.student-combobox{position:relative;height:44px;border:1px solid #cfd9e6;border-radius:10px;background:#fff}.student-combobox:focus-within{border-color:var(--blue);outline:3px solid rgba(46,99,199,.12)}.student-combobox input,.student-combobox input:focus,.student-combobox input:disabled{height:100%;border:0!important;outline:0!important;background:transparent!important;padding-right:44px}.student-combobox.disabled{background:#f3f5f8;color:#9aa7b7}.student-combobox .combobox-trigger{position:absolute;top:50%;right:6px;display:grid;width:28px;height:28px;place-items:center;padding:0;border:0;border-radius:6px;background:transparent;color:#314967;transform:translateY(-50%)}.student-combobox .combobox-trigger svg{width:18px;height:18px;fill:none;stroke:currentColor;stroke-linecap:round;stroke-linejoin:round;stroke-width:2.2}.student-combobox .combobox-trigger:hover:not(:disabled){background:#edf3fc}.student-combobox .combobox-trigger:disabled{color:#9aa7b7;cursor:not-allowed}.login-select{position:relative;height:44px;border:1px solid #cfd9e6;border-radius:10px;background:#fff}.login-select:focus-within{border-color:var(--blue);outline:3px solid rgba(46,99,199,.12)}.login-select select,.login-select select:focus,.login-select select:disabled{height:100%;border:0!important;outline:0!important;appearance:none;-webkit-appearance:none;background:transparent!important;padding-right:44px}.login-select.disabled{background:#f3f5f8}.login-select .select-icon{position:absolute;top:50%;right:11px;display:grid;width:18px;height:18px;place-items:center;color:#314967;pointer-events:none;transform:translateY(-50%)}.login-select .select-icon svg{width:18px;height:18px;fill:none;stroke:currentColor;stroke-linecap:round;stroke-linejoin:round;stroke-width:2.2}.login-select.disabled .select-icon{color:#9aa7b7}:root{font-family:PingFang SC,Microsoft YaHei,system-ui,sans-serif;color:#18314f;background:#f4f7fb;font-synthesis:none;--navy:#173a70;--navy2:#214b86;--blue:#2e63c7;--blue-soft:#eaf1ff;--ink:#18314f;--muted:#718096;--line:#dfe7f1;--yellow:#ffd45c;--green:#2f9b69;--orange:#ef8c3a;--red:#d85b5b}*{box-sizing:border-box}html,body,#app{margin:0;min-height:100%;background:#f4f7fb}button,textarea{font:inherit}button{cursor:pointer}.app-shell{width:100%;min-height:100dvh}.page{min-height:100dvh;padding-bottom:78px}.content{width:min(100%,720px);margin:0 auto;padding:16px 15px 96px}.mobile-head{position:relative;padding:32px max(20px,env(safe-area-inset-left)) 22px;background:linear-gradient(135deg,#214b86,#3972cf);color:#fff}.mobile-head:after{content:"";position:absolute;right:20px;bottom:-18px;width:86px;height:86px;border:17px solid rgba(255,255,255,.07);border-radius:50%}.mobile-head p{margin:0 0 7px;color:#dce8ff;font-size:12px}.mobile-head h1{position:relative;z-index:1;font-size:25px;letter-spacing:-.03em;margin:0 0 6px}.mobile-head>span{position:relative;z-index:1;font-size:12px;color:#dce8ff}.mobile-head.compact{padding-bottom:24px}.avatar-button{position:absolute;z-index:2;right:20px;top:35px;width:39px;height:39px;border:1px solid rgba(255,255,255,.36);border-radius:50%;background:#ffffff26;color:#fff;font-weight:800}.demo-banner,.recovery-banner{padding:9px 15px;text-align:center;font-size:11px;background:#fff4c8;color:#725600;border-bottom:1px solid #efd985}.list-content{padding-top:12px}.tabs{display:flex;border-bottom:1px solid var(--line);margin-bottom:16px}.tabs button{position:relative;flex:1;border:0;border-bottom:2px solid transparent;background:transparent;padding:11px 4px;color:#718096;font-size:13px}.tabs button.active{color:var(--blue);border-color:var(--blue);font-weight:750}.tabs b{display:inline-grid;place-items:center;min-width:19px;height:19px;margin-left:2px;padding:0 5px;background:#edf1f6;border-radius:99px;font-size:10px}.tabs button.active b{background:var(--blue-soft)}.practice-card{display:block;width:100%;text-align:left;background:#fff;border:1px solid #e0e7f0;border-radius:15px;padding:15px;margin-bottom:12px;color:inherit;box-shadow:0 4px 15px #1d406f09}.practice-card:disabled{cursor:default;opacity:.86}.practice-card:focus-visible,.filter-scroll button:focus-visible,.bottomnav button:focus-visible,.question-grid button:focus-visible{outline:3px solid rgba(46,99,199,.3);outline-offset:2px}.card-heading{display:flex;align-items:center;justify-content:space-between}.subject-label{font-size:9px;font-weight:750;letter-spacing:.08em;color:#2e63c7}.practice-card h2{font-size:16px;margin:3px 0 7px}.practice-card>p{font-size:11px;color:#78869a;margin:0 0 12px}.chevron{color:#9cabc0;font-size:24px}.progressbar{height:7px;background:#edf1f6;border-radius:99px;overflow:hidden;margin:12px 0 9px}.progressbar i{display:block;height:100%;background:var(--blue);border-radius:inherit}.practice-meta{display:flex;align-items:center;font-size:11px;color:#718096}.practice-meta .pill{margin-left:auto}.pill{display:inline-block;padding:5px 8px;border-radius:999px;font-size:10px;font-weight:750}.blue{background:#e7efff;color:#285db6}.green{background:#e2f5ea;color:#24734c}.orange{background:#fff0dd;color:#a85c20}.red{background:#fde8e8;color:#b34444}.empty-state{display:grid;place-items:center;gap:7px;text-align:center;min-height:210px;color:#8390a3}.empty-state:before{content:"✓";display:grid;place-items:center;width:54px;height:54px;border-radius:18px;background:#eaf1ff;color:#2e63c7;font-size:22px}.empty-state b{color:#435a75}.empty-state span{font-size:12px}.bottomnav{position:fixed;z-index:20;left:0;right:0;bottom:0;height:calc(66px + env(safe-area-inset-bottom));padding-bottom:env(safe-area-inset-bottom);background:#fff;border-top:1px solid #dfe6ef;display:flex;box-shadow:0 -5px 20px #1f3a5d0a}.bottomnav button{flex:1;border:0;background:transparent;color:#7c899b;font-size:10px;display:grid;place-items:center;align-content:center;gap:3px}.bottomnav button span{display:grid;place-items:center;width:24px;height:24px;border-radius:8px;font-size:11px;font-weight:900}.bottomnav button.active{color:var(--blue);font-weight:750}.bottomnav button.active span{background:var(--blue-soft)}.answer-page{padding-bottom:76px}.answer-head{position:sticky;z-index:10;top:0;min-height:69px;background:#fff;padding:12px 15px;display:flex;align-items:center;border-bottom:1px solid var(--line)}.back{width:35px;height:35px;border:0;background:transparent;font-size:31px;line-height:1;color:#34597f;padding:0;margin-right:4px}.answer-head>div{display:grid}.answer-head b{font-size:14px}.answer-head div span{font-size:10px;color:var(--muted);margin-top:2px}.save-summary{margin-left:auto;color:var(--green);font-size:10px}.save-summary.saving{color:var(--blue)}.save-summary.unsynced{color:var(--orange)}.answer-content{padding-bottom:95px}.question-card{background:#fff;border-radius:15px;padding:17px;margin-bottom:13px;border:1px solid var(--line)}.qnum{color:var(--blue);font-size:11px;font-weight:800}.qtext{font-size:16px;line-height:1.75;margin:9px 0 18px;white-space:pre-line}.question-image{width:100%;max-height:260px;object-fit:contain;margin:0 0 15px;border-radius:10px;background:#f8fafc}.answer-label{display:block;font-size:11px;font-weight:750;margin-bottom:7px}.answer-box{display:block;width:100%;min-height:112px;resize:vertical;border:1px solid #cfd9e6;border-radius:11px;padding:12px;font-size:14px;color:#3f5773;background:#fff;line-height:1.65}.answer-box:focus{outline:3px solid rgba(46,99,199,.12);border-color:var(--blue)}.answer-box:disabled{background:#f3f5f8;color:#8b98a8}.save-state{text-align:right;color:var(--green);font-size:10px;margin-top:7px}.save-state.saving{color:var(--blue)}.save-state.unsynced{color:var(--orange)}.navigator{padding-bottom:14px}.question-grid{display:grid;grid-template-columns:repeat(7,1fr);gap:7px;margin-top:12px}.question-grid button{position:relative;aspect-ratio:1;border:1px solid #dfe6ef;border-radius:9px;background:#f6f8fb;color:#64748a;font-size:11px}.question-grid button span{position:absolute;right:2px;top:0;color:var(--green);font-size:8px}.question-grid button.answered{background:#edf7f1;color:#24734c}.question-grid button.current{background:var(--blue);border-color:var(--blue);color:#fff;font-weight:800}.question-grid button.locked{box-shadow:inset 0 0 0 1px var(--green)}.submitbar{position:fixed;z-index:15;bottom:0;left:0;right:0;padding:11px 14px calc(11px + env(safe-area-inset-bottom));background:#fff;border-top:1px solid var(--line);display:flex;gap:9px}.submitbar button{flex:1;height:43px;border:0;border-radius:10px;font-weight:750}.submitbar button:disabled{opacity:.42}.submitbar .outline{background:#eef3fa;color:#365678}.submitbar .primary{background:var(--navy);color:#fff}.submitbar .warm{background:var(--yellow);color:#173a70}.mistake-practice-card{padding:17px}.mistake-result{margin-top:2px}.mistake-result-head{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:12px 0 8px;border-top:1px solid #e8eef5}.mistake-result-head h2{margin:0;font-size:17px;color:#244264}.mistake-result-head .verdict{font-size:12px;font-weight:800}.mistake-result dl{margin:4px 0 0}.mistake-result dl div{display:grid;grid-template-columns:67px minmax(0,1fr);gap:8px;margin:7px 0;font-size:12px;line-height:1.55}.mistake-result dt{color:#8a97a9}.mistake-result dd{margin:0;color:#425b76;word-break:break-word}.mistake-result .answer-reveal{margin-top:13px}.mistake-result .answer-reveal p{margin:5px 0 12px;font-size:12px;line-height:1.65;color:#50647e;white-space:pre-line}.mistake-result .answer-reveal p:last-child{margin-bottom:0}.grading-page{min-height:100dvh;display:grid;place-items:center;text-align:center;padding:32px;background:linear-gradient(#f1f6ff,#fff)}.grading-page>div{max-width:350px}.spinner{width:76px;height:76px;border-radius:50%;border:8px solid #dfe9f8;border-top-color:var(--blue);margin:0 auto 22px;animation:spin .9s linear infinite}.grading-page .eyebrow{font-size:10px;color:var(--green);font-weight:800;letter-spacing:.08em}.grading-page h1{font-size:23px;margin:6px 0 10px}.grading-page>div>p:not(.eyebrow){font-size:13px;color:var(--muted);line-height:1.75;margin:0}.time-pill{display:inline-block;margin:20px 0 18px;padding:6px 10px;border-radius:99px;background:var(--blue-soft);color:var(--blue);font-size:11px}.secondary-button,.primary-button{height:42px;border:0;border-radius:10px;padding:0 16px;font-weight:750}.secondary-button{background:#eef3fa;color:#365678}.grading-page .secondary-button{display:block;margin:0 auto}.result-page{padding-bottom:0}.result-top{position:relative;padding:25px 19px 22px;background:linear-gradient(135deg,#214b86,#3972cf);color:#fff}.result-top .back{margin-left:-9px}.back.light{color:#fff}.result-top>span{display:block;font-size:12px;color:#dce8ff}.result-top strong{font-size:27px;display:block;margin:8px 0}.result-top p{font-size:12px;color:#dce8ff;margin:0;line-height:1.6}.result-summary{display:flex;gap:8px;margin-top:14px}.result-summary span{background:#ffffff24;padding:6px 9px;border-radius:8px;font-size:10px}.result-content{padding-bottom:28px}.result-item{background:#fff;border-radius:14px;padding:15px;margin-bottom:11px;border:1px solid var(--line)}.result-item .verdict{float:right;font-size:12px;font-weight:750}.right{color:var(--green)}.wrong{color:var(--red)}.muted{color:var(--muted)}.result-item h2{font-size:14px;margin:0 0 9px}.result-question{font-size:13px!important;color:#314967!important}.result-item p{font-size:11px;color:#64748a;line-height:1.65;margin:5px 0}.result-item dl{margin:12px 0 0}.result-item dl div{display:grid;grid-template-columns:67px 1fr;font-size:11px;margin:6px 0}.result-item dt{color:#8a97a9}.result-item dd{margin:0;color:#425b76}.answer-reveal{margin-top:11px;background:#f6f8fb;border-radius:10px;padding:11px}.answer-reveal b{font-size:10px;color:#365678}.hidden-answer{padding:9px 10px;background:#fff8df;color:#725b14!important;border-radius:8px}.retry{width:100%;height:40px;margin-top:8px;border:0;border-radius:9px;background:#fff0bd;color:#755500;font-weight:750}.filter-scroll{display:flex;gap:7px;overflow:auto;margin:0 -15px 13px;padding:2px 15px 5px;scrollbar-width:none}.filter-scroll button{white-space:nowrap;padding:7px 11px;background:#fff;border:1px solid var(--line);border-radius:99px;color:#617188;font-size:11px}.filter-scroll button.active{background:var(--navy);border-color:var(--navy);color:#fff}.mistake-card{background:#fff;border:1px solid var(--line);border-radius:14px;padding:15px;margin-bottom:11px}.mistake-card .knowledge{margin-left:7px;color:#718096;font-size:10px}.mistake-card h2{font-size:14px;line-height:1.55;margin:11px 0 7px}.mistake-card>p{font-size:10px;color:#78869a}.mistake-actions{display:flex;align-items:center;gap:13px}.detail-toggle{border:0;background:transparent;color:var(--blue);font-size:11px;padding:4px 0}.danger-link{color:#b44747}.mistake-detail{margin-top:9px;padding:10px;background:#f6f8fb;border-radius:9px}.mistake-detail p{font-size:11px;line-height:1.65;color:#50647e}.mistake-detail b{color:#314967}.mistake-practice{display:grid;gap:7px;margin-top:12px;padding-top:12px;border-top:1px solid #dfe7f1}.mistake-practice label{font-size:11px;font-weight:750;color:#314967}.mistake-practice textarea{min-height:76px;resize:vertical;border:1px solid #cfd9e6;border-radius:9px;padding:9px;font-size:12px;color:#3f5773;background:#fff}.mistake-practice .primary-button{height:38px;justify-self:start}.profile-card{background:#fff;border:1px solid var(--line);border-radius:16px;padding:24px;text-align:center}.profile-avatar{display:grid;place-items:center;width:64px;height:64px;margin:0 auto 10px;border-radius:20px;background:var(--blue-soft);color:#2e63c7;font-size:23px;font-weight:850}.profile-card h2{margin:0;font-size:19px}.profile-card>p{color:var(--muted);font-size:12px}.status-row{display:flex;justify-content:space-between;border-top:1px solid #edf1f6;margin-top:22px;padding-top:15px;font-size:12px}.status-row b{color:var(--green)}.status-row i{display:inline-block;width:7px;height:7px;background:var(--green);border-radius:50%;margin-right:5px}.logout-button{width:100%;height:44px;margin-top:15px;border:1px solid #e8caca;border-radius:10px;background:#fff;color:#b44747}.auth-page{position:relative;min-height:100dvh;display:grid;place-items:center;padding:25px;background:linear-gradient(145deg,#edf4ff,#fff9df);overflow:hidden}.math-pattern{position:absolute;color:#2652920d;font-size:74px;font-weight:900;white-space:nowrap;transform:rotate(-12deg)}.auth-card{position:relative;width:min(100%,390px);padding:29px 25px;background:#fff;border:1px solid #dce4ef;border-radius:20px;box-shadow:0 20px 55px #1e3b6224}.brand-mark{display:grid;place-items:center;width:44px;height:44px;border-radius:13px;background:var(--yellow);color:var(--navy);font-size:21px;font-weight:900}.auth-card .eyebrow{margin:20px 0 5px;color:var(--blue);font-size:10px;font-weight:850;letter-spacing:.1em}.auth-card h1{font-size:24px;margin:0 0 8px}.auth-copy{margin:0 0 22px;font-size:12px;color:var(--muted);line-height:1.65}.login-form{display:grid;gap:12px}.auth-submit{width:100%;height:46px;border:0;border-radius:11px;background:#1677ff;color:#fff;font-weight:750}.auth-submit:disabled{cursor:not-allowed;opacity:.55}.privacy-note{text-align:center;margin:13px 0 0;color:#8a97a9;font-size:10px}.account-alert{display:grid;gap:4px;margin:0 0 14px;padding:11px;background:#fff2e9;border-radius:9px;color:#8c4923;font-size:11px}.account-alert b{font-size:12px}.loading-overlay{position:fixed;z-index:80;inset:0;display:grid;place-items:center;align-content:center;gap:10px;background:#f4f7fbd1;-webkit-backdrop-filter:blur(2px);backdrop-filter:blur(2px);font-size:12px;color:#50647e}.mini-spinner{width:27px;height:27px;border:3px solid #dfe9f8;border-top-color:var(--blue);border-radius:50%;animation:spin .8s linear infinite}.toast{position:fixed;z-index:100;left:50%;top:20px;transform:translate(-50%);max-width:calc(100% - 30px);padding:10px 14px;background:#18314f;color:#fff;border-radius:9px;box-shadow:0 8px 24px #0000002e;font-size:12px}.modal-backdrop{position:fixed;z-index:90;inset:0;display:grid;place-items:end center;padding:16px;background:#11243c73}.confirm-card{width:min(100%,410px);padding:22px;background:#fff;border-radius:18px;text-align:center}.confirm-icon{display:grid;place-items:center;width:49px;height:49px;margin:0 auto 11px;border-radius:15px;background:#fff0bd;color:#755500;font-size:20px;font-weight:850}.confirm-card h2{margin:0;font-size:18px}.confirm-card p{font-size:12px;color:var(--muted);line-height:1.65}.confirm-card>div:last-child{display:flex;gap:9px;margin-top:18px}.confirm-card button{flex:1}.primary-button{background:var(--navy);color:#fff}@keyframes spin{to{transform:rotate(360deg)}}@media(min-width:760px){body{background:#eaf0f7}.app-shell{width:430px;margin:0 auto;background:#f4f7fb;box-shadow:0 0 44px #1e3b621f}.bottomnav,.submitbar{left:50%;right:auto;width:430px;transform:translate(-50%)}.modal-backdrop{place-items:center}.mobile-head{padding-top:38px}.auth-page{width:100vw;margin-left:calc((430px - 100vw)/2)}}@media(prefers-reduced-motion:reduce){.spinner,.mini-spinner{animation:none}}.account-picker{display:grid;gap:7px;text-align:left;color:#435a75;font-size:11px;font-weight:750}.account-picker input,.account-picker select{width:100%;height:44px;padding:0 11px;border:1px solid #cfd9e6;border-radius:10px;background:#fff;color:#314967;font-size:13px}.account-picker input::placeholder{color:#a4afbd}.account-picker input:focus,.account-picker select:focus{outline:3px solid rgba(46,99,199,.12);border-color:var(--blue)}.account-picker input:disabled,.account-picker select:disabled{cursor:not-allowed;background:#f3f5f8;color:#9aa7b7}.account-picker input:disabled::placeholder{color:#b7c1cf}.student-combobox{position:relative}.student-combobox input{padding-right:37px}.student-combobox .combobox-arrow{position:absolute;inset:0;width:100%;height:44px;margin:0;padding:0;border:0;border-radius:10px;background:transparent;color:#314967;pointer-events:none;appearance:auto;-webkit-appearance:menulist}.student-suggestions{position:absolute;z-index:5;top:calc(100% + 5px);left:0;right:0;max-height:182px;overflow:auto;padding:5px;background:#fff;border:1px solid #cfd9e6;border-radius:10px;box-shadow:0 10px 24px #1e3b6226}.student-suggestions button{display:block;width:100%;min-height:38px;padding:9px 10px;border:0;border-radius:7px;background:transparent;color:#314967;text-align:left;font:inherit;font-size:13px}.student-suggestions button:hover,.student-suggestions button.active{background:#eaf1ff;color:#245bb6}.student-suggestion-status{display:block;padding:10px;color:#718096;font-size:11px}.profile-action-button{width:100%;height:44px;margin-top:15px;border:1px solid #cbd9ed;border-radius:10px;background:#fff;color:#285db6;font-weight:750}.password-dialog{width:min(100%,410px);padding:22px;background:#fff;border-radius:18px}.password-dialog h2{margin:0;font-size:18px}.password-dialog>p{font-size:12px;color:var(--muted);line-height:1.65}.password-dialog form{display:grid;gap:11px;margin-top:16px}.password-dialog label{display:grid;gap:6px;color:#435a75;font-size:11px;font-weight:750}.password-dialog input{width:100%;height:43px;padding:0 11px;border:1px solid #cfd9e6;border-radius:10px;background:#fff;color:#314967;font-size:13px}.password-dialog input:focus{outline:3px solid rgba(46,99,199,.12);border-color:var(--blue)}.dialog-alert{padding:9px 10px;background:#fff2e9;border-radius:8px;color:#a14927;font-size:11px;line-height:1.55}.dialog-actions{display:flex;gap:9px;margin-top:7px}.dialog-actions button{flex:1}
