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

header {
    background: #35424a;
    color: #ffffff;
    padding: 10px 0;
    text-align: center;
}

h1 {
    margin: 0;
}

.container {
    width: 80%;
    margin: auto;
    overflow: hidden;
}

.card-form {
    background: #ffffff;
    padding: 20px;
    border-radius: 5px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
}

.card-form input[type="text"],
.card-form input[type="number"],
.card-form select {
    width: 100%;
    padding: 10px;
    margin: 10px 0;
    border: 1px solid #ccc;
    border-radius: 5px;
}

.card-form button {
    background: #35424a;
    color: #ffffff;
    border: none;
    padding: 10px 15px;
    cursor: pointer;
    border-radius: 5px;
}

.card-form button:hover {
    background: #45a049;
}

.card-list {
    margin-top: 20px;
}

.card-item {
    background: #ffffff;
    padding: 15px;
    margin: 10px 0;
    border-radius: 5px;
    box-shadow: 0 0 5px rgba(0, 0, 0, 0.1);
}

.card-item h3 {
    margin: 0;
}

.card-item p {
    margin: 5px 0;
}

.footer {
    text-align: center;
    padding: 20px;
    background: #35424a;
    color: #ffffff;
    position: relative;
    bottom: 0;
    width: 100%;
}

#loading-spinner {
    display: none;
    border: 16px solid #f3f3f3;
    border-radius: 50%;
    border-top: 16px solid #3498db;
    width: 60px;
    height: 60px;
    animation: spin 2s linear infinite;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}