Modern (Signup and Login) Form on Single Page

:root {
    --primary: #0A0E27;
    --secondary: #1A1F3A;
    --accent: #00D9FF;
    --accent-dark: #00B8D4;
    --error: #FF4757;
    --success: #00D084;
    --warning: #FFA801;
    --text-primary: #FFFFFF;
    --text-secondary: #A0AEC0;
    --input-bg: rgba(255, 255, 255, 0.03);
    --input-border: rgba(255, 255, 255, 0.1);
    --input-focus: rgba(0, 217, 255, 0.3);
}
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
body {
    font-family: 'DM Sans', sans-serif;
    background: linear-gradient(135deg, #0A0E27 0%, #1A1F3A 50%, #0F1629 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
    position: relative;
    overflow-x: hidden;
}
.container {
    position: relative;
    z-index: 1;
    width: 100%;
    max-width: 480px;
    background: rgba(26, 31, 58, 0.6);
    backdrop-filter: blur(20px);
    border-radius: 24px;
    border: 1px solid rgba(255, 255, 255, 0.1);
    box-shadow: 0 24px 48px rgba(0, 0, 0, 0.4),
    0 0 80px rgba(0, 217, 255, 0.1);
    overflow: hidden;
    animation: slideUp 0.6s cubic-bezier(0.34, 1.56, 0.64, 1);
}
@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(40px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}
.form-container {
    padding: 48px 40px;
}
.header {
    text-align: center;
    margin-bottom: 40px;
}
.logo {
    font-family: 'Syne', sans-serif;
    font-size: 32px;
    font-weight: 800;
    background: linear-gradient(135deg, var(--accent) 0%, #8A2BE2 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 12px;
    letter-spacing: -0.5px;
}
.subtitle {
    color: var(--text-secondary);
    font-size: 14px;
    font-weight: 400;
}
.tabs {
    display: flex;
    gap: 12px;
    margin-bottom: 32px;
    background: var(--input-bg);
    padding: 6px;
    border-radius: 12px;
    border: 1px solid var(--input-border);
}
.tab {
    flex: 1;
    padding: 12px;
    background: transparent;
    border: none;
    color: var(--text-secondary);
    font-family: 'DM Sans', sans-serif;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    border-radius: 8px;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
}
.tab.active {
    background: linear-gradient(135deg, var(--accent) 0%, #00B8D4 100%);
    color: var(--primary);
    box-shadow: 0 4px 16px rgba(0, 217, 255, 0.3);
}
.tab:hover:not(.active) {
    background: rgba(255, 255, 255, 0.05);
    color: var(--text-primary);
}
.form-group {
    margin-bottom: 24px;
    animation: fadeIn 0.5s ease-out;
    animation-fill-mode: both;
}
.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; }
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}
label {
    display: block;
    margin-bottom: 8px;
    color: var(--text-primary);
    font-size: 13px;
    font-weight: 500;
    letter-spacing: 0.3px;
}
.input-wrapper {
    position: relative;
}
input {
    width: 100%;
    padding: 14px 16px;
    background: var(--input-bg);
    border: 2px solid var(--input-border);
    border-radius: 12px;
    color: var(--text-primary);
    font-family: 'DM Sans', sans-serif;
    font-size: 15px;
    transition: all 0.3s ease;
    outline: none;
}
input::placeholder {
    color: rgba(160, 174, 192, 0.5);
}
input:focus {
    border-color: var(--accent);
    background: rgba(255, 255, 255, 0.05);
    box-shadow: 0 0 0 4px var(--input-focus);
}
input.error {
    border-color: var(--error);
}
input.success {
    border-color: var(--success);
}
.validation-icon {
    position: absolute;
    right: 16px;
    top: 50%;
    transform: translateY(-50%);
    font-size: 18px;
    opacity: 0;
    transition: all 0.3s ease;
}
.validation-icon.show {
    opacity: 1;
    animation: bounceIn 0.4s cubic-bezier(0.68, -0.55, 0.265, 1.55);
}
@keyframes bounceIn {
    0% { transform: translateY(-50%) scale(0); }
    50% { transform: translateY(-50%) scale(1.2); }
    100% { transform: translateY(-50%) scale(1); }
}
.error-message,
.success-message {
    margin-top: 8px;
    font-size: 12px;
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 6px;
    opacity: 0;
    transform: translateY(-4px);
    transition: all 0.3s ease;
    max-height: 0;
    overflow: hidden;
}
.error-message.show,
.success-message.show {
    opacity: 1;
    transform: translateY(0);
    max-height: 50px;
}
.error-message {
    color: var(--error);
}
.success-message {
    color: var(--success);
}
.password-strength {
    margin-top: 12px;
    opacity: 0;
    transition: opacity 0.3s ease;
}
.password-strength.show {
    opacity: 1;
}
.strength-label {
    font-size: 12px;
    color: var(--text-secondary);
    margin-bottom: 6px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.strength-text {
    font-weight: 600;
}
.strength-text.weak { color: var(--error); }
.strength-text.medium { color: var(--warning); }
.strength-text.strong { color: var(--success); }
.strength-bar {
    height: 4px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 4px;
    overflow: hidden;
}
.strength-progress {
    height: 100%;
    width: 0;
    transition: all 0.4s ease;
    border-radius: 4px;
}
.strength-progress.weak {
    width: 33%;
    background: linear-gradient(90deg, var(--error), #FF6B81);
}
.strength-progress.medium {
    width: 66%;
    background: linear-gradient(90deg, var(--warning), #FFB84D);
}
.strength-progress.strong {
    width: 100%;
    background: linear-gradient(90deg, var(--success), #00E396);
}
.requirements {
    margin-top: 12px;
    padding: 12px;
    background: rgba(0, 0, 0, 0.2);
    border-radius: 8px;
    border: 1px solid rgba(255, 255, 255, 0.05);
    opacity: 0;
    max-height: 0;
    overflow: hidden;
    transition: all 0.3s ease;
}
.requirements.show {
    opacity: 1;
    max-height: 200px;
}
.requirement {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 12px;
    color: var(--text-secondary);
    margin-bottom: 6px;
    transition: color 0.3s ease;
}
.requirement:last-child {
    margin-bottom: 0;
}
.requirement.met {
    color: var(--success);
}
.requirement-icon {
    font-size: 14px;
    transition: transform 0.3s ease;
}
.requirement.met .requirement-icon {
    transform: scale(1.2);
}
.submit-btn {
    width: 100%;
    padding: 16px;
    background: linear-gradient(135deg, var(--accent) 0%, #00B8D4 100%);
    border: none;
    border-radius: 12px;
    color: var(--primary);
    font-family: 'DM Sans', sans-serif;
    font-size: 15px;
    font-weight: 700;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 8px 24px rgba(0, 217, 255, 0.3);
    position: relative;
    overflow: hidden;
}
.submit-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
    transition: left 0.5s ease;
}
.submit-btn:hover::before {
    left: 100%;
}
.submit-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 12px 32px rgba(0, 217, 255, 0.4);
}
.submit-btn:active {
    transform: translateY(0);
}
.submit-btn:disabled {
    background: rgba(255, 255, 255, 0.1);
    color: var(--text-secondary);
    cursor: not-allowed;
    box-shadow: none;
}
.submit-btn:disabled:hover {
    transform: none;
}
.divider {
    display: flex;
    align-items: center;
    gap: 16px;
    margin: 32px 0;
    opacity: 0;
    animation: fadeIn 0.5s ease-out 0.5s forwards;
}
.divider::before,
.divider::after {
    content: '';
    flex: 1;
    height: 1px;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.1), transparent);
}
.divider span {
    color: var(--text-secondary);
    font-size: 13px;
    font-weight: 500;
}
.social-login {
    display: flex;
    gap: 12px;
    opacity: 0;
    animation: fadeIn 0.5s ease-out 0.6s forwards;
}
.social-btn {
    flex: 1;
    padding: 14px;
    background: var(--input-bg);
    border: 2px solid var(--input-border);
    border-radius: 12px;
    color: var(--text-primary);
    font-family: 'DM Sans', sans-serif;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}
.social-btn:hover {
    background: rgba(255, 255, 255, 0.08);
    border-color: rgba(255, 255, 255, 0.2);
    transform: translateY(-2px);
}
.footer-text {
    text-align: center;
    margin-top: 24px;
    color: var(--text-secondary);
    font-size: 13px;
    opacity: 0;
    animation: fadeIn 0.5s ease-out 0.7s forwards;
}
.footer-text a {
    color: var(--accent);
    text-decoration: none;
    font-weight: 600;
    transition: color 0.3s ease;
}
.footer-text a:hover {
    color: var(--text-primary);
}
.hidden {
    display: none !important;
}
@media (max-width: 640px) {
    .form-container {
        padding: 32px 24px;
    }
    .logo {
        font-size: 28px;
    }
    body::before,
    body::after {
        width: 400px;
        height: 400px;
    }
}

// Tab Switching
const tabs = document.querySelectorAll('.tab');
const loginForm = document.getElementById('loginForm');
const registerForm = document.getElementById('registerForm');
const toggleLink = document.getElementById('toggleLink');
const subtitle = document.querySelector('.subtitle');
tabs.forEach(tab => {
    tab.addEventListener('click', () => {
        const tabType = tab.dataset.tab;
        switchTab(tabType);
    });
});
toggleLink.addEventListener('click', (e) => {
    e.preventDefault();
    const isLoginActive = loginForm.classList.contains('hidden');
    switchTab(isLoginActive ? 'login' : 'register');
});
function switchTab(tabType) {
    tabs.forEach(t => t.classList.remove('active'));
    document.querySelector(`[data-tab="${tabType}"]`).classList.add('active');
    if (tabType === 'login') {
        loginForm.classList.remove('hidden');
        registerForm.classList.add('hidden');
        subtitle.textContent = 'Welcome back, please enter your details';
        toggleLink.textContent = 'Sign up';
        toggleLink.parentElement.innerHTML = "Don't have an account? <a href='#' id='toggleLink'>Sign up</a>";
    } else {
        loginForm.classList.add('hidden');
        registerForm.classList.remove('hidden');
        subtitle.textContent = 'Create your account to get started';
        toggleLink.textContent = 'Sign in';
        toggleLink.parentElement.innerHTML = "Already have an account? <a href='#' id='toggleLink'>Sign in</a>";
    }
    // Re-attach event listener to new link
    document.getElementById('toggleLink').addEventListener('click', (e) => {
        e.preventDefault();
        const isLoginActive = loginForm.classList.contains('hidden');
        switchTab(isLoginActive ? 'login' : 'register');
    });
}
// Validation Functions
const validators = {
    email: (value) => {
        const emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
        if (!value) return { valid: false, message: 'Email is required' };
        if (!emailRegex.test(value)) return { valid: false, message: 'Please enter a valid email address' };
        return { valid: true, message: 'Email looks good!' };
    },
    password: (value, isLogin = false) => {
        if (!value) return { valid: false, message: 'Password is required' };
        if (isLogin) return { valid: true };
        const requirements = {
            length: value.length >= 8,
            uppercase: /[A-Z]/.test(value),
            lowercase: /[a-z]/.test(value),
            number: /\d/.test(value),
            special: /[!@#$%^&*(),.?":{}|<>]/.test(value)
        };
        const metRequirements = Object.values(requirements).filter(Boolean).length;
        if (metRequirements < 5) {
            return {
                valid: false,
                message: 'Password does not meet all requirements',
                requirements,
                strength: metRequirements <= 2 ? 'weak' : metRequirements <= 3 ? 'medium' : 'strong'
            };
        }
        return {
            valid: true,
            message: 'Strong password!',
            requirements,
            strength: 'strong'
        };
    },
    name: (value) => {
        if (!value) return { valid: false, message: 'Name is required' };
        if (value.length < 2) return { valid: false, message: 'Name must be at least 2 characters' };
        if (!/^[a-zA-Z\s]+$/.test(value)) return { valid: false, message: 'Name can only contain letters and spaces' };
        return { valid: true, message: 'Name looks good!' };
    },
    confirmPassword: (value, password) => {
        if (!value) return { valid: false, message: 'Please confirm your password' };
        if (value !== password) return { valid: false, message: 'Passwords do not match' };
        return { valid: true, message: 'Passwords match!' };
    }
};
// Live Validation
function validateField(input, validatorName, ...args) {
    const wrapper = input.closest('.form-group');
    const icon = wrapper.querySelector('.validation-icon');
    const errorMsg = wrapper.querySelector('.error-message');
    const successMsg = wrapper.querySelector('.success-message');
    const result = validators[validatorName](input.value, ...args);
    // Clear previous states
    input.classList.remove('error', 'success');
    icon.classList.remove('show');
    errorMsg.classList.remove('show');
    successMsg.classList.remove('show');
    if (!input.value) {
        return result;
    }
    if (result.valid) {
        input.classList.add('success');
        icon.textContent = '✓';
        icon.style.color = 'var(--success)';
        icon.classList.add('show');
        successMsg.textContent = result.message;
        successMsg.classList.add('show');
    } else {
        input.classList.add('error');
        icon.textContent = '✕';
        icon.style.color = 'var(--error)';
        icon.classList.add('show');
        errorMsg.textContent = result.message;
        errorMsg.classList.add('show');
    }
    return result;
}
// Password Strength Indicator
function updatePasswordStrength(input, result) {
    const wrapper = input.closest('.form-group');
    const strengthContainer = wrapper.querySelector('.password-strength');
    const strengthText = wrapper.querySelector('.strength-text');
    const strengthProgress = wrapper.querySelector('.strength-progress');
    const requirementsContainer = wrapper.querySelector('.requirements');
    if (!input.value) {
        strengthContainer.classList.remove('show');
        requirementsContainer.classList.remove('show');
        return;
    }
    strengthContainer.classList.add('show');
    requirementsContainer.classList.add('show');
    if (result.strength) {
        strengthProgress.className = 'strength-progress ' + result.strength;
        strengthText.className = 'strength-text ' + result.strength;
        strengthText.textContent = result.strength.charAt(0).toUpperCase() + result.strength.slice(1);
    }
    if (result.requirements) {
        Object.keys(result.requirements).forEach(req => {
            const reqElement = wrapper.querySelector(`[data-requirement="${req}"]`);
            if (result.requirements[req]) {
                reqElement.classList.add('met');
                reqElement.querySelector('.requirement-icon').textContent = '✓';
            } else {
                reqElement.classList.remove('met');
                reqElement.querySelector('.requirement-icon').textContent = '○';
            }
        });
    }
}
// Login Form Validation
const loginEmail = document.getElementById('loginEmail');
const loginPassword = document.getElementById('loginPassword');
loginEmail.addEventListener('input', () => {
    validateField(loginEmail, 'email');
});
loginEmail.addEventListener('blur', () => {
    validateField(loginEmail, 'email');
});
loginPassword.addEventListener('input', () => {
    validateField(loginPassword, 'password', true);
});
loginPassword.addEventListener('blur', () => {
    validateField(loginPassword, 'password', true);
});
// Register Form Validation
const registerName = document.getElementById('registerName');
const registerEmail = document.getElementById('registerEmail');
const registerPassword = document.getElementById('registerPassword');
const registerConfirmPassword = document.getElementById('registerConfirmPassword');
registerName.addEventListener('input', () => {
    validateField(registerName, 'name');
});
registerName.addEventListener('blur', () => {
    validateField(registerName, 'name');
});
registerEmail.addEventListener('input', () => {
    validateField(registerEmail, 'email');
});
registerEmail.addEventListener('blur', () => {
    validateField(registerEmail, 'email');
});
registerPassword.addEventListener('input', () => {
    const result = validateField(registerPassword, 'password', false);
    updatePasswordStrength(registerPassword, result);
    // Also revalidate confirm password if it has a value
    if (registerConfirmPassword.value) {
        validateField(registerConfirmPassword, 'confirmPassword', registerPassword.value);
    }
});
registerPassword.addEventListener('blur', () => {
    const result = validateField(registerPassword, 'password', false);
    updatePasswordStrength(registerPassword, result);
});
registerConfirmPassword.addEventListener('input', () => {
    validateField(registerConfirmPassword, 'confirmPassword', registerPassword.value);
});
registerConfirmPassword.addEventListener('blur', () => {
    validateField(registerConfirmPassword, 'confirmPassword', registerPassword.value);
});
// Form Submission
loginForm.addEventListener('submit', (e) => {
    e.preventDefault();
    const emailResult = validateField(loginEmail, 'email');
    const passwordResult = validateField(loginPassword, 'password', true);
    if (emailResult.valid && passwordResult.valid) {
        console.log('Login form submitted successfully!', {
            email: loginEmail.value,
            password: loginPassword.value
        });
        alert('Login successful! (This is a demo)');
    }
});
registerForm.addEventListener('submit', (e) => {
    e.preventDefault();
    const nameResult = validateField(registerName, 'name');
    const emailResult = validateField(registerEmail, 'email');
    const passwordResult = validateField(registerPassword, 'password', false);
    const confirmPasswordResult = validateField(registerConfirmPassword, 'confirmPassword', registerPassword.value);
    if (nameResult.valid && emailResult.valid && passwordResult.valid && confirmPasswordResult.valid) {
        console.log('Registration form submitted successfully!', {
            name: registerName.value,
            email: registerEmail.value,
            password: registerPassword.value
        });
        alert('Registration successful! (This is a demo)');
    }
});
// Social Login Buttons
document.querySelectorAll('.social-btn').forEach(btn => {
    btn.addEventListener('click', () => {
        const provider = btn.textContent.trim();
        console.log(`${provider} login clicked`);
        alert(`${provider} login would happen here (This is a demo)`);
    });
});