body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #6dd5ed, #2193b0);
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    color: #333;
}

.signup-container {
    display: flex;
    width: 80%;
    max-width: 1200px;
    margin: 50px auto;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
    background-color: white;
    transition: transform 0.3s ease;
}

.signup-intro, .signup-form-container {
    flex: 1;
    padding: 60px;
}

.signup-intro {
    background: linear-gradient(135deg, #f0f9ff, #c6dbf7);
    color: #444;
    position: relative;
    overflow: hidden;
}

.signup-intro h2 {
    margin-bottom: 30px;
    color: #2193b0;
    font-size: 2.2em;
    font-weight: 600;
}

.signup-intro p {
    line-height: 1.7;
    margin-bottom: 25px;
    font-size: 1.1em;
}

.signup-form-container h2 {
    text-align: center;
    color: #2193b0;
    margin-bottom: 30px;
    font-size: 2.2em;
    font-weight: 600;
}

.signup-form-container input[type="text"],
.signup-form-container input[type="password"],
.signup-form-container input[type="email"] {
    width: 100%;
    padding: 15px;
    margin-bottom: 20px;
    border: 1px solid #ddd;
    border-radius: 8px;
    box-sizing: border-box;
    font-size: 1em;
    transition: border-color 0.3s ease;
}

.signup-form-container input[type="text"]:focus,
.signup-form-container input[type="password"]:focus,
.signup-form-container input[type="email"]:focus {
    border-color: #2193b0;
    outline: none;
}

.signup-form-container button {
    background: linear-gradient(135deg, #6dd5ed, #2193b0);
    color: white;
    padding: 15px 20px;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    width: 100%;
    font-size: 1.1em;
    transition: background 0.3s ease;
}

.signup-form-container button:hover {
    background: linear-gradient(135deg, #2193b0, #6dd5ed);
}

.error-message, .success-message {
    text-align: center;
    margin-bottom: 15px;
    padding: 10px;
    border-radius: 8px;
}

.error-message {
    color: #e74c3c;
    background-color: #f8d7da;
    border: 1px solid #f5c6cb;
}

.success-message {
    color: #28a745;
    background-color: #d4edda;
    border: 1px solid #c3e6cb;
}

.signup-form-container p {
    text-align: center;
    margin-top: 20px;
}

.signup-form-container a {
    color: #2193b0;
    text-decoration: none;
    transition: color 0.3s ease;
}

.signup-form-container a:hover {
    color: #6dd5ed;
}

/* Hiệu ứng động cho phần giới thiệu */
.signup-intro::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -50%;
    width: 100%;
    height: 100%;
    background: rgba(255, 255, 255, 0.1);
    transform: rotate(-35deg);
    transition: transform 0.5s ease-in-out;
}

.signup-intro:hover::before {
    transform: rotate(25deg);
}

/* Responsive design */
@media (max-width: 768px) {
    .signup-container {
        flex-direction: column;
        width: 95%;
    }

    .signup-intro,
    .signup-form-container {
        padding: 40px;
    }

    .signup-intro {
        display: none;
    }
    .signup-form-container input {
        width: 100%!important;
    }

    .signup-form-container .form-group {
        margin-bottom: 10px;
    }
    .login-intro {
        padding: 10px;
    }

    .login-intro p {
        margin-bottom: 0px;
    }

    .login-intro h2 {
        margin-bottom: 0px;
        font-size: 2em;
        text-align: center;
    }

    div#loginModal {
        margin: 0 auto;
    }

    form#form_login {
        padding: 10px;
    }

    form#form_login input {
        width: 100%;
    }

    .login-form h2 {
        margin-bottom: 5px;
        font-size: 1.5em;
    }

    form#form_login p {
        margin: 0px;
    }
}