:root{--bg:#f7f8fc;--surface:#fff;--text:#172033;--muted:#71809a;--line:#e6eaf1;--accent:#4457f5;--accent-soft:#eef0ff;--good:#18794e;--good-soft:#e9f8ef;--danger:#c7414b;--danger-soft:#fff0f1}*{box-sizing:border-box}body{background:var(--bg);color:var(--text);margin:0;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,PingFang SC,Microsoft YaHei,sans-serif}button,input,a{font:inherit}button{cursor:pointer}button:disabled{cursor:not-allowed;opacity:.5}.login-shell{background:radial-gradient(circle at top right, #e4e9ff, transparent 36%), var(--bg);place-items:center;min-height:100vh;padding:24px;display:grid}.login-card{background:var(--surface);border:1px solid var(--line);border-radius:24px;width:min(100%,410px);padding:36px;box-shadow:0 20px 60px #2c375d1a}.brand-mark,.brand-dot{color:#fff;background:var(--accent);place-items:center;font-weight:800;display:inline-grid}.brand-mark{border-radius:14px;width:46px;height:46px;font-size:22px}.brand-dot{border-radius:9px;width:28px;height:28px}h1,h2,h3,p{margin-top:0}h1{letter-spacing:-.03em;margin-bottom:10px;font-size:clamp(26px,4vw,36px)}h2{margin-bottom:8px;font-size:20px}h3{margin-bottom:10px;font-size:17px}.eyebrow{color:var(--accent);letter-spacing:.04em;margin-bottom:8px;font-size:13px;font-weight:700}.muted,small{color:var(--muted)}.login-card label{color:var(--muted);gap:8px;margin-top:18px;font-size:14px;display:grid}input{border:1px solid var(--line);width:100%;color:var(--text);border-radius:10px;padding:12px 14px}.primary,.secondary,.link-button,.quick-card,.select-card,.option,.back,.sidebar button,.bottom-nav button,.filter-row button,.segmented button,.table-row{color:var(--text);background:0 0;border:0}.primary{background:var(--accent);color:#fff;border-radius:10px;padding:11px 16px;font-weight:700}.secondary{border:1px solid var(--line);background:var(--surface);border-radius:9px;padding:9px 13px}.wide{width:100%;margin-top:20px}.demo-switch{color:var(--muted);flex-wrap:wrap;align-items:center;gap:10px;margin-top:22px;font-size:13px;display:flex}.demo-switch button,.link-button{color:var(--accent);padding:0}.operator-entry{margin-top:10px}.test-hint{color:var(--muted);text-align:center;margin:16px 0 0;font-size:12px;line-height:1.6}.app-shell{min-height:100vh}.topbar{border-bottom:1px solid var(--line);-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);z-index:5;background:#ffffffe0;justify-content:space-between;align-items:center;height:64px;padding:0 clamp(18px,4vw,52px);display:flex;position:sticky;top:0}.brand,.top-actions{align-items:center;gap:10px;display:flex}.divider{background:var(--line);width:1px;height:18px}.role-label{color:var(--muted);font-size:14px}.toast{z-index:20;background:var(--text);color:#fff;border-radius:10px;padding:12px 16px;position:fixed;top:76px;right:24px;box-shadow:0 12px 30px #0000002e}.learner-layout{grid-template-columns:minmax(300px,430px) minmax(240px,1fr);align-items:start;gap:44px;max-width:1060px;margin:36px auto;padding:0 22px;display:grid}.mobile-frame{background:var(--surface);border:1px solid var(--line);border-radius:28px;overflow:hidden;box-shadow:0 18px 52px #313e601a}.mobile-header{justify-content:space-between;padding:24px 22px 16px;display:flex}.mobile-header h2{margin:0}.avatar{background:var(--accent-soft);width:38px;height:38px;color:var(--accent);border:0;border-radius:50%;font-weight:800}.mobile-content{min-height:570px;padding:18px 22px 24px}.hero{color:#fff;background:linear-gradient(145deg,#4356f4,#5e6fff);border-radius:18px;padding:20px}.hero h2{margin:14px 0 8px;font-size:22px}.hero p{color:#e1e5ff;margin:0 0 14px;font-size:13px}.hero .primary{color:var(--accent);background:#fff}.pill{width:fit-content;color:var(--muted);background:#f1f3f7;border-radius:999px;align-items:center;padding:4px 8px;font-size:12px;font-weight:700;display:inline-flex}.pill.good{background:var(--good-soft);color:var(--good)}.pill.accent{background:var(--accent-soft);color:var(--accent)}.hero .pill{color:#fff;background:#ffffff2e}.quick-grid{grid-template-columns:1fr 1fr;gap:10px;margin:16px 0;display:grid}.quick-card{text-align:left;border:1px solid var(--line);background:#fff;border-radius:14px;gap:5px;padding:14px;display:grid}.quick-card span{color:var(--muted);font-size:12px}.icon{color:var(--accent);font-size:20px}.line-card,.info-row{border-bottom:1px solid var(--line);justify-content:space-between;align-items:center;gap:12px;padding:13px 0;display:flex}.line-card:last-child,.info-row:last-child{border-bottom:0}.line-card div,.info-row span{gap:4px;display:grid}.back{color:var(--accent);margin:-5px 0 14px}.choice-stack{gap:9px;margin:18px 0;display:grid}.select-card{border:1px solid var(--line);background:#fff;border-radius:12px;justify-content:space-between;padding:13px;display:flex}.select-card.selected{border-color:var(--accent);background:var(--accent-soft);color:var(--accent)}.select-card span{color:var(--muted);font-size:12px}.segmented{background:#f2f4f8;border-radius:10px;grid-template-columns:1fr 1fr;margin-bottom:14px;padding:4px;display:grid}.segmented button{border-radius:8px;padding:9px}.segmented button.selected{color:var(--accent);background:#fff;font-weight:700;box-shadow:0 1px 4px #00000014}.segmented.compact{grid-template-columns:repeat(3,1fr)}.exam-card,.question-card,.result-card{border:1px solid var(--line);background:#fff;border-radius:16px;padding:18px}.exam-card h3{margin-top:14px}.question-meta,.section-heading{color:var(--muted);justify-content:space-between;align-items:center;font-size:13px;display:flex}.question-card h3{margin:16px 0;line-height:1.55}.option{text-align:left;border:1px solid var(--line);border-radius:10px;width:100%;margin:8px 0;padding:12px;display:block}.answer-explain{background:#f6f7fb;border-radius:12px;margin-top:14px;padding:12px}.answer-explain p{color:var(--muted);margin:6px 0 0;font-size:13px}.result-card{text-align:center}.result-circle{background:var(--accent-soft);width:76px;height:76px;color:var(--accent);border-radius:50%;place-items:center;margin-bottom:12px;font-size:28px;font-weight:800;display:inline-grid}.ranking{margin:12px 0}.ranking div{border-bottom:1px solid var(--line);grid-template-columns:45px 1fr auto;align-items:center;gap:8px;padding:11px 0;display:grid}.ranking small{font-size:12px}.bottom-nav{border-top:1px solid var(--line);grid-template-columns:repeat(5,1fr);padding:9px 4px;display:grid}.bottom-nav button{color:var(--muted);padding:7px 2px;font-size:12px}.bottom-nav button.active{color:var(--accent);font-weight:800}.learner-notes{padding-top:16px}.learner-notes h2{margin-bottom:16px}.dashboard-layout{grid-template-columns:230px minmax(0,1fr);min-height:calc(100vh - 64px);display:grid}.sidebar{border-right:1px solid var(--line);background:#fff;padding:28px 18px}.sidebar h2{font-size:18px}.sidebar button{text-align:left;width:100%;color:var(--muted);border-radius:9px;margin:3px 0;padding:11px 12px;display:block}.sidebar button.side-active{background:var(--accent-soft);color:var(--accent);font-weight:800}.dashboard-main{width:100%;max-width:1340px;padding:clamp(24px,4vw,46px)}.dashboard-top{justify-content:space-between;align-items:flex-start;gap:16px;margin-bottom:24px;display:flex}.dashboard-top h1{margin-bottom:0}.stats{grid-template-columns:repeat(3,minmax(0,1fr));gap:14px;margin-bottom:22px;display:grid}.stat,.panel,.student-detail{border:1px solid var(--line);background:#fff;border-radius:16px;padding:18px}.stat{gap:7px;display:grid}.stat span{color:var(--muted);font-size:13px}.stat strong{font-size:30px}.filter-row{flex-wrap:wrap;gap:8px;margin-bottom:18px;display:flex}.filter-row button{border:1px solid var(--line);background:#fff;border-radius:9px;padding:9px 11px}.filter-row button.filter-active{background:var(--accent);color:#fff;border-color:var(--accent)}.sales-content{grid-template-columns:minmax(580px,1fr) minmax(240px,.42fr);align-items:start;gap:18px;display:grid}.data-table{border:1px solid var(--line);background:#fff;border-radius:16px;overflow:hidden}.table-grid{grid-template-columns:1.1fr 1fr 1fr 1.2fr .8fr;align-items:center;gap:10px;display:grid}.table-head{color:var(--muted);background:#fafbfc;padding:12px 14px;font-size:12px}.table-row{text-align:left;border-top:1px solid var(--line);background:#fff;width:100%;padding:13px 14px}.table-row:hover,.table-row.row-selected{background:var(--accent-soft)}.table-row span{gap:3px;display:grid}.table-row small{font-size:12px}.danger-text{color:var(--danger);font-weight:700}.student-detail{position:sticky;top:84px}.student-detail h2{margin:12px 0 2px}.two-columns{grid-template-columns:repeat(2,minmax(0,1fr));gap:18px;margin-bottom:18px;display:grid}.panel{margin-bottom:18px}.bar-row{grid-template-columns:110px 1fr 42px;align-items:center;gap:10px;padding:10px 0;display:grid}.bar{background:#edf0f4;border-radius:50px;height:10px;overflow:hidden}.bar i{background:var(--accent);border-radius:inherit;height:100%;display:block}.user-grid{grid-template-columns:1.3fr 1fr .8fr 1fr auto;align-items:center;gap:10px;display:grid}.exam-grid{grid-template-columns:.55fr 1.3fr 1fr 1fr .7fr auto;align-items:center;gap:10px;display:grid}.flow-panel{grid-template-columns:repeat(4,1fr);gap:14px;display:grid}.flow-panel div{border-bottom:2px solid var(--line);padding-bottom:12px}.flow-panel span{color:var(--muted);margin-top:6px;font-size:13px;display:block}.knowledge-row{text-align:left;border:0;border-bottom:1px solid var(--line);background:#fff;grid-template-columns:34px 1fr 1.5fr auto;gap:10px;width:100%;padding:13px 0;display:grid}.knowledge-row:hover{background:var(--accent-soft)}@media (max-width:900px){.learner-layout{grid-template-columns:1fr}.learner-notes{display:none}.dashboard-layout{grid-template-columns:1fr}.sidebar{border-right:0;border-bottom:1px solid var(--line);flex-wrap:wrap;align-items:center;gap:8px;padding:14px;display:flex}.sidebar p,.sidebar h2{display:none}.sidebar button{width:auto;margin:0}.sales-content{grid-template-columns:1fr}.student-detail{position:static}.dashboard-main{padding:22px}}@media (max-width:620px){.topbar{padding:0 16px}.brand .muted,.divider,.role-label{display:none}.stats,.two-columns{grid-template-columns:1fr}.dashboard-top{flex-direction:column}.flow-panel{grid-template-columns:1fr 1fr}.sales-content{overflow:hidden}.data-table{overflow-x:auto}.mobile-content{min-height:540px}}.option{grid-template-columns:28px 1fr auto;align-items:center;gap:8px;display:grid}.option>span{width:25px;height:25px;color:var(--muted);background:#f1f3f7;border-radius:7px;place-items:center;font-size:12px;font-weight:800;display:grid}.option.option-selected{border-color:var(--accent);background:var(--accent-soft)}.option.option-selected>span{background:var(--accent);color:#fff}.option.correct{border-color:var(--good);background:var(--good-soft);color:var(--good)}.option.correct>span{background:var(--good);color:#fff}.option.incorrect{border-color:var(--danger);background:var(--danger-soft);color:var(--danger)}.answer-explain p{line-height:1.65}.answer-good{background:var(--good-soft)}.answer-wrong{background:var(--danger-soft)}.ranking .ranking-self{background:var(--accent-soft);color:var(--accent);border-radius:10px;margin:0 -10px;padding:11px 10px}.self-rank{background:var(--accent-soft);color:var(--accent);border-radius:10px;margin-top:14px;padding:12px;font-weight:800}.note-copy{margin-top:18px;line-height:1.7}.upload-panel{padding:22px}.template-link{color:var(--text);white-space:nowrap;text-decoration:none}.upload-drop{cursor:pointer;background:#fafbfe;border:1.5px dashed #b9c1d2;border-radius:16px;align-content:center;place-items:center;gap:8px;min-height:160px;margin-top:18px;transition:all .2s;display:grid}.upload-drop:hover{border-color:var(--accent);background:var(--accent-soft)}.upload-drop input{opacity:0;pointer-events:none;width:1px;height:1px;position:absolute}.upload-icon{background:var(--accent-soft);width:42px;height:42px;color:var(--accent);border-radius:12px;place-items:center;font-size:24px;display:grid}.upload-drop small{color:var(--muted)}.error-box{background:var(--danger-soft);color:var(--danger);border:1px solid #ffcdd1;border-radius:12px;margin:14px 0;padding:10px 14px}.error-box p{margin:5px 0;font-size:13px}.question-table{border:1px solid var(--line);border-radius:12px;margin-top:14px;overflow:hidden}.question-table-head,.question-table-row{grid-template-columns:130px 80px minmax(280px,1fr) 70px;align-items:center;gap:12px;padding:11px 12px;display:grid}.question-table-head{color:var(--muted);background:#fafbfc;font-size:12px}.question-table-row{border-top:1px solid var(--line);font-size:13px}.stem-cell{gap:6px;line-height:1.5;display:grid}.stem-cell small{white-space:normal;line-height:1.5}.empty-state{text-align:center;color:var(--muted);padding:42px 18px}.empty-state strong{color:var(--text);font-size:17px}.empty-state p{margin:8px 0 0}.empty-banner{background:#fff9e8;border:1px solid #f0d99d;border-radius:14px;margin-bottom:14px;padding:18px}.empty-banner p{color:var(--muted);margin:6px 0 12px;font-size:13px}.exam-top{justify-content:space-between;align-items:center;display:flex}.exam-top .back{margin-bottom:10px}.question-nav{justify-content:space-between;gap:12px;margin-top:18px;display:flex}.answer-progress{text-align:center;color:var(--muted);margin-top:12px;font-size:12px}.result-list{gap:10px;margin-top:14px;display:grid}.result-detail,.mistake-card{border:1px solid var(--line);background:#fff;border-radius:12px;padding:13px}.result-detail summary,.mistake-card summary{cursor:pointer;list-style:none}.result-detail summary{align-items:center;gap:9px;display:flex}.result-ok{color:var(--good)}.result-bad{color:var(--danger)}.result-detail>p,.mistake-card>p{margin:14px 0 8px;line-height:1.6}.mistake-card{margin:10px 0}.mistake-card summary{justify-content:space-between;gap:12px;display:flex}.mistake-card summary div{gap:9px;display:grid}.mistake-card summary>span{color:var(--accent);white-space:nowrap;font-size:13px}.history-title{margin-top:28px}.history-row{border-bottom:1px solid var(--line);justify-content:space-between;align-items:center;padding:12px 0;display:flex}.history-row div{gap:5px;display:grid}.history-row>span{color:var(--accent);font-weight:800}@media (max-width:620px){.section-heading{flex-direction:column;align-items:stretch;gap:12px}.question-table{overflow-x:auto}.question-table-head,.question-table-row{min-width:680px}.learner-layout{margin:0;padding:0}.mobile-frame{border-left:0;border-right:0;border-radius:0;min-height:calc(100vh - 64px)}.mobile-content{padding-left:16px;padding-right:16px}.dashboard-main{padding:18px 14px}.sidebar{flex-wrap:nowrap;overflow-x:auto}.sidebar button{white-space:nowrap}}.sidebar button{align-items:center;gap:9px;display:flex}.side-icon{width:25px;height:25px;color:var(--muted);background:#f1f3f7;border-radius:8px;place-items:center;font-size:12px;font-weight:800;display:inline-grid}.sidebar button.side-active .side-icon{background:var(--accent);color:#fff}.four-stats{grid-template-columns:repeat(4,minmax(0,1fr))}.overview-row{border-bottom:1px solid var(--line);justify-content:space-between;align-items:center;gap:12px;padding:12px 0;display:flex}.overview-row:last-child{border-bottom:0}.overview-row div{gap:4px;display:grid}.overview-row small{font-size:12px}.bar-danger{background:var(--danger)!important}.workflow-cards{grid-template-columns:repeat(5,minmax(0,1fr));gap:10px;display:grid}.workflow-cards button{text-align:left;border:1px solid var(--line);color:var(--text);background:#fff;border-radius:12px;gap:6px;padding:14px;display:grid}.workflow-cards button:hover{border-color:var(--accent);background:var(--accent-soft)}.workflow-cards span{background:var(--accent-soft);width:27px;height:27px;color:var(--accent);border-radius:8px;place-items:center;font-weight:800;display:grid}.workflow-cards small{font-size:12px}.point-layout{grid-template-columns:minmax(260px,.5fr) minmax(520px,1.5fr);align-items:start}.form-label{color:var(--muted);gap:7px;margin-top:15px;font-size:13px;display:grid}.form-label textarea{resize:vertical;border:1px solid var(--line);width:100%;min-height:90px;color:var(--text);font:inherit;border-radius:10px;padding:12px 14px}.point-list{display:grid}.point-row{border-bottom:1px solid var(--line);grid-template-columns:78px minmax(0,1fr) auto;align-items:center;gap:12px;padding:13px 0;display:grid}.point-row:last-child{border-bottom:0}.point-row>div:nth-child(2){gap:5px;display:grid}.point-row small{font-size:12px}.point-order{align-items:center;gap:4px;display:flex}.point-order strong{color:var(--muted);margin-right:3px}.point-order button{border:1px solid var(--line);background:#fff;border-radius:6px;width:23px;height:23px;padding:0}.release-toggle{border:1px solid var(--line);color:var(--muted);background:#fff;border-radius:999px;align-items:center;gap:7px;padding:7px 10px;display:flex}.release-toggle span{background:#b6bfce;border-radius:50%;width:8px;height:8px}.release-toggle.released{background:var(--good-soft);color:var(--good);border-color:#a4dec1}.release-toggle.released span{background:var(--good)}.exam-editor-layout{grid-template-columns:minmax(600px,1.45fr) minmax(280px,.55fr);align-items:start;gap:18px;display:grid}.exam-editor,.exam-list-panel{min-width:0}.form-grid{grid-template-columns:1fr 1fr;gap:12px;display:grid}.question-select-heading{justify-content:space-between;align-items:center;margin:20px 0 10px;display:flex}.question-picker{gap:7px;max-height:390px;padding-right:4px;display:grid;overflow:auto}.question-picker label{border:1px solid var(--line);cursor:pointer;border-radius:10px;grid-template-columns:20px 1fr;align-items:start;gap:10px;padding:10px;display:grid}.question-picker label.picked{border-color:var(--accent);background:var(--accent-soft)}.question-picker input{width:16px;accent-color:var(--accent);margin-top:3px}.question-picker span{gap:5px;display:grid}.question-picker small{font-size:12px}.editor-actions,.card-actions,.top-button-group{align-items:center;gap:9px;display:flex}.editor-actions{justify-content:flex-end;margin-top:18px}.exam-list-card{border:1px solid var(--line);border-radius:13px;margin-top:10px;padding:14px}.exam-list-card h3{margin:12px 0 7px}.exam-list-card p{color:var(--muted);margin-bottom:8px;font-size:12px;line-height:1.55}.exam-list-card .section-heading{align-items:center}.card-actions{flex-wrap:wrap;margin-top:14px}.danger-button{background:var(--danger-soft);color:var(--danger);border:1px solid #f2c5c9;border-radius:9px;padding:9px 13px}.small-button{padding:6px 9px;font-size:12px}.good-text{color:var(--good)}.data-panel{padding:0;overflow:hidden}.attempt-table{overflow-x:auto}.attempt-head,.attempt-row{grid-template-columns:110px 1.2fr 90px 1fr 160px 150px;align-items:center;gap:12px;min-width:920px;padding:12px 14px;display:grid}.attempt-head{color:var(--muted);background:#fafbfc;font-size:12px}.attempt-row{border-top:1px solid var(--line);font-size:13px}.attempt-row>span{gap:4px;display:grid}.attempt-row small{font-size:11px}.question-table.with-actions .question-table-head,.question-table.with-actions .question-table-row{grid-template-columns:130px 80px minmax(280px,1fr) 60px 70px}@media (max-width:1050px){.four-stats{grid-template-columns:repeat(2,1fr)}.workflow-cards{grid-template-columns:repeat(3,1fr)}.point-layout,.exam-editor-layout{grid-template-columns:1fr}}@media (max-width:620px){.four-stats{grid-template-columns:1fr}.workflow-cards{grid-template-columns:1fr 1fr}.form-grid{grid-template-columns:1fr}.top-button-group{flex-wrap:wrap;width:100%}.point-row{grid-template-columns:70px minmax(170px,1fr) auto;min-width:520px}.point-list{overflow-x:auto}.exam-editor-layout{display:block}.exam-editor,.exam-list-panel{margin-bottom:16px}.question-picker{max-height:330px}}.pill.danger{background:var(--danger-soft);color:var(--danger)}.account-search{width:min(280px,100%)}.account-preview{border:1px solid var(--line);border-radius:12px;margin-top:14px;overflow:hidden}.account-preview>div{border-top:1px solid var(--line);grid-template-columns:repeat(4,1fr);gap:12px;padding:11px 13px;font-size:13px;display:grid}.account-preview>div:first-child{border-top:0}.account-list-panel{overflow:hidden}.account-table{margin:16px -18px -18px;overflow-x:auto}.account-head,.account-row{grid-template-columns:1.25fr 1fr 1fr 90px 210px;align-items:center;gap:12px;min-width:760px;padding:12px 18px;display:grid}.account-head{color:var(--muted);background:#fafbfc;font-size:12px}.account-row{border-top:1px solid var(--line);font-size:13px}.account-row>span:first-child{gap:4px;display:grid}.account-row small{font-size:11px}@media (max-width:620px){.account-preview{overflow-x:auto}.account-preview>div{min-width:620px}}.option-instruction{color:var(--muted);margin:0 0 9px;font-size:12px}.question-media{gap:10px;margin:0 0 14px;display:grid}.question-media img{object-fit:contain;border:1px solid var(--line);background:#f7f8fb;border-radius:12px;width:100%;max-height:360px;display:block}.option-content{gap:8px;min-width:0;line-height:1.5;display:grid}.option-content img{object-fit:contain;background:#fff;border-radius:8px;width:min(100%,260px);max-height:190px;display:block}.option-with-image{align-items:start}.review-options{gap:8px;margin:0 0 14px;display:grid}.review-option{border:1px solid var(--line);background:#fff;border-radius:10px;grid-template-columns:28px minmax(0,1fr);align-items:start;gap:9px;padding:9px 10px;display:grid}.review-option>strong{width:25px;height:25px;color:var(--muted);background:#eef1f7;border-radius:7px;place-items:center;display:grid}.review-option-answer{background:#f1fbf6;border-color:#98d7bd}.review-option-answer>strong{color:#fff;background:#13865d}.media-badge{width:fit-content;color:var(--accent);background:var(--accent-soft);border-radius:999px;padding:2px 7px;font-weight:700}