*{margin:0;padding:0;box-sizing:border-box}
:root{--bg:#070a14;--card:#111527;--card2:#171c33;--border:#22274a;--text:#e6e9f5;--muted:#8b8fb5;--primary:#6366f1;--accent:#22d3ee}
body{font-family:Inter,system-ui,sans-serif;background:var(--bg);color:var(--text);line-height:1.6}
nav{position:sticky;top:0;z-index:20;display:flex;gap:16px;align-items:center;padding:12px 20px;background:rgba(7,10,20,0.95);backdrop-filter:blur(10px);border-bottom:1px solid var(--border);flex-wrap:wrap}
.logo{font-weight:800;font-size:18px} .logo span{color:var(--primary);font-weight:400}
.nav-mid{flex:1;max-width:520px} .nav-mid input{width:100%;padding:10px 14px;border-radius:10px;background:var(--card);border:1px solid var(--border);color:white;outline:none}
.nav-mid input:focus{border-color:var(--primary)}
.nav-right{display:flex;align-items:center;gap:10px;font-size:12px}
.progressBar{width:110px;height:8px;background:var(--card);border-radius:20px;overflow:hidden;border:1px solid var(--border)}
#progressFill{height:100%;width:0;background:linear-gradient(90deg,var(--primary),var(--accent));transition:width 0.3s}
.hero{text-align:center;padding:36px 20px;border-bottom:1px solid var(--border);background:radial-gradient(600px 300px at 50% 0%, rgba(99,102,241,0.15), transparent)}
.hero h1{font-size:42px;line-height:1.1} .hero h1 span{background:linear-gradient(90deg,var(--primary),var(--accent));-webkit-background-clip:text;-webkit-text-fill-color:transparent}
.hero p{max-width:640px;margin:12px auto 0;color:var(--muted)}
.hero-stats{display:flex;gap:12px;justify-content:center;margin-top:14px;font-weight:700;font-size:13px;opacity:0.8}
.layout{display:grid;grid-template-columns:280px 1fr;min-height:calc(100vh - 140px)}
.sidebar{background:var(--card);border-right:1px solid var(--border);padding:16px;position:sticky;top:62px;height:calc(100vh - 62px);overflow:auto}
.side-group{margin-bottom:18px}
.side-group h4{font-size:11px;letter-spacing:0.8px;opacity:0.5;margin-bottom:8px;text-transform:uppercase}
.side-item{display:flex;gap:10px;align-items:center;padding:9px 10px;border-radius:10px;cursor:pointer;border:1px solid transparent;font-size:13px}
.side-item:hover{background:var(--card2)} .side-item.active{background:var(--card2);border-color:var(--primary);color:white}
.side-item .icon{width:32px;height:32px;border-radius:8px;display:grid;place-items:center;font-weight:800;font-size:13px;flex-shrink:0}
.side-item.done{opacity:1} .side-item.done::after{content:"✓";margin-left:auto;color:#22c55e;font-weight:800}
.content{padding:24px;max-width:980px}
.card{background:var(--card);border:1px solid var(--border);border-radius:16px;padding:20px;margin-bottom:16px}
.card h2{font-size:26px;margin-bottom:6px} .card .sub{color:var(--muted);margin-bottom:12px}
.pills{display:flex;gap:8px;flex-wrap:wrap;margin:10px 0} .pill{font-size:11px;padding:4px 8px;border-radius:20px;background:var(--card2);border:1px solid var(--border)}
.grid2{display:grid;grid-template-columns:1fr 1fr;gap:12px}
@media(max-width:900px){.grid2{grid-template-columns:1fr} .layout{grid-template-columns:1fr} .sidebar{position:static;height:auto}}
.code-wrap{background:#0b0f1e;border:1px solid var(--border);border-radius:12px;overflow:hidden;margin:10px 0}
.code-head{display:flex;justify-content:space-between;align-items:center;padding:8px 12px;background:var(--card2);font-size:12px;border-bottom:1px solid var(--border)}
.code-head button{padding:4px 10px;border-radius:6px;border:1px solid var(--border);background:var(--card);color:white;cursor:pointer;font-size:11px;font-weight:700}
.code-head button:hover{border-color:var(--primary)}
pre{margin:0;padding:14px;overflow:auto;font-family:JetBrains Mono,monospace;font-size:13px;line-height:1.5;white-space:pre}
pre code{color:#cbd5e1}
.btn{padding:8px 14px;border-radius:10px;border:1px solid var(--border);background:var(--card2);color:white;cursor:pointer;font-weight:700;font-size:13px}
.btn.primary{background:var(--primary);border-color:var(--primary)}
.btn.small{padding:6px 10px;font-size:12px}
.topic{border:1px solid var(--border);border-radius:12px;padding:14px;background:var(--card2)}
.topic h4{margin-bottom:6px;font-size:14px}
.topic p{font-size:13px;color:var(--muted)}
.modal{position:fixed;inset:0;background:rgba(0,0,0,0.65);display:none;place-items:center;z-index:50;padding:20px}
.modal.open{display:grid}
.modal-box{background:var(--card);border:1px solid var(--border);border-radius:16px;max-width:740px;width:100%;padding:16px;max-height:92vh;overflow:auto}
.modal-head{display:flex;justify-content:space-between;align-items:center;margin-bottom:10px}
.modal-head button{background:var(--card2);border:1px solid var(--border);color:white;border-radius:8px;padding:6px 10px;cursor:pointer}
#playCode{width:100%;background:#0b0f1e;color:#e2e8f0;border:1px solid var(--border);border-radius:10px;padding:12px;font-family:JetBrains Mono,monospace;font-size:13px}
#playOut{background:#0b0f1e;border:1px solid var(--border);border-radius:10px;padding:12px;margin-top:10px;min-height:48px;white-space:pre-wrap;font-family:JetBrains Mono,monospace;font-size:13px}
.modal-actions{display:flex;gap:8px;margin-top:10px;flex-wrap:wrap}
.quizQ{padding:12px;border:1px solid var(--border);border-radius:10px;margin:8px 0;background:var(--card2)}
.quizQ button{margin-top:8px}
.badge{display:inline-block;padding:2px 8px;border-radius:20px;font-size:11px;font-weight:800;background:var(--primary);color:white}
.lang-hero{display:flex;gap:14px;align-items:center}
.lang-icon{width:48px;height:48px;border-radius:12px;display:grid;place-items:center;font-weight:800;font-size:18px}
/* TRACK BLOCKS */
.tracks-grid{display:grid;grid-template-columns:1fr 1fr;gap:14px;margin-top:14px}
@media(max-width:800px){.tracks-grid{grid-template-columns:1fr}}
.track-card{border-radius:16px;padding:18px;border:1px solid var(--border);cursor:pointer;position:relative;overflow:hidden;transition:transform 0.15s, border-color 0.15s}
.track-card:hover{transform:translateY(-2px);border-color:var(--primary)}
.track-card::after{content:"";position:absolute;inset:0;background:linear-gradient(135deg, transparent, rgba(255,255,255,0.06));pointer-events:none}
.track-top{display:flex;gap:12px;align-items:center;margin-bottom:10px}
.track-emoji{width:42px;height:42px;border-radius:10px;display:grid;place-items:center;font-size:20px;background:rgba(255,255,255,0.08);border:1px solid rgba(255,255,255,0.12)}
.track-title{font-weight:800;font-size:16px} .track-desc{font-size:12px;color:var(--muted)}
.track-langs{display:flex;gap:6px;flex-wrap:wrap;margin:10px 0}
.track-lang{font-size:11px;padding:4px 8px;border-radius:20px;background:rgba(0,0,0,0.3);border:1px solid rgba(255,255,255,0.15);font-weight:700}
.track-meta{display:flex;gap:8px;flex-wrap:wrap;font-size:11px;opacity:0.8;margin-top:8px}
.track-meta span{padding:3px 8px;border-radius:20px;background:var(--card2);border:1px solid var(--border)}
.track-progress{height:6px;background:rgba(0,0,0,0.3);border-radius:20px;overflow:hidden;margin-top:10px;border:1px solid rgba(255,255,255,0.1)}
.track-progress-fill{height:100%;border-radius:20px;transition:width 0.3s}
a.link{color:var(--accent);text-decoration:none} a.link:hover{text-decoration:underline}
.status-dot{width:8px;height:8px;border-radius:50%;display:inline-block;margin-right:6px}
.card.collapsible{padding:0;overflow:hidden}
.coll-head{display:flex;justify-content:space-between;align-items:center;padding:16px 20px;cursor:pointer;background:var(--card2);user-select:none}
.coll-head:hover{background:#1c2140}
.coll-body{padding:16px 20px;display:none}
.card.collapsible.open .coll-body{display:block}
.card.collapsible.open .coll-arrow{transform:rotate(180deg)}
.coll-arrow{transition:transform 0.2s;font-size:14px}
.view-banner{background:rgba(245,158,11,0.12);border:1px solid #f59e0b;color:#fde68a;padding:12px 14px;border-radius:12px;margin:12px 0;font-size:13px;line-height:1.5}
.view-banner strong{color:#f59e0b}
/* stepper */
.stepper{display:flex;flex-direction:column;gap:12px;margin:16px 0}
.step-card{display:flex;gap:14px;align-items:center;padding:16px;border-radius:14px;border:1px solid var(--border);background:var(--card2);position:relative}
.step-card.locked{opacity:0.55;filter:grayscale(0.2)}
.step-card.done{background:rgba(34,197,94,0.08);border-color:#22c55e}
.step-card.active{border-color:var(--primary);background:rgba(99,102,241,0.08)}
.step-num{width:44px;height:44px;border-radius:10px;display:grid;place-items:center;font-weight:800;flex-shrink:0;border:1px solid var(--border)}
.step-card.done .step-num{background:#22c55e;color:black;border-color:#22c55e}
.step-card.locked .step-num{background:#1a1a2a;color:#666}
.step-info{flex:1}
.step-info h4{font-size:14px;margin:0}
.step-info p{font-size:12px;color:var(--muted);margin:2px 0 0}
.step-action{flex-shrink:0}
.badge-lock{font-size:11px;padding:3px 8px;border-radius:20px;background:#2a2a3a;color:#888;border:1px solid #333}
.mission-box{background:#0b0f1e;border:1px solid var(--border);border-radius:12px;padding:14px;margin:10px 0}
.mission-box h4{margin-bottom:8px}
.code-task textarea{width:100%;background:#070a14;color:#e2e8f0;border:1px solid var(--border);border-radius:10px;padding:10px;font-family:JetBrains Mono,monospace;font-size:13px;min-height:110px}
.autocomplete{position:absolute;background:#1a1f3a;border:1px solid var(--primary);border-radius:8px;max-height:140px;overflow:auto;z-index:10;display:none;box-shadow:0 8px 20px rgba(0,0,0,0.4)}
.autocomplete div{padding:6px 10px;cursor:pointer;font-family:JetBrains Mono,monospace;font-size:12px}
.autocomplete div.active, .autocomplete div:hover{background:var(--primary);color:white}
.final-card{background:linear-gradient(135deg,#6366f1,#22d3ee);border:none;color:white}
.final-card .btn{background:rgba(0,0,0,0.2);border-color:rgba(255,255,255,0.3);color:white}