os-gui/style.css

body {
    margin: 0;
    font-family: Arial, sans-serif;
    background: #282c34;
    height: 100vh;
    overflow: hidden;
    user-select: none;
}

#new-window-btn {
    position: fixed;
    top: 10px;
    left: 10px;
    padding: 8px 16px;
    z-index: 1000;
    cursor: pointer;
}

#desktop {
    position: relative;
    width: 100vw;
    height: 100vh;
    overflow: hidden;
}

.window {
    position: absolute;
    width: 400px;
    height: 300px;
    border: 1px solid #888;
    background: white;
    box-shadow: 0 0 10px rgba(0,0,0,0.7);
    display: flex;
    flex-direction: column;
    user-select: none;
}

.window-noborder {
    border: 0px #000 !important;
}

.window-header {
    background: #444;
    color: white;
    padding: 6px 10px;
    cursor: grab;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.window-header:active {
    cursor: grabbing;
}

.window-title {
    font-weight: bold;
    font-size: 14px;
}

.window-close-btn {
    background: #ff4d4d;
    border: none;
    color: white;
    font-weight: bold;
    cursor: pointer;
    width: 22px;
    height: 22px;
    border-radius: 3px;
    display: flex;
    align-items: center;
    justify-content: center;
    line-height: 0;
}

.window-iframe {
    flex: 1;
    border: none;
    width: 100%;
}

.window-hidden {
    display: none !important;
}

.background-layer-windower {
    z-index: -4;
}