* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html, body {
    height: 100%;
}

body {
    font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    display: flex;
    flex-direction: column;
}

/* Layout */
.app {
    display: flex;
    flex: 1;
    min-height: 0;
}

/* Sidebar */
.sidebar {
    width: 280px;
    border-right: 1px solid #ccc;
    padding: 10px;
    display: flex;
    flex-direction: column;
    gap: 8px;
    background: #f7f7f7;
}

#openFolderBtn {
    padding: 8px 10px;
    border: 1px solid #999;
    background: #e0e0e0;
    cursor: pointer;
    font-size: 14px;
}

#openFolderBtn:hover {
    background: #d0d0d0;
}

#folderPath {
    font-size: 12px;
    color: #555;
    word-break: break-all;
}

/* Tree */
.tree {
    flex: 1;
    overflow: auto;
    border: 1px solid #ddd;
    padding: 5px;
    background: #fff;
    direction: ltr;
    font-size: 13px;
}

.tree ul {
    list-style: none;
    margin-left: 16px;
}

.tree li {
    margin: 2px 0;
}

.dir-label,
.file-label {
    cursor: pointer;
    padding: 2px 4px;
    border-radius: 3px;
    display: inline-block;
    user-select: none;
}

.dir-label::before {
    content: "📁 ";
}

.file-label::before {
    content: "📄 ";
}

.file-label.image::before {
    content: "🖼️ ";
}

.file-label.active {
    background: #0077ff;
    color: #fff;
}

.dir.open > .dir-label::before {
    content: "📂 ";
}

/* انتخاب نود درخت */
.tree .selected {
    background: #e6f0ff;
    outline: 1px solid #0077ff;
}

/* مقصد Drop برای دایرکتوری */
.dir-label.drop-target {
    background: #d0ebff;
}