
}

.hero-signup h1 {
  font-size: 2.5rem;
  margin-bottom: 1rem;
}

.hero-signup p {
  font-size: 1.2rem;
  margin-bottom: 2rem;
}

main {
  max-width: 800px;
  margin: 0 auto;
  padding: 3rem 2rem;
}

.signup-container {
  background-color: white;
  border-radius: 10px;
  padding: 3rem;
  box-shadow: 0 4px 8px rgba(0,0,0,0.1);
  position: relative;
  overflow: hidden;
}

.signup-container::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 5px;
  background: linear-gradient(90deg, var(--primary), var(--secondary));
}

.form-group {
  margin-bottom: 1.5rem;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

label {
  display: block;
  margin-bottom: 0.5rem;
  font-weight: 600;
  color: var(--dark);
}

input[type="text"],
input[type="email"],
input[type="password"],
select {
  width: 100%;
  padding: 0.8rem;
  border: 2px solid #e0e0e0;
  border-radius: 8px;
  font-size: 1rem;
  transition: border-color 0.3s;
  background-color: white;
}

input[type="text"]:focus,
input[type="email"]:focus,
input[type="password"]:focus,
select:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.1);
}

select {
  cursor: pointer;
}

.password-requirements {
  font-size: 0.9rem;
  color: #666;
  margin-top: 0.5rem;
  padding: 0.8rem;
  background-color: #f8f9fa;
  border-radius: 6px;
  border-left: 4px solid var(--primary);
}

.password-requirements ul {
  margin-left: 1rem;
  margin-top: 0.5rem;
}

.grade-info {
  background-color: #e8f4fd;
  padding: 1rem;
  border-radius: 8px;
  margin-top: 0.5rem;
  font-size: 0.9rem;
  color: var(--primary);
}

.btn {
  display: inline-block;
  background-color: var(--primary);
  color: white;
  padding: 1rem 2rem;
  border-radius: 50px;
  text-decoration: none;
  font-weight: 600;
  transition: transform 0.3s, box-shadow 0.3s;
  box-shadow: 0 4px 6px rgba(0,0,0,0.1);
  border: none;
  cursor: pointer;
  font-size: 1rem;
  width: 100%;
  margin-top: 1rem;
}

.btn:hover {
  transform: translateY(-3px);
  box-shadow: 0 6px 8px rgba(0,0,0,0.15);
  background-color: #2980b9;
}

.btn:disabled {
  background-color: #95a5a6;
  cursor: not-allowed;
  transform: none;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.login-link {
  text-align: center;
  margin-top: 2rem;
  padding-top: 2rem;
  border-top: 1px solid #eee;
}

.login-link a {
  color: var(--primary);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.3s;
}

.login-link a:hover {
  color: #2980b9;
}

.error-message {
  color: var(--accent);
  font-size: 0.9rem;
  margin-top: 0.3rem;
  display: none;
}

.success-message {
  color: var(--secondary);
  font-size: 0.9rem;
  margin-top: 0.3rem;
  display: none;
}

.password-strength {
  height: 4px;
  border-radius: 2px;
  margin-top: 0.5rem;
  background-color: #e0e0e0;
  overflow: hidden;
}

.password-strength-bar {
  height: 100%;
  width: 0;
  transition: width 0.3s, background-color 0.3s;
  border-radius: 2px;
}

.strength-weak {
  background-color: var(--accent);
}

.strength-medium {
  background-color: var(--warning);
}

.strength-strong {
  background-color: var(--secondary);
}

footer {
  background-color: var(--dark);
  color: white;
  padding: 3rem 2rem;
  text-align: center;
  margin-top: 3rem;
}

.footer-content {
  max-width: 1200px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2rem;
  text-align: left;
}

.footer-section h3 {
  margin-bottom: 1rem;
  font-size: 1.2rem;
  border-bottom: 2px solid var(--primary);
  padding-bottom: 0.5rem;
  display: inline-block;
}

.footer-section ul {
  list-style: none;
}

.footer-section li {
  margin-bottom: 0.5rem;
}

.footer-section a {
  color: #bdc3c7;
  text-decoration: none;
  transition: color 0.3s;
}

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

.footer-bottom {
  margin-top: 2rem;
  padding-top: 1rem;
  border-top: 1px solid #34495e;
}

@media (max-width: 768px) {
  .hero-signup h1 {
    font-size: 2rem;
  }

  .hero-signup p {
    font-size: 1rem;
  }

  .form-row {
    grid-template-columns: 1fr;
  }

  .signup-container {
    padding: 2rem 1.5rem;
  }

  main {
    padding: 2rem 1rem;
  }
}