body {
    background-color: #181818;
    color: white;
    font-family: Arial;
    margin: 0;
    padding: 20px;
}

nav {
    background-color: #292929;
    padding: 15px;
    text-align: center;
}

nav a {
    color: white;
    text-decoration: none;
    margin: 15px;
}

nav a:hover {
    color: red;
}

h1 {
    color: white;
}

h2 {
    color: white;
}

img {
    border-radius: 10px;
}

.calculator-description {
    text-align: center;
    margin-bottom: 25px;
}

.calculator-container {
    background-color: #292929;
    width: 350px;
    margin: 30px auto;
    padding: 25px;
    border-radius: 15px;
    box-shadow: 0px 0px 15px #000000;
}

.calculator-container label {
    display: block;
    margin-top: 12px;
    margin-bottom: 5px;
    font-weight: bold;
}

.calculator-container input[type="number"] {
    width: 100%;
    padding: 12px;
    box-sizing: border-box;
    border: 1px solid #555555;
    border-radius: 7px;
    background-color: #181818;
    color: white;
    font-size: 16px;
}

.calculator-container .resultaat {
    width: 100%;
    height: 65px;
    padding: 10px;
    box-sizing: border-box;
    background-color: #181818;
    color: white;
    border: 2px solid red;
    border-radius: 7px;
    font-size: 18px;
    font-weight: bold;
}

.operator-list {
    background-color: #202020;
    padding: 10px;
    border-radius: 7px;
}

.calculator-container .operator-list label {
    font-weight: normal;
    margin: 8px 0;
}

.calculator-buttons {
    display: flex;
    gap: 10px;
    margin-top: 20px;
}

.submit {
    flex: 1;
    padding: 12px;
    background-color: red;
    color: white;
    border: none;
    border-radius: 7px;
    cursor: pointer;
    font-size: 16px;
}

.reset {
    flex: 1;
    padding: 12px;
    background-color: #555555;
    color: white;
    border: none;
    border-radius: 7px;
    cursor: pointer;
    font-size: 16px;
}

.submit:hover {
    background-color: darkred;
}

.reset:hover {
    background-color: #777777;
}

body.calculator-page,
body.contact-page,
body.converter-page {
    text-align: center;
}

.contact-description {
    text-align: center;
    margin-bottom: 25px;
}

.contact-container {
    background-color: #292929;
    width: 400px;
    margin: 30px auto;
    padding: 25px;
    border-radius: 15px;
    box-shadow: 0px 0px 15px #000000;
}

.contact-container label {
    display: block;
    margin-top: 12px;
    margin-bottom: 5px;
    font-weight: bold;
}

.contact-container input,
.contact-container select {
    width: 100%;
    padding: 12px;
    box-sizing: border-box;
    border: 1px solid #555;
    border-radius: 7px;
    background-color: #181818;
    color: white;
    font-size: 15px;
}

.birthday-fields {
    display: flex;
    gap: 10px;
}

.birthday-fields input {
    width: 33.33%;
}

.contact-buttons {
    display: flex;
    gap: 10px;
    margin-top: 20px;
}

.contact-result {
    background-color: #292929;
    width: 400px;
    margin: 25px auto;
    padding: 20px;
    border-radius: 15px;
    box-shadow: 0px 0px 15px #000000;
}

.contact-result li {
    margin-bottom: 10px;
}