:root{
  --primary:#6556e8;--primary-dark:#4d3ed0;--secondary:#16a6d9;--accent:#ff9f43;--green:#19b394;
  --ink:#1f2a44;--text:#536079;--muted:#7d89a2;--line:#e5e9f2;--soft:#f7f8fc;--white:#fff;
  --danger:#ee5b69;--success:#1cab79;--shadow:0 22px 65px rgba(55,50,116,.12);--shadow-sm:0 12px 34px rgba(55,50,116,.09);
  --radius:24px;--radius-sm:16px;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;font-family:Nunito,Arial,sans-serif;color:var(--text);background:#fff;line-height:1.65;overflow-x:hidden}
button,input,select{font:inherit}button{cursor:pointer}a{text-decoration:none;color:inherit}img{max-width:100%;display:block}
.container{width:min(1180px,calc(100% - 40px));margin:0 auto}.hidden{display:none!important}
.site-header{position:sticky;top:0;z-index:100;background:rgba(255,255,255,.94);backdrop-filter:blur(18px);border-bottom:1px solid rgba(229,233,242,.9);box-shadow:0 8px 30px rgba(55,50,116,.04)}
.nav-wrap{height:82px;display:flex;align-items:center;justify-content:space-between;gap:26px;position:relative;z-index:2}.brand{display:flex;align-items:center;gap:12px;flex:0 0 auto}.brand-mark{width:48px;height:48px;border-radius:15px;display:grid;place-items:center;background:linear-gradient(145deg,var(--primary),#826fff);color:#fff;font-size:23px;box-shadow:0 11px 24px rgba(101,86,232,.28)}.brand-mark.small{width:42px;height:42px;border-radius:13px;font-size:19px}.brand-copy{display:flex;flex-direction:column;line-height:1.15}.brand-copy strong{font-size:19px;color:var(--ink);font-weight:900}.brand-copy small{font-size:10px;color:var(--muted);font-weight:700;letter-spacing:.25px;margin-top:4px}.main-nav{display:flex;align-items:center;gap:5px}.main-nav a{display:flex;align-items:center;gap:7px;padding:11px 12px;border-radius:12px;font-size:13px;font-weight:800;color:#58647c;transition:.2s}.main-nav a i{font-size:12px;color:#9aa3b6}.main-nav a:hover,.main-nav a.active{color:var(--primary);background:#f1efff}.main-nav a.active i{color:var(--primary)}.menu-toggle{display:none;width:46px;height:46px;border:0;border-radius:13px;background:#f2f1ff;color:var(--primary);font-size:18px}.header-decoration{position:absolute;border-radius:50%;filter:blur(1px);opacity:.2}.header-decoration-one{width:120px;height:120px;background:#a896ff;left:-70px;top:-70px}.header-decoration-two{width:90px;height:90px;background:#7ae2d1;right:8%;top:-72px}
.hero-section{position:relative;overflow:hidden;background:linear-gradient(135deg,#f8f7ff 0%,#f7fbff 50%,#f3fffb 100%);min-height:650px;display:flex;align-items:center}.hero-grid-bg{position:absolute;inset:0;background-image:linear-gradient(rgba(101,86,232,.055) 1px,transparent 1px),linear-gradient(90deg,rgba(101,86,232,.055) 1px,transparent 1px);background-size:38px 38px;mask-image:linear-gradient(to right,#000,transparent 76%)}.hero-section:before{content:"";position:absolute;width:520px;height:520px;border-radius:50%;background:radial-gradient(circle,rgba(122,108,255,.18),transparent 68%);top:-170px;right:-90px}.hero-section:after{content:"";position:absolute;width:360px;height:360px;border-radius:50%;background:radial-gradient(circle,rgba(25,179,148,.14),transparent 70%);bottom:-160px;left:-100px}.hero-layout{display:grid;grid-template-columns:1.02fr .98fr;align-items:center;gap:70px;padding:74px 0;position:relative;z-index:2}.eyebrow{display:inline-flex;align-items:center;gap:8px;padding:8px 13px;border-radius:999px;background:rgba(101,86,232,.1);color:var(--primary);font-size:11px;font-weight:900;letter-spacing:.4px;text-transform:uppercase}.hero-copy h1{font-size:58px;line-height:1.06;letter-spacing:-2.6px;color:var(--ink);margin:20px 0 20px;font-weight:900}.hero-copy h1 span{background:linear-gradient(100deg,var(--primary),#1aaea0);-webkit-background-clip:text;background-clip:text;color:transparent}.hero-copy>p{font-size:17px;max-width:620px;margin:0;color:#647089}.hero-actions{display:flex;gap:12px;flex-wrap:wrap;margin-top:30px}.btn{border:0;border-radius:14px;padding:13px 19px;display:inline-flex;justify-content:center;align-items:center;gap:9px;font-size:13px;font-weight:900;transition:.22s}.btn:hover{transform:translateY(-2px)}.btn-primary{background:linear-gradient(135deg,var(--primary),#7766f4);color:#fff;box-shadow:0 12px 24px rgba(101,86,232,.25)}.btn-primary:hover{box-shadow:0 16px 30px rgba(101,86,232,.31)}.btn-secondary{background:#fff;color:var(--ink);border:1px solid var(--line);box-shadow:var(--shadow-sm)}.btn-secondary:hover{border-color:#c9c3ff;color:var(--primary)}.btn-ghost{background:#f5f6fa;color:#5e6a80;border:1px solid #edf0f5}.btn-white{background:#fff;color:var(--primary);box-shadow:0 12px 30px rgba(35,31,91,.17)}.btn-large{padding:15px 22px;font-size:14px}.hero-points{display:flex;align-items:center;gap:18px;flex-wrap:wrap;margin-top:22px;color:#6f7a90;font-size:11px;font-weight:800}.hero-points span{display:flex;align-items:center;gap:6px}.hero-points i{color:var(--green)}
.hero-visual{position:relative;min-height:430px;display:flex;align-items:center}.math-board{width:100%;background:#fff;border:1px solid rgba(222,225,240,.95);border-radius:27px;box-shadow:0 35px 90px rgba(51,45,115,.18);overflow:hidden;transform:rotate(1.3deg)}.board-top{height:44px;background:#f5f6fa;border-bottom:1px solid #e9ebf3;display:flex;align-items:center;gap:7px;padding:0 16px}.board-top>span{width:8px;height:8px;border-radius:50%;background:#ff7f81}.board-top>span:nth-child(2){background:#ffc35b}.board-top>span:nth-child(3){background:#58d197}.board-top small{margin-left:auto;color:#9aa3b6;font-size:10px;font-weight:800}.board-content{padding:28px}.board-title{display:flex;align-items:center;justify-content:space-between;color:#7b859b;font-size:11px;font-weight:800}.board-title i{width:34px;height:34px;border-radius:11px;background:#fff6e5;color:#ff9a24;display:grid;place-items:center}.equation-preview{display:flex;align-items:center;justify-content:center;gap:16px;padding:31px 10px;margin:20px 0;border-radius:20px;background:linear-gradient(135deg,#f3f1ff,#f5fbff);border:1px solid #e9e6ff}.equation-preview b{font-size:35px;color:var(--ink)}.equation-preview em{font-style:normal;font-size:24px;color:#8c95a9;font-weight:800}.equation-preview strong{font-size:40px;color:var(--primary)}.number-line{display:flex;align-items:center;color:#8a94a8;font-size:9px;font-weight:800}.number-line i{height:2px;background:#dfe4ed;flex:1;position:relative}.number-line i:after{content:"";position:absolute;right:-2px;top:-2px;width:6px;height:6px;background:var(--primary);border-radius:50%}.mini-stat-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:9px;margin-top:25px}.mini-stat-grid div{border-radius:14px;background:#fafbfe;border:1px solid #edf0f5;padding:13px 8px;text-align:center}.mini-stat-grid i{display:block;color:var(--primary);font-size:16px;margin-bottom:5px}.mini-stat-grid span{font-size:9px;color:#78849a;font-weight:800}.floating-math{position:absolute;background:#fff;border:1px solid #eceefa;border-radius:13px;padding:10px 14px;box-shadow:var(--shadow-sm);color:var(--ink);font-size:12px;font-weight:900}.fm-one{top:25px;right:-15px;transform:rotate(6deg);color:var(--accent)}.fm-two{bottom:29px;left:-22px;transform:rotate(-5deg);color:var(--primary)}.fm-three{bottom:78px;right:-28px;color:var(--green)}.fm-three i{margin-right:5px}
.feature-strip{position:relative;z-index:5;margin-top:-1px;background:#fff;border-top:1px solid #edf0f5;border-bottom:1px solid #edf0f5}.feature-strip-grid{display:grid;grid-template-columns:repeat(4,1fr)}.feature-strip-grid>div{display:grid;grid-template-columns:45px 1fr;grid-template-rows:auto auto;gap:0 12px;align-items:center;padding:23px 22px;border-right:1px solid #edf0f5}.feature-strip-grid>div:last-child{border-right:0}.strip-icon{grid-row:1/3;width:44px;height:44px;border-radius:14px;display:grid;place-items:center;font-size:17px}.strip-icon.purple{background:#f0edff;color:var(--primary)}.strip-icon.blue{background:#e8f7fc;color:var(--secondary)}.strip-icon.orange{background:#fff3e4;color:var(--accent)}.strip-icon.green{background:#e9faf6;color:var(--green)}.feature-strip strong{font-size:12px;color:var(--ink);font-weight:900}.feature-strip small{font-size:9px;color:var(--muted);font-weight:700}
.section{padding:82px 0}.section-soft{background:var(--soft)}.section-heading{margin-bottom:35px}.section-heading.centered{text-align:center;max-width:680px;margin:0 auto 40px}.section-kicker{display:block;color:var(--primary);font-size:10px;font-weight:900;letter-spacing:1.2px;text-transform:uppercase;margin-bottom:7px}.section-kicker.light{color:#ded9ff}.section-heading h2,.demo-copy h2{font-size:37px;line-height:1.18;letter-spacing:-1.3px;color:var(--ink);margin:0 0 10px}.section-heading p{margin:0;color:var(--muted);font-size:14px}.learning-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:18px}.learning-card{position:relative;overflow:hidden;background:#fff;border:1px solid var(--line);border-radius:22px;padding:27px;min-height:330px;display:flex;flex-direction:column;box-shadow:0 12px 34px rgba(55,50,116,.055);transition:.25s}.learning-card:before{content:"";position:absolute;width:130px;height:130px;border-radius:50%;right:-55px;top:-55px;opacity:.13}.learning-card:hover{transform:translateY(-7px);box-shadow:var(--shadow);border-color:transparent}.purple-card:before{background:var(--primary)}.blue-card:before{background:var(--secondary)}.orange-card:before{background:var(--accent)}.green-card:before{background:var(--green)}.learning-icon{width:56px;height:56px;border-radius:17px;display:grid;place-items:center;font-size:22px;margin-bottom:20px}.purple-card .learning-icon{background:#f0edff;color:var(--primary)}.blue-card .learning-icon{background:#e8f7fc;color:var(--secondary)}.orange-card .learning-icon{background:#fff3e4;color:var(--accent)}.green-card .learning-icon{background:#e9faf6;color:var(--green)}.card-label{font-size:9px;font-weight:900;letter-spacing:1px;text-transform:uppercase;color:#9aa3b6}.learning-card h3{font-size:21px;color:var(--ink);margin:5px 0 9px}.learning-card p{font-size:12px;color:#748097;margin:0 0 20px}.learning-card b{margin-top:auto;font-size:11px;color:var(--primary)}.learning-card b i{margin-left:6px;transition:.2s}.learning-card:hover b i{transform:translateX(4px)}
.demo-layout{display:grid;grid-template-columns:.8fr 1.2fr;gap:70px;align-items:center}.demo-copy>p{font-size:14px;color:var(--muted)}.check-list{list-style:none;padding:0;margin:24px 0 0;display:grid;gap:12px}.check-list li{display:flex;align-items:center;gap:10px;font-size:12px;font-weight:800;color:#5f6a81}.check-list i{width:24px;height:24px;border-radius:8px;background:#eaf9f4;color:var(--green);display:grid;place-items:center;font-size:10px}.quick-calculator{background:#fff;border:1px solid var(--line);border-radius:25px;padding:28px;box-shadow:var(--shadow)}.calculator-head{display:flex;justify-content:space-between;align-items:center;margin-bottom:22px}.calculator-head span{color:var(--ink);font-size:15px;font-weight:900}.calculator-head span i{color:var(--accent);margin-right:7px}.calculator-head small{font-size:9px;color:var(--muted)}.quick-input-row{display:grid;grid-template-columns:1fr 105px 1fr;gap:12px;align-items:end}.quick-input-row label,.number-field,.sim-inputs label{display:grid;gap:7px}.quick-input-row label>span,.number-field>span,.sim-inputs label{font-size:10px;font-weight:900;color:#6b768c}.quick-input-row input,.quick-input-row select,.number-field input,.sim-inputs input{width:100%;height:50px;border:1px solid #dfe4ed;border-radius:13px;background:#fbfcfe;color:var(--ink);font-weight:900;padding:0 14px;outline:0;transition:.2s}.quick-input-row select{text-align:center;font-size:20px}.quick-input-row input:focus,.quick-input-row select:focus,.number-field input:focus,.sim-inputs input:focus{border-color:#a69cff;box-shadow:0 0 0 4px rgba(101,86,232,.09);background:#fff}.quick-result{margin-top:17px;background:linear-gradient(135deg,#f1efff,#f2fbff);border:1px solid #e4e0ff;border-radius:17px;padding:18px 20px;display:flex;align-items:center;justify-content:space-between;gap:15px}.quick-result small{font-size:9px;color:#7c879c;font-weight:800}.quick-result strong{font-size:23px;color:var(--primary)}.calculator-actions{display:flex;gap:10px;margin-top:15px}.cta-panel{background:linear-gradient(135deg,#5948d7,#7565ed 58%,#16aa9d);border-radius:28px;padding:43px 48px;color:#fff;display:flex;align-items:center;justify-content:space-between;gap:30px;box-shadow:0 25px 65px rgba(75,62,190,.25);position:relative;overflow:hidden}.cta-panel:after{content:"π + √";position:absolute;right:190px;top:-30px;font-size:110px;font-weight:900;color:rgba(255,255,255,.05);transform:rotate(-10deg)}.cta-panel h2{font-size:31px;line-height:1.2;margin:0 0 7px}.cta-panel p{font-size:12px;margin:0;color:#e5e1ff}.cta-panel .btn{position:relative;z-index:2;white-space:nowrap}
.page-hero{position:relative;overflow:hidden}.compact-hero{min-height:325px;display:flex;align-items:center}.purple-hero{background:linear-gradient(135deg,#5545d6,#7563ee)}.blue-hero{background:linear-gradient(135deg,#147cb9,#1aadd5)}.orange-hero{background:linear-gradient(135deg,#ef7f2c,#f6a53f)}.green-hero{background:linear-gradient(135deg,#0d977f,#22b89a)}.compact-hero:before{content:"";position:absolute;inset:0;background-image:radial-gradient(rgba(255,255,255,.14) 1px,transparent 1px);background-size:24px 24px;mask-image:linear-gradient(90deg,#000,transparent)}.compact-hero:after{content:"";position:absolute;width:400px;height:400px;border-radius:50%;border:70px solid rgba(255,255,255,.06);right:-80px;top:-150px}.page-hero-inner{position:relative;z-index:2;display:flex;align-items:center;justify-content:space-between;gap:50px;padding:65px 0;color:#fff}.page-hero .eyebrow{color:#fff;background:rgba(255,255,255,.14)}.page-hero h1{font-size:48px;line-height:1.05;letter-spacing:-1.7px;margin:15px 0 10px}.page-hero p{font-size:14px;max-width:650px;color:rgba(255,255,255,.83);margin:0}.hero-symbols{display:grid;grid-template-columns:repeat(2,78px);gap:11px;transform:rotate(4deg)}.hero-symbols span{height:78px;border-radius:22px;background:rgba(255,255,255,.14);border:1px solid rgba(255,255,255,.2);display:grid;place-items:center;font-size:31px;font-weight:900;box-shadow:inset 0 0 25px rgba(255,255,255,.04)}.hero-mascot{width:160px;height:140px;border-radius:37% 45% 42% 40%;background:rgba(255,255,255,.14);border:1px solid rgba(255,255,255,.2);display:grid;place-items:center;position:relative;transform:rotate(4deg)}.hero-mascot i{font-size:57px}.hero-mascot span{position:absolute;right:-10px;top:10px;background:#fff;color:#178dbf;padding:7px 10px;border-radius:9px;font-size:10px;font-weight:900;transform:rotate(-3deg)}.formula-hero-card{background:rgba(255,255,255,.14);border:1px solid rgba(255,255,255,.24);border-radius:22px;padding:25px 34px;display:grid;text-align:center;transform:rotate(3deg);box-shadow:0 18px 45px rgba(147,71,9,.15)}.formula-hero-card span{font-size:30px;font-weight:900}.formula-hero-card small{font-size:10px;color:rgba(255,255,255,.75);margin-top:4px}.simulation-orbit{width:160px;height:160px;border:1px solid rgba(255,255,255,.3);border-radius:50%;display:grid;place-items:center;position:relative}.simulation-orbit:before{content:"";position:absolute;width:105px;height:105px;border:1px dashed rgba(255,255,255,.28);border-radius:50%}.simulation-orbit i{font-size:45px}.simulation-orbit span{position:absolute;width:36px;height:36px;border-radius:50%;background:#fff;color:#10917a;display:grid;place-items:center;font-weight:900;font-size:12px}.simulation-orbit span:nth-child(1){top:-6px;left:24px}.simulation-orbit span:nth-child(2){right:-5px;top:60px}.simulation-orbit span:nth-child(3){left:20px;bottom:-8px}.page-section{min-height:500px}
.calculator-layout{display:grid;grid-template-columns:1.35fr .65fr;gap:30px;align-items:start}.calculator-panel{background:#fff;border:1px solid var(--line);border-radius:26px;padding:31px;box-shadow:var(--shadow-sm)}.panel-heading{display:flex;align-items:center;justify-content:space-between;margin-bottom:24px}.panel-heading h2{color:var(--ink);font-size:29px;margin:0;line-height:1}.panel-badge{display:inline-flex;align-items:center;gap:7px;padding:8px 11px;background:#fff5e5;color:#ee8b20;border-radius:10px;font-size:9px;font-weight:900}.operation-picker{display:grid;grid-template-columns:repeat(4,1fr);gap:10px}.operation-button{border:1px solid var(--line);background:#fafbfe;border-radius:15px;padding:15px 8px;display:flex;flex-direction:column;align-items:center;gap:7px;color:#6f7a90;transition:.2s}.operation-button i{font-size:19px}.operation-button span{font-size:9px;font-weight:900}.operation-button:hover,.operation-button.active{border-color:#a89eff;background:#f1efff;color:var(--primary);box-shadow:0 7px 20px rgba(101,86,232,.12)}.number-input-grid{display:grid;grid-template-columns:1fr 68px 1fr;gap:14px;align-items:end;margin-top:24px}.number-field>div{position:relative}.number-field i{position:absolute;left:15px;top:50%;transform:translateY(-50%);width:23px;height:23px;border-radius:7px;background:#eeeaff;color:var(--primary);display:grid;place-items:center;font-size:9px;z-index:2}.number-field input{height:58px;padding-left:48px;font-size:18px}.operator-display{width:58px;height:58px;border-radius:17px;background:linear-gradient(135deg,var(--primary),#7969ef);color:#fff;display:grid;place-items:center;font-size:27px;font-weight:900;box-shadow:0 12px 25px rgba(101,86,232,.23)}.large-actions{margin-top:22px}.result-card{margin-top:23px;border:1px solid #dfe9ff;border-radius:19px;background:linear-gradient(135deg,#f4f1ff,#f2fbff);padding:21px;display:flex;align-items:flex-start;gap:16px}.result-icon{width:45px;height:45px;border-radius:14px;background:#fff;color:var(--accent);display:grid;place-items:center;box-shadow:0 8px 20px rgba(63,56,130,.1);flex:0 0 auto}.result-card>div:last-child{display:grid}.result-card small{font-size:9px;color:#7a869c;font-weight:900}.result-card strong{font-size:28px;color:var(--primary);line-height:1.2;margin:2px 0}.result-card p{font-size:10px;margin:0;color:#6b778e}.tips-column{display:grid;gap:12px}.info-card{border:1px solid var(--line);border-radius:18px;background:#fff;padding:17px;display:flex;gap:13px;box-shadow:0 8px 25px rgba(55,50,116,.05)}.info-icon{width:41px;height:41px;border-radius:13px;display:grid;place-items:center;flex:0 0 auto}.info-icon.purple{background:#f0edff;color:var(--primary)}.info-icon.blue{background:#e8f7fc;color:var(--secondary)}.info-icon.orange{background:#fff3e4;color:var(--accent)}.info-icon.green{background:#e9faf6;color:var(--green)}.info-card h3{font-size:13px;color:var(--ink);margin:0}.info-card p{font-size:9px;margin:2px 0 7px;color:#7c879b}.info-card code{font-family:Nunito,Arial,sans-serif;background:#f6f7fa;border-radius:7px;padding:4px 8px;font-size:9px;font-weight:900;color:#58657a}.example-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:14px}.example-grid button{border:1px solid var(--line);background:#fff;border-radius:18px;padding:20px;text-align:left;display:grid;transition:.2s}.example-grid button:hover{transform:translateY(-4px);border-color:#c3bcff;box-shadow:var(--shadow-sm)}.example-grid span{font-size:9px;text-transform:uppercase;letter-spacing:.8px;color:var(--muted);font-weight:900}.example-grid strong{font-size:22px;color:var(--ink);margin:4px 0 12px}.example-grid em{font-style:normal;font-size:9px;color:var(--primary);font-weight:900}.example-grid em i{margin-left:4px}
.practice-shell{max-width:1000px}.practice-setup,.practice-stage,.practice-result{background:#fff;border:1px solid var(--line);border-radius:27px;padding:34px;box-shadow:var(--shadow-sm)}.setup-heading{text-align:center;max-width:570px;margin:0 auto 29px}.setup-heading h2{font-size:32px;color:var(--ink);margin:0 0 6px}.setup-heading p{font-size:12px;color:var(--muted);margin:0}.setup-group{margin-top:25px}.setup-group>label{display:block;color:var(--ink);font-size:12px;font-weight:900;margin-bottom:11px}.choice-grid{display:grid;gap:10px}.operation-choice{grid-template-columns:repeat(5,1fr)}.difficulty-choice{grid-template-columns:repeat(3,1fr)}.choice-grid button{border:1px solid var(--line);border-radius:16px;background:#fbfcfe;padding:16px 10px;display:flex;flex-direction:column;align-items:center;gap:4px;color:#707c91;transition:.2s}.choice-grid button i{font-size:20px;margin-bottom:4px}.choice-grid button span{font-size:11px;font-weight:900}.choice-grid button small{font-size:8px;color:#9aa3b6}.choice-grid button:hover,.choice-grid button.active{border-color:#a9a0ff;background:#f2f0ff;color:var(--primary);box-shadow:0 8px 22px rgba(101,86,232,.1)}.level-dot{width:25px;height:8px;border-radius:99px;margin-bottom:6px}.level-dot.one{background:#38c693}.level-dot.two{background:#f6b64b}.level-dot.three{background:#ef6875}.setup-footer{display:flex;align-items:center;justify-content:space-between;gap:30px;margin-top:29px;padding-top:24px;border-top:1px solid #edf0f5}.setup-footer>div{display:flex;align-items:center;gap:10px;font-size:10px;color:#748096}.setup-footer>div i{color:var(--secondary);font-size:17px}.practice-topbar{display:grid;grid-template-columns:1fr auto;gap:30px;align-items:end;padding-bottom:23px;border-bottom:1px solid #edf0f5}.practice-topbar small,.practice-score small{font-size:9px;color:var(--muted);font-weight:900}.progress-track{height:9px;border-radius:99px;background:#edf0f5;overflow:hidden;margin-top:7px}.progress-track span{display:block;width:10%;height:100%;border-radius:99px;background:linear-gradient(90deg,var(--secondary),var(--primary));transition:.35s}.practice-score{text-align:right}.practice-score strong{display:block;color:var(--primary);font-size:20px}.question-card{text-align:center;max-width:650px;margin:35px auto 5px}.question-number{display:inline-flex;padding:7px 11px;border-radius:999px;background:#eef7fc;color:var(--secondary);font-size:9px;font-weight:900}.question-card>p{font-size:12px;color:var(--muted);margin:15px 0 9px}.question-equation{font-size:56px;line-height:1.15;color:var(--ink);font-weight:900;letter-spacing:1px;margin-bottom:26px}.question-card form{display:flex;align-items:end;gap:10px;max-width:500px;margin:auto}.answer-field{display:grid;gap:6px;text-align:left;flex:1}.answer-field span{font-size:9px;font-weight:900;color:#68748a}.answer-field input{width:100%;height:55px;border:1px solid #dfe4ed;border-radius:14px;padding:0 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button.active{background:#f2f0ff;color:var(--primary)}.simulation-tabs button.active>i{background:var(--primary);color:#fff}.simulation-workspace{border:1px solid var(--line);border-radius:25px;background:#fff;padding:31px;box-shadow:var(--shadow-sm);min-height:680px}.simulation-pane{display:none}.simulation-pane.active{display:block}.sim-heading{display:flex;align-items:flex-start;gap:15px}.sim-icon{width:55px;height:55px;border-radius:17px;display:grid;place-items:center;font-size:22px;flex:0 0 auto}.sim-icon.purple{background:#f0edff;color:var(--primary)}.sim-icon.blue{background:#e8f7fc;color:var(--secondary)}.sim-icon.orange{background:#fff3e4;color:var(--accent)}.sim-icon.green{background:#e9faf6;color:var(--green)}.sim-heading>div>span{font-size:8px;text-transform:uppercase;letter-spacing:1px;color:var(--muted);font-weight:900}.sim-heading h2{font-size:29px;color:var(--ink);margin:1px 0 2px;line-height:1.1}.sim-heading 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var(--accent);background:rgba(255,159,67,.12)}.circle-shape>div:after{content:"";position:absolute;height:3px;width:62px;background:var(--accent);left:50%;top:50%;transform-origin:left}.circle-shape span{position:absolute;left:54%;top:42%;font-size:10px;font-weight:900;color:#d77c22}.cube-shape>div,.block-shape>div{width:125px;height:125px;background:rgba(25,179,148,.15);border:4px solid var(--green);position:relative;transform:skewY(-7deg)}.cube-shape>div:before,.block-shape>div:before{content:"";position:absolute;width:34px;height:100%;border:4px solid var(--green);border-left:0;right:-38px;top:-18px;transform:skewY(40deg);background:rgba(25,179,148,.08)}.cube-shape>div:after,.block-shape>div:after{content:"";position:absolute;width:100%;height:31px;border:4px solid var(--green);border-bottom:0;left:14px;top:-35px;transform:skewX(-47deg);background:rgba(25,179,148,.08)}.cube-shape span,.block-shape span{position:absolute;left:50%;top:50%;transform:translate(-50%,-50%) skewY(7deg);color:#108f77;font-size:11px;font-weight:900}.block-shape>div{width:180px;height:95px;border-color:var(--primary);background:rgba(101,86,232,.12)}.block-shape>div:before,.block-shape>div:after{border-color:var(--primary);background:rgba(101,86,232,.07)}.block-shape span{color:var(--primary)}.sim-inputs{display:grid;grid-template-columns:repeat(2,1fr);gap:13px}.sim-inputs.one-input{grid-template-columns:1fr}.sim-inputs.three-inputs{grid-template-columns:repeat(3,1fr)}.sim-inputs label{font-size:9px}.sim-inputs input{height:51px;margin-top:6px}.sim-formula{margin-top:16px;padding:14px 17px;border-radius:13px;background:#f6f7fb;color:#59657a;font-size:11px;font-weight:900;text-align:center}.sim-results{display:grid;grid-template-columns:repeat(2,1fr);gap:11px;margin-top:13px}.sim-results.one-result{grid-template-columns:1fr}.sim-results.three-results{grid-template-columns:repeat(3,1fr)}.sim-results>div{border:1px solid #e6e8f5;border-radius:15px;background:linear-gradient(135deg,#fbfbff,#f8fcff);padding:16px;text-align:center;display:grid}.sim-results small{font-size:8px;color:var(--muted);font-weight:900;text-transform:uppercase;letter-spacing:.6px}.sim-results strong{font-size:28px;color:var(--primary);line-height:1.2;margin:3px 0}.sim-results span{font-size:8px;color:#9aa3b4;font-weight:800}.numeric-visual{gap:25px}.numeric-visual strong{min-width:120px;text-align:center;font-size:37px;color:var(--primary)}.numeric-visual i{color:#a7afbd}.discount-visual{gap:50px}.discount-visual>span{width:115px;height:115px;border-radius:50%;background:#fff1df;color:var(--accent);display:grid;place-items:center;position:relative}.discount-visual>span i{font-size:55px}.discount-visual>span b{position:absolute;color:#fff;font-size:15px}.discount-visual>div{display:grid}.discount-visual small{font-size:9px;color:var(--muted);font-weight:900}.discount-visual strong{font-size:25px;color:var(--ink)}.average-visual{gap:9px}.average-visual span{width:50px;height:50px;border-radius:14px;background:#fff;border:1px solid #e2e5ef;color:#667289;display:grid;place-items:center;font-weight:900}.average-visual i{margin:0 8px;color:#a7afbd}.average-visual strong{font-size:35px;color:var(--green)}.speed-selector{display:flex;gap:7px;margin:22px 0 0;padding:5px;border-radius:13px;background:#f5f6fa}.speed-selector button{border:0;background:transparent;border-radius:10px;padding:9px 12px;flex:1;font-size:9px;font-weight:900;color:#7a8599}.speed-selector button.active{background:#fff;color:var(--primary);box-shadow:0 5px 16px rgba(55,50,116,.08)}.speed-visual{gap:0}.speed-visual i{font-size:36px;color:var(--primary)}.speed-visual i:last-child{color:var(--danger)}.speed-visual span{width:55%;height:3px;background:repeating-linear-gradient(90deg,#b9c0cf 0 12px,transparent 12px 22px);margin:0 18px}.site-footer{background:#202942;color:#b4bdd0;padding:30px 0}.footer-inner{display:grid;grid-template-columns:1.3fr auto auto;align-items:center;gap:35px}.footer-brand{display:flex;align-items:center;gap:12px}.footer-brand strong{display:block;color:#fff;font-size:14px}.footer-brand p{font-size:9px;margin:2px 0 0}.footer-links{display:flex;gap:20px}.footer-links a{font-size:9px;font-weight:900}.footer-links a:hover{color:#fff}.copyright{font-size:9px;margin:0}.back-to-top{position:fixed;right:20px;bottom:20px;width:44px;height:44px;border:0;border-radius:14px;background:var(--primary);color:#fff;box-shadow:0 10px 25px rgba(101,86,232,.3);opacity:0;visibility:hidden;transform:translateY(10px);transition:.2s;z-index:80}.back-to-top.show{opacity:1;visibility:visible;transform:translateY(0)}
@media(max-width:1100px){.main-nav a{padding:10px 8px;font-size:11px}.main-nav a i{display:none}.hero-layout{gap:42px}.hero-copy h1{font-size:50px}.learning-card{padding:23px}.formula-grid{grid-template-columns:repeat(2,1fr)}.simulation-layout{grid-template-columns:275px 1fr}}
@media(max-width:920px){.nav-wrap{height:72px}.menu-toggle{display:grid;place-items:center}.main-nav{position:fixed;top:80px;left:20px;right:20px;display:none;flex-direction:column;align-items:stretch;background:#fff;border:1px solid var(--line);border-radius:18px;padding:12px;box-shadow:0 25px 70px rgba(44,39,101,.2)}.main-nav.open{display:flex}.main-nav a{font-size:13px;padding:12px}.main-nav a i{display:inline-block}.hero-layout{grid-template-columns:1fr;padding:60px 0 85px}.hero-copy{text-align:center}.hero-copy>p{margin:auto}.hero-actions,.hero-points{justify-content:center}.hero-visual{max-width:650px;width:100%;margin:auto}.feature-strip-grid{grid-template-columns:repeat(2,1fr)}.feature-strip-grid>div:nth-child(2){border-right:0}.feature-strip-grid>div:nth-child(-n+2){border-bottom:1px solid #edf0f5}.learning-grid{grid-template-columns:repeat(2,1fr)}.demo-layout{grid-template-columns:1fr;gap:35px}.calculator-layout{grid-template-columns:1fr}.tips-column{grid-template-columns:repeat(2,1fr)}.operation-choice{grid-template-columns:repeat(3,1fr)}.simulation-layout{grid-template-columns:1fr}.simulation-menu{position:static}.simulation-tabs{grid-template-columns:repeat(3,1fr)}.simulation-tabs button{align-items:center}.simulation-workspace{min-height:auto}.footer-inner{grid-template-columns:1fr auto}.copyright{grid-column:1/-1}.page-hero-inner{padding:55px 0}.example-grid{grid-template-columns:repeat(2,1fr)}}
@media(max-width:640px){.container{width:min(100% - 28px,1180px)}.brand-mark{width:42px;height:42px;border-radius:13px;font-size:19px}.brand-copy strong{font-size:16px}.brand-copy small{font-size:8px}.main-nav{left:12px;right:12px;top:78px}.hero-section{min-height:auto}.hero-layout{padding:48px 0 65px}.hero-copy h1{font-size:40px;letter-spacing:-1.8px}.hero-copy>p{font-size:14px}.hero-actions .btn{width:100%}.hero-points{gap:10px}.hero-visual{display:none}.feature-strip-grid{grid-template-columns:1fr 1fr}.feature-strip-grid>div{grid-template-columns:36px 1fr;padding:16px 10px;gap:0 8px}.strip-icon{width:35px;height:35px;border-radius:11px;font-size:14px}.feature-strip strong{font-size:10px}.feature-strip small{font-size:8px}.section{padding:58px 0}.section-heading h2,.demo-copy h2{font-size:29px}.learning-grid{grid-template-columns:1fr}.learning-card{min-height:285px}.quick-calculator{padding:20px}.quick-input-row{grid-template-columns:1fr}.quick-result{align-items:flex-start;flex-direction:column}.calculator-actions{flex-direction:column}.calculator-actions .btn{width:100%}.cta-panel{padding:32px 23px;flex-direction:column;text-align:center}.cta-panel h2{font-size:25px}.page-hero-inner{padding:48px 0}.page-hero h1{font-size:38px}.hero-symbols,.hero-mascot,.formula-hero-card,.simulation-orbit{display:none}.calculator-panel{padding:20px}.panel-heading{align-items:flex-start;gap:10px}.panel-heading h2{font-size:25px}.panel-badge{display:none}.operation-picker{grid-template-columns:repeat(2,1fr)}.number-input-grid{grid-template-columns:1fr;align-items:center}.operator-display{margin:auto;width:48px;height:48px}.tips-column{grid-template-columns:1fr}.example-grid{grid-template-columns:1fr}.practice-setup,.practice-stage,.practice-result{padding:21px}.operation-choice,.difficulty-choice{grid-template-columns:1fr 1fr}.setup-footer{flex-direction:column;align-items:stretch}.setup-footer .btn{width:100%}.practice-topbar{gap:15px}.question-equation{font-size:42px}.question-card form{flex-direction:column;align-items:stretch}.question-card form .btn{width:100%}.result-summary{grid-template-columns:1fr}.result-actions{flex-direction:column}.formula-toolbar{align-items:flex-start;flex-direction:column}.formula-grid{grid-template-columns:1fr}.compact-learning-banner{flex-direction:column;align-items:flex-start}.simulation-menu{padding:15px}.simulation-tabs{grid-template-columns:1fr 1fr}.simulation-tabs button{padding:9px}.simulation-tabs button>i{width:32px;height:32px}.simulation-workspace{padding:20px}.sim-heading h2{font-size:25px}.shape-visual,.numeric-visual,.discount-visual,.average-visual,.speed-visual{height:165px}.rectangle-shape>div{width:170px;height:90px}.triangle-shape>div{transform:scale(.8)}.sim-inputs,.sim-inputs.three-inputs{grid-template-columns:1fr}.sim-results,.sim-results.three-results{grid-template-columns:1fr}.numeric-visual{gap:8px}.numeric-visual strong{min-width:90px;font-size:28px}.discount-visual{gap:20px}.discount-visual>span{width:90px;height:90px}.discount-visual>span i{font-size:45px}.discount-visual strong{font-size:19px}.average-visual span{width:40px;height:40px}.average-visual strong{font-size:27px}.speed-selector{flex-direction:column}.footer-inner{grid-template-columns:1fr;text-align:center}.footer-brand{justify-content:center}.footer-links{justify-content:center}.copyright{grid-column:auto}.back-to-top{right:14px;bottom:14px}}