body {
    font-family: Arial, sans-serif;
    background: #f4f7fb;
    margin: 0;
    padding: 0;
}

.container {
    width: 900px;
    margin: auto;
    background: #fff;
    padding: 25px;
    margin-top: 30px;
    border-radius: 8px;
    box-shadow: 0px 0px 10px rgba(0,0,0,0.1);
}

h2 {
    color: #003366;
}

.course-box {
    border: 1px solid #ddd;
    padding: 15px;
    margin-bottom: 15px;
    border-radius: 6px;
}

.btn {
    background: #007BFF;
    color: #fff;
    padding: 10px 18px;
    border: none;
    border-radius: 5px;
    text-decoration: none;
    cursor: pointer;
}

.btn:hover {
    background: #0056b3;
}

.nav-btn{
    width:auto !important;
    display:inline-block;
    padding:8px 18px;
    margin:0 5px;
    background:#FF8C00;
    color:white;
    border:none;
    border-radius:5px;
    cursor:pointer;
    text-decoration:none;
    font-size:14px;
}

.notice {
    background: #fff3cd;
    padding: 10px;
    border-left: 5px solid orange;
    margin-bottom: 15px;
}

.success {
    background: #d4edda;
    padding: 10px;
    border-left: 5px solid green;
}

.fail {
    background: #f8d7da;
    padding: 10px;
    border-left: 5px solid red;
}