ul{list-style-type:none;padding:10px;margin:0}.arrow{display:inline-block;width:8px;height:8px;border:solid #333;border-width:0 1px 1px 0;transform:rotate(45deg);margin-left:20px;margin-right:10px;transition:transform .3s ease}.arrow-up{transform:rotate(-135deg)}.arrow2,.arrow-down{transform:rotate(45deg)}.arrow2{display:inline-block;width:8px;height:8px;border:solid #333;border-color:#f4f4f4;border-width:0 1px 1px 0;margin-left:20px;margin-right:10px;transition:transform .3s ease}.arrow-up2{transform:rotate(-135deg)}.arrow-down2{transform:rotate(45deg)}.nested-content{padding-left:20px;background-color:#f4f4f4;overflow:hidden;max-height:0;opacity:0;transition:max-height .3s ease,opacity .3s ease}.nested-content.open{max-height:1000px;opacity:1}.fas.fa-folder{color:#333;transition:color .3s ease;width:10px;height:10px;margin-right:10px}.fas.fa-folder-open{color:#ffeb3b;margin-right:10px}.fas.fa-pen{color:#666;font-size:14px;cursor:pointer;transition:color .3s ease,transform .3s ease}.fas.fa-pen:hover{color:#007bff;transform:scale(1.1)}.fas fa-plus{color:#666;font-size:14px;cursor:pointer;transition:color .3s ease,transform .3s ease}.fas.fa-plus:hover{color:#228b22;transform:scale(1.1)}.fas fa-book{color:#666;font-size:14px;cursor:pointer;transition:color .3s ease,transform .3s ease}.fas.fa-book:hover{color:navy;transform:scale(1.1)}.fas fa-trash{color:#666;font-size:14px;cursor:pointer;transition:color .3s ease,transform .3s ease}.fas.fa-trash:hover{color:#8b0000;transform:scale(1.1)}input.upload-input{display:inline-block;margin-left:10px;width:50%}.file-list{padding-left:10px;margin-top:5px}.file-item{margin-bottom:5px}