*{box-sizing:border-box}:root{--ink:#26314a;--muted:#71809b;--p:#7158e8;--p-dark:#5842c5;--green:#3fc58b;--orange:#ff9f50;--red:#e95e70;--line:#e8edf5;--surface:#fff;--shadow:0 12px 36px #65789c18}
html,body{margin:0;min-height:100%;font-family:Inter,system-ui,-apple-system,"Segoe UI",sans-serif;color:var(--ink);font-size:16px}body{background:radial-gradient(circle at 10% 5%,#dff5ff,transparent 27%),radial-gradient(circle at 92% 12%,#f2e3ff,transparent 29%),linear-gradient(#f8fbff,#fff9ef);min-height:100vh}a{color:var(--p);text-decoration:none}button,input,select,textarea{font:inherit}button,a{ -webkit-tap-highlight-color:transparent}.hidden{display:none!important}
.wrap{max-width:1180px;margin:auto;padding:26px 22px 54px}.admin-wrap{max-width:1280px}.narrow-wrap{max-width:820px}.wide-wrap{max-width:1100px}.top{display:flex;align-items:center;justify-content:space-between;gap:16px}.logo{font-weight:950;font-size:25px}.logo b{color:var(--p)}.chips{display:flex;gap:8px;flex-wrap:wrap}.chip{background:#fff;padding:9px 13px;border-radius:999px;font-weight:850;box-shadow:0 6px 20px #63759a18;white-space:nowrap}
.appbar{position:sticky;top:0;z-index:50;background:#ffffffeb;backdrop-filter:blur(16px);border-bottom:1px solid #e8edf5}.appbar-inner{max-width:1280px;margin:auto;min-height:68px;padding:9px 22px;display:flex;align-items:center;gap:24px}.brand{font-size:21px;font-weight:950;color:var(--ink);white-space:nowrap}.brand b{color:var(--p)}.mainnav{display:flex;align-items:center;gap:5px;flex:1}.mainnav a{padding:10px 13px;border-radius:12px;color:#5f6d86;font-weight:750}.mainnav a:hover,.mainnav a.active{background:#f0edff;color:var(--p)}.userbox{display:flex;align-items:center;gap:10px}.userbox>span{display:flex;flex-direction:column;text-align:right;line-height:1.25}.userbox small{color:var(--muted)}.userbox form,.row-actions form,.card-actions form{margin:0}.icon-btn{border:0;background:#fff;border-radius:12px;min-width:40px;height:40px;display:inline-grid;place-items:center;cursor:pointer;box-shadow:0 5px 16px #65789c18;color:var(--ink)}
.hero{margin-top:22px;padding:32px;border-radius:34px;background:linear-gradient(135deg,#7359e8,#578ce9 58%,#48b9d5);color:#fff;display:grid;grid-template-columns:1fr 190px;align-items:center;box-shadow:0 20px 55px #675fd238}.hero h1{font-size:clamp(31px,5vw,50px);margin:0 0 8px}.hero p{font-size:18px;margin:5px 0}.fox{font-size:108px;text-align:center;filter:drop-shadow(0 12px 10px #0002)}
.mission,.panel{background:#fff;border-radius:25px;padding:24px;box-shadow:var(--shadow)}.mission{margin-top:20px;display:grid;grid-template-columns:1fr auto;align-items:center;gap:18px}.mission h2,.panel h2{margin-top:0}.muted{color:var(--muted)}.start,.primary,.secondary{display:inline-flex;align-items:center;justify-content:center;border:0;border-radius:16px;padding:13px 20px;font-weight:900;cursor:pointer;line-height:1.2}.start{border-radius:20px;padding:16px 25px;color:#fff;background:linear-gradient(135deg,#ffb04c,#ff8d59);box-shadow:0 9px 23px #ff9a4d42}.primary{color:#fff;background:var(--p);box-shadow:0 8px 20px #7158e838}.primary:hover{background:var(--p-dark)}.secondary{background:#edf1f7;color:var(--ink)}.secondary:hover{background:#e3e9f3}.btn-block{width:100%}.start:disabled,.primary:disabled,.check:disabled{opacity:.6;cursor:not-allowed}.pathbox{margin-top:20px}.path{display:flex;justify-content:center;align-items:center;gap:8px;flex-wrap:wrap;font-size:28px}.node{width:55px;height:55px;display:grid;place-items:center;background:#fff;border-radius:50%;box-shadow:0 7px 20px #64779b25}.line{height:6px;width:55px;background:#dfe5ef;border-radius:8px}
.lesson{max-width:760px;margin:auto;padding:28px 20px}.head{display:flex;align-items:center;gap:11px}.home{border:0;background:#fff;border-radius:14px;padding:10px 13px;cursor:pointer;box-shadow:0 5px 16px #65789c18}.progress{flex:1;height:13px;background:#e5eaf3;border-radius:20px;overflow:hidden}.progress span{display:block;height:100%;background:linear-gradient(90deg,#4fc991,#70a6ff);transition:width .35s ease}.qcard{margin-top:18px;background:#fff;border-radius:32px;padding:31px;text-align:center;box-shadow:0 18px 50px #65789c20}.tag{display:inline-block;padding:7px 12px;border-radius:999px;background:#eef1ff;color:#6352c8;font-weight:900;font-size:13px}.meta{font-size:13px;color:var(--muted);margin-top:8px}.question{font-size:clamp(27px,5vw,42px);line-height:1.3;font-weight:950;margin:28px auto;max-width:650px;word-break:break-word}.answer{width:min(450px,95%);padding:17px;border:3px solid #e4e9f1;border-radius:18px;text-align:center;font-size:24px;outline:none;background:#fff}.answer:focus{border-color:#8874ed;box-shadow:0 0 0 4px #8874ed1a}.check{display:block;margin:17px auto 0;border:0;border-radius:18px;padding:15px 34px;background:var(--p);color:#fff;font-weight:950;cursor:pointer}.feedback{min-height:36px;margin-top:17px;font-weight:900;font-size:18px}.ok{color:#28a66e}.bad{color:#df5869}.result{max-width:700px;margin:35px auto;text-align:center}.reward{font-size:82px}.result h1{font-size:38px}.grid3{display:grid;grid-template-columns:repeat(3,1fr);gap:13px}.stat{text-align:center}.stat b{font-size:28px;display:block}.section{margin-top:22px}.mistake,.setrow{padding:13px 0;border-top:1px solid var(--line)}.setrow{display:flex;justify-content:space-between;gap:14px;align-items:center}.small,small{font-size:13px;color:var(--muted)}
.auth-page{display:grid;place-items:center;padding:22px}.auth-shell{width:min(460px,100%);margin:auto}.install-shell{width:min(760px,100%)}.auth-card{background:#fff;border-radius:30px;padding:34px;box-shadow:0 24px 70px #53688e2b;text-align:center}.auth-logo{font-size:64px}.auth-card h1{margin:6px 0;font-size:34px}.stack-form{display:flex;flex-direction:column;gap:17px;margin-top:25px;text-align:left}.form-grid{display:grid;grid-template-columns:1fr 1fr;gap:18px;margin-top:22px;text-align:left}.span-2{grid-column:span 2}.field{display:flex;flex-direction:column;gap:7px;min-width:0}.field label{font-weight:800;color:#44516a}.field input,.field select,.field textarea,.inline-filter select{width:100%;min-height:48px;border:1.5px solid #dfe5ef;border-radius:14px;background:#fff;padding:11px 13px;outline:none;color:var(--ink)}.field input:focus,.field select:focus,.field textarea:focus,.inline-filter select:focus{border-color:#8874ed;box-shadow:0 0 0 4px #8874ed15}.field textarea{min-height:140px;resize:vertical}.form-divider{border-top:1px solid var(--line);padding-top:18px;font-weight:950;color:var(--p)}.form-actions{display:flex;justify-content:flex-end;gap:10px;align-items:center;margin-top:5px}.toggle-row{display:flex;align-items:center;gap:10px;font-weight:800}.toggle-row input{width:19px;height:19px}.alert{padding:13px 15px;border-radius:14px;margin:14px 0;text-align:left;font-weight:700}.alert.success,.flash.success{background:#e9fbf3;color:#167a50}.alert.danger,.flash.danger{background:#fff0f2;color:#bd3d50}.alert.warning,.flash.warning{background:#fff7df;color:#8a6516}.alert.info,.flash.info{background:#eef5ff;color:#315f9b}
.flash-stack{position:fixed;z-index:100;top:82px;right:20px;width:min(380px,calc(100% - 40px));display:flex;flex-direction:column;gap:8px}.flash{padding:13px 16px;border-radius:14px;box-shadow:0 12px 35px #34435e25;background:#fff;font-weight:800}.page-head{display:flex;align-items:flex-start;justify-content:space-between;gap:20px;margin-bottom:22px}.page-head h1{margin:0 0 7px;font-size:clamp(28px,4vw,39px)}.page-head p{margin:0;color:var(--muted);font-size:17px}.inline-filter{display:flex;align-items:center;gap:10px;background:#fff;padding:10px 12px;border-radius:15px;box-shadow:var(--shadow)}.inline-filter label{font-weight:800;white-space:nowrap}.profile-banner{padding:24px 28px;border-radius:25px;background:linear-gradient(135deg,#6651da,#5292e8);color:#fff;display:flex;justify-content:space-between;align-items:center;gap:18px;box-shadow:0 16px 45px #5b68d52f}.profile-banner h2{margin:4px 0;font-size:32px}.profile-banner p{margin:0;opacity:.8}.eyebrow{text-transform:uppercase;font-size:12px;letter-spacing:.12em;font-weight:900;opacity:.75}.profile-banner .chip{color:var(--ink)}.dashboard-grid{display:grid;grid-template-columns:1fr 1fr;gap:20px}.section-title{display:flex;justify-content:space-between;align-items:center;gap:14px}.section-title h2{margin:0}.score-pill{display:inline-flex;padding:7px 10px;border-radius:999px;background:#f0edff;color:#5e49c7;font-weight:900;white-space:nowrap}.empty-state{text-align:center;padding:55px 25px}.empty-state>div{font-size:64px}.empty-state h2{margin-bottom:7px}
.metric-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:16px}.metric-card{background:#fff;border-radius:22px;padding:20px;box-shadow:var(--shadow);display:flex;align-items:center;gap:15px}.metric-card>span{width:52px;height:52px;border-radius:17px;background:#f2efff;display:grid;place-items:center;font-size:26px}.metric-card b{display:block;font-size:29px}.metric-card small{font-size:14px}.filter-panel{padding:18px}.filter-row{display:flex;align-items:flex-end;gap:13px}.filter-row .grow{flex:1}.filter-button{min-height:48px}.table-panel{padding:0;overflow:hidden}.table-scroll{overflow:auto}.table-scroll table{width:100%;border-collapse:collapse;min-width:850px}.table-scroll th,.table-scroll td{padding:15px 17px;text-align:left;border-bottom:1px solid var(--line);vertical-align:middle}.table-scroll th{font-size:13px;text-transform:uppercase;letter-spacing:.04em;color:#68758d;background:#fafbfe}.table-scroll td>small{display:block;margin-top:4px}.row-actions{display:flex;align-items:center;justify-content:flex-end;gap:7px}.role-badge,.status{display:inline-flex;padding:6px 9px;border-radius:999px;font-size:12px;font-weight:900;white-space:nowrap}.role-badge.admin{background:#eeeaff;color:#5d48c6}.role-badge.parent{background:#e8f4ff;color:#2870a9}.role-badge.student{background:#e8fbf2;color:#22815a}.status.on{background:#e7faef;color:#1f8154}.status.off{background:#f1f3f7;color:#737d90}.empty-cell{text-align:center!important;color:var(--muted);padding:35px!important}.import-panel{display:flex;align-items:center;justify-content:space-between;gap:20px}.import-panel h2{margin-bottom:7px}.import-panel p{margin:0}.import-form{display:flex;align-items:center;gap:10px}.import-form input{max-width:250px}.cards-list{display:flex;flex-direction:column;gap:14px}.set-card{background:#fff;border-radius:22px;padding:20px 22px;box-shadow:var(--shadow);display:flex;align-items:center;justify-content:space-between;gap:18px}.set-main{display:flex;gap:15px;align-items:center;min-width:0}.set-icon{width:55px;height:55px;border-radius:18px;background:#f0edff;display:grid;place-items:center;font-size:28px;flex:none}.set-title-row{display:flex;align-items:center;gap:10px;flex-wrap:wrap}.set-title-row h2{margin:0;font-size:20px}.set-main p{margin:6px 0;color:#56647d}.card-actions{display:flex;align-items:center;justify-content:flex-end;gap:8px;flex-wrap:wrap}.code-editor{min-height:520px!important;font-family:"SFMono-Regular",Consolas,"Liberation Mono",monospace;font-size:14px;line-height:1.55;tab-size:2;white-space:pre}
@media(max-width:980px){.appbar-inner{flex-wrap:wrap;gap:9px}.mainnav{order:3;width:100%;overflow:auto;padding-bottom:1px}.mainnav a{white-space:nowrap}.metric-grid{grid-template-columns:repeat(2,1fr)}.dashboard-grid{grid-template-columns:1fr}.set-card{align-items:flex-start;flex-direction:column}.card-actions{justify-content:flex-start}.import-panel{align-items:flex-start;flex-direction:column;width:100%}.import-form{width:100%;flex-wrap:wrap}.filter-row{flex-wrap:wrap}.filter-row .field{flex:1 1 180px}}
@media(max-width:700px){.wrap{padding:17px 14px 40px}.appbar-inner{padding:8px 14px}.brand{font-size:19px}.userbox>span{display:none}.student-top{align-items:flex-start;flex-direction:column}.hero{grid-template-columns:1fr;padding:25px 20px;border-radius:26px}.hero h1{font-size:34px}.hero p{font-size:16px}.fox{display:none}.mission{grid-template-columns:1fr;padding:20px}.start{width:100%}.grid3,.metric-grid{grid-template-columns:1fr}.qcard{padding:24px 14px}.line{width:25px}.lesson{padding:18px 12px}.answer{font-size:20px}.page-head{flex-direction:column;align-items:stretch}.page-head>.primary,.page-head>.secondary{width:100%}.form-grid{grid-template-columns:1fr}.span-2{grid-column:span 1}.auth-card{padding:27px 20px}.profile-banner{align-items:flex-start;flex-direction:column}.profile-banner .chips{width:100%}.inline-filter{width:100%;align-items:stretch;flex-direction:column}.inline-filter select{width:100%}.setrow{align-items:flex-start;flex-direction:column}.score-pill{align-self:flex-start}.form-actions{justify-content:stretch}.form-actions>*{flex:1}.import-form{flex-direction:column;align-items:stretch}.import-form input{max-width:none;width:100%}.card-actions{width:100%}.card-actions>*{flex:1}.card-actions form button{width:100%}.flash-stack{top:76px;right:12px;width:calc(100% - 24px)}.code-editor{min-height:430px!important}}

/* ===== Bộ đề trực quan & luồng vào thi 4.1 ===== */
.builder-wrap{max-width:1240px}.set-builder-form{display:flex;flex-direction:column;gap:22px}.builder-meta{padding:26px}.compact-grid{grid-template-columns:2fr 1fr}.builder-section{display:flex;flex-direction:column;gap:16px}.builder-toolbar{display:flex;align-items:flex-end;justify-content:space-between;gap:20px;padding:4px 2px}.builder-toolbar h2{margin:0 0 6px;font-size:27px}.builder-toolbar p{margin:0;color:var(--muted)}.builder-toolbar-actions{display:flex;align-items:center;gap:10px}.question-counter,.step-badge{display:inline-flex;align-items:center;justify-content:center;border-radius:999px;background:#efeaff;color:#5e49c7;padding:9px 13px;font-weight:900;white-space:nowrap}.step-badge{padding:6px 10px;font-size:12px}.question-builder-list{display:flex;flex-direction:column;gap:18px}.question-builder-card{background:#fff;border:1px solid #e8edf5;border-radius:25px;padding:0 24px 24px;box-shadow:var(--shadow);scroll-margin-top:90px;overflow:hidden}.question-card-head{display:flex;align-items:center;justify-content:space-between;gap:18px;margin:0 -24px 22px;padding:17px 24px;background:linear-gradient(135deg,#faf9ff,#f7fbff);border-bottom:1px solid var(--line)}.question-card-title{display:flex;align-items:center;gap:13px;min-width:0}.question-card-title h3{margin:0 0 3px}.question-card-title small{display:block;max-width:560px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.question-number{width:42px;height:42px;border-radius:14px;display:grid;place-items:center;background:var(--p);color:#fff;font-size:18px;font-weight:950;box-shadow:0 8px 18px #7158e83d;flex:none}.question-card-actions{display:flex;align-items:center;gap:8px}.icon-text-button{padding:9px 12px;border-radius:12px}.danger-button,.mini-danger{border:0;background:#fff0f2;color:#bd3d50;font-weight:900;cursor:pointer}.danger-button:hover,.mini-danger:hover{background:#ffe3e7}.question-grid{grid-template-columns:1fr 1.25fr 1fr 1.75fr;margin-top:0}.question-text-field{margin-top:18px}.question-text-field textarea{min-height:108px;font-size:18px;line-height:1.5}.type-field{margin-top:18px;max-width:470px}.answer-editor-panel{margin-top:18px;border:1px solid #e5eaf3;background:#fbfcff;border-radius:19px;padding:18px}.answer-editor-panel h4{margin:0 0 5px;font-size:17px}.builder-help{margin:0 0 14px;color:var(--muted);font-size:14px}.answer-builder-list,.option-builder-list{display:flex;flex-direction:column;gap:9px}.answer-builder-row,.option-builder-row{display:grid;align-items:center;gap:9px}.answer-builder-row{grid-template-columns:1fr 42px}.option-builder-row{grid-template-columns:20px 48px 1fr 42px}.answer-builder-row input,.option-builder-row input[type="text"],.option-builder-row input:not([type]){width:100%;min-height:47px;border:1.5px solid #dfe5ef;border-radius:13px;padding:10px 12px;outline:none}.option-builder-row input[type="radio"]{width:19px;height:19px;accent-color:var(--green)}.correct-label{font-size:12px;font-weight:900;color:#22815a}.mini-danger{height:42px;width:42px;border-radius:12px;font-size:22px}.small-button{margin-top:12px;padding:9px 13px;border-radius:12px;font-size:14px}.add-question-bottom{border:2px dashed #cfc7fb;background:#f8f6ff;color:#604bc8;border-radius:20px;padding:17px;font-weight:950;font-size:16px;cursor:pointer}.add-question-bottom:hover{background:#f0edff}.sticky-savebar{position:sticky;bottom:14px;z-index:30;display:flex;align-items:center;justify-content:space-between;gap:20px;background:#ffffffed;backdrop-filter:blur(16px);border:1px solid #e1e6f0;border-radius:20px;padding:14px 17px;box-shadow:0 15px 45px #3a4e752b}.sticky-savebar>div:first-child{display:flex;flex-direction:column}.sticky-savebar small{margin-top:3px}.workflow-guide{display:flex;align-items:center;gap:17px;border:1px solid #dfd8ff}.workflow-guide h2{margin:0 0 6px}.workflow-guide p{margin:0;color:#56647d;line-height:1.6}.workflow-icon{width:56px;height:56px;border-radius:18px;background:#f0edff;display:grid;place-items:center;font-size:29px;flex:none}.preview-button{display:inline-flex;align-items:center;justify-content:center;border-radius:14px;padding:12px 16px;background:#e8fbf2;color:#197a51;font-weight:900}.preview-button:hover{background:#d7f6e7}.page-head-actions{display:flex;gap:9px;flex-wrap:wrap}.preview-wrap{max-width:900px}.preview-shell{max-width:760px;margin:auto}.preview-head{display:flex;align-items:center;gap:13px}.preview-card{margin-top:17px}.preview-actions{display:flex;align-items:center;justify-content:center;gap:10px;margin-top:17px}.preview-actions .check{margin:0}.preview-result{max-width:680px;margin:30px auto;text-align:center}.centered-actions{justify-content:center}.choice-grid{width:min(610px,100%);margin:0 auto;display:grid;grid-template-columns:1fr 1fr;gap:12px}.choice-button{min-height:58px;border:2px solid #e1e6ef;border-radius:17px;background:#fff;color:var(--ink);padding:12px 15px;text-align:left;font-weight:850;cursor:pointer;transition:transform .15s ease,border-color .15s ease,background .15s ease}.choice-button:hover{transform:translateY(-1px);border-color:#a89af0}.choice-button.selected{border-color:var(--p);background:#f1eeff;box-shadow:0 0 0 3px #7158e815}.choice-button.correct-choice{border-color:#39b77e;background:#e8fbf2;color:#167a50}.choice-button.wrong-choice{border-color:#e95e70;background:#fff0f2;color:#bd3d50}.choice-button:disabled{cursor:default;opacity:.9}.student-hero{margin-bottom:20px}.active-mission{border:2px solid #f7cc83}.choose-mission{border:1px solid #ece6ff}.set-section-title{margin-bottom:15px}.set-section-title h2{margin:0 0 5px}.set-section-title p{margin:0}.student-set-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:17px}.student-set-card{display:flex;flex-direction:column;min-height:315px;background:#fff;border:1px solid #e5eaf3;border-radius:24px;padding:20px;box-shadow:var(--shadow);transition:transform .18s ease,box-shadow .18s ease,border-color .18s ease}.student-set-card:hover{transform:translateY(-3px);box-shadow:0 18px 42px #65789c24}.student-set-card.current{border:2px solid #ffb454;background:linear-gradient(#fffdf7,#fff)}.student-set-top{display:flex;align-items:center;justify-content:space-between}.student-set-icon{width:50px;height:50px;border-radius:16px;background:#f0edff;display:grid;place-items:center;font-size:25px}.set-code{display:inline-block;margin-top:15px;color:var(--p);font-weight:950;font-size:13px;letter-spacing:.06em}.student-set-card h3{margin:5px 0 7px;font-size:21px;line-height:1.35}.student-set-card p{margin:0;color:var(--muted)}.student-set-stats{display:flex;gap:7px;flex-wrap:wrap;margin:16px 0}.student-set-stats span{background:#f5f7fa;border-radius:999px;padding:6px 9px;font-size:12px;font-weight:800;color:#5d6a82}.student-set-card .set-start-button{width:100%;margin-top:auto}.student-set-card .set-start-button:disabled{background:#c9d0dc;box-shadow:none}.set-code+ h3{word-break:break-word}

@media(max-width:1050px){.question-grid{grid-template-columns:1fr 1fr}.student-set-grid{grid-template-columns:repeat(2,1fr)}}
@media(max-width:760px){.builder-toolbar,.sticky-savebar{align-items:stretch;flex-direction:column}.builder-toolbar-actions{justify-content:space-between}.builder-toolbar-actions .primary{flex:1}.question-builder-card{padding:0 15px 18px}.question-card-head{align-items:flex-start;flex-direction:column;margin:0 -15px 18px;padding:15px}.question-card-actions{width:100%}.question-card-actions button{flex:1}.question-grid,.compact-grid{grid-template-columns:1fr}.choice-grid,.student-set-grid{grid-template-columns:1fr}.option-builder-row{grid-template-columns:20px 38px 1fr 38px}.page-head-actions{width:100%}.page-head-actions>*{flex:1}.sticky-savebar{bottom:8px}.sticky-savebar .form-actions{width:100%}.workflow-guide{align-items:flex-start}.preview-actions{align-items:stretch;flex-direction:column}.preview-actions>*{width:100%}}

/* ===== Import bộ đề Excel 4.2 ===== */
.import-excel-wrap{max-width:1180px}.import-instruction{display:flex;align-items:center;gap:17px;border:1px solid #ded7ff}.import-instruction h2{margin:0 0 7px}.import-instruction p{margin:0;color:#56647d;line-height:1.65}.import-instruction code,.excel-rules code{background:#f0edff;color:#5741c1;border-radius:7px;padding:2px 6px;font-weight:850}.excel-upload-panel{max-width:880px;margin-left:auto;margin-right:auto}.excel-upload-form{margin-top:20px}.excel-dropzone{min-height:245px;border:2px dashed #c8bff4;border-radius:24px;background:linear-gradient(135deg,#fbfaff,#f7fbff);display:flex;flex-direction:column;align-items:center;justify-content:center;text-align:center;padding:28px;cursor:pointer;transition:border-color .18s ease,transform .18s ease,background .18s ease}.excel-dropzone:hover{border-color:var(--p);transform:translateY(-2px);background:#f6f3ff}.excel-dropzone b{font-size:21px;margin:7px 0}.excel-dropzone small{color:var(--muted);line-height:1.5}.excel-dropzone input{margin-top:18px;max-width:420px;width:100%;border:1px solid #dfe5ef;background:#fff;border-radius:13px;padding:10px}.excel-file-icon{font-size:58px}.excel-upload-form .form-actions{margin-top:16px}.excel-rule-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}.excel-rule-grid>div{border:1px solid #e4e9f2;background:#fbfcff;border-radius:17px;padding:17px}.excel-rule-grid b{display:block;margin-bottom:6px;color:#5541bd}.excel-rule-grid p{margin:0;color:#637089;line-height:1.55}.import-summary{display:flex;align-items:center;gap:18px;border:1px solid #cfeede}.success-icon{background:#e5f9ef;color:#167a50;font-weight:950}.import-summary-main{min-width:0}.import-summary h2{margin:3px 0 12px}.import-summary .chips{justify-content:flex-start}.import-preview-head{display:flex;align-items:center;justify-content:space-between;gap:16px;padding:20px 22px;border-bottom:1px solid var(--line)}.import-preview-head h2{margin:0 0 4px}.import-preview-head p{margin:0;color:var(--muted)}.import-preview-table{min-width:980px!important}.import-preview-table td small{display:block;color:var(--muted);margin-top:5px}.preview-question-text{min-width:310px;max-width:480px;white-space:normal;line-height:1.5}.import-confirm-bar{max-width:1180px;margin:20px auto 0}.section{margin-top:20px}
@media(max-width:760px){.import-instruction,.import-summary{align-items:flex-start}.excel-rule-grid{grid-template-columns:1fr}.excel-upload-form .form-actions{flex-direction:column}.excel-upload-form .form-actions>*{width:100%}.import-preview-head{align-items:flex-start;flex-direction:column}.import-confirm-bar{align-items:stretch}.import-confirm-bar .form-actions{width:100%}}

/* ===== Nâng cấp 4.3: nhóm đề, ảnh câu hỏi, thư viện bài học ===== */
.admin-two-column{display:grid;grid-template-columns:minmax(320px,.8fr) minmax(0,1.7fr);gap:20px;align-items:start}.row-actions{display:flex;align-items:center;justify-content:flex-end;gap:7px;flex-wrap:wrap}.row-actions form{margin:0}.row-actions .secondary,.row-actions button{padding:8px 11px;border-radius:11px;font-size:13px}.table-panel td small{display:block;color:var(--muted);margin-top:4px;max-width:520px;white-space:normal}.set-group-section{margin-top:28px}.set-section-heading{display:flex;align-items:flex-end;justify-content:space-between;gap:16px;margin-bottom:14px}.set-section-heading h2,.set-section-heading h3{margin:2px 0 0}.set-section-heading.compact{align-items:center;margin:0 0 12px}.set-section-heading.compact h3{font-size:20px}.student-set-group+ .student-set-group{margin-top:28px}.hero-actions{display:flex;gap:10px;flex-wrap:wrap;margin-top:18px}.hero-actions a{display:inline-flex;align-items:center;justify-content:center}.question-media-panel{margin-top:18px;padding:18px;border:1px solid #e3e8f1;background:linear-gradient(135deg,#fbfcff,#f8f6ff);border-radius:19px}.question-media-info h4{margin:0 0 5px}.question-media-grid{display:grid;grid-template-columns:190px minmax(0,1fr);gap:18px;align-items:start}.question-image-preview{min-height:145px;border:2px dashed #d7ddec;border-radius:17px;background:#fff;display:grid;place-items:center;overflow:hidden;color:var(--muted);font-weight:800}.question-image-preview img{width:100%;height:170px;object-fit:contain;background:#fff}.question-media-controls{display:grid;gap:12px}.question-media-controls .field{margin:0}.question-media-controls input[type=file]{padding:10px;background:#fff}.remove-image-check{display:flex!important;align-items:center;gap:7px;color:#b53d51;font-weight:850;font-size:14px;cursor:pointer}.remove-image-check input{width:18px!important;height:18px;accent-color:#d84f63}.question-illustration{display:block;width:min(620px,100%);max-height:360px;object-fit:contain;margin:18px auto 20px;border-radius:20px;background:#fff;box-shadow:0 8px 28px #42577b17;border:1px solid #e5eaf2}.admin-question-thumb{width:120px;height:82px;object-fit:contain;border-radius:12px;background:#fff;border:1px solid #e1e6ee}.media-report{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:11px 13px;border-radius:12px;margin-top:8px}.media-report.ok{background:#e9f9f1;color:#176d4b}.media-report.bad{background:#fff0f2;color:#ae3348}.media-report span{font-size:14px}.lesson-admin-group-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px}.lesson-group-admin-card{display:flex;flex-direction:column;gap:12px;padding:16px}.lesson-group-admin-card>img,.lesson-placeholder{width:100%;height:130px;border-radius:16px;object-fit:cover;background:#f0edff;display:grid;place-items:center;font-size:44px}.lesson-group-admin-card h3{margin:4px 0}.lesson-group-admin-card p{margin:0;color:var(--muted)}.mini-image-pair{display:flex;gap:6px}.mini-image-pair img{width:55px;height:45px;object-fit:cover;border-radius:8px;border:1px solid #e1e6ee}.form-image-preview{display:block;width:150px;height:110px;object-fit:contain;margin-top:10px;border-radius:14px;border:1px solid #e2e7ef;background:#fff}.form-image-preview.large{width:100%;max-width:360px;height:210px}.lesson-content-input{min-height:320px!important;font-size:17px;line-height:1.7}.lesson-image-upload-grid{display:grid;grid-template-columns:1fr 1fr;gap:20px}.toggle-line{display:flex;align-items:center;gap:9px;margin-top:18px;font-weight:900}.toggle-line input{width:20px;height:20px;accent-color:var(--p)}.student-lesson-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px}.student-lesson-card{display:flex;flex-direction:column;overflow:hidden;background:#fff;border:1px solid #e3e8f1;border-radius:24px;box-shadow:var(--shadow);transition:transform .18s ease,box-shadow .18s ease;color:var(--ink)}.student-lesson-card:hover{transform:translateY(-4px);box-shadow:0 20px 44px #65789c27}.student-lesson-card>img,.lesson-card-placeholder{width:100%;height:205px;object-fit:cover;background:linear-gradient(135deg,#efeaff,#e9f8ff);display:grid;place-items:center;font-size:62px}.student-lesson-body{display:flex;flex-direction:column;padding:18px;min-height:190px}.student-lesson-body h3{margin:5px 0 8px;font-size:22px}.student-lesson-body p{margin:0;color:var(--muted);line-height:1.55}.lesson-open{margin-top:auto;padding-top:17px;color:var(--p);font-weight:950;font-size:13px;letter-spacing:.04em}.lesson-reader-wrap{max-width:920px}.lesson-reader-card{overflow:hidden;background:#fff;border:1px solid #e1e6ef;border-radius:30px;box-shadow:0 20px 55px #5267851f}.lesson-reader-cover{width:100%;height:min(420px,45vw);min-height:240px;object-fit:cover}.lesson-reader-content{padding:clamp(22px,5vw,55px)}.lesson-reader-illustration{display:block;width:min(650px,100%);max-height:440px;object-fit:contain;margin:0 auto 35px;border-radius:24px;background:#fafafa}.lesson-text{font-size:clamp(23px,3.3vw,34px);line-height:1.9;font-weight:750;letter-spacing:.02em;text-align:center;color:#26314a}.lesson-reader-nav{display:flex;align-items:center;justify-content:space-between;gap:14px;margin-top:20px}.lesson-reader-nav a{max-width:48%}.mainnav{flex-wrap:wrap}.mainnav a{white-space:nowrap}
@media(max-width:1050px){.admin-two-column{grid-template-columns:1fr}.lesson-admin-group-grid,.student-lesson-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.question-media-grid{grid-template-columns:150px minmax(0,1fr)}}
@media(max-width:760px){.question-media-grid,.lesson-image-upload-grid{grid-template-columns:1fr}.question-image-preview{min-height:120px}.question-image-preview img{height:190px}.lesson-admin-group-grid,.student-lesson-grid{grid-template-columns:1fr}.lesson-reader-content{padding:22px 16px}.lesson-text{font-size:23px;line-height:1.75}.lesson-reader-nav{align-items:stretch;flex-direction:column}.lesson-reader-nav a,.lesson-reader-nav span{max-width:none;width:100%}.hero-actions{flex-direction:column}.hero-actions a{width:100%}.set-section-heading{align-items:flex-start}.media-report{align-items:flex-start;flex-direction:column}.admin-question-thumb{width:90px;height:70px}}

/* ===== Nâng cấp 4.4: chi tiết từng lượt thi ===== */
.session-detail-wrap{max-width:1240px}.back-link{display:inline-block;margin-bottom:8px;font-weight:850}.session-profile{display:grid;grid-template-columns:minmax(240px,.75fr) minmax(0,1.25fr);align-items:center}.session-set-info{padding-left:28px;border-left:1px solid #ffffff55}.session-set-info h3{margin:4px 0 7px;font-size:22px}.session-set-info p{margin:0}.session-metrics{grid-template-columns:repeat(4,minmax(0,1fr))}.session-metrics .metric-card b{font-size:23px}.session-summary-bar{display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:0;padding:0;overflow:hidden}.session-summary-bar>div{display:flex;flex-direction:column;gap:7px;padding:18px 20px;border-right:1px solid var(--line)}.session-summary-bar>div:last-child{border-right:0}.session-summary-bar b{font-size:13px;color:var(--muted);text-transform:uppercase;letter-spacing:.04em}.session-summary-bar span{font-weight:900}.answer-review-list{display:grid;gap:18px}.answer-review-card{padding:0;overflow:hidden;border:1px solid var(--line)}.answer-review-card.correct{border-left:5px solid var(--green)}.answer-review-card.wrong{border-left:5px solid var(--red)}.answer-review-card.unanswered{border-left:5px solid #a7b0c0}.answer-review-head{display:grid;grid-template-columns:auto 1fr auto;align-items:center;gap:14px;padding:16px 20px;background:#fbfcff;border-bottom:1px solid var(--line)}.question-number{font-size:18px;font-weight:950}.question-tags{display:flex;gap:7px;flex-wrap:wrap}.question-tags span{padding:6px 9px;background:#eef1f7;color:#52617b;border-radius:9px;font-size:12px;font-weight:850}.answer-state{padding:8px 11px;border-radius:999px;font-size:13px;font-weight:950;white-space:nowrap}.answer-state.correct{background:#e7f9f0;color:#18784f}.answer-state.wrong{background:#fff0f2;color:#b83b50}.answer-state.unanswered{background:#eff2f6;color:#68758b}.answer-review-body{display:grid;grid-template-columns:minmax(0,1.45fr) minmax(300px,.7fr);gap:24px;padding:22px}.question-code-label{display:inline-block;margin-bottom:7px;color:var(--p);font-weight:900}.answer-question-column h2{margin:0 0 16px;font-size:22px;line-height:1.55}.review-question-image{display:block;width:min(520px,100%);max-height:330px;object-fit:contain;border:1px solid var(--line);border-radius:18px;background:#fff;margin:14px 0}.review-options{display:grid;gap:9px}.review-option{display:grid;grid-template-columns:36px 1fr auto;align-items:center;gap:10px;padding:11px 13px;border:1px solid #e2e7f0;border-radius:13px;background:#fff}.review-option>b{display:grid;place-items:center;width:30px;height:30px;border-radius:9px;background:#eef1f7}.review-option em{font-size:11px;font-style:normal;font-weight:900;padding:5px 7px;border-radius:999px;background:#eef1f7;color:#5c6980}.review-option.correct-option{border-color:#8bd7b5;background:#f0fbf6}.review-option.correct-option>b{background:#d9f5e8;color:#13744a}.review-option.given-option{box-shadow:inset 0 0 0 2px #7560e52b}.review-option.given-option em:last-child{background:#ece8ff;color:#5b45c6}.answer-result-column{display:flex;flex-direction:column;gap:10px;padding:16px;border-radius:18px;background:#f8f9fc;border:1px solid #e5e9f1}.answer-data-row{display:flex;align-items:flex-start;justify-content:space-between;gap:18px;padding-bottom:10px;border-bottom:1px solid #e1e6ef}.answer-data-row span{color:var(--muted);font-size:13px}.answer-data-row b{text-align:right;word-break:break-word}.attempt-history{display:grid;gap:8px;margin-top:4px}.attempt-history>span{font-size:13px;color:var(--muted);font-weight:850}.attempt-entry{display:grid;grid-template-columns:auto 1fr;gap:4px 10px;padding:10px 11px;border-radius:12px;background:#fff;border:1px solid #e1e6ef}.attempt-entry>b{font-size:13px}.attempt-entry>span{font-weight:850;word-break:break-word}.attempt-entry>em{grid-column:1/-1;font-size:11px;font-style:normal;color:var(--muted)}.attempt-entry.ok{border-color:#a5dfc5;background:#f2fbf7}.attempt-entry.bad{border-color:#f0bdc5;background:#fff7f8}.legacy-attempt-note{margin:3px 0 0;padding:10px;border-radius:10px;background:#fff8df;color:#7b6320;font-size:12px;line-height:1.5}.detail-button{display:inline-flex;white-space:nowrap}
@media(max-width:980px){.session-metrics{grid-template-columns:repeat(2,minmax(0,1fr))}.session-summary-bar{grid-template-columns:repeat(3,minmax(0,1fr))}.session-summary-bar>div:nth-child(3){border-right:0}.session-summary-bar>div:nth-child(-n+3){border-bottom:1px solid var(--line)}.answer-review-body{grid-template-columns:1fr}.session-profile{grid-template-columns:1fr;gap:18px}.session-set-info{padding:18px 0 0;border-left:0;border-top:1px solid #ffffff55}}
@media(max-width:620px){.session-metrics,.session-summary-bar{grid-template-columns:1fr}.session-summary-bar>div{border-right:0!important;border-bottom:1px solid var(--line)!important}.session-summary-bar>div:last-child{border-bottom:0!important}.answer-review-head{grid-template-columns:1fr;align-items:flex-start}.answer-state{justify-self:start}.answer-review-body{padding:16px}.answer-question-column h2{font-size:19px}.review-option{grid-template-columns:34px 1fr}.review-option em{grid-column:2}.answer-data-row{flex-direction:column;gap:4px}.answer-data-row b{text-align:left}.attempt-entry{grid-template-columns:1fr}}