Animated Form Validation

.form-container {
  background: linear-gradient(135deg, #f8f9ff 0%, #ffffff 100%);
  padding: 40px 20px;
  border-radius: 20px;
  max-width: 500px;
  margin: 0 auto;
  box-shadow: 0 15px 35px rgba(0, 0, 0, 0.1);
}

.form-demo {
  background: white;
  border-radius: 15px;
  padding: 30px;
  box-shadow: 0 5px 20px rgba(0, 0, 0, 0.05);
}

.form-header {
  text-align: center;
  margin-bottom: 30px;
}

.form-header h2 {
  margin: 0 0 10px 0;
  color: #333;
  font-size: 2rem;
  font-weight: 700;
}

.form-header p {
  color: #666;
  font-size: 1.1rem;
  margin: 0;
}

.registration-form {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.form-group {
  animation: slideInUp 0.6s ease-out;
}

.form-group:nth-child(1) { animation-delay: 0.1s; }
.form-group:nth-child(2) { animation-delay: 0.2s; }
.form-group:nth-child(3) { animation-delay: 0.3s; }
.form-group:nth-child(4) { animation-delay: 0.4s; }
.form-group:nth-child(5) { animation-delay: 0.5s; }

.form-group label {
  display: block;
  margin-bottom: 8px;
  font-weight: 600;
  color: #333;
  font-size: 0.95rem;
}

.input-wrapper {
  position: relative;
}

.input-wrapper input {
  width: 100%;
  padding: 15px 15px 15px 50px;
  border: 2px solid #e2e8f0;
  border-radius: 12px;
  font-size: 1rem;
  transition: all 0.3s ease;
  box-sizing: border-box;
}

.input-wrapper input:focus {
  outline: none;
  border-color: #667eea;
  box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.input-wrapper input.valid {
  border-color: #27ae60;
  background: rgba(39, 174, 96, 0.05);
}

.input-wrapper input.invalid {
  border-color: #e74c3c;
  background: rgba(231, 76, 60, 0.05);
}

.input-icon {
  position: absolute;
  left: 15px;
  top: 50%;
  transform: translateY(-50%);
  font-size: 1.2rem;
  color: #999;
}

.input-wrapper input:focus + .input-icon {
  color: #667eea;
}

.input-wrapper input.valid + .input-icon {
  color: #27ae60;
}

.input-wrapper input.invalid + .input-icon {
  color: #e74c3c;
}

.validation-message {
  margin-top: 8px;
  font-size: 0.85rem;
  min-height: 20px;
  transition: all 0.3s ease;
}

.validation-message.success {
  color: #27ae60;
}

.validation-message.error {
  color: #e74c3c;
}

.checkbox-group {
  margin-top: 10px;
}

.checkbox-label {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  cursor: pointer;
  font-size: 0.9rem;
  line-height: 1.5;
}

.checkbox-label input {
  display: none;
}

.checkmark {
  width: 20px;
  height: 20px;
  border: 2px solid #e2e8f0;
  border-radius: 4px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.3s ease;
  flex-shrink: 0;
  margin-top: 2px;
}

.checkbox-label input:checked + .checkmark {
  background: #667eea;
  border-color: #667eea;
}

.checkbox-label input:checked + .checkmark::after {
  content: '✓';
  color: white;
  font-size: 12px;
}

.checkbox-label input:focus + .checkmark {
  box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.terms-link {
  color: #667eea;
  text-decoration: none;
  font-weight: 600;
}

.terms-link:hover {
  text-decoration: underline;
}

.submit-btn {
  padding: 16px;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  border: none;
  border-radius: 12px;
  font-size: 1.1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  margin-top: 10px;
  box-shadow: 0 5px 15px rgba(102, 126, 234, 0.4);
}

.submit-btn:hover:not(:disabled) {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(102, 126, 234, 0.6);
}

.submit-btn:disabled {
  opacity: 0.7;
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}

.submit-btn.loading {
  position: relative;
  color: transparent;
}

.submit-btn.loading::after {
  content: '';
  position: absolute;
  width: 20px;
  height: 20px;
  border: 3px solid rgba(255, 255, 255, 0.3);
  border-top: 3px solid white;
  border-radius: 50%;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  animation: spin 1s linear infinite;
}

/* Animations */
@keyframes slideInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes shake {
  0%, 100% { transform: translateX(0); }
  20%, 60% { transform: translateX(-5px); }
  40%, 80% { transform: translateX(5px); }
}

@keyframes spin {
  0% { transform: translate(-50%, -50%) rotate(0deg); }
  100% { transform: translate(-50%, -50%) rotate(360deg); }
}

.shake {
  animation: shake 0.5s ease-in-out;
}

/* Responsive */
@media (max-width: 768px) {
  .form-container {
    padding: 30px 15px;
  }
  
  .form-demo {
    padding: 20px;
  }
  
  .form-header h2 {
    font-size: 1.7rem;
  }
  
  .input-wrapper input {
    padding: 12px 12px 12px 45px;
  }
  
  .input-icon {
    font-size: 1rem;
    left: 12px;
  }
}

document.addEventListener('DOMContentLoaded', function() {
  // Get form elements
  const form = document.getElementById('registrationForm');
  const fullNameInput = document.getElementById('fullName');
  const emailInput = document.getElementById('email');
  const passwordInput = document.getElementById('password');
  const confirmPasswordInput = document.getElementById('confirmPassword');
  const termsCheckbox = document.getElementById('terms');
  const submitBtn = document.getElementById('submitBtn');
  
  // Validation messages
  const nameValidation = document.getElementById('nameValidation');
  const emailValidation = document.getElementById('emailValidation');
  const passwordValidation = document.getElementById('passwordValidation');
  const confirmPasswordValidation = document.getElementById('confirmPasswordValidation');
  const termsValidation = document.getElementById('termsValidation');
  
  // Validation patterns
  const emailPattern = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
  const passwordPattern = /^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[@$!%*?&])[A-Za-z\d@$!%*?&]{8,}$/;
  
  // Real-time validation
  fullNameInput.addEventListener('input', validateName);
  emailInput.addEventListener('input', validateEmail);
  passwordInput.addEventListener('input', validatePassword);
  confirmPasswordInput.addEventListener('input', validateConfirmPassword);
  termsCheckbox.addEventListener('change', validateTerms);
  
  // Form submission
  form.addEventListener('submit', function(e) {
    e.preventDefault();
    
    // Validate all fields
    const isNameValid = validateName();
    const isEmailValid = validateEmail();
    const isPasswordValid = validatePassword();
    const isConfirmPasswordValid = validateConfirmPassword();
    const isTermsValid = validateTerms();
    
    // If all validations pass
    if (isNameValid && isEmailValid && isPasswordValid && isConfirmPasswordValid && isTermsValid) {
      // Show loading state
      submitBtn.classList.add('loading');
      submitBtn.disabled = true;
      
      // Simulate form submission
      setTimeout(() => {
        alert('Account created successfully!');
        form.reset();
        clearValidationMessages();
        submitBtn.classList.remove('loading');
        submitBtn.disabled = false;
      }, 2000);
    } else {
      // Shake invalid fields
      shakeInvalidFields();
    }
  });
  
  // Validate name
  function validateName() {
    const name = fullNameInput.value.trim();
    
    if (name === '') {
      showError(fullNameInput, nameValidation, 'Name is required');
      return false;
    } else if (name.length < 2) {
      showError(fullNameInput, nameValidation, 'Name must be at least 2 characters');
      return false;
    } else {
      showSuccess(fullNameInput, nameValidation, 'Name looks good!');
      return true;
    }
  }
  
  // Validate email
  function validateEmail() {
    const email = emailInput.value.trim();
    
    if (email === '') {
      showError(emailInput, emailValidation, 'Email is required');
      return false;
    } else if (!emailPattern.test(email)) {
      showError(emailInput, emailValidation, 'Please enter a valid email address');
      return false;
    } else {
      showSuccess(emailInput, emailValidation, 'Valid email address!');
      return true;
    }
  }
  
  // Validate password
  function validatePassword() {
    const password = passwordInput.value;
    
    if (password === '') {
      showError(passwordInput, passwordValidation, 'Password is required');
      return false;
    } else if (password.length < 8) {
      showError(passwordInput, passwordValidation, 'Password must be at least 8 characters');
      return false;
    } else if (!passwordPattern.test(password)) {
      showError(passwordInput, passwordValidation, 'Password must contain uppercase, lowercase, number, and special character');
      return false;
    } else {
      showSuccess(passwordInput, passwordValidation, 'Strong password!');
      validateConfirmPassword(); // Re-validate confirm password
      return true;
    }
  }
  
  // Validate confirm password
  function validateConfirmPassword() {
    const password = passwordInput.value;
    const confirmPassword = confirmPasswordInput.value;
    
    if (confirmPassword === '') {
      showError(confirmPasswordInput, confirmPasswordValidation, 'Please confirm your password');
      return false;
    } else if (password !== confirmPassword) {
      showError(confirmPasswordInput, confirmPasswordValidation, 'Passwords do not match');
      return false;
    } else {
      showSuccess(confirmPasswordInput, confirmPasswordValidation, 'Passwords match!');
      return true;
    }
  }
  
  // Validate terms
  function validateTerms() {
    if (!termsCheckbox.checked) {
      termsValidation.textContent = 'You must agree to the terms and conditions';
      termsValidation.className = 'validation-message error';
      return false;
    } else {
      termsValidation.textContent = '';
      termsValidation.className = 'validation-message';
      return true;
    }
  }
  
  // Show error
  function showError(input, validationElement, message) {
    input.classList.remove('valid');
    input.classList.add('invalid');
    validationElement.textContent = message;
    validationElement.className = 'validation-message error';
  }
  
  // Show success
  function showSuccess(input, validationElement, message) {
    input.classList.remove('invalid');
    input.classList.add('valid');
    validationElement.textContent = message;
    validationElement.className = 'validation-message success';
  }
  
  // Clear validation messages
  function clearValidationMessages() {
    const inputs = [fullNameInput, emailInput, passwordInput, confirmPasswordInput];
    const validationElements = [nameValidation, emailValidation, passwordValidation, confirmPasswordValidation];
    
    inputs.forEach(input => {
      input.classList.remove('valid', 'invalid');
    });
    
    validationElements.forEach(element => {
      element.textContent = '';
      element.className = 'validation-message';
    });
    
    termsValidation.textContent = '';
    termsValidation.className = 'validation-message';
  }
  
  // Shake invalid fields
  function shakeInvalidFields() {
    const invalidFields = form.querySelectorAll('.invalid');
    invalidFields.forEach(field => {
      field.classList.add('shake');
      setTimeout(() => {
        field.classList.remove('shake');
      }, 500);
    });
  }
});