/* Ra đề kiểm tra — giao diện SaaS tối giản (kiểu Shadcn / Linear). Mọi luật nằm trong .rd. */
.rd{--fg:#18181b;--mut:#71717a;--line:#e4e4e7;--in:#d4d4d8;--soft:#f4f4f5;--bg:#fafafa;--acc:#3874ff;--acc-s:#2557d6;--ok:#15803d;--ok-bg:#f0fdf4;--ok-ln:#bbf7d0;--bad:#dc2626;
font:14px/1.5 Inter,"Be Vietnam Pro",ui-sans-serif,system-ui,"Segoe UI",Roboto,Arial,sans-serif;color:var(--fg);-webkit-font-smoothing:antialiased;font-variant-numeric:tabular-nums}
.rd,.rd *{box-sizing:border-box}
.rd [hidden]{display:none!important}
.rd h1,.rd h2,.rd h3,.rd p{margin:0;font-family:inherit;color:inherit}
.rd button,.rd input,.rd select,.rd textarea{font:inherit;color:inherit}
.rd svg{display:block;flex:none;width:16px;height:16px;fill:none;stroke:currentColor;stroke-width:1.75;stroke-linecap:round;stroke-linejoin:round}
.rd svg.rd-sprite{position:absolute;width:0;height:0}
.rd svg.rd-big{width:28px;height:28px;color:var(--mut)}

/* Tiêu đề trang */
.rd-head{margin:0 0 24px}
.rd .rd-head h1{font-size:24px;line-height:32px;font-weight:600;letter-spacing:-.02em}
.rd .rd-head p{margin-top:4px;color:var(--mut);max-width:64ch}

/* Bố cục 2 cột */
.rd.tw-container-fluid{max-width:none;margin:0;zoom:.9}
.rd-grid{display:grid;grid-template-columns:380px minmax(0,1fr);gap:24px;align-items:start}
.rd-rail{display:grid;gap:16px}
.rd-card{background:#fff;border:1px solid var(--line);border-radius:12px;box-shadow:0 1px 2px rgba(0,0,0,.04)}

/* Thông báo */
.rd-alert{display:flex;gap:10px;align-items:flex-start;margin-bottom:16px;padding:12px 14px;border:1px solid var(--line);border-radius:10px;font-size:13.5px}
.rd-alert.ok{background:var(--ok-bg);border-color:var(--ok-ln);color:#166534}
.rd-alert.bad{margin:0 0 14px;background:#fef2f2;border-color:#fecaca;color:#991b1b}
.rd-alert svg{margin-top:2px}

/* Tạo đề / Nhập đề: chuyển chế độ bằng CSS thuần */
.rd-create{position:relative}
.rd-mode{position:absolute;opacity:0;pointer-events:none}
.rd-tabs{display:flex;gap:2px;margin:12px 12px 0;padding:3px;background:var(--soft);border-radius:8px}
.rd .rd-tabs label{flex:1;padding:6px 8px;border-radius:6px;text-align:center;font-weight:500;color:var(--mut);cursor:pointer}
#exModeGen:checked~.rd-tabs label[for=exModeGen],#exModeImp:checked~.rd-tabs label[for=exModeImp]{background:#fff;color:var(--fg);box-shadow:0 1px 2px rgba(0,0,0,.1)}
#exModeGen:focus-visible~.rd-tabs label[for=exModeGen],#exModeImp:focus-visible~.rd-tabs label[for=exModeImp]{outline:2px solid var(--acc)}
#exModeGen:checked~.rd-pane-imp,#exModeImp:checked~.rd-pane-gen{display:none}
.rd-pane{padding:16px}

/* Form */
.rd-row{display:grid;gap:12px}
.rd-r2{grid-template-columns:1fr 1fr}
.rd-r3{grid-template-columns:repeat(3,1fr)}
.rd-r21{grid-template-columns:3fr 2fr}
.rd-f{display:grid;gap:6px;margin-bottom:14px;align-content:start}
.rd-f>span{font-size:13px;font-weight:500}
.rd input[type=text],.rd input[type=number],.rd select,.rd textarea{width:100%;height:36px;padding:0 10px;border:1px solid var(--in);border-radius:8px;background:#fff;box-shadow:0 1px 2px rgba(0,0,0,.04);transition:border-color .12s,box-shadow .12s}
.rd textarea{height:auto;padding:8px 10px;resize:vertical;line-height:1.5}
.rd-f>.rd-suf{position:relative;display:block;font-size:14px;font-weight:400}
.rd .rd-suf input{padding-right:46px;-moz-appearance:textfield;appearance:textfield}
.rd .rd-suf input::-webkit-outer-spin-button,.rd .rd-suf input::-webkit-inner-spin-button{-webkit-appearance:none;margin:0}
.rd-suf i{position:absolute;right:11px;top:0;line-height:36px;font-style:normal;font-size:13px;color:var(--mut);pointer-events:none}
.rd ::placeholder{color:#a1a1aa}
.rd input:focus,.rd select:focus,.rd textarea:focus{outline:0;border-color:var(--acc);box-shadow:0 0 0 3px rgba(56,116,255,.2)}
.rd input.is-bad,.rd select.is-bad{border-color:var(--bad)}
.rd input.is-bad:focus,.rd select.is-bad:focus{box-shadow:0 0 0 3px rgba(220,38,38,.18)}
.rd-err{color:var(--bad);font-size:12.5px;font-style:normal}
.rd-hint{margin:10px 0 0;color:var(--mut);font-size:12.5px;line-height:1.55}
.rd-hint code{padding:0 4px;border-radius:4px;background:var(--soft)}
.rd-check{display:flex;gap:8px;align-items:center;margin:12px 0;font-size:13px}
.rd-mt{margin-top:14px}

/* Nút */
.rd .rd-btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;height:36px;padding:0 14px;border:1px solid transparent;border-radius:8px;font-size:14px;font-weight:500;line-height:1;text-decoration:none;white-space:nowrap;cursor:pointer;transition:background .12s}
.rd .rd-btn:focus-visible{outline:2px solid var(--acc);outline-offset:2px}
.rd .rd-btn:disabled{opacity:.5;cursor:not-allowed}
.rd .rd-btn-pri{width:100%;background:#18181b;color:#fafafa}
.rd .rd-btn-pri:hover{background:#3f3f46}
.rd .rd-btn-out{height:32px;padding:0 12px;font-size:13px;background:#fff;border-color:var(--in);box-shadow:0 1px 2px rgba(0,0,0,.04)}
.rd .rd-btn-out:hover{background:var(--soft)}
.rd .rd-btn-solid{height:32px;padding:0 12px;font-size:13px;background:#18181b;color:#fafafa}
.rd .rd-btn-solid:hover{background:#3f3f46}
.rd .rd-wide{width:100%}

/* Nhóm chọn: mức độ, tab nhập đề, hiện/ẩn đáp án */
.rd .tw-mode-switch,.rd .tw-mode-btn{all:unset;box-sizing:border-box}
.rd .rd-seg,.rd .tw-mode-switch{display:flex;gap:2px;padding:3px;background:var(--soft);border-radius:8px}
.rd-tabs2{margin-bottom:14px}
.rd .rd-seg label{position:relative;flex:1}
.rd .rd-seg input{position:absolute;inset:0;opacity:0;cursor:pointer}
.rd .rd-seg-b,.rd .tw-mode-btn,.rd .rd-tab{display:block;flex:1;padding:5px 12px;border:0;border-radius:6px;background:none;text-align:center;font-size:13px;font-weight:500;color:var(--mut);white-space:nowrap;cursor:pointer}
.rd .rd-seg input:checked+.rd-seg-b,.rd .tw-mode-btn-active,.rd .rd-tab.tw-tab-btn-active{background:#fff;color:var(--fg);box-shadow:0 1px 2px rgba(0,0,0,.1)}
.rd .rd-seg input:focus-visible+.rd-seg-b,.rd .tw-mode-btn:focus-visible,.rd .rd-tab:focus-visible{outline:2px solid var(--acc)}

/* Tải tệp / OCR */
.rd .tw-file-drop{all:unset;box-sizing:border-box;display:flex;flex-direction:column;align-items:center;gap:4px;padding:24px 16px;border:1px dashed var(--in);border-radius:10px;background:var(--bg);text-align:center;cursor:pointer}
.rd .tw-file-drop:hover,.rd .tw-file-drop.tw-file-drop-has-file{border-color:var(--acc);background:#f5f8ff}
.rd .tw-file-drop b{font-weight:500}
.rd .tw-file-drop small{color:var(--mut);font-size:12.5px;word-break:break-all}
.rd-prog{height:6px;margin-top:12px;border-radius:9px;background:var(--soft);overflow:hidden}
.rd-prog i{display:block;width:0;height:100%;background:var(--fg);transition:width .2s}

/* Đề đã lưu */
.rd-hh{display:flex;align-items:center;justify-content:space-between;padding:14px 16px 8px}
.rd .rd-hh h2{font-size:14px;font-weight:600}
.rd-count{min-width:22px;padding:0 6px;border-radius:6px;background:var(--soft);text-align:center;color:var(--mut);font-size:12px;font-weight:500;line-height:20px}
.rd-hs{position:relative;padding:0 12px 8px}
.rd-hs svg{position:absolute;left:24px;top:10px;color:#a1a1aa}
.rd .rd-hs input{padding-left:32px}
.rd-hist{max-height:340px;padding:0 8px 8px;overflow:auto}
.rd .tw-history-item{all:unset;box-sizing:border-box;position:relative;display:flex;align-items:center;gap:4px;padding-right:4px;border-radius:8px}
.rd .tw-history-item:hover{background:var(--bg)}
.rd .tw-history-item.tw-history-item-active{background:var(--soft)}
.rd .tw-history-item.tw-history-item-active::before{content:"";position:absolute;left:0;top:10px;bottom:10px;width:2px;border-radius:2px;background:var(--acc)}
.rd .rd-hlink{display:grid;flex:1;gap:2px;min-width:0;padding:8px 8px 8px 12px;color:inherit;text-decoration:none}
.rd-ht{overflow:hidden;font-weight:500;text-overflow:ellipsis;white-space:nowrap}
.rd-hm{display:flex;gap:8px;align-items:center;color:var(--mut);font-size:12.5px}
.rd-tag{padding:0 6px;border:1px solid var(--line);border-radius:5px;background:#fff;font-size:12px;line-height:18px}
.rd .rd-del{display:grid;place-items:center;width:28px;height:28px;border:0;border-radius:6px;background:none;color:#a1a1aa;cursor:pointer}
.rd .rd-del:hover{background:#fee2e2;color:var(--bad)}
.rd-none{display:none;padding:14px;text-align:center;color:var(--mut)}
.rd-nolib{padding:0 16px 18px;color:var(--mut)}

/* Đề thi */
.rd-paper{overflow:hidden}
.rd-ph{display:flex;flex-wrap:wrap;gap:16px;justify-content:space-between;align-items:flex-start;padding:24px 28px 20px;border-bottom:1px solid var(--line)}
.rd .rd-ph h2{font-size:24px;line-height:32px;font-weight:600;letter-spacing:-.02em}
.rd-meta{display:flex;flex-wrap:wrap;gap:6px;margin-top:10px}
.rd-pill{padding:2px 10px;border:1px solid var(--line);border-radius:6px;background:var(--bg);font-size:12.5px;font-weight:500}
.rd-tools{display:flex;flex-wrap:wrap;gap:8px;align-items:center}
.rd-pb{padding:4px 28px 28px}
.rd-sec{display:flex;align-items:baseline;gap:10px;margin:28px 0 10px}
.rd .rd-sec h3{font-size:15px;font-weight:600}
.rd-sec span{color:var(--mut);font-size:13px}
.rd-scroll{overflow-x:auto}
.rd-mx{width:100%;border-collapse:separate;border-spacing:0;border:1px solid var(--line);border-radius:10px;overflow:hidden}
.rd-mx th,.rd-mx td{padding:10px 14px;border-bottom:1px solid var(--line);text-align:center}
.rd-mx th{background:var(--bg);color:var(--mut);font-size:13px;font-weight:500}
.rd-mx th:first-child,.rd-mx td:first-child{text-align:left}
.rd-mx tr:last-child td{border-bottom:0}
.rd-mx b{font-weight:600}
.rd-note{padding:12px 14px;border:1px dashed var(--in);border-radius:10px;color:var(--mut)}

/* Câu hỏi: nội dung bên trái, mức độ + điểm căn phải như cột chấm điểm */
.rd-q{display:grid;grid-template-columns:minmax(0,1fr) auto;gap:10px 24px;padding:16px 0;border-top:1px solid var(--line)}
.rd-qt{font-size:15px;line-height:24px;overflow-wrap:anywhere}
.rd-qn{margin-right:4px;font-weight:600}
.rd-side{display:flex;flex-direction:column;align-items:flex-end;gap:2px;min-width:92px;font-size:12.5px;color:var(--mut)}
.rd-pts{font-size:13px;font-weight:600;color:var(--fg)}
.rd-lv{display:inline-flex;gap:6px;align-items:center}
.rd-lv::before{content:"";width:7px;height:7px;border-radius:50%;background:#c7d2fe}
.rd-lv.l2::before{background:#93a9fb}
.rd-lv.l3::before{background:#5b7df0}
.rd-lv.l4::before{background:#2f3fa8}
.rd-opts{grid-column:1/-1;display:grid;grid-template-columns:1fr 1fr;gap:8px}
.rd-opt{display:flex;gap:10px;align-items:flex-start;padding:8px 12px;border:1px solid var(--line);border-radius:8px}
.rd-ol{display:grid;place-items:center;flex:none;width:22px;height:22px;border-radius:6px;background:var(--soft);font-size:12px;font-weight:600}
.rd-opt.ok{background:var(--ok-bg);border-color:var(--ok-ln)}
.rd-opt.ok .rd-ol{background:var(--ok);color:#fff}
.rd-opt.ok::after{content:"✓";margin-left:auto;color:var(--ok);font-weight:700}
.tw-hide-answers .rd-opt.ok{background:none;border-color:var(--line)}
.tw-hide-answers .rd-opt.ok .rd-ol{background:var(--soft);color:inherit}
.tw-hide-answers .rd-opt.ok::after{content:none}

/* Trạng thái rỗng */
.rd-empty{display:grid;justify-items:center;gap:6px;padding:72px 24px;text-align:center;color:var(--mut)}
.rd .rd-empty h3{font-size:16px;font-weight:600;color:var(--fg)}
.rd-empty p{max-width:40ch}
.rd-ei{display:grid;place-items:center;width:48px;height:48px;margin-bottom:6px;border:1px solid var(--line);border-radius:12px;background:var(--bg)}

@media (max-width:1200px){.rd-grid{grid-template-columns:1fr}.rd-rail{grid-template-columns:repeat(2,minmax(0,1fr));align-items:start}}
@media (max-width:820px){.rd-rail{grid-template-columns:1fr}}
@media (max-width:640px){.rd-opts{grid-template-columns:1fr}.rd-r3{grid-template-columns:1fr 1fr}.rd-r3>.rd-f:last-child{grid-column:1/-1}.rd-q{grid-template-columns:1fr}.rd-side{flex-direction:row;align-items:center;gap:12px}.rd-ph,.rd-pb{padding-left:16px;padding-right:16px}}
@media (max-width:360px){.rd-r2,.rd-r21{grid-template-columns:1fr}}
@media (prefers-reduced-motion:reduce){.rd *{transition:none!important}}
@media print{.rd-grid{display:block}.rd-rail,.rd-head,.rd-alert,.rd-tools{display:none!important}.rd-card{border:0}.rd.tw-container-fluid{zoom:1;max-width:none;padding:0}.rd-q{break-inside:avoid}}
/* ===== v7: bố cục dọc — thẻ chế độ xếp ngang + khung kéo thả lớn + đề đã lưu dạng lưới ===== */
.rd .rd-modes{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:14px;margin:0 0 16px}
.rd .rd-mc{all:unset;box-sizing:border-box;display:grid;gap:4px;align-content:start;padding:16px;border:1px solid var(--line);border-radius:12px;background:#fff;box-shadow:0 1px 2px rgba(0,0,0,.04);cursor:pointer;transition:border-color .12s,box-shadow .12s,background .12s}
.rd .rd-mc:hover{border-color:#a9c0ff;box-shadow:0 2px 8px rgba(56,116,255,.12)}
.rd .rd-mc:focus-visible{outline:2px solid var(--acc);outline-offset:2px}
.rd .rd-mc.is-active{border-color:var(--acc);background:#f5f8ff;box-shadow:0 0 0 3px rgba(56,116,255,.15)}
.rd-mi{display:grid;place-items:center;width:40px;height:40px;margin-bottom:6px;border-radius:10px;background:var(--soft);color:var(--mut)}
.rd-mi svg{width:20px;height:20px}
.rd .rd-mc.is-active .rd-mi{background:var(--acc);color:#fff}
.rd-mc b{font-size:15px;font-weight:600}
.rd-mc small{color:var(--mut);font-size:12.5px;line-height:1.45}

.rd-work{margin-bottom:16px}
.rd-work .rd-pane{padding:20px}
.rd-g6{display:grid;grid-template-columns:repeat(6,minmax(0,1fr));gap:14px 16px}
.rd-g6>.rd-f{margin:0}
.rd-g6>.s1{grid-column:span 1}.rd-g6>.s2{grid-column:span 2}.rd-g6>.s3{grid-column:span 3}
.rd-meta-row{margin-top:18px}
.rd-end{align-content:end}
.rd-go{width:auto;min-width:240px;margin:18px 0 0 auto;display:flex}
.rd-end .rd-btn-pri{width:100%}

.rd .rd-drop{all:unset;box-sizing:border-box;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:8px;min-height:280px;padding:32px 20px;border:2px dashed var(--in);border-radius:14px;background:var(--bg);text-align:center;cursor:pointer;transition:border-color .12s,background .12s}
.rd .rd-drop:hover,.rd .rd-drop.is-over,.rd .rd-drop.tw-file-drop-has-file{border-color:var(--acc);background:#f5f8ff}
.rd .rd-drop.is-over{border-style:solid;box-shadow:0 0 0 4px rgba(56,116,255,.15)}
.rd svg.rd-up{width:56px;height:56px;color:var(--acc);stroke-width:1.5}
.rd .rd-drop b{font-size:20px;font-weight:600}
.rd-drop-sub{max-width:60ch;color:var(--mut);font-size:13.5px;word-break:break-all}
.rd-drop-btn{margin-top:6px;padding:8px 18px;border-radius:8px;background:#18181b;color:#fafafa;font-weight:500}
.rd-drop:hover .rd-drop-btn{background:#3f3f46}
.rd .rd-pane textarea{min-height:240px}

.rd .rd-saved .rd-hh{padding:16px 20px 10px}
.rd .rd-saved .rd-hs{max-width:420px;padding:0 20px 12px}
.rd .rd-saved .rd-hs svg{left:32px}
.rd .rd-hist{display:grid;grid-template-columns:repeat(auto-fill,minmax(260px,1fr));gap:10px;max-height:none;padding:0 20px 20px;overflow:visible}
.rd .tw-history-item{border:1px solid var(--line);background:#fff}
.rd .tw-history-item:hover{border-color:#a9c0ff;background:#fff}
.rd .rd-hist .rd-none{grid-column:1/-1}
.rd .rd-saved .rd-nolib{padding:0 20px 20px}

@media (max-width:1100px){.rd .rd-modes{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media (max-width:900px){.rd-g6{grid-template-columns:1fr 1fr}.rd-g6>.s1,.rd-g6>.s2{grid-column:auto}.rd-g6>.s3{grid-column:1/-1}.rd-go{width:100%;margin-left:0}}
@media (max-width:520px){.rd .rd-modes,.rd-g6{grid-template-columns:1fr}.rd .rd-drop{min-height:220px}.rd .rd-drop b{font-size:17px}}