body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

header {
    color: white;
    text-align: center;
    padding: 1em;
}

header img {
    max-width: 100%;
    height: auto;
}

footer {
    background-color: #004474;
    color: white;
    text-align: center;
    padding: 1em;
}

footer a {
    color: white;
    text-decoration: none;
}

footer a:hover {
    color: #45a049; /* Το πράσινο χρώμα του κουμπιού "Υποβολή" */
}

footer p {
    margin: 0.5em 0;
}

footer p span.separator {
    display: inline;
}

@media (max-width: 600px) {
    footer p {
        display: flex;
        flex-direction: column;
        align-items: center;
    }

    footer a {
        margin-bottom: 0.5em;
    }

    footer p span.separator {
        display: none;
    }
}

main {
    flex: 1;
    padding: 1em;
    max-width: 600px;
    margin: auto;
}

form {
    display: flex;
    flex-direction: column;
}

form p {
    text-align: justify;
}

label {
    margin-top: 1em;
}

input, textarea, button {
    padding: 0.5em;
    margin-top: 0.5em;
    font-size: 1em;
}

button {
    margin-top: 1em;
    background-color: #4CAF50;
    color: white;
    border: none;
    cursor: pointer;
}

button:hover {
    background-color: #45a049;
}

input:invalid, textarea:invalid {
    border-color: red;
}

.invalid {
    border-color: red !important;
}

.required::after {
    content: " *";
    color: red;
}

.tooltip {
    cursor: pointer;
    color: blue;
    text-decoration: underline;
}

.tooltip:hover::after {
    content: attr(title);
    position: absolute;
    background: #333;
    color: #fff;
    padding: 5px;
    border-radius: 5px;
    z-index: 1000;
}

/* Styles for the popup */
.popup {
    display: none;
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 80%;
    max-width: 600px;
    padding: 1em;
    background-color: white;
    border: 2px solid #333;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.5);
    z-index: 1001;
}

.popup.active {
    display: block;
}

.popup-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    z-index: 1000;
}

.popup-overlay.active {
    display: block;
}