:root {
            --primary: #2563eb;
            --primary-dark: #1e40af;
            --secondary: #f59e0b;
            --accent:  #10b981;
            --dark: #1e293b;
            --light: #f8fafc;
            --gray: #64748b;
            --light-gray: #e2e8f0;
            --danger: #ef4444;
            --success: #22c55e;
            --border-radius: 8px;
            --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
            --transition: all 0.3s ease;
        }

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

        body {
            background: linear-gradient(rgba(2,6,23,.72),rgba(2,6,23,.72)), url('https://www.shutterstock.com/image-photo/automotive-engineer-working-on-electric-600nw-2204219067.jpg') center/cover fixed;
            min-height: 100vh;
            display: flex;
            align-items: center;
            justify-content: center;
            padding: 20px;
            padding-top: 90px;
        }

        /* Navigation */
        .main-nav {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            background: linear-gradient(180deg, rgba(255,255,255,.9), rgba(255,255,255,.82));
            backdrop-filter: saturate(1.2) blur(8px);
            box-shadow: 0 10px 30px rgba(2,6,23,.12);
            border-bottom: 1px solid rgba(148,163,184,.25);
            z-index: 1000;
            padding: 15px 0;
            transition: all 0.3s ease;
        }

        .main-nav.scrolled {
            padding: 15px 0;
            background: linear-gradient(180deg, rgba(255,255,255,.98), rgba(255,255,255,.94));
            box-shadow: 0 12px 32px rgba(2,6,23,.16);
        }

        .nav-container {
            display: flex;
            justify-content: space-between;
            align-items: center;
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 20px;
        }

        .nav-logo {
            display: flex;
            align-items: center;
            gap: 12px;
            font-weight: 700;
            font-size: 1.5rem;
            color: var(--primary-dark);
        }

        .nav-logo svg {
            width: 40px;
            height: 40px;
        }

        .nav-menu {
            display: flex;
            list-style: none;
            gap: 30px;
        }

        .nav-menu a {
            color: var(--dark);
            font-weight: 600;
            position: relative;
            padding: 8px 6px;
            border-radius: 6px;
        }

        .nav-menu a::after {
            content: '';
            position: absolute;
            bottom: -5px;
            left: 0;
            width: 0;
            height: 2px;
            background-color: var(--primary);
            transition: var(--transition);
        }

        .nav-menu a:hover::after,
        .nav-menu a.active::after {
            width: 100%;
        }

        .nav-menu a.active {
            color: var(--primary);
        }

        .nav-actions {
            display: flex;
            gap: 15px;
        }

        .nav-toggle {
            display: none;
            flex-direction: column;
            cursor: pointer;
        }

        .nav-toggle span {
            width: 25px;
            height: 3px;
            background-color: var(--dark);
            margin: 2px 0;
            transition: var(--transition);
        }

        .signup-container {
            background: white;
            border-radius: 20px;
            box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
            overflow: hidden;
            width: 100%;
            max-width: 1000px;
            display: grid;
            grid-template-columns: 1fr 1fr;
            min-height: 700px;
        }

        .signup-left {
            background: linear-gradient(135deg, var(--accent) 0%, var(--primary) 100%);
            padding: 60px 40px;
            display: flex;
            flex-direction: column;
            justify-content: center;
            align-items: center;
            text-align: center;
            color: white;
            position: relative;
            overflow: hidden;
        }

        .signup-left::before {
            content: '';
            position: absolute;
            top: -50%;
            left: -50%;
            width: 200%;
            height: 200%;
            background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><circle cx="50" cy="50" r="2" fill="rgba(255,255,255,0.1)"/></svg>') repeat;
            animation: float 20s infinite linear;
        }

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

        .brand-logo {
            width: 80px;
            height: 80px;
            background: rgba(255, 255, 255, 0.2);
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            margin-bottom: 30px;
            position: relative;
            z-index: 1;
        }

        .brand-logo i {
            font-size: 2.5rem;
            color: white;
        }

        .signup-left h2 {
            font-size: 2.5rem;
            margin-bottom: 20px;
            position: relative;
            z-index: 1;
        }

        .signup-left p {
            font-size: 1.1rem;
            opacity: 0.9;
            line-height: 1.6;
            position: relative;
            z-index: 1;
        }

        .signup-right {
            padding: 40px;
            display: flex;
            flex-direction: column;
            justify-content: center;
            max-height: 700px;
            overflow-y: auto;
        }

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

        .signup-header h1 {
            font-size: 2rem;
            color: var(--dark);
            margin-bottom: 10px;
        }

        .signup-header p {
            color: var(--gray);
            font-size: 1rem;
        }

        .form-row {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 20px;
        }

        .form-group {
            margin-bottom: 20px;
        }

        .form-group.full-width {
            grid-column: 1 / -1;
        }

        .form-group label {
            display: block;
            margin-bottom: 8px;
            font-weight: 600;
            color: var(--dark);
        }

        .form-input {
            width: 100%;
            padding: 12px 15px;
            border: 2px solid var(--light-gray);
            border-radius: var(--border-radius);
            font-size: 1rem;
            transition: var(--transition);
            background: white;
        }

        .form-input:focus {
            outline: none;
            border-color: var(--primary);
            box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
        }

        .form-input.error {
            border-color: var(--danger);
        }

        .input-group {
            position: relative;
        }

        .input-icon {
            position: absolute;
            left: 15px;
            top: 50%;
            transform: translateY(-50%);
            color: var(--gray);
            font-size: 1.1rem;
        }

        .input-group .form-input {
            padding-left: 45px;
        }

        .password-toggle {
            position: absolute;
            right: 15px;
            top: 50%;
            transform: translateY(-50%);
            color: var(--gray);
            cursor: pointer;
            font-size: 1.1rem;
        }

        .form-select {
            width: 100%;
            padding: 12px 15px;
            border: 2px solid var(--light-gray);
            border-radius: var(--border-radius);
            font-size: 1rem;
            background: white;
            cursor: pointer;
        }

        .checkbox-group {
            display: flex;
            align-items: flex-start;
            gap: 10px;
            margin-bottom: 25px;
        }

        .checkbox-group input[type="checkbox"] {
            width: 18px;
            height: 18px;
            accent-color: var(--primary);
            margin-top: 2px;
        }

        .checkbox-group label {
            margin: 0;
            font-weight: 400;
            color: var(--gray);
            line-height: 1.5;
        }

        .checkbox-group a {
            color: var(--primary);
            text-decoration: none;
        }

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

        .btn {
            display: inline-flex;
            align-items: center;
            justify-content: center;
            padding: 15px 30px;
            border-radius: var(--border-radius);
            font-weight: 600;
            cursor: pointer;
            transition: var(--transition);
            border: none;
            font-size: 1rem;
            text-decoration: none;
            gap: 10px;
        }

        .btn-primary {
            background: var(--primary);
            color: white;
            width: 100%;
        }

        .btn-primary:hover {
            background: var(--primary-dark);
            transform: translateY(-2px);
            box-shadow: 0 10px 25px rgba(37, 99, 235, 0.3);
        }

        .btn-google {
            background: white;
            color: var(--dark);
            border: 2px solid var(--light-gray);
            width: 100%;
            margin-top: 15px;
        }

        .btn-google:hover {
            background: var(--light);
            border-color: var(--gray);
        }

        .divider {
            text-align: center;
            margin: 25px 0;
            position: relative;
            color: var(--gray);
        }

        .divider::before {
            content: '';
            position: absolute;
            top: 50%;
            left: 0;
            right: 0;
            height: 1px;
            background: var(--light-gray);
        }

        .divider span {
            background: white;
            padding: 0 20px;
        }

        .login-link {
            text-align: center;
            margin-top: 25px;
            color: var(--gray);
        }

        .login-link a {
            color: var(--primary);
            text-decoration: none;
            font-weight: 600;
        }

        .login-link a:hover {
            color: var(--primary-dark);
        }

        .back-home {
            position: absolute;
            top: 20px;
            left: 20px;
            color: white;
            text-decoration: none;
            display: flex;
            align-items: center;
            gap: 10px;
            font-weight: 500;
            transition: var(--transition);
            z-index: 2;
        }

        .back-home:hover {
            transform: translateX(-5px);
        }

        .error-message {
            color: var(--danger);
            font-size: 0.9rem;
            margin-top: 5px;
            display: none;
        }

        .password-strength {
            margin-top: 5px;
            font-size: 0.9rem;
        }

        .strength-weak { color: var(--danger); }
        .strength-medium { color: var(--secondary); }
        .strength-strong { color: var(--success); }

        @media (max-width: 768px) {
            .signup-container {
                grid-template-columns: 1fr;
                max-width: 500px;
            }
            
            .signup-left {
                padding: 40px 20px;
                min-height: 200px;
            }
            
            .signup-right {
                padding: 40px 20px;
            }

            .input-group {
                position: relative;
            }
        }