a {
    color: blue;
    text-decoration: underline;
}
    
a:visited {
    color: purple;
}
    
body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
}

header {
    background-color: #f8f9fa;
    padding: 20px;
    text-align: center;
}

.title {
    margin: 0;
}

nav {
    background-color: #343a40;
    color: white;
    padding: 15px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

nav ul {
    list-style-type: none;
    padding: 0;
    margin: 0;
    display: flex;
}

nav ul li {
    display: inline;
    margin-right: 20px;
}

nav ul li .a-nav {
    color: white;
    text-decoration: none;
}

main {
    padding: 20px;
}

.footer {
    background-color: #343a40;
    padding: 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: white;
    font-size: 12px;
}

.copyright {
    margin: 0;
}

.contact a {
    color: white;
    text-decoration: none;
    display: inline-block; 
}

@media only screen and (max-width: 480px) {
    .contact a {
        color: white;
        text-decoration: none;
        display: inline-block;
        padding: 10px;  /* Add padding to increase tap target size */
        margin: 0 10px;  /* Add margin to prevent overlap */
    }
}

.pre1 {
    font-family: Arial, sans-serif;
    font-size: 20px;
    text-align: center;
  }
.pre2 {
    font-family: Arial, sans-serif;
    font-size: 16px;
  }

.adapt {
    max-width: 100%;
    height: auto;
}

.container {
    width: 300px;
    padding: 16px;
    background-color: #ffffff;
    margin: 0 auto;
    margin-top: 100px;
    border-radius: 8px;
    box-shadow: 0px 0px 10px 0px rgba(0,0,0,0.1);
}

label {
    color: #4a4a4a;
    font-weight: bold;
}

input[type="number"] {
    width: 100%;
    padding: 6px;
    margin: 10px 0;
    border-radius: 4px;
    border: 1px solid #ccc;
}

button {
    width: 100%;
    background-color: #007bff;
    color: white;
    padding: 10px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 18px;
}

button:hover {
    background-color: #0056b3;
}

#result {
    margin-top: 20px;
    font-size: 20px;
    font-weight: bold;
    color: #4a4a4a;
}