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

header {
    background-color: #333;
    color: #fff;
    padding: 10px 0;
    text-align: center;
}

header .logo {
    display: flex;
    justify-content: center;
    align-items: center;
}

header .logo img {
    height: 40px;
    margin-right: 10px;
}

header .logo h1 {
    margin: 0;
    font-size: 24px;
    color: #ff6300;
}

.clock {
    position: fixed;
    top: 10px;
    left: 10px;
    background-color: #333;
    color: #fff;
    padding: 10px;
    border-radius: 5px;
    font-size: 18px;
    z-index: 1000; /* นำหน้าส่วนอื่น */
}

.file-system {
    max-width: 600px;
    margin: 20px auto;
    background-color: #fff;
    border: 1px solid #ddd;
    padding: 20px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
}

.file-list {
    list-style-type: none;
    padding-left: 20px;
}

.file-list .folder > ul {
    display: none;
    margin-left: 20px;
    padding-left: 0;
}

.file-list .folder::before {
    content: "\1F4C1"; /* Folder icon */
    margin-right: 10px;
}

.file-list .file::before {
    content: "\1F4C4"; /* File icon */
    margin-right: 10px;
}

.folder.open > ul {
    display: block;
}

.watermark {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    opacity: 0.1;
    pointer-events: none;
}

.watermark img {
    max-width: 100%;
    max-height: 100%;
}