/* Thiết lập chung cho toàn trang */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background-color: #f4f6f9;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 16px;
}

/* --- Auth container --- */
.auth-container {
    background: #ffffff;
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    width: 100%;
    max-width: 400px;
}

.auth-container h2 {
    text-align: center;
    margin-bottom: 20px;
    color: #333;
    font-size: 24px;
}

/* --- Form --- */
.form-group {
    margin-bottom: 15px;
}

.form-group label {
    display: block;
    margin-bottom: 5px;
    color: #555;
    font-weight: 500;
}

.form-group input {
    width: 100%;
    padding: 10px 12px;
    border: 1px solid #ddd;
    border-radius: 6px;
    font-size: 14px;
    transition: border-color 0.3s;
}

.form-group input:focus {
    border-color: #007bff;
    outline: none;
}

.btn-submit {
    width: 100%;
    padding: 11px;
    background-color: #007bff;
    border: none;
    border-radius: 6px;
    color: white;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.3s;
    margin-top: 10px;
}

.btn-submit:hover {
    background-color: #0056b3;
}

.alert-error {
    background-color: #f8d7da;
    color: #721c24;
    padding: 10px;
    border-radius: 6px;
    margin-bottom: 15px;
    font-size: 14px;
    border: 1px solid #f5c6cb;
}

.alert-success {
    background-color: #d4edda;
    color: #155724;
    padding: 10px;
    border-radius: 6px;
    margin-bottom: 15px;
    font-size: 14px;
    border: 1px solid #c3e6cb;
}

.back-link {
    text-align: center;
    margin-top: 20px;
}

.back-link a {
    color: #007bff;
    text-decoration: none;
    font-size: 14px;
}

.back-link a:hover {
    text-decoration: underline;
}

/* --- Responsive --- */
@media screen and (max-width: 480px) {
    body {
        align-items: center;
        height: auto;
        min-height: 100vh;
        padding: 12px;
    }

    .auth-container {
        padding: 20px 16px;
    }

    .auth-container h2 {
        font-size: 20px;
        margin-bottom: 16px;
    }

    .form-group input {
        padding: 9px 10px;
        font-size: 13px;
    }

    .btn-submit {
        padding: 10px;
        font-size: 15px;
    }
}