*{box-sizing:border-box}
body{margin:0;background:var(--bg);color:var(--ink);font-family:"Manrope","Inter",system-ui,sans-serif;line-height:1.55;padding:0 0 80px}
a{color:var(--cyan)}
img,svg{max-width:100%}
header{padding:38px 20px 18px;text-align:center;background:linear-gradient(180deg,var(--bg2),transparent);border-bottom:1px solid var(--line)}
header .tag{color:var(--cyan);font-family:"JetBrains Mono",monospace;font-size:12px;letter-spacing:1px;text-transform:uppercase}
header h1{margin:6px 0 4px;font-size:28px;letter-spacing:-.5px}
header p{color:var(--muted);margin:6px auto 0;font-size:15px;max-width:720px}
.wrap{max-width:1160px;margin:0 auto;padding:0 20px}
.railwrap{max-width:1160px;margin:18px auto 0;padding:0 20px}
.rail{display:flex;gap:8px;flex-wrap:wrap;align-items:stretch}
.rail a{flex:1 1 120px;min-width:120px;text-decoration:none;display:block;border:1px solid var(--line);border-radius:10px;padding:9px 12px;background:var(--panel);transition:.14s}
.rail a:hover{border-color:var(--cyan);transform:translateY(-2px)}
.rail a .rn{font-family:"JetBrains Mono",monospace;font-size:11px;color:var(--muted)}
.rail a .rt{font-size:13px;color:var(--ink);font-weight:700;margin-top:2px}
.rail a.cur{border-color:var(--cyan);background:linear-gradient(180deg,rgba(34,211,238,.12),transparent)}
.rail a.cur .rn{color:var(--cyan)}
.rail a.done .rt::after{content:" \2713";color:var(--green)}
@media(max-width:760px){.rail a{flex:1 1 45%;min-width:0}}
.topnav{max-width:1160px;margin:14px auto 0;padding:0 20px}
.nav-back{display:inline-flex;align-items:center;gap:7px;text-decoration:none;font-family:"JetBrains Mono",monospace;font-size:13px;padding:7px 14px;border-radius:9px;border:1px solid var(--line);background:var(--panel);color:var(--muted)}
.nav-back:hover{border-color:var(--cyan);color:var(--cyan);background:rgba(34,211,238,.06)}
.modnav{display:flex;justify-content:space-between;align-items:center;flex-wrap:wrap;gap:14px;max-width:1160px;margin:38px auto 0;padding:18px;border:1px solid var(--line);border-radius:14px;background:linear-gradient(180deg,var(--panel),var(--bg2))}
.modnav .mn-label{font-family:"JetBrains Mono",monospace;font-size:11px;color:var(--muted);text-transform:uppercase;letter-spacing:.06em;margin-bottom:4px}
.modnav .mn-title{font-size:15px;color:var(--ink);font-weight:700}
.nav-next{display:inline-flex;align-items:center;gap:9px;text-decoration:none;padding:12px 20px;border-radius:11px;background:var(--cyan);color:#04222b;font-weight:700;font-size:14px}
.nav-next:hover{filter:brightness(1.08)}
.nav-prev{display:inline-flex;align-items:center;gap:7px;text-decoration:none;font-family:"JetBrains Mono",monospace;font-size:13px;padding:9px 16px;border-radius:9px;border:1px solid var(--line);background:var(--panel2);color:var(--muted)}
.nav-prev:hover{border-color:var(--cyan);color:var(--cyan)}
@media(max-width:620px){.modnav{flex-direction:column;align-items:stretch}}
.intro{margin-top:28px}
.hook{font-size:16px;color:var(--ink);line-height:1.7;padding:14px 18px;background:var(--panel);border:1px solid var(--line);border-radius:10px;border-left:3px solid var(--cyan)}
.section{margin-top:46px}
.sec-head{display:flex;align-items:baseline;gap:14px;flex-wrap:wrap;margin-bottom:6px}
.sec-num{font-family:"JetBrains Mono",monospace;font-size:13px;color:var(--cyan);border:1px solid var(--line);border-radius:8px;padding:4px 10px;background:var(--bg2)}
.sec-head h2{font-size:23px;margin:0;letter-spacing:-.3px}
.sec-sub{color:var(--muted);font-size:14.5px;margin:4px 0 0;max-width:820px}
.badges{display:flex;gap:7px;flex-wrap:wrap;margin:12px 0 2px}
.b{font-family:"JetBrains Mono",monospace;font-size:11px;letter-spacing:.04em;text-transform:uppercase;padding:4px 10px;border-radius:999px;border:1px solid var(--line)}
.b.fgos{color:var(--green);background:rgba(52,211,153,.08);border-color:rgba(52,211,153,.35)}
.b.exam{color:var(--amber);background:rgba(252,211,77,.08);border-color:rgba(252,211,77,.35)}
.code-box{background:var(--panel2);border:1px solid var(--line);border-radius:8px;padding:14px 18px;font-family:"JetBrains Mono",monospace;font-size:13px;color:var(--amber);overflow-x:auto;margin:12px 0}
.theory-block{background:rgba(34,211,238,.03);border-left:3px solid var(--cyan);padding:16px 20px;border-radius:0 10px 10px 0;margin:16px 0}
.example-box{background:rgba(252,211,77,.04);border-left:3px solid var(--amber);padding:16px 20px;border-radius:0 10px 10px 0;margin:16px 0}
.iv-shell{background:var(--panel);border:1px solid var(--line);border-radius:14px;padding:24px;margin:28px 0;position:relative;overflow:hidden;max-width:100%}
.iv-shell::before{content:'';position:absolute;top:0;left:0;right:0;height:3px;background:linear-gradient(90deg,var(--cyan),var(--amber))}
.iv-head{display:flex;align-items:center;gap:10px;margin-bottom:18px}
.iv-head .iv-icon{width:34px;height:34px;border-radius:10px;display:flex;align-items:center;justify-content:center;font-size:17px;background:var(--bg2);border:1px solid var(--line)}
.iv-head .iv-title{font-weight:700;font-size:16px}
.iv-body{min-height:80px}
.iv-opts{display:flex;gap:8px;flex-wrap:wrap;margin-top:4px}
.iv-opt{cursor:pointer;user-select:none;padding:10px 18px;border-radius:9px;border:1px solid var(--line);background:var(--panel2);color:var(--ink);font-size:13px;font-weight:600;transition:.14s}
.iv-opt:hover{border-color:var(--cyan);color:var(--cyan)}
.btn-c{padding:10px 20px;border-radius:9px;border:1px solid var(--line);background:var(--panel2);color:var(--ink);font-weight:600;font-size:13px;cursor:pointer;transition:.14s;display:inline-flex;align-items:center;gap:6px}
.btn-c:hover{border-color:var(--cyan);color:var(--cyan)}
.btn-c.primary{background:var(--cyan);color:#04222b;border-color:var(--cyan)}
.btn-c.primary:hover{filter:brightness(1.08)}
.result-box{padding:12px 16px;border-radius:8px;margin:12px 0;font-size:14px}
.result-box.ok{background:rgba(52,211,153,.08);border:1px solid rgba(52,211,153,.35);color:var(--green)}
.result-box.fail{background:rgba(248,113,113,.08);border:1px solid rgba(248,113,113,.35);color:var(--red)}
.grid3{display:grid;grid-template-columns:repeat(3,1fr);gap:14px;margin:16px 0}
.grid2{display:grid;grid-template-columns:repeat(2,1fr);gap:14px;margin:16px 0}
.card-sm{background:var(--panel2);border:1px solid var(--line);border-radius:10px;padding:15px;text-align:center}
.diagram-box{background:var(--bg2);border-radius:12px;padding:16px;margin:16px 0;text-align:center}
.diagram-box svg{max-width:100%;height:auto}
.ttable{width:100%;border-collapse:collapse;font-size:13px;margin:12px 0;font-family:"JetBrains Mono",monospace}
.ttable th{background:var(--panel);color:var(--cyan);padding:8px 12px;border:1px solid var(--line);text-align:center;font-weight:600}
.ttable td{padding:6px 12px;border:1px solid var(--line);text-align:center;color:var(--ink)}
.ttable .on{color:var(--amber);font-weight:700}
.gate-svg{display:block;margin:8px auto;max-width:100%}
.dash-wrap{background:var(--panel);border:1px solid var(--line);border-radius:14px;padding:20px;margin:20px 0}
.dash-grid{display:grid;grid-template-columns:1fr 1fr;gap:16px}
@media(max-width:760px){.dash-grid{grid-template-columns:1fr}.grid3,.grid2{grid-template-columns:1fr}}
.test-q{background:var(--panel2);border:1px solid var(--line);border-radius:10px;padding:16px;margin-bottom:12px;max-width:100%;overflow-wrap:anywhere}
.test-q label{display:block;margin-top:8px;cursor:pointer;font-size:14px;padding:4px 0;max-width:100%;overflow-wrap:anywhere}
input[type=radio]{margin-right:6px}
.btnrow{display:flex;gap:12px;flex-wrap:wrap}
.quest{background:var(--panel);border:1px solid var(--line);border-radius:14px;padding:24px;margin:28px 0}
.quest-bar{display:flex;align-items:center;gap:16px;margin-bottom:20px;flex-wrap:wrap}
.xp{font-family:"JetBrains Mono",monospace;font-size:14px;color:var(--amber);font-weight:700}
.prog{flex:1;height:8px;background:var(--bg2);border-radius:999px;overflow:hidden;border:1px solid var(--line)}
.prog i{display:block;width:0%;height:100%;background:linear-gradient(90deg,var(--cyan),var(--green));transition:.3s}
.quest-body{font-size:15px;line-height:1.7;min-height:80px}

.iv-opt{transition:all .18s ease}
.iv-opt:hover{transform:translateY(-2px);box-shadow:0 4px 12px rgba(34,211,238,.12)}
.iv-opt.sel{border-color:var(--cyan)!important;background:rgba(34,211,238,.12)!important;transform:translateY(-2px)}
.btn-c{transition:all .18s ease}
.btn-c:hover{transform:translateY(-2px);box-shadow:0 4px 12px rgba(34,211,238,.15)}
.result-box{animation:fadeIn .35s ease}
@keyframes fadeIn{0%{opacity:0;transform:translateY(8px)}100%{opacity:1;transform:translateY(0)}}
.card-sm,.modnav,.iv-shell{transition:border-color .2s ease,transform .2s ease}
.card-sm:hover{border-color:var(--cyan)!important;transform:translateY(-3px);box-shadow:0 6px 20px rgba(34,211,238,.08)}
.dash-wrap{animation:fadeIn .4s ease}
.test-q{transition:background .2s ease}
.test-q:hover{background:rgba(34,211,238,.04)}
.label{display:inline-flex;align-items:center;padding:10px 14px;border-radius:8px;cursor:pointer;background:var(--panel);border:1px solid var(--line);margin:4px 0;transition:all .15s}
.label:hover{border-color:var(--cyan)}
.label.right{background:rgba(52,211,153,.12);border-color:rgba(52,211,153,.4);color:var(--green)}
.label.bad{background:rgba(248,113,113,.1);border-color:rgba(248,113,113,.35);color:var(--red)}
.feedback{padding:12px 16px;border-radius:8px;font-size:14px;font-weight:600;margin-top:10px}
.feedback.good{background:rgba(52,211,153,.1);border:1px solid rgba(52,211,153,.35);color:var(--green)}
.feedback.bad{background:rgba(248,113,113,.1);border:1px solid rgba(248,113,113,.35);color:var(--red)}
.callout{border-left:4px solid var(--cyan);padding:14px 18px;background:rgba(34,211,238,.04);border-radius:0 10px 10px 0;margin:16px 0}
.callout.cyan{border-color:var(--cyan)}
.callout.amber{border-color:var(--amber);background:rgba(252,211,77,.04)}
.callout.green{border-color:var(--green);background:rgba(52,211,153,.05)}
.callout.violet{border-color:var(--violet);background:rgba(167,139,250,.05)}
.callout.red{border-color:var(--red);background:rgba(248,113,113,.05)}
.callout .ct{font-weight:700;font-size:13px;text-transform:uppercase;letter-spacing:.05em;color:var(--cyan);display:block;margin-bottom:6px}
.callout.amber .ct{color:var(--amber)}
.callout.green .ct{color:var(--green)}
.callout.violet .ct{color:var(--violet)}
.callout.red .ct{color:var(--red)}
.mt-wrap{background:var(--panel);border:1px solid var(--line);border-radius:14px;padding:22px;margin:0 0 18px;width:100%;max-width:100%;overflow:hidden}
.mt-head{display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:10px;margin-bottom:16px}
.mt-title{font-weight:700;font-size:15px;display:flex;align-items:center;gap:8px}
.mt-counter{font-family:'JetBrains Mono',monospace;font-size:13px;color:var(--muted)}
.mt-streak{display:inline-flex;align-items:center;gap:5px;background:rgba(252,211,77,.12);border:1px solid rgba(252,211,77,.35);border-radius:999px;padding:3px 10px;font-size:12px;font-weight:700;color:var(--amber)}
.mt-xp-bar{background:var(--bg2);border:1px solid var(--line);border-radius:999px;height:10px;overflow:hidden;flex:1;min-width:120px}
.mt-xp-fill{height:100%;background:linear-gradient(90deg,var(--cyan),var(--green));transition:width .4s ease;border-radius:999px}
.mt-xp-info{font-family:'JetBrains Mono',monospace;font-size:11px;color:var(--muted);white-space:nowrap}
.mt-nav{margin-top:14px}
.mt-result-body{text-align:center;padding:20px}
.mt-result-body .big{font-size:48px;margin-bottom:8px}
@media(max-width:620px){.iv-shell,.mt-wrap{padding:16px}.btnrow .btn-c{flex:1 1 100%;justify-content:center}.ttable{font-size:12px}.ttable th,.ttable td{padding:6px 8px}.mt-head{align-items:flex-start}.mt-xp-info{width:100%}}