What is incorrect about this code? Its written in C

Question

This code keeps giving the package weight must be greater then 0 output no matter what I input. How would I go about fixing this issue.

  #define _CRT_SECURE_NO_WARNINGS 
    #include <stdio.h> 

    int main(void)
    {
      
        double packageWeight = 0.0; 
        const double TWOPOUNDS = 1.25; 
        const double LESSSIX = 2.50; 
        const double LESSTEN = 3.90;
        const double OVERTEN = 4.40;
        double shippingCost = 0.00;

    
        printf("Enter the weight of the package: ");
        scanf("%.1lf", &packageWeight);

        if (packageWeight <= 2) {
        shippingCost = TWOPOUNDS; 
        }
        else if (packageWeight <= 6) {
            shippingCost = LESSSIX;
        }
        else if (packageWeight <= 10) {
        shippingCost = LESSTEN;
        }
        else if (packageWeight >= 10) {
        shippingCost = OVERTEN; 
        }
        if (packageWeight <= 0) {
                printf("The weight of the package must be greater than 0.00.\n");
        }
        else if (packageWeight > 0) {
            printf("The shipping charge is $%.2lf.\n", shippingCost);
        }
        return 0;
 }

Answer 1

anyway , your scanf is wrong, corrected below. Plus you should be dealing with invalid input

while (true) {
    printf("Enter the weight of the package: ");
    int ret = scanf("%lf", &packageWeight);
    if (ret == 1)
        break;
    int c;
    while ((c = getchar()) != '\n' && c != EOF);
}

the extra logic detects if the user enters say, 'dunno' at the prompt