*{box-sizing:border-box}body{margin:0;font-family:Inter,ui-sans-serif,system-ui,-apple-system,"Segoe UI",Arial,sans-serif;background:var(--bg);color:var(--text);line-height:1.55}button,input,select,textarea{font:inherit}button{cursor:pointer}a{color:inherit;text-decoration:none}.top{height:76px;display:flex;align-items:center;justify-content:space-between;padding:0 max(24px,calc((100vw - 1190px)/2));background:var(--paper);border-bottom:1px solid var(--line);gap:16px;position:sticky;top:0;z-index:3}.brand{font-weight:900;letter-spacing:1.7px;white-space:nowrap}.logo{display:inline-grid;place-items:center;width:36px;height:36px;background:#624fe4;color:white;border-radius:12px;margin-right:8px}.brand-sub{color:var(--muted);font-weight:600;font-size:12px;letter-spacing:0}.top nav{display:flex;gap:24px;font-size:13px;font-weight:650;color:var(--muted)}.top nav a:hover,a.link{color:var(--primary)}.head-actions{display:flex;align-items:center;gap:10px}.icon-btn{border:1px solid var(--line);border-radius:11px;padding:8px 12px;background:var(--paper);color:var(--text)}.btn{border:0;border-radius:11px;background:var(--primary);color:var(--on-primary);padding:11px 20px;font-weight:700;display:inline-flex;align-items:center;justify-content:center;gap:9px;transition:transform .15s,opacity .15s}.btn:hover{transform:translateY(-1px);opacity:.9}.btn.secondary{background:var(--primary2);color:var(--primary)}.btn.outline{background:transparent;color:var(--text);border:1px solid var(--line)}.btn.small{padding:7px 11px;font-size:12px}main{max-width:1190px;margin:0 auto;min-height:calc(100vh - 205px);padding:38px 24px 80px}h1,h2,h3,p{margin-top:0}h1{font-size:clamp(31px,4vw,52px);letter-spacing:-1.9px;line-height:1.12;margin-bottom:16px}h2{font-size:26px;letter-spacing:-.7px;margin-bottom:20px}h3{font-size:18px;margin-bottom:9px}p{color:var(--muted)}.eyebrow{color:var(--primary);font-size:11px;letter-spacing:2px;font-weight:800;text-transform:uppercase;margin-bottom:16px}.hero{display:grid;grid-template-columns:1.1fr .9fr;gap:36px;align-items:center;padding:46px 0 60px}.hero h1 span{color:var(--primary)}.hero p{font-size:17px;max-width:550px}.hero-actions{display:flex;gap:12px;flex-wrap:wrap;margin:28px 0}.chips{display:flex;gap:12px;flex-wrap:wrap}.chip{font-size:12px;color:var(--muted);padding:7px 11px;background:var(--paper);border:1px solid var(--line);border-radius:30px}.visual{padding:26px;border-radius:30px;background:linear-gradient(140deg,#6652df,#927bec);min-height:330px;box-shadow:0 20px 65px #5948db32;position:relative;color:white}.visual .floating{background:#ffffffee;color:#202445;border-radius:18px;padding:19px;box-shadow:0 16px 36px #10113729}.visual h3{font-size:22px}.visual .tiny{font-size:12px;color:#777c96}.visual .bottom{margin:25px 0 0 50px}.progressbar{height:9px;background:var(--surface);border-radius:20px;overflow:hidden;margin:12px 0}.progressbar>span{display:block;height:100%;background:var(--primary);border-radius:20px}.section-head{display:flex;justify-content:space-between;align-items:end;gap:20px;margin:22px 0}.muted{color:var(--muted)}.grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:18px}.grid.three{grid-template-columns:repeat(3,minmax(0,1fr))}.card{background:var(--paper);border:1px solid var(--line);border-radius:19px;padding:25px;box-shadow:var(--shadow)}.subject{display:flex;flex-direction:column;gap:10px;min-height:240px}.subject .bigicon{font-size:32px;background:var(--primary2);border-radius:16px;width:64px;height:64px;display:grid;place-items:center}.subject.social .bigicon{background:#ddf8f2}.subject h3{font-size:23px}.subject .meta{margin-top:auto;color:var(--primary);font-weight:750;font-size:13px}.path{color:var(--muted);font-size:13px;margin-bottom:20px}.path a{color:var(--primary)}.lesson-list{display:grid;gap:12px}.lesson-list .item{padding:18px 22px;background:var(--paper);border:1px solid var(--line);border-radius:14px;display:flex;justify-content:space-between;align-items:center;gap:20px}.item p{font-size:13px;margin:4px 0 0}.pill{border-radius:25px;padding:5px 10px;font-size:11px;background:var(--primary2);color:var(--primary);white-space:nowrap}.lesson-layout{display:grid;grid-template-columns:minmax(0,1fr) 300px;gap:23px}.lesson-body{font-size:16px}.lesson-body p{color:var(--text);line-height:1.85}.term{border-top:1px solid var(--line);padding:11px 0}.term strong{color:var(--primary)}.notice{padding:16px 20px;border-radius:13px;background:var(--primary2);margin:17px 0;color:var(--text)}.notice.teal{background:#e6f7f4;color:#154a47}body.dark .notice.teal{background:#204340;color:white}.sidebar{position:sticky;top:100px;align-self:start}.sidebar button{width:100%;margin-top:9px}.question{margin:20px 0}.answers{display:grid;gap:10px;margin:18px 0}.answer{display:block;text-align:left;border:1px solid var(--line);background:var(--paper);padding:13px 15px;border-radius:11px;color:var(--text);width:100%}.answer.selected{border:2px solid var(--primary);background:var(--primary2)}.answer input{margin-right:8px}.form-field{display:block;width:100%;border:1px solid var(--control-line);background:var(--paper);color:var(--text);border-radius:11px;padding:12px 13px;margin:10px 0 16px}.row{display:flex;align-items:center;gap:11px;flex-wrap:wrap}.result{border-radius:12px;padding:15px;background:var(--primary2);margin-top:16px}.good{color:var(--success)}.bad{color:var(--danger)}.stat{font-size:32px;font-weight:850;color:var(--text);letter-spacing:-1px}.stat-label{font-size:12px;color:var(--muted)}.feedback{font-size:13px}.auth{max-width:440px;margin:28px auto}.chat{height:310px;overflow:auto;display:flex;flex-direction:column;gap:12px;padding:15px;background:var(--bg);border-radius:14px;border:1px solid var(--line)}.bubble{padding:11px 15px;border-radius:14px;max-width:85%;white-space:pre-wrap}.bubble.bot{align-self:start;background:var(--paper);border:1px solid var(--line)}.bubble.me{align-self:end;background:var(--primary);color:var(--on-primary)}.two-columns{display:grid;grid-template-columns:1fr 1fr;gap:20px}footer{text-align:center;padding:25px;color:var(--muted);border-top:1px solid var(--line);font-size:12px}footer p{font-size:11px;margin:8px}#toast{position:fixed;bottom:25px;right:25px;background:#20243d;color:white;border-radius:10px;padding:13px 17px;display:none;z-index:9;max-width:330px}.empty{padding:25px;text-align:center;color:var(--muted)}.tag{font-size:12px;color:var(--muted)}@media(max-width:900px){.top nav{gap:12px;overflow:auto}.top{padding:14px 20px}.hero{gap:15px}.lesson-layout{grid-template-columns:1fr}.sidebar{position:static}.grid.three{grid-template-columns:repeat(2,1fr)}}@media(max-width:680px){.top{height:auto;flex-wrap:wrap;gap:8px}.top nav{order:3;width:100%;padding:8px 0;white-space:nowrap;overflow-x:auto}.brand-sub{display:none}main{padding:25px 16px 55px}.hero,.grid,.grid.three,.two-columns{grid-template-columns:1fr}.hero{padding:13px 0 28px}.visual{min-height:265px}.lesson-list .item{align-items:flex-start}.card{padding:19px}h1{letter-spacing:-1px}}