:root{
  --bg:#071214;--bg2:#0b191c;--card:#0d2023cc;--card2:#10292d;--line:#2b464a;
  --text:#ecf7f5;--muted:#91aaa8;--mint:#79f2cb;--cyan:#63d9ee;--amber:#ffc96b;
  --danger:#ff847c;--r:24px;--shadow:0 24px 70px rgba(0,0,0,.28)
}
*{box-sizing:border-box}html{background:var(--bg);color-scheme:dark}body{margin:0;min-height:100vh;background:
radial-gradient(circle at 8% -12%,rgba(99,217,238,.16),transparent 32rem),
radial-gradient(circle at 110% 42%,rgba(121,242,203,.12),transparent 36rem),
linear-gradient(145deg,var(--bg),#081517 55%,#061013);font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;color:var(--text)}
button,input,select,textarea{font:inherit}.grain{position:fixed;inset:0;pointer-events:none;opacity:.17;background-image:url("data:image/svg+xml,%3Csvg viewBox='0 0 180 180' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.9' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='.08'/%3E%3C/svg%3E")}
.topbar{position:sticky;top:0;z-index:20;height:76px;display:flex;align-items:center;justify-content:space-between;padding:10px clamp(14px,3vw,34px);backdrop-filter:blur(18px);background:linear-gradient(180deg,rgba(7,18,20,.92),rgba(7,18,20,.58));border-bottom:1px solid rgba(121,242,203,.1)}
.brand{display:flex;align-items:center;gap:10px;border:0;background:none;color:var(--text);padding:0;cursor:pointer;text-align:left}.brand-mark{width:42px;height:42px;display:grid;place-items:center;border:1px solid var(--mint);border-radius:13px 18px 13px 18px;font-weight:900;color:var(--bg);background:var(--mint);box-shadow:0 0 30px rgba(121,242,203,.18)}.brand b{font-size:17px;letter-spacing:.04em}.brand small{display:block;font-size:9px;letter-spacing:.22em;color:var(--muted);margin-top:2px}.top-actions{display:flex;align-items:center;gap:10px}
.hint-switch{display:flex;align-items:center;gap:8px;color:var(--muted);font-size:12px;cursor:pointer}.hint-switch input{display:none}.hint-switch i{width:44px;height:25px;border-radius:999px;background:#1a3033;border:1px solid var(--line);position:relative;transition:.2s}.hint-switch i:after{content:"";position:absolute;width:17px;height:17px;left:3px;top:3px;border-radius:50%;background:#90a4a3;transition:.2s}.hint-switch input:checked+i{background:rgba(121,242,203,.15);border-color:var(--mint)}.hint-switch input:checked+i:after{transform:translateX(19px);background:var(--mint)}.icon-btn{border:1px solid var(--line);background:var(--card2);color:var(--mint);width:39px;height:39px;border-radius:13px;cursor:pointer}
.app-shell{width:min(1180px,100%);margin:0 auto;padding:28px clamp(14px,3vw,34px) 110px}.eyebrow{color:var(--mint);font-size:11px;text-transform:uppercase;letter-spacing:.18em;font-weight:800}.hero{position:relative;padding:26px 0 20px}.hero h1{font-size:clamp(38px,7vw,78px);line-height:.94;letter-spacing:-.055em;margin:10px 0 14px;max-width:850px}.hero h1 em{font-style:normal;color:transparent;-webkit-text-stroke:1px rgba(236,247,245,.78)}.hero p{max-width:680px;color:var(--muted);font-size:clamp(15px,2vw,18px);line-height:1.6}.hero-orbit{position:absolute;right:2%;top:12px;width:150px;height:150px;border:1px solid rgba(99,217,238,.22);border-radius:50%;opacity:.7}.hero-orbit:before,.hero-orbit:after{content:"";position:absolute;border-radius:50%;border:1px dashed rgba(121,242,203,.22)}.hero-orbit:before{inset:23px}.hero-orbit:after{inset:48px;background:rgba(121,242,203,.05)}
.mode-grid{display:grid;grid-template-columns:repeat(12,1fr);gap:14px;margin-top:26px}.mode-card{grid-column:span 4;min-height:240px;padding:22px;border:1px solid var(--line);border-radius:var(--r);background:linear-gradient(160deg,rgba(15,38,41,.92),rgba(8,22,24,.78));box-shadow:var(--shadow);position:relative;overflow:hidden;cursor:pointer;transition:.22s;color:var(--text);text-align:left}.mode-card:hover{transform:translateY(-3px);border-color:rgba(121,242,203,.55)}.mode-card:after{content:"";position:absolute;width:170px;height:170px;border-radius:40% 60% 55% 45%;right:-55px;bottom:-70px;border:1px solid rgba(121,242,203,.2);transform:rotate(25deg)}.mode-card:nth-child(2):after{border-color:rgba(99,217,238,.24)}.mode-card:nth-child(3):after{border-color:rgba(255,201,107,.24)}.mode-index{font-size:11px;color:var(--muted);letter-spacing:.16em}.mode-icon{display:inline-grid;place-items:center;width:52px;height:52px;border-radius:18px;background:rgba(121,242,203,.1);color:var(--mint);font-size:26px;margin:30px 0 14px}.mode-card h2{font-size:26px;letter-spacing:-.03em;margin:0 0 8px}.mode-card p{color:var(--muted);line-height:1.5;margin:0 0 18px}.mode-card .go{font-size:12px;color:var(--mint);font-weight:800;letter-spacing:.08em;text-transform:uppercase}
.status-strip{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;margin:18px 0 6px}.status{border:1px solid rgba(43,70,74,.7);border-radius:18px;padding:14px;background:rgba(9,25,27,.55)}.status b{display:block;font-size:22px}.status small{color:var(--muted)}
.page-head{display:flex;justify-content:space-between;align-items:end;gap:20px;margin:8px 0 24px}.page-head h1{font-size:clamp(34px,5vw,58px);letter-spacing:-.045em;margin:6px 0}.page-head p{color:var(--muted);max-width:650px;line-height:1.55;margin:0}.back-btn,.ghost-btn,.primary-btn,.chip{border:1px solid var(--line);border-radius:14px;background:rgba(13,32,35,.8);color:var(--text);padding:10px 13px;cursor:pointer}.primary-btn{background:var(--mint);color:#062019;border-color:var(--mint);font-weight:800}.ghost-btn:hover,.back-btn:hover,.chip:hover{border-color:var(--mint)}
.toolbar{display:flex;gap:10px;flex-wrap:wrap;margin-bottom:18px}.search{flex:1;min-width:220px;border:1px solid var(--line);border-radius:16px;background:#0a1a1d;color:var(--text);padding:12px 14px;outline:none}.search:focus{border-color:var(--cyan)}.filter-row{display:flex;gap:8px;flex-wrap:wrap;margin:10px 0 20px}.chip{font-size:12px;padding:8px 11px}.chip.active{border-color:var(--mint);background:rgba(121,242,203,.1);color:var(--mint)}
.card-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:13px}.card{border:1px solid var(--line);background:linear-gradient(155deg,rgba(13,32,35,.93),rgba(8,22,24,.88));border-radius:20px;padding:18px;box-shadow:0 14px 40px rgba(0,0,0,.16)}.click-card{cursor:pointer;transition:.2s}.click-card:hover{transform:translateY(-2px);border-color:rgba(99,217,238,.5)}.card h3{margin:6px 0 8px;font-size:19px}.card p{margin:0;color:var(--muted);line-height:1.5}.tag{font-size:10px;letter-spacing:.1em;text-transform:uppercase;color:var(--cyan)}.bookref{font-size:11px;color:#728c8a;margin-top:12px}.progress{height:5px;background:#183033;border-radius:99px;overflow:hidden;margin-top:14px}.progress i{display:block;height:100%;background:linear-gradient(90deg,var(--cyan),var(--mint));border-radius:99px}
.panel{border:1px solid var(--line);background:rgba(10,26,29,.82);border-radius:22px;padding:20px;margin:14px 0}.panel h2,.panel h3{margin-top:0}.notice{border-left:3px solid var(--amber);background:rgba(255,201,107,.08);padding:14px 16px;border-radius:0 14px 14px 0;color:#e8d7ad;font-size:13px;line-height:1.5}.notice.mint{border-left-color:var(--mint);background:rgba(121,242,203,.07);color:#bde8db}
.form-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px}.field{display:flex;flex-direction:column;gap:6px}.field label{font-size:11px;color:var(--muted);text-transform:uppercase;letter-spacing:.08em}.field input,.field select,.field textarea{width:100%;border:1px solid var(--line);background:#081719;color:var(--text);border-radius:14px;padding:12px 13px;outline:none}.field input:focus,.field select:focus,.field textarea:focus{border-color:var(--cyan)}.field small{color:#667f7d}.full{grid-column:1/-1}.calc-result{margin-top:16px;border-radius:18px;padding:17px;background:linear-gradient(135deg,rgba(121,242,203,.12),rgba(99,217,238,.07));border:1px solid rgba(121,242,203,.28)}.calc-result .value{font-size:clamp(28px,5vw,42px);font-weight:850;letter-spacing:-.04em}.calc-result .unit{font-size:16px;color:var(--mint);margin-left:5px}.steps{margin-top:12px;padding-top:12px;border-top:1px dashed rgba(121,242,203,.24);font-size:13px;color:#c4d6d3;line-height:1.65}.steps code{color:var(--mint);background:rgba(0,0,0,.2);padding:2px 5px;border-radius:6px}.hint-hidden .steps{display:none}
.quiz-box{max-width:820px}.question{font-size:24px;line-height:1.35;margin:12px 0 20px}.answers{display:grid;gap:10px}.answer{border:1px solid var(--line);background:#0b1d20;color:var(--text);padding:14px;border-radius:15px;text-align:left;cursor:pointer}.answer:hover{border-color:var(--cyan)}.answer.correct{border-color:var(--mint);background:rgba(121,242,203,.11)}.answer.wrong{border-color:var(--danger);background:rgba(255,132,124,.09)}
.flashcard{min-height:280px;display:grid;place-items:center;text-align:center;padding:26px;border:1px solid var(--line);border-radius:26px;background:radial-gradient(circle at 50% 20%,rgba(99,217,238,.09),transparent 55%),#0b1f22;cursor:pointer}.flashcard b{font-size:clamp(24px,4vw,34px);max-width:720px}.flashcard p{font-size:18px;line-height:1.6;color:#c7d9d6;max-width:760px}.flashcard .flip{display:block;color:var(--mint);font-size:11px;letter-spacing:.1em;margin-top:20px;text-transform:uppercase}
.table-wrap{overflow:auto;border:1px solid var(--line);border-radius:18px}table{width:100%;border-collapse:collapse;min-width:720px}th,td{padding:10px;border-bottom:1px solid rgba(43,70,74,.55);text-align:left;font-size:13px}th{color:var(--muted);font-size:10px;text-transform:uppercase;letter-spacing:.08em;background:#0a1b1e;position:sticky;top:0}td input{width:100%;min-width:90px;background:#071719;border:1px solid #294347;border-radius:9px;color:var(--text);padding:8px}.num{text-align:right}.danger-btn{border:0;background:transparent;color:var(--danger);cursor:pointer}.summary-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:10px;margin-top:14px}.summary-box{padding:14px;border:1px solid var(--line);border-radius:16px;background:#0a1c1f}.summary-box b{display:block;font-size:22px}.summary-box small{color:var(--muted)}
.source-list{display:grid;gap:8px}.source-item{display:flex;gap:12px;align-items:flex-start;padding:12px;border:1px solid var(--line);border-radius:14px}.source-item b{font-size:13px}.source-item p{font-size:12px;color:var(--muted);margin:3px 0}.source-item a{color:var(--mint)}
.bottom-nav{position:fixed;z-index:30;left:50%;bottom:max(12px,env(safe-area-inset-bottom));transform:translateX(-50%);display:none;gap:4px;padding:6px;border:1px solid rgba(43,70,74,.85);border-radius:20px;background:rgba(7,18,20,.88);backdrop-filter:blur(18px);box-shadow:0 16px 50px rgba(0,0,0,.34)}.bottom-nav button{border:0;background:none;color:#6f8c8a;width:68px;padding:7px 5px;border-radius:14px}.bottom-nav button.active{background:rgba(121,242,203,.1);color:var(--mint)}.bottom-nav span{display:block;font-size:18px}.bottom-nav small{font-size:9px}.toast{position:fixed;left:50%;bottom:96px;transform:translate(-50%,15px);opacity:0;pointer-events:none;z-index:50;background:#e9faf5;color:#0b2420;padding:10px 14px;border-radius:12px;font-size:12px;font-weight:700;transition:.2s}.toast.show{opacity:1;transform:translate(-50%,0)}
@media(max-width:900px){.mode-card{grid-column:span 6}.card-grid{grid-template-columns:repeat(2,1fr)}.summary-grid{grid-template-columns:repeat(2,1fr)}.hero-orbit{opacity:.35}}
@media(max-width:650px){.app-shell{padding-top:18px}.topbar{height:66px}.hint-switch span{display:none}.mode-grid{display:block}.mode-card{width:100%;min-height:190px;margin-bottom:12px}.mode-icon{margin:18px 0 10px}.status-strip{grid-template-columns:1fr 1fr}.status:last-child{grid-column:1/-1}.card-grid{grid-template-columns:1fr}.form-grid{grid-template-columns:1fr}.page-head{display:block}.page-head .back-btn{margin-bottom:10px}.bottom-nav{display:flex}.summary-grid{grid-template-columns:1fr 1fr}.hero h1{font-size:47px}.hero-orbit{width:100px;height:100px;top:26px}.top-actions{gap:4px}}