.form-group{margin-bottom:1rem}.form{margin-top:1rem}.form label{margin-bottom:.5rem}.form button{margin-top:1rem}.form-control{display:block;width:100%;padding:.375rem .75rem;font-size:1.1rem;font-weight:400;line-height:1.5;color:#212529;background-color:#fff;background-clip:padding-box;border:1px solid #ced4da;-webkit-appearance:none;-moz-appearance:none;appearance:none;border-radius:.25rem;transition:border-color .15s ease-in-out, box-shadow .15s ease-in-out}.book_filter_list .book-classnumber{margin:30px 0 15px}.book_filter_list .bookcard-item{width:180px;height:320px;display:inline-block;vertical-align:top;text-align:center;margin-right:10px;margin-bottom:25px;padding:15px 5px;border-radius:16px;background:var(--card-bg);box-shadow:rgba(0,0,0,0.05) 0px 2px 15px;position:relative;overflow:hidden}@media (max-width: 450px){.book_filter_list .bookcard-item{width:100%}}.book_filter_list .bookcard-item::before{content:"";position:absolute;top:0px;left:0px;width:100%;height:4px;background:linear-gradient(90deg, var(--primary) 0, var(--primary-light) 100%)}.book_filter_list .bookcard-item .cover{width:150px;height:170px;margin:auto}.book_filter_list .bookcard-item .cover img{max-width:100%;max-height:100%;border-radius:12px;border:1px solid rgba(0,0,0,0.1);box-shadow:0 2px 4px rgba(0,0,0,0.05);-o-object-fit:contain;object-fit:contain}.book_filter_list .bookcard-item p{margin:10px 0 0;text-align:center;color:var(--text)}.book_filter{margin-top:20px}.book_filter .btn-classnumber{width:100px;margin-right:10px;margin-bottom:10px}.book_filter .btn-classnumber-active{background-color:var(--primary-dark)}.book_filter .btn-subject{margin-right:10px;margin-bottom:10px}.book_filter .btn-subject-active{background-color:var(--secondary-dark)}.book_filter .subject-gap{margin-top:20px}.task_structure{list-style:none;margin-top:30px}.task_structure .newlevel{margin-left:1rem;border-left:2px solid var(--primary-light);padding-left:1.5rem}.task_structure .newlevel.level-0{margin-left:0;border-left:none;padding-left:0}.task_structure .chapter{padding:0.5rem 0;font-size:1rem;font-weight:500}.task_structure .chapter span::before{content:'📑';margin-right:5px}.task_structure .chapter.level-0{box-shadow:0 2px 8px rgba(0,0,0,0.05);margin-bottom:1rem;margin-top:1rem;transition:all 0.2s ease;position:relative;padding:1rem 1.25rem;font-size:1.1rem;font-weight:600;background:var(--card-bg);border-radius:8px}.task_structure .chapter.level-0::before{content:'';position:absolute;left:0;top:0;height:100%;width:3px;background:var(--primary);border-radius:8px 0 0 8px}.task_structure .chapter.level-0 span::before{content:'📚';margin-right:5px;font-size:1.2rem}.task_structure .task-list{--size: 45px}.task_structure .task-list li{display:inline-block;min-width:var(--size);min-height:var(--size);text-align:center;border-radius:.5rem;border-color:var(--border);margin-right:3px;margin-bottom:10px;line-height:var(--size)}.task_structure .task-list li.noexist{border:1px solid transparent;padding:0 5px;border-color:var(--border)}.task_structure .task-list li a{width:100%;display:block;padding:0 5px;color:var(--card-bg);background-color:var(--primary);border-radius:.5rem}.task_structure .task-list li a:hover{background-color:var(--primary-dark);color:var(--card-bg)}@media (max-width: 768px){.task_structure .task-list{grid-template-columns:repeat(auto-fill, minmax(50px, 1fr));gap:0.4rem}.task_structure.level-1,.task_structure.level-2{margin-left:1rem;padding-left:1rem}}