@font-face{font-family:KaTeX_Main;src:url('/vendor/katex/fonts/KaTeX_Main-Regular.woff2')}*{box-sizing:border-box}body{margin:0;background:#f6f7fc;color:#252d35;font-family:Inter,-apple-system,BlinkMacSystemFont,'Segoe UI','Microsoft YaHei',sans-serif;font-size:14px;line-height:1.6}button,input,textarea,select{font:inherit}button,a,input,textarea,select{outline-offset:4px}button{cursor:pointer;border:1px solid #e0e5e7;background:white;color:#3b454f;border-radius:8px;padding:9px 14px;font-weight:500;transition:background .15s}button:hover{background:#eeeef6;border-color:#b3b4cc}button:disabled{opacity:.5;cursor:wait}button.primary{background:#5057d9;color:white;border-color:#5057d9}button.primary:hover{background:#4147bd}button.text{border:0;background:transparent;padding:5px 8px;color:#5c6b73}button.danger{color:#b04d43}.loading{padding:80px;color:#6b777d}input,textarea,select{border:1px solid #dce2e5;background:white;border-radius:8px;padding:10px 12px;color:#28333d}textarea{resize:vertical;line-height:1.8}input:focus,textarea:focus,select:focus{outline:2px solid #8385ad;border-color:transparent}a{color:#5057d9}h1,h2,h3,p{margin-top:0}h1{font-size:28px;letter-spacing:-1px;line-height:1.35;font-weight:650}h2{font-size:19px}h3{font-size:15px}small,.muted{color:#829097}.eyebrow{font-size:11px;font-weight:650;letter-spacing:2px;color:#7174a1;text-transform:uppercase}.app-shell{display:grid;grid-template-columns:220px minmax(0,1fr);min-height:100vh}.sidebar{background:#fff;border-right:1px solid #e6eaeb;display:flex;flex-direction:column;padding:30px 18px;position:fixed;width:220px;inset:0 auto 0 0;z-index:5}.logo{display:flex;align-items:center;gap:11px;padding:0 12px 30px}.logo img{width:35px;height:35px}.logo strong{font-size:22px;letter-spacing:3px}.logo small{display:block;font-size:10px;letter-spacing:1px}.nav-label{font-size:10px;letter-spacing:2px;color:#9ba5aa;padding:24px 13px 9px}.nav-item{border:0;background:transparent;display:flex;align-items:center;gap:12px;width:100%;text-align:left;padding:11px 13px;margin:3px 0;color:#6a777e}.nav-item.active{background:#ebecf5;color:#5057d9;font-weight:650}.nav-item svg{width:18px;height:18px;fill:none;stroke:currentColor;stroke-width:1.7}.nav-item .count{margin-left:auto;font-size:11px;background:#e5e6ee;padding:0 7px;border-radius:5px}.sidebar-bottom{margin-top:auto;border-top:1px solid #edf0f0;padding:18px 10px 0}.status-dot{display:inline-block;background:#8b8db2;width:6px;height:6px;border-radius:50%;margin-right:7px}.main{grid-column:2;min-width:0}.topbar{height:75px;background:#fff;border-bottom:1px solid #e6eaeb;padding:0 38px;display:flex;align-items:center;justify-content:space-between}.breadcrumbs{color:#97a1a8;font-size:12px}.breadcrumbs b{color:#3c3d59;font-weight:500;margin-left:10px}.top-right{display:flex;align-items:center;gap:22px;color:#7b878b;font-size:12px}.avatar{background:#e4e4ed;width:30px;height:30px;display:grid;place-items:center;border-radius:50%;color:#454767}.content{padding:32px 38px 48px;max-width:1560px;margin:auto}.page-heading{display:flex;align-items:center;justify-content:space-between;gap:20px;margin-bottom:25px}.page-heading h1{margin-bottom:6px}.page-heading p{color:#8b969c;margin-bottom:0;font-size:13px}.row{display:flex;align-items:center;gap:10px;flex-wrap:wrap}.space{justify-content:space-between}.hero{display:grid;grid-template-columns:1fr 280px;background:#e9e9f0;border:1px solid #dadae6;border-radius:14px;overflow:hidden;margin-bottom:24px;min-height:210px}.hero-copy{padding:29px 32px}.hero h2{font-size:25px;margin:12px 0 10px;color:#2f3046}.hero p{color:#5f628f;font-size:13px}.hero-art{position:relative;display:flex;align-items:center;justify-content:center;background:#e1e2ed}.hero-art svg{width:250px;height:170px}.hero-art .label{position:absolute;bottom:13px;font-size:10px;letter-spacing:2px;color:#7b7da7}.stats{display:grid;grid-template-columns:repeat(4,1fr);gap:16px;margin-bottom:28px}.stat{background:#fff;border:1px solid #e5e9eb;border-radius:10px;padding:20px 22px}.stat .value{font-size:27px;font-weight:600;letter-spacing:-1px;display:block;margin:6px 0 1px;color:#32334a}.stat .unit{font-size:12px;font-weight:400;color:#898bb1;letter-spacing:0;margin-left:7px}.stat small{font-size:11px}.two-col{display:grid;grid-template-columns:minmax(0,1.6fr) minmax(280px,1fr);gap:23px}.panel{background:white;border:1px solid #e4e9eb;border-radius:12px;padding:23px;margin-bottom:22px}.panel-heading{display:flex;align-items:center;justify-content:space-between;margin-bottom:20px}.panel-heading h2{font-size:16px;margin:0}.subject-card{display:flex;gap:17px;padding:19px 0;border-top:1px solid #eef1f1;align-items:center}.subject-icon{width:45px;height:45px;display:grid;place-items:center;background:#ebebf4;color:#54577f;font-size:25px;border-radius:11px}.subject-card h3{margin-bottom:4px}.subject-card p{font-size:12px;color:#8a959b;margin:0}.grow{flex:1}.progress{height:4px;background:#e9eaf4;border-radius:4px;margin-top:12px;width:170px}.progress i{height:100%;display:block;background:#8486ad;border-radius:4px}.tag{font-size:10px;padding:3px 8px;border-radius:5px;background:#edeef6;color:#5f618e;display:inline-block;white-space:nowrap}.tag.amber{background:#fcf2e2;color:#ad854e}.tag.red{background:#fbefed;color:#ae756b}.section-title{font-size:16px;font-weight:600;margin:24px 0 16px}.activity-row{padding:13px 0;border-top:1px solid #eef1f1;display:flex;gap:12px;align-items:center}.activity-row p{font-size:12px;margin:0;color:#8a969a}.activity-dot{width:8px;height:8px;border-radius:50%;background:#a3a4c1;flex:none}.calendar{display:grid;grid-template-columns:repeat(7,1fr);gap:7px;text-align:center;font-size:11px}.calendar .day{aspect-ratio:1;display:grid;place-items:center;border-radius:6px;background:#f6f7f7;color:#9da5aa}.calendar .day.done{background:#c5c6dc;color:#3b3d60}.calendar .day.today{box-shadow:inset 0 0 0 1px #5a5d88}.calendar-head{color:#a2abaf;margin-bottom:7px}.empty{color:#95a0a5;text-align:center;padding:35px 15px;line-height:1.9;font-size:13px}.filters{display:flex;align-items:center;gap:10px;margin-bottom:20px;flex-wrap:wrap}.filters input{flex:1;min-width:180px}.question-list{display:grid;gap:12px}.q-card{background:white;border:1px solid #e1e2eb;border-radius:10px;padding:21px 24px;cursor:pointer;display:flex;gap:18px;align-items:center}.q-card:hover{border-color:#989abb;box-shadow:0 4px 18px #263a2810}.q-num{font-family:monospace;font-size:13px;color:#9698b9}.q-card h3{margin:0 0 7px}.q-card .meta{font-size:11px;color:#8486ad;display:flex;gap:14px}.q-card .arrow{margin-left:auto;color:#8b8db1}.practice-header{margin-bottom:20px}.practice-layout{display:grid;grid-template-columns:minmax(420px,1fr) 350px;gap:22px;align-items:start}.question-panel{padding:29px 32px}.question-panel h1{font-size:24px;margin:16px 0 26px}.prose{line-height:1.95;overflow-wrap:anywhere;font-size:14px}.prose p{margin-bottom:15px}.prose pre{white-space:pre-wrap;background:#f0f0f7;padding:12px;border-radius:6px}.prose img{max-width:100%}.prose .katex-display{overflow-x:auto;overflow-y:hidden;padding:7px 0}.prose .katex{font-size:1.12em}.divider{height:1px;background:#e9eaf4;margin:24px 0}.answer-editor{width:100%;min-height:185px;background:#f8f9fc;font-family:'SFMono-Regular',Consolas,monospace;font-size:13px;border:1px solid #dadbe7;line-height:1.9}.editor-top{display:flex;align-items:center;justify-content:space-between;margin-bottom:10px}.editor-top span{font-size:11px;color:#8a8cb1}.preview{min-height:55px;background:#fafafd;border:1px dashed #dddde8;padding:14px 17px;border-radius:7px;margin:13px 0 18px;color:#4f5177}.preview:empty{display:none}.grading{margin-top:20px;background:#f3f3f9;padding:15px;border-radius:8px}.grading label{font-size:12px;color:#5d5f8b;display:block;margin-bottom:10px}.tabs{display:flex;gap:0;border-bottom:1px solid #e3e4ed;margin:-5px -8px 20px}.tab{flex:1;white-space:nowrap;border:0;border-radius:0;padding:12px 4px;background:transparent;font-size:12px;color:#8688af}.tab.active{color:#313358;border-bottom:2px solid #313358;font-weight:600}.side-panel{position:sticky;top:20px;padding:19px 20px;max-height:calc(100vh - 45px);overflow:auto}.helper-intro{font-size:12px;color:#898bb1;margin-bottom:22px}.hint{background:#f1f1f8;border:1px solid #dfe0ea;border-radius:8px;padding:15px;margin-bottom:13px}.hint h3{font-size:11px;letter-spacing:1px;color:#5d5f8b;margin-bottom:8px}.hint .prose{font-size:13px}.full-width{width:100%}.solution{padding-top:17px;margin-top:20px;border-top:1px solid #e2e3ec}.solution h3{color:#353755}.symbol-search{width:100%;font-size:12px;margin-bottom:12px}.symbol-grid{display:grid;grid-template-columns:1fr 1fr;gap:7px}.symbol{padding:10px 7px;text-align:center;border:1px solid #e2e3ec;font-size:12px}.symbol small{display:block;font-size:10px;color:#9495b7;margin-top:5px}.chat-message{padding:12px 14px;border-radius:9px;margin-bottom:12px;font-size:12px}.chat-message.user{background:#ebecf5;margin-left:25px}.chat-message.assistant{background:#f3f3f9}.chat-message .prose{font-size:12px}.chat-message .who{font-size:10px;color:#7073a0;letter-spacing:1px;margin-bottom:7px}.chat-input{width:100%;min-height:90px;font-size:12px;margin:8px 0}.chat-progress{font-size:11px;color:#6f719f;padding:10px 0}.upload-zone{border:1px dashed #b3b5cd;border-radius:11px;background:#f7f7fb;padding:35px;text-align:center}.upload-zone input{border:0;background:transparent;max-width:100%}.file-row{display:flex;align-items:center;gap:16px;border-top:1px solid #e9eaf4;padding:18px 0}.file-row h3{font-size:13px;margin-bottom:4px}.file-row small{font-size:11px}.form-grid{display:grid;grid-template-columns:1fr 1fr;gap:17px}.form-grid label,.field{display:flex;flex-direction:column;gap:7px;font-size:12px;color:#6a6c9b}.form-grid input,.form-grid select,.field input,.field textarea{width:100%}.form-grid .wide{grid-column:1/-1}.review-editor textarea{min-height:95px}.review-editor .stem{min-height:160px}.login-page{min-height:100vh;display:grid;grid-template-columns:1fr 1fr;background:#fff}.login-brand{background:#e4e4ee;padding:65px;display:flex;flex-direction:column;justify-content:center;align-items:center}.login-brand h1{font-size:42px;color:#5057d9;margin-top:30px;letter-spacing:6px}.login-brand p{color:#6b6e9d}.login-box{display:flex;align-items:center;justify-content:center;padding:50px}.login-form{max-width:340px;width:100%}.login-form h2{font-size:25px;margin-bottom:7px}.login-form .field{margin-top:18px}.login-form button{margin-top:25px}.notice{background:#f7f5e9;border:1px solid #eae4cd;border-radius:8px;padding:13px 17px;font-size:12px;color:#9a8759;margin-bottom:20px}.error{color:#b25043;font-size:12px;margin-top:10px}.exam-question-nav{display:flex;gap:7px;flex-wrap:wrap;margin-bottom:20px}.exam-question-nav button{width:35px;padding:7px 0}.exam-question-nav button.active{background:#5057d9;color:white}.exam-question-nav button.answered{border-color:#7f81aa}.timer{font-family:monospace;font-size:19px;color:#444667;background:#e9e9f3;padding:5px 12px;border-radius:6px}.timer.urgent{color:#b74c43;background:#f9ece8}.table{width:100%;border-collapse:collapse;font-size:12px}.table th{color:#7f81aa;text-align:left;font-weight:500;padding:12px}.table td{border-top:1px solid #e9e9f3;padding:14px 12px}.bar{height:6px;background:#e9e9f1;border-radius:6px;overflow:hidden;flex:1}.bar i{display:block;height:100%;background:#7e80a9}.legend{font-size:11px;color:#7f81a9}.view-toolbar{display:flex;align-items:center;justify-content:space-between;margin-bottom:20px}#toast{position:fixed;bottom:28px;left:50%;transform:translateX(-50%) translateY(100px);background:#5057d9;color:white;padding:11px 22px;border-radius:9px;z-index:100;opacity:0;transition:.2s;max-width:80vw;font-size:13px}#toast.show{transform:translateX(-50%) translateY(0);opacity:1}.job-box{margin-top:14px;border:1px solid #d7d8e7;background:#f3f3fa;border-radius:8px;padding:16px}.job-box pre{white-space:pre-wrap;max-height:250px;overflow:auto;font-size:11px}.login-decoration{width:100%;max-width:400px}.draft-note{font-size:11px;color:#7c7ea8}.mobile-notice{display:none}@media(min-width:1500px){.practice-layout{grid-template-columns:minmax(550px,1fr) 390px}}@media(max-width:1100px){.sidebar{width:180px;padding:25px 10px}.app-shell{grid-template-columns:180px 1fr}.content{padding:25px}.topbar{padding:0 25px}.practice-layout{grid-template-columns:minmax(350px,1fr) 300px}.question-panel{padding:24px}.stats{gap:10px}.stat{padding:17px}.hero{grid-template-columns:1fr 220px}.two-col{grid-template-columns:1fr}.hero-art{overflow:hidden}}@media(max-width:800px){.app-shell{grid-template-columns:75px 1fr}.sidebar{width:75px;padding:24px 10px}.logo{padding:0 10px 20px}.logo div,.nav-label,.nav-item span,.sidebar-bottom{display:none}.nav-item{justify-content:center}.main{min-width:0}.content{padding:20px}.topbar{padding:0 20px}.top-right span{display:none}.practice-layout{grid-template-columns:1fr}.side-panel{position:static;max-height:none}.hero{grid-template-columns:1fr}.hero-art{display:none}.stats{grid-template-columns:1fr 1fr}.login-page{grid-template-columns:1fr}.login-brand{display:none}.form-grid{grid-template-columns:1fr}.q-card{padding:18px}.page-heading{align-items:flex-start}.two-col{display:block}}

/* Blue and violet study workspace */
:root{--accent:#5057d9;--violet:#7959d4;--ink:#252b48;--soft:#eef0ff}
body{color:var(--ink);background:#f6f7fc}
button{transition:background .18s,border-color .18s,box-shadow .18s,transform .18s}
button.primary{box-shadow:0 4px 10px #5057d91c}button.primary:hover{box-shadow:0 6px 16px #5057d92b;transform:translateY(-1px)}
.sidebar{background:linear-gradient(180deg,#fff 60%,#f6f5ff);border-color:#e8e9f4}
.logo strong{color:#303557}.nav-item.active{background:linear-gradient(100deg,#e9edff,#f0eaff);color:#5552c8;box-shadow:inset 3px 0 #7770dc}.nav-item:hover{background:#f2f3fe}
.topbar{background:#ffffffed;border-color:#e9eaf3}.avatar{background:#eeebff;color:#6b55b6}
.hero{background:linear-gradient(115deg,#edf2ff 0%,#f0ecff 100%);border-color:#dfe3fa;border-radius:18px;box-shadow:0 8px 30px #5057d908;min-height:228px}
.hero h2{color:#323867;font-size:28px}.hero p{color:#707c9d}.hero-art{background:radial-gradient(ellipse at center,#e2ddff99,transparent 72%);border-left:1px solid #e0e1f777}.hero-art svg{width:270px;height:185px}.hero-art .label{color:#8282ac}
.panel,.stat,.q-card{border-color:#e6e8f3;box-shadow:0 3px 14px #30366004}.stat{border-radius:13px}.stat .value{color:#3b4273}.panel{border-radius:14px}.subject-icon{background:#eeedff;color:#7163cd}
.subject-card:nth-child(3) .subject-icon{background:#eaf1ff;color:#5478d2}.subject-card:nth-child(4) .subject-icon{background:#f3eaff;color:#9762c5}
.progress i,.bar i{background:linear-gradient(90deg,#6484e8,#9174df)}
.login-brand{background:radial-gradient(ellipse at 25% 25%,#e2e9ff,transparent 65%),linear-gradient(145deg,#f1f4ff,#ede7ff)}
.login-brand h1{color:#5057d9}.login-brand p{color:#7681a3}.answer-editor{background:#fcfcff}.preview{background:#f8f9ff}.hint{background:#f6f6ff;border-color:#e4e3f6}
:focus-visible{outline:2px solid #7773dc}

/* Tablet: compact labelled rail, touch targets and portrait reading flow. */
.tablet-practice-tools{display:none}
@media (max-width:1200px){
 .app-shell{grid-template-columns:88px minmax(0,1fr)}
 .sidebar{width:88px;padding:22px 8px;overflow-y:auto}
 .logo{padding:0 0 20px;justify-content:center}.logo div,.nav-label,.sidebar-bottom{display:none}
 .nav-item{flex-direction:column;justify-content:center;gap:4px;padding:10px 2px;font-size:11px;min-height:64px;position:relative}
 .nav-item span{display:block}.nav-item .count{position:absolute;right:2px;top:2px;font-size:9px}.nav-item svg{width:21px;height:21px}
 .content{padding:24px}.topbar{padding:0 24px;height:64px}
 .practice-layout{grid-template-columns:minmax(0,1fr) 310px;gap:16px}
 .question-panel{padding:24px}.question-panel h1{font-size:22px}.side-panel{padding:16px;top:16px}
 .hero{grid-template-columns:minmax(0,1fr) 220px}.hero-copy{padding:26px}.hero h2{font-size:24px}
 .stats{gap:12px}.stat{padding:16px}.two-col{grid-template-columns:1fr}
 .q-card{min-width:0}.q-card .grow,.file-row .grow{min-width:0;overflow-wrap:anywhere}
}
@media (max-width:1000px){
 .practice-layout{grid-template-columns:minmax(0,1fr)}
 .side-panel{position:static;max-height:none;overflow:visible;scroll-margin-top:18px}
 .tablet-practice-tools{display:flex;gap:8px;margin-bottom:16px;flex-wrap:wrap}
 .tablet-practice-tools button{flex:1;white-space:nowrap}
 .question-panel{scroll-margin-top:18px}.hero{grid-template-columns:1fr}.hero-art{display:none}
 .stats{grid-template-columns:repeat(2,minmax(0,1fr))}.page-heading{align-items:flex-start}
 .form-grid{grid-template-columns:minmax(0,1fr)}.form-grid .wide{grid-column:1}
 .filters input,.filters select{min-width:0;max-width:100%}.filters input{flex-basis:100%}
 .file-row{flex-wrap:wrap}.panel{min-width:0;overflow-wrap:anywhere}.panel:has(>.table){overflow-x:auto}
 .view-toolbar{flex-wrap:wrap;gap:12px}.question-panel .row{flex-wrap:wrap}
 .login-page{grid-template-columns:1fr}.login-brand{display:none}.login-box{padding:36px 24px;min-height:100dvh}
}
@media (pointer:coarse){
 button,input,select{min-height:44px}button{touch-action:manipulation;-webkit-tap-highlight-color:transparent}
 input,textarea,select{font-size:16px}.answer-editor,.chat-input{font-size:16px;min-height:180px}
 .tab{min-height:48px;font-size:13px}.symbol{min-height:64px;font-size:14px}
 .nav-item{min-height:64px}.exam-question-nav button{width:44px;min-height:44px}
 .prose{font-size:16px;line-height:1.9}.hint .prose,.chat-message .prose{font-size:15px}
 .grading .row button{flex:1 1 120px}.topbar button{min-width:44px}
 .side-panel{max-height:none}.answer-editor{resize:vertical}
}
@media (prefers-reduced-motion:reduce){button{transition:none}button.primary:hover{transform:none}}