:root {
            --primary: #3498db;
            --secondary: #2c3e50;
            --accent: #e74c3c;
            --bg-gradient: linear-gradient(135deg, #2c3e50 0%, #3498db 100%);
        }

        body {
            margin: 0;
            padding: 0;
            font-family: 'Poppins', sans-serif;
            background: var(--bg-gradient);
            display: flex;
            justify-content: center;
            align-items: center;
            min-height: 100vh;
        }

        .container {
            background: rgba(255, 255, 255, 0.95);
            width: 90%;
            max-width: 400px;
            padding: 50px 30px;
            border-radius: 20px;
            box-shadow: 0 15px 35px rgba(0,0,0,0.2);
            text-align: center;
            backdrop-filter: blur(10px); /* Efecto cristal */
        }

        .logo {
            font-size: 32px;
            font-weight: 800;
            color: var(--secondary);
            margin-bottom: 10px;
            letter-spacing: -1px;
        }

        .subtitle {
            color: #7f8c8d;
            margin-bottom: 30px;
            font-size: 14px;
        }

        .input-group {
            position: relative;
            margin-bottom: 20px;
        }

        .input-group i {
            position: absolute;
            left: 15px;
            top: 50%;
            transform: translateY(-50%);
            color: var(--primary);
            transition: 0.3s;
        }

        .input-group input {
            width: 100%;
            padding: 15px 15px 15px 45px;
            border: 2px solid #f1f2f6;
            border-radius: 12px;
            font-size: 15px;
            transition: all 0.3s;
            box-sizing: border-box;
            outline: none;
            background: #f9f9f9;
        }

        .input-group input:focus {
            border-color: var(--primary);
            background: #fff;
            box-shadow: 0 0 8px rgba(52, 152, 219, 0.2);
        }

        /* Mejora visual del icono al enfocar */
        .input-group input:focus + i {
            color: var(--secondary);
        }

        .btn-login {
            width: 100%;
            background: var(--primary);
            background: linear-gradient(to right, #3498db, #2980b9);
            color: white;
            padding: 16px;
            border: none;
            border-radius: 12px;
            font-size: 16px;
            font-weight: 600;
            cursor: pointer;
            transition: transform 0.2s, box-shadow 0.2s;
            margin-top: 10px;
        }

        .btn-login:hover {
            transform: translateY(-2px);
            box-shadow: 0 5px 15px rgba(52, 152, 219, 0.4);
        }

        .btn-login:active {
            transform: translateY(0);
        }

        .footer-links {
            margin-top: 25px;
            font-size: 14px;
            color: #7f8c8d;
        }

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

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

        /* Optimización para móviles muy pequeños */
        @media (max-width: 480px) {
            .container {
                padding: 40px 20px;
            }
            .logo {
                font-size: 26px;
            }
        }