:root{--bg:#f7f8fc;--surface:#fff;--ink:#111827;--navy:#111827;--navy-deep:#0b1020;--ice:#4169ff;--ice-soft:#e7ecff;--muted:#667085;--line:#e5e7eb;--primary:#4169ff;--primary-dark:#3457d5;--primary-soft:#e7ecff;--green:#1f9d55;--green-soft:#e6f6ec;--red:#d64545;--red-soft:#fdeeee;--amber:#f06445;--amber-soft:#fdeee9;--gold:#4169ff;--gold-soft:#e7ecff;--coral:#f06445;--coral-soft:#fdeee9;--radius:12px;--shadow:0 1px 3px #11182714;--shadow-card:0 1px 2px #1118270d, 0 4px 16px #1118270f}*{box-sizing:border-box}body{background:var(--bg);color:var(--ink);-webkit-font-smoothing:antialiased;margin:0;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica Neue,Arial,sans-serif;line-height:1.55}a{color:var(--primary);text-decoration:none}a:hover{text-decoration:underline}.container{max-width:1080px;margin:0 auto;padding:0 20px}.topnav{background:var(--surface);border-bottom:1px solid var(--line);z-index:50;position:sticky;top:0}.topnav-inner{justify-content:space-between;align-items:center;height:60px;display:flex}.brand{color:var(--ink);font-size:1.25rem;font-weight:800}.brand span{color:var(--primary)}.nav-links{align-items:center;gap:18px;display:flex}.nav-links a{color:var(--muted);font-weight:500}.nav-links a:hover{color:var(--ink);text-decoration:none}.nav-links a.btn,.nav-links a.btn:hover{color:#fff}.btn{cursor:pointer;background:var(--primary);color:#fff;border:none;border-radius:10px;padding:10px 20px;font-size:.95rem;font-weight:600;transition:background .15s,transform .15s,box-shadow .15s;display:inline-block;box-shadow:0 1px 2px #4169ff40}.btn:hover{background:var(--primary-dark);color:#fff;text-decoration:none;box-shadow:0 4px 12px #4169ff4d}.btn:active{transform:translateY(1px)}.btn:disabled{opacity:.55;cursor:not-allowed}.btn-secondary{background:var(--surface);color:var(--ink);border:1px solid 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#f3c2c2;border-radius:8px;margin-bottom:14px;padding:10px 14px;font-size:.92rem}.form-ok{background:var(--green-soft);color:var(--green);border:1px solid #bfe6cc;border-radius:8px;margin-bottom:14px;padding:10px 14px;font-size:.92rem}.hero{text-align:center;padding:72px 0 48px}.hero h1{letter-spacing:-.02em;margin:0 0 12px;font-size:2.6rem}.hero p{color:var(--muted);max-width:620px;margin:0 auto 28px;font-size:1.15rem}.hero-cta{flex-wrap:wrap;justify-content:center;gap:12px;display:flex}.feature-grid{grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:16px;margin:40px 0;display:grid}.feature-card{opacity:0;animation:.6s forwards card-rise;position:relative;overflow:hidden}.feature-card:before{content:"";background:linear-gradient(90deg, var(--primary), transparent);opacity:0;height:3px;transition:opacity .25s;position:absolute;top:0;left:0;right:0}.feature-card:hover{border-color:var(--primary-soft);transform:translateY(-6px);box-shadow:0 12px 32px #4169ff24}.feature-card:hover:before{opacity:1}@keyframes card-rise{0%{opacity:0;transform:translateY(24px)}to{opacity:1;transform:translateY(0)}}.feature-icon{background:var(--primary-soft);width:44px;height:44px;color:var(--primary);border-radius:12px;justify-content:center;align-items:center;margin-bottom:12px;transition:transform .25s,background .25s,color .25s;display:flex}.feature-icon svg{width:24px;height:24px}.feature-card:hover .feature-icon{background:var(--primary);color:#fff;transform:scale(1.1)rotate(-6deg)}.feature-grid h3{margin:0 0 6px;font-size:1.05rem}.feature-grid p{color:var(--muted);margin:0;font-size:.95rem}.plans{grid-template-columns:repeat(auto-fit,minmax(260px,1fr));gap:18px;margin:32px 0;display:grid}.plan{position:relative}.plan.hot{border:2px solid var(--primary)}.plan-badge{background:var(--primary);color:#fff;border-radius:20px;padding:3px 10px;font-size:.75rem;font-weight:700;position:absolute;top:-12px;right:16px}.plan h3{margin-top:0}.plan .price{margin:8px 0;font-size:2rem;font-weight:800}.plan ul{color:var(--muted);padding-left:20px}.plan li{margin-bottom:6px}.dash{min-height:calc(100vh - 60px);display:flex}.sidebar{background:var(--surface);border-right:1px solid var(--line);flex-shrink:0;width:230px;height:calc(100vh - 60px);padding:20px 12px;position:sticky;top:60px;overflow-y:auto}.sidebar a{color:var(--muted);border-radius:8px;margin-bottom:2px;padding:9px 12px;font-weight:500;display:block}.sidebar a:hover{background:var(--bg);color:var(--ink);text-decoration:none}.sidebar a.active{background:var(--primary-soft);color:var(--primary);font-weight:700}.sidebar .side-label{text-transform:uppercase;letter-spacing:.06em;color:var(--muted);padding:14px 12px 6px;font-size:.72rem}.dash-main{flex:1;max-width:960px;padding:28px}.dash-head{flex-wrap:wrap;justify-content:space-between;align-items:center;gap:12px;margin-bottom:20px;display:flex}.dash-head 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.score.low{color:var(--red)}.flash-grid{grid-template-columns:repeat(auto-fill,minmax(220px,1fr));gap:14px;display:grid}.flashcard{cursor:pointer;text-align:center;flex-direction:column;justify-content:center;align-items:center;min-height:170px;transition:transform .15s;display:flex}.flashcard:hover{transform:translateY(-2px)}.flashcard .tag{color:var(--muted);margin-bottom:8px;font-size:.75rem}.flashcard .hint{color:var(--muted);margin-top:10px;font-size:.78rem}.note-item{margin-bottom:12px}.note-item .note-meta{color:var(--muted);justify-content:space-between;align-items:center;margin-top:8px;font-size:.8rem;display:flex}.footer{border-top:1px solid var(--line);color:var(--muted);margin-top:60px;padding:28px 0;font-size:.9rem}@media (max-width:760px){.dash{flex-direction:column}.sidebar{border-right:none;border-bottom:1px solid var(--line);width:100%;height:auto;padding:10px;display:flex;position:static;overflow-x:auto}.sidebar a{white-space:nowrap;margin-bottom:0}.sidebar .side-label{display:none}.dash-main{padding:18px 14px}.hero h1{font-size:2rem}.nav-links .hide-sm{display:none}}.instant-feedback{border-radius:10px;margin-top:12px;padding:10px 14px;font-size:.95rem;font-weight:700}.instant-feedback.is-correct{background:var(--green-soft);color:var(--green);border:1px solid var(--green)}.instant-feedback.is-wrong{background:var(--red-soft);color:var(--red);border:1px solid var(--red)}.option:disabled{cursor:default}.free-badge{background:var(--ice-soft);color:var(--navy);border:1px solid var(--ice);border-radius:999px;margin-bottom:16px;padding:8px 18px;font-size:.9rem;font-weight:700;display:inline-block}.btn-glow{background:var(--navy);border:1px solid var(--ice);border-radius:8px;padding:8px 20px;font-size:.95rem;font-weight:600;animation:2s ease-in-out infinite login-glow;display:inline-block;color:#fff!important;text-decoration:none!important}@keyframes login-glow{0%,to{box-shadow:0 0 6px #4169ff59}50%{box-shadow:0 0 16px #4169ff8c,0 0 28px #4169ff38}}.hero-split{align-items:center;gap:40px;padding:56px 0 40px;display:flex}.hero-text{flex:1;min-width:0}.hero-text h1{margin:16px 0 12px;font-size:2.6rem;line-height:1.15}.hero-visual{flex:1;justify-content:center;min-width:0;display:flex}.ecg-card{aspect-ratio:4/3.4;background:linear-gradient(135deg, var(--navy) 0%, var(--navy-deep) 100%);width:100%;max-width:420px;box-shadow:var(--shadow);border-radius:20px;justify-content:center;align-items:center;display:flex;position:relative;overflow:visible}.ecg-line{filter:drop-shadow(0 0 8px #4169ff99);width:78%;animation:3.2s ease-in-out infinite ecg-draw}@keyframes ecg-draw{0%{opacity:.55;transform:scaleX(.96)}50%{opacity:1;transform:scaleX(1)}to{opacity:.55;transform:scaleX(.96)}}.neuron-card{overflow:visible}.neuron-svg{width:88%;height:auto}.soma-halo{transform-origin:200px 170px;animation:4s ease-in-out infinite halo-breathe}@keyframes halo-breathe{0%,to{opacity:.6;transform:scale(.94)}50%{opacity:1;transform:scale(1.06)}}.nucleus{transform-origin:200px 170px;animation:2.4s ease-in-out infinite nucleus-pulse}@keyframes nucleus-pulse{0%,to{opacity:.7;transform:scale(.9)}50%{opacity:1;transform:scale(1.12)}}.synapse{filter:drop-shadow(0 0 4px #4169ffe6);animation:3s ease-in-out infinite synapse-blink}@keyframes synapse-blink{0%,to{opacity:.45}50%{opacity:1}}.stat-float{background:var(--surface);border:1px solid var(--line);z-index:5;white-space:nowrap;border-radius:14px;padding:10px 16px;animation:4s ease-in-out infinite float-y;position:absolute;box-shadow:0 10px 28px #1118272e}.stat-float-1{animation-delay:0s;top:-22px;right:-14px}.stat-float-2{animation-delay:1.3s;bottom:-20px;left:-16px}.stat-float-3{animation-delay:2.6s;bottom:26px;right:-22px}@keyframes float-y{0%,to{transform:translateY(0)}50%{transform:translateY(-9px)}}.stat-num{color:var(--primary);font-size:1.35rem;font-weight:800;line-height:1.1}.stat-label{color:var(--muted);font-size:.78rem;font-weight:500}@media (max-width:820px){.hero-split{flex-direction:column;padding:36px 0 30px}.hero-text h1{font-size:2rem}.hero-visual{width:100%}.ecg-card{max-width:360px}.stat-float{padding:8px 12px}.stat-float-1{top:-18px;right:8px}.stat-float-2{bottom:-18px;left:8px}.stat-float-3{bottom:24px;right:4px}}@keyframes pulse-soft{0%,to{opacity:1}50%{opacity:.55}}