body {
    font-family: Arial, sans-serif;
    background-color: #f4f4f4;
    margin: 0;
    padding: 0;
}

.container {
    width: 90%;
    max-width: 600px;
    margin: 0 auto;
    padding: 20px;
    background-color: #fff;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    margin-top: 50px;
}

h1, h2 {
    text-align: center;
}

form {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.input-group {
    display: flex;
    align-items: center;
    margin-bottom: 10px;
    width: 100%;
    max-width: 300px;
}

label {
    flex: 1;
}

input {
    flex: 2;
    margin: 10px 0;
    padding: 10px;
}

.qr-scan-button {
    margin-left: 10px;
    padding: 10px 20px;
    background-color: #007BFF;
    color: white;
    border: none;
    cursor: pointer;
    border-radius: 5px;
}

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

#number {
    text-align: center;
    font-size: 1.2em;
}

#keypad {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 10px;
    margin: 20px 0;
    width: 100%;
    max-width: 300px;
}

.key {
    width: 100%;
    height: 60px;
    font-size: 1.5em;
    text-align: center;
    background-color: #555; /* Dunkelgrau */
    color: white;
    border: 1px solid #ccc;
    border-radius: 5px;
    cursor: pointer;
}

.key:active {
    background-color: #333; /* Dunkleres Grau beim Klicken */
}

#deleteKey {
    background-color: #f44336;
    color: white;
}

#submitKey {
    grid-column: span 3;
    background-color: #28a745; /* Grün */
    color: white;
    border-radius: 5px;
}

.key:hover, #deleteKey:hover, #submitKey:hover {
    background-color: #777; /* Helleres Grau beim Hover */
}

#submitKey:hover {
    background-color: #218838; /* Dunkleres Grün beim Hover */
}

button {
    padding: 10px 20px;
    background-color: #007BFF;
    color: white;
    border: none;
    cursor: pointer;
    margin-top: 10px;
}

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

#checkinList {
    margin-top: 20px;
    width: 100%;
}

ul {
    list-style-type: none;
    padding: 0;
    width: 100%;
}

li {
    background-color: #e0e0e0;
    padding: 10px;
    margin: 5px 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.remove-btn {
    background-color: #f44336;
    color: white;
    border: none;
    padding: 5px 10px;
    cursor: pointer;
    border-radius: 5px;
}

.remove-btn:hover {
    background-color: #d32f2f;
}

#success-message {
    background-color: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
    padding: 10px;
    margin-top: 10px;
    text-align: center;
    border-radius: 5px;
}

@media (max-width: 600px) {
    .container {
        padding: 10px;
    }

    label, input {
        margin: 5px 0;
    }

    #keypad {
        gap: 5px;
    }

    .key {
        height: 50px;
        font-size: 1.2em;
    }

    button {
        padding: 10px;
    }

    .remove-btn {
        padding: 5px;
    }
}