/* Ngân hàng đề — chỉ thêm class nhd-*, không sửa giao diện cũ */
.nhd-hero{background:linear-gradient(115deg,var(--navy) 0%,var(--navy2) 78%,#4E93CE 100%);border-radius:20px;padding:20px 24px;color:#fff;display:flex;align-items:center;gap:20px;margin-bottom:14px;position:relative;overflow:hidden}.nhd-hero:after{content:"";position:absolute;right:0;top:0;bottom:0;width:34%;opacity:.15;background:repeating-linear-gradient(135deg,transparent 0 18px,#fff 18px 19px)}.nhd-hero>*{position:relative;z-index:1}.nhd-hero h2{font-size:20px;margin-bottom:4px}.nhd-hero p{font-size:13px;opacity:.83}.nhd-hero-count{margin-left:auto;text-align:right}.nhd-hero-count b{font-size:14px;display:block}.nhd-hero-count small{font-size:9.5px;letter-spacing:1.2px;opacity:.85}
.nhd-tabs{display:flex;gap:7px;align-items:center;flex-wrap:wrap;margin-bottom:14px}.nhd-tabs button{border:1px solid var(--vien);background:#fff;color:#53617a;padding:8px 15px;border-radius:999px;font-weight:600}.nhd-tabs button.on{background:var(--navy);border-color:var(--navy);color:#fff}.nhd-tabs .nhd-refresh{margin-left:auto;color:var(--navy2)}
.nhd-note{background:#fff;border-left:4px solid var(--cam);border-radius:14px;padding:11px 14px;margin-bottom:14px;box-shadow:0 2px 10px rgba(31,56,100,.04);font-size:12.5px}.nhd-steps{margin:12px 0 0 22px;line-height:1.8}
.nhd-tax-grid{display:grid;grid-template-columns:repeat(4,minmax(205px,1fr));gap:12px}.nhd-tax-col{background:#fff;border:1px solid var(--vien);border-radius:18px;min-height:420px;overflow:hidden;box-shadow:0 2px 12px rgba(31,56,100,.04)}.nhd-tax-head{display:flex;align-items:center;justify-content:space-between;padding:13px 14px;border-bottom:1px solid var(--vien)}.nhd-tax-head small,.nhd-card-head small{color:var(--mo);font-size:9.5px;letter-spacing:1px}.nhd-tax-head h3,.nhd-card-head h3{font-size:15px}.nhd-tax-head>button{width:32px;height:32px;border:0;border-radius:50%;background:var(--navy2);color:#fff;font-size:18px}.nhd-tax-list{padding:8px;max-height:520px;overflow:auto}.nhd-tax-item{display:grid;grid-template-columns:48px minmax(0,1fr) auto;gap:8px;align-items:center;padding:9px;border:1px solid transparent;border-radius:11px;cursor:pointer;margin-bottom:3px}.nhd-tax-item:hover{background:#F5F8FC}.nhd-tax-item.on{background:var(--xnhat);border-color:#BBCBE3}.nhd-tax-code{font-family:Consolas,monospace;color:var(--navy2);font-size:11px;font-weight:700}.nhd-tax-name{font-size:12.5px;font-weight:600}.nhd-tax-actions{display:flex;gap:3px;opacity:0}.nhd-tax-item:hover .nhd-tax-actions,.nhd-tax-item.on .nhd-tax-actions{opacity:1}.nhd-tax-actions button{width:25px;height:25px;border:0;border-radius:7px;background:#fff;color:#6e7d94}.nhd-empty{padding:30px 10px;text-align:center;color:var(--mo);font-size:12px}.nhd-empty.big{padding:40px}.nhd-path{background:#fff;border-radius:15px;border-left:4px solid var(--navy2);padding:12px 15px;margin-top:13px;display:flex;align-items:center;gap:11px}.nhd-path span{font-size:10px;color:var(--mo);text-transform:uppercase}.nhd-path b{flex:1}
.nhd-bar{display:flex;gap:8px;align-items:center;flex-wrap:wrap;margin-bottom:13px}.nhd-bar input{min-width:220px}.nhd-table-wrap{overflow:auto}.nhd-table{min-width:1050px}.nhd-table .nhd-stem{font-family:"Times New Roman",Times,serif;font-size:12pt;max-width:430px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.nhd-path-cell{font-size:11px;color:var(--mo);max-width:250px}.nhd-sm{padding:4px 10px!important;font-size:11.5px!important}
.nhd-editor-grid{display:grid;grid-template-columns:minmax(560px,1.05fr) minmax(500px,.95fr);gap:13px;align-items:start}.nhd-editor{overflow:visible}.nhd-preview-stack{display:grid;gap:13px;position:sticky;top:79px}.nhd-card-head{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:13px 16px;border-bottom:1px solid var(--vien)}.nhd-card-body{padding:16px}.nhd-grid2{display:grid;grid-template-columns:1fr 1fr;gap:11px}.nhd-grid4{display:grid;grid-template-columns:1.35fr .65fr .75fr 1.2fr;gap:10px}.nhd-field{margin-bottom:12px}.nhd-field label{display:block;color:var(--mo);font-size:10px;font-weight:700;text-transform:uppercase;letter-spacing:.4px;margin-bottom:4px}.nhd-field input,.nhd-field select,.nhd-field textarea{width:100%}.nhd-field textarea{resize:vertical;min-height:72px}.nhd-content textarea,.nhd-answer-row textarea{font-family:"Times New Roman",Times,serif;font-size:12pt;line-height:1.5}.nhd-rule{background:#FDF3EF;border-left:4px solid var(--cam);border-radius:11px;padding:9px 12px;margin-bottom:12px;font-size:12px}.nhd-answer-row{display:grid;grid-template-columns:32px minmax(0,1fr) 65px;gap:8px;align-items:start;margin-bottom:7px}.nhd-answer-row>b{height:32px;display:grid;place-items:center;border:1px solid var(--vien);border-radius:9px;background:#F7F9FC}.nhd-answer-row textarea{min-height:57px}.nhd-answer-row select{margin-top:0}.nhd-radio{font-size:11px!important;text-transform:none!important;color:var(--chu)!important;padding-top:8px;white-space:nowrap}.nhd-radio input{width:auto}.nhd-code{height:180px!important;font-family:Consolas,monospace!important;font-size:11.5px!important}.nhd-actions{display:flex;gap:7px;flex-wrap:wrap;margin-top:4px}
.nhd-preview{padding:23px 25px 28px;min-height:350px}.nhd-q-meta{display:flex;justify-content:space-between;align-items:center}.nhd-q-meta b{color:var(--navy2);font-family:Consolas,monospace}.nhd-q-meta span{font-size:11px;color:var(--mo)}.nhd-math{font-family:"Times New Roman",Times,serif;font-size:12pt;line-height:1.5}.nhd-pre-options{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin-top:20px}.nhd-pre-option{min-height:60px;border:1.5px solid var(--vien);border-radius:14px;padding:10px 12px;display:flex;align-items:center;gap:10px;font-family:"Times New Roman",Times,serif;font-size:12pt}.nhd-pre-option>b{width:34px;height:34px;flex:0 0 34px;border-radius:50%;display:grid;place-items:center;border:1px solid #c9d5e5;font-family:"Segoe UI",sans-serif;font-size:13px}.nhd-pre-option.correct{background:#EDF4FC;border:2px solid var(--navy2)}.nhd-pre-option.correct>b{background:var(--navy2);color:#fff;border-color:var(--navy2)}.nhd-pre-option em{margin-left:auto;color:var(--navy2);font-family:"Segoe UI";font-size:11px}.nhd-short-answer,.nhd-pre-solution{margin-top:16px;padding:11px;border-radius:11px;background:#F7F9FC}.nhd-svg-frame{width:100%;height:300px;border:0;background:#fff}.nhd-ok{font-size:10px;background:#EAF6ED;color:#2F6D42;padding:4px 8px;border-radius:999px;font-weight:700}
.nhd-settings-grid{display:grid;grid-template-columns:1fr 1fr;gap:13px}.nhd-switch{display:flex;align-items:center;gap:8px;margin-bottom:14px;font-weight:600}.nhd-switch input{width:18px;height:18px}.nhd-code-example{font-family:Consolas,monospace;font-size:22px;font-weight:700;color:var(--navy2);padding:16px;background:#F4F7FC;border-radius:13px;text-align:center;margin-bottom:13px}.nhd-rules{margin-left:20px;line-height:1.8}
.nhd-modal{position:fixed;inset:0;z-index:100;background:rgba(20,32,54,.5);display:grid;place-items:center;padding:20px}.nhd-modal-box{width:min(460px,100%);background:#fff;border-radius:18px;box-shadow:0 24px 70px rgba(15,28,52,.28)}.nhd-modal-head{display:flex;align-items:center;padding:14px 17px;border-bottom:1px solid var(--vien)}.nhd-modal-head h3{font-size:15px}.nhd-modal-head button{margin-left:auto;border:0;background:none;font-size:24px;color:var(--mo)}.nhd-modal-body{padding:17px}.nhd-modal-body>div{margin-bottom:12px}.nhd-modal-body label{display:block;font-size:10px;color:var(--mo);font-weight:700;text-transform:uppercase;margin-bottom:4px}.nhd-modal-body input,.nhd-modal-body select{width:100%}.nhd-modal-body small{font-size:10px;color:var(--mo)}.nhd-modal-actions{display:flex;justify-content:flex-end;gap:7px;margin-bottom:0!important}
@media(max-width:1250px){.nhd-tax-grid{grid-template-columns:1fr 1fr}.nhd-editor-grid{grid-template-columns:1fr}.nhd-preview-stack{position:static}}@media(max-width:720px){.nhd-tax-grid,.nhd-settings-grid,.nhd-grid2,.nhd-grid4,.nhd-pre-options{grid-template-columns:1fr}.nhd-hero-count{display:none}.nhd-path{align-items:flex-start;flex-direction:column}.nhd-answer-row{grid-template-columns:32px minmax(0,1fr)}.nhd-answer-row>*:last-child{grid-column:2}.nhd-tabs .nhd-refresh{margin-left:0}}
.nhd-actions .btn.danger{background:#fff;color:var(--do);border:1px solid rgba(160,48,39,.28)}.nhd-path .btn:disabled{opacity:.45;cursor:not-allowed}