:root{--bg:#0c0c0e;--panel:#111114;--line:#2a2a31;--soft:#85828e;--text:#eeeaf3;--purple:#a76cff;--mint:#4ee0b6;--orange:#ffb31a;--red:#ff8e77}*{box-sizing:border-box}html,body{margin:0;min-height:100%;background:var(--bg);color:var(--text);font-family:'Noto Sans SC','DM Sans',sans-serif}button,input{font:inherit}.app{min-height:100vh;background:radial-gradient(ellipse at 51% 46%,#1b1622 0,#0c0c0e 54%);position:relative;overflow:hidden}.topbar{height:67px;display:flex;align-items:center;gap:17px;padding:0 22px;border-bottom:1px solid var(--line)}.icon-btn{border:0;background:transparent;color:#aaa7b2;font-size:19px;cursor:pointer;padding:5px}.icon-btn:hover{color:#fff}.brand{display:none;align-items:center;gap:8px;color:#fff}.brand span{color:var(--purple)}.course-title{display:flex;gap:10px;align-items:center;font-size:14px;margin-left:5px}.course-title span{color:#c6c3cc}.top-actions{display:flex;gap:12px;margin-left:auto}.progress-track{height:9px;margin:0 18px;border-bottom:1px solid #3a3941;position:relative}.progress-track:before{content:'';position:absolute;top:3px;left:0;right:0;height:3px;background:#25252b;border-radius:4px}.progress-track i{display:block;position:absolute;top:3px;left:0;width:12%;height:3px;background:var(--mint);border-radius:4px}.workspace{display:flex;min-height:calc(100vh - 76px)}.left-rail{width:66px;border-right:1px solid #212127;display:flex;flex-direction:column;align-items:center;padding:22px 0 17px;gap:23px}.rail-item{width:43px;height:44px;border-radius:10px;display:flex;flex-direction:column;align-items:center;justify-content:center;color:#6f6d76;font-size:19px;cursor:pointer}.rail-item small{font-size:9px;margin-top:3px}.rail-item.active,.rail-item:hover{background:#1f162b;color:#b77bff}.rail-spacer{flex:1}.lesson-panel{display:flex;flex:1;flex-direction:column;min-width:0}.lesson-toolbar{height:84px;padding:0 29px;display:flex;align-items:center;justify-content:space-between}.lesson-meta{display:flex;gap:17px;align-items:center;color:#77747f}.timer{font-size:14px}.counter{width:34px;height:34px;border:1px solid #49464f;border-radius:50%;display:grid;place-items:center;font-size:10px;color:#d3d0d9}.score{font-size:26px;color:var(--orange)}.difficulty{display:flex;gap:2px;border:1px solid #332640;background:#18121e;padding:5px;border-radius:15px}.difficulty button{border:0;background:transparent;color:#8d56ce;border-radius:9px;padding:8px 10px;cursor:pointer}.difficulty button.selected{background:#28153e;color:#b071ff}.lesson-content{flex:1;display:flex;flex-direction:column;align-items:center;justify-content:center;padding-bottom:55px}.mode-label{font-size:11px;text-transform:uppercase;letter-spacing:1.5px;color:#706b78;margin-bottom:42px}.mode-label span{color:#9b5fec;padding:0 8px}.prompt{font-size:28px;font-weight:500;letter-spacing:.7px;text-align:center;margin-bottom:60px;max-width:850px}.input-shell{width:min(850px,74vw);position:relative}.input-shell input{width:100%;border:0;outline:0;background:transparent;color:#f1eef5;text-align:center;font:500 25px 'DM Sans','Noto Sans SC',sans-serif;padding:3px 0 16px}.input-shell input::placeholder{color:#65616b}.input-line{height:2px;background:repeating-linear-gradient(90deg,#9f65f3 0 16%,#76737c 16% 20%,transparent 20% 21%);opacity:.9}.token-row{display:none;gap:7px;justify-content:center;flex-wrap:wrap;margin:0 0 13px}.token{padding:6px 9px;background:#251833;border:1px solid #9d61e9;border-radius:6px;color:#c293ff;font:13px 'DM Sans'}.feedback{height:28px;margin-top:22px;font-size:14px}.feedback.success{color:var(--mint)}.feedback.error{color:var(--red)}.answer-hint{height:22px;color:#9d68e9;font-size:13px}.lesson-footer{height:111px;display:flex;align-items:center;justify-content:space-between;padding:0 7.5%}.arrow{border:0;background:none;color:#7d7a83;font-size:38px;cursor:pointer}.arrow:hover{color:#fff}.actions{display:flex;gap:29px;align-items:center}.actions button{border:0;background:transparent;color:#8f8c96;display:flex;align-items:center;gap:8px;cursor:pointer}.actions button:hover{color:#d0adff}.actions .submit{color:#c7c3cf}.actions span{font-size:13px}kbd{border:1px solid #554f5d;border-bottom-width:2px;border-radius:5px;background:#19191e;color:#d8d4dc;padding:3px 6px;font:11px 'DM Sans',sans-serif}.assistant{position:absolute;bottom:21px;right:27px;border:0;background:none;font-size:29px;filter:drop-shadow(0 0 8px #5de7ff);cursor:pointer}.drawer{position:absolute;z-index:5;left:0;top:0;bottom:0;width:330px;background:#151419;border-right:1px solid #393441;transform:translateX(-100%);transition:transform .25s ease;padding:24px 20px;box-shadow:12px 0 35px #0008}.drawer.open{transform:translateX(0)}.drawer-head{display:flex;justify-content:space-between;align-items:center}.drawer-head button,.modal-close{border:0;background:none;color:#aaa6b1;font-size:24px;cursor:pointer}.drawer-sub{font-size:12px;color:#77747f;margin:8px 0 23px}.chapter{display:flex;align-items:center;gap:12px;padding:14px 10px;border-radius:12px;color:#a7a4ad;margin-bottom:6px}.chapter.current{background:#251936;color:#f0eaf7}.chapter>span{color:#806b9e;font:12px 'DM Sans'}.chapter div{flex:1}.chapter b,.chapter small{display:block}.chapter b{font-size:13px}.chapter small{font-size:11px;color:#77717f;margin-top:4px}.chapter em{font-style:normal;color:#a86eff;font-size:11px}.drawer-foot{border-top:1px solid #2e2c34;margin-top:20px;padding-top:20px}.drawer-foot button{border:1px dashed #5e556d;background:none;color:#a69eaf;width:100%;padding:12px;border-radius:9px;cursor:pointer}.modal{display:none;position:absolute;z-index:6;inset:0;background:#0009;align-items:center;justify-content:center}.modal.open{display:flex}.modal-card{width:min(520px,90vw);background:#19181e;border:1px solid #423d4a;border-radius:16px;padding:28px;position:relative;box-shadow:0 20px 60px #0008}.modal-close{position:absolute;right:16px;top:12px}.modal h2{margin:0 0 18px;font-size:19px}.modal p{color:#9995a0;font-size:13px;line-height:1.8}.stat-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:9px}.stat-box{background:#24212a;border-radius:10px;padding:15px}.stat-box b{font-size:21px;display:block;color:var(--purple)}.stat-box small{color:#8f8997;font-size:11px}.review-row{display:flex;gap:10px;align-items:center;padding:13px 0;border-bottom:1px solid #2d2a32}.review-row span{color:var(--orange)}.review-row p{margin:0;color:#d5d0d9;font-size:13px}.review-row small{display:block;color:#7c7782;margin-top:3px}@media(max-width:800px){.brand{display:flex}.course-title{display:none}.left-rail{display:none}.lesson-toolbar{padding:0 15px}.prompt{font-size:21px;margin-bottom:45px}.input-shell{width:84vw}.input-shell input{font-size:19px}.lesson-footer{height:160px;padding:0 12px}.actions{gap:11px;flex-wrap:wrap;justify-content:center;max-width:300px}.actions button{gap:4px}.actions span{font-size:10px}.actions kbd{font-size:9px;padding:3px}.difficulty button{padding:7px}.drawer{width:88vw}}
.token.ok{border-color:#3ebf9d;background:#143b34;color:#61e8bf}.token.bad{border-color:#c75e57;background:#41201f;color:#ff9c8a}
.mode-bar{display:flex;gap:5px;margin-bottom:28px;background:#17151b;border:1px solid #302b37;border-radius:10px;padding:4px}.mode-bar button{border:0;background:transparent;color:#807a89;border-radius:7px;padding:7px 11px;font-size:11px;cursor:pointer}.mode-bar button.active{background:#2b193e;color:#c08aff}.choice-token{cursor:pointer;white-space:normal;line-height:1.45}.choice-token:hover{background:#2b193e;color:#d6b3ff;border-color:#a76cff}