* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        body {
            font-family: 'Inter', sans-serif;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            min-height: 100vh;
            display: flex;
            align-items: center;
            justify-content: center;
            padding: 20px;
            transition: background 0.3s;
        }

        /* Light/Dark mode support for body (optional) */
        body.light {
            background: #f0f2f5;
        }

        .auth-container {
            width: 100%;
            max-width: 460px;
            margin: 0 auto;
        }

        .auth-card {
            background: rgba(255, 255, 255, 0.98);
            backdrop-filter: blur(2px);
            border-radius: 32px;
            box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
            overflow: hidden;
            transition: all 0.3s ease;
        }

        body.light .auth-card {
            background: #ffffff;
            box-shadow: 0 20px 35px -10px rgba(0, 0, 0, 0.1);
        }

        .auth-header {
            padding: 32px 32px 0 32px;
            text-align: center;
        }

        .auth-header h1 {
            font-size: 1.9rem;
            font-weight: 700;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            -webkit-background-clip: text;
            background-clip: text;
            color: transparent;
            margin-bottom: 8px;
        }

        .auth-header p {
            color: #6c757d;
            font-size: 0.9rem;
        }

        .form-container {
            padding: 32px;
        }

        .auth-form {
            display: none;
            animation: fadeSlide 0.35s cubic-bezier(0.2, 0.9, 0.4, 1.1) forwards;
        }

        .auth-form.active-form {
            display: block;
        }

        @keyframes fadeSlide {
            from {
                opacity: 0;
                transform: translateY(12px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }

        .input-group {
            margin-bottom: 22px;
        }

        .input-group label {
            display: block;
            margin-bottom: 8px;
            font-weight: 500;
            font-size: 0.85rem;
            color: #2d3748;
        }

        .input-group input {
            width: 100%;
            padding: 14px 16px;
            border-radius: 20px;
            border: 1.5px solid #e2e8f0;
            font-size: 0.95rem;
            transition: all 0.2s;
            background: #fff;
            outline: none;
        }

        .input-group input:focus {
            border-color: #667eea;
            box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.2);
        }

        .auth-btn {
            width: 100%;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            color: white;
            border: none;
            padding: 14px;
            border-radius: 40px;
            font-weight: 600;
            font-size: 1rem;
            cursor: pointer;
            transition: transform 0.2s, box-shadow 0.2s;
            margin-top: 8px;
        }

        .auth-btn:hover {
            transform: translateY(-1px);
            box-shadow: 0 10px 20px -5px rgba(102, 126, 234, 0.4);
        }

        .auth-footer {
            text-align: center;
            margin-top: 28px;
            font-size: 0.85rem;
            color: #4a5568;
        }

        .auth-footer a {
            color: #667eea;
            text-decoration: none;
            font-weight: 600;
            cursor: pointer;
            transition: 0.2s;
        }

        .auth-footer a:hover {
            text-decoration: underline;
        }

        .error-text {
            color: #e53e3e;
            font-size: 0.75rem;
            margin-top: 6px;
            display: block;
        }

        .divider {
            display: flex;
            align-items: center;
            text-align: center;
            margin: 24px 0 20px;
        }

        .divider::before,
        .divider::after {
            content: '';
            flex: 1;
            border-bottom: 1px solid #e2e8f0;
        }

        .divider span {
            padding: 0 12px;
            color: #a0aec0;
            font-size: 0.8rem;
        }

        .social-buttons {
            display: flex;
            gap: 16px;
            justify-content: center;
        }

        .social-btn {
            width: 48px;
            height: 48px;
            border-radius: 50%;
            background: #f7fafc;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.2rem;
            color: #4a5568;
            cursor: pointer;
            transition: 0.2s;
            border: 1px solid #e2e8f0;
        }

        .social-btn:hover {
            background: #edf2f7;
            transform: translateY(-2px);
        }

        .theme-switch {
            position: fixed;
            top: 24px;
            right: 24px;
            background: rgba(255,255,255,0.2);
            backdrop-filter: blur(8px);
            border-radius: 40px;
            padding: 10px 16px;
            cursor: pointer;
            border: none;
            font-size: 1.2rem;
            color: white;
            z-index: 10;
            transition: 0.2s;
        }

        body.light .theme-switch {
            background: rgba(0,0,0,0.1);
            color: #2d3748;
        }

        .theme-switch:hover {
            transform: scale(1.03);
        }

        @media (max-width: 500px) {
            .auth-card {
                border-radius: 24px;
            }
            .form-container {
                padding: 24px;
            }
        }