body {
    font-family: Arial, sans-serif;
    line-height: 1.6;
    margin: 0;
    padding: 0;
    background-color: #f4f4f4;
}

.container {
    width: 80%;
    margin: auto;
    overflow: hidden;
    padding: 20px;
}

h1, h2 {
    color: #333;
}

input[type="text"],
input[type="password"],
input[type="file"],
select,
button {
    display: block;
    width: 100%;
    padding: 10px;
    margin-bottom: 10px;
    border: 1px solid #ddd;
    border-radius: 4px;
}

button {
    background-color: #333;
    color: #fff;
    border: none;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

button:hover {
    background-color: #555;
}

button:disabled {
    background-color: #999;
    cursor: not-allowed;
}

nav ul {
    list-style-type: none;
    padding: 0;
    background-color: #333;
    overflow: hidden;
}

nav ul li {
    float: left;
}

nav ul li a {
    display: block;
    color: white;
    text-align: center;
    padding: 14px 16px;
    text-decoration: none;
}

nav ul li a:hover {
    background-color: #111;
}

section {
    margin-bottom: 20px;
    background-color: #fff;
    padding: 20px;
    border-radius: 4px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

#leadDetails {
    background-color: #e9e9e9;
    padding: 10px;
    border-radius: 4px;
    margin-bottom: 10px;
}

#callControls {
    display: flex;
    justify-content: space-between;
}

#callControls button {
    width: 48%;
}

#navigation {
    display: flex;
    justify-content: space-between;
    margin-top: 20px;
}

#navigation button {
    width: 48%;
}

#csvPreview, #campaignList, #userList {
    margin-top: 20px;
    border: 1px solid #ddd;
    padding: 10px;
    border-radius: 4px;
}