:root{--ink:#183153;--muted:#65758b;--blue:#2764e7;--blue-dark:#194bb5;--sky:#eaf2ff;--cream:#fffaf0;--yellow:#f4b942;--green:#1f9d71;--red:#d94b4b;--white:#fff;--line:#dce5f2;--shadow:0 18px 50px rgba(31,55,92,.10)}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:#f7f9fc;color:var(--ink);font-family:Inter,ui-rounded,"Trebuchet MS",system-ui,sans-serif;line-height:1.5}.topbar{height:72px;padding:0 max(24px,calc((100vw - 1120px)/2));display:flex;align-items:center;justify-content:space-between;background:rgba(255,255,255,.94);border-bottom:1px solid var(--line);position:sticky;top:0;z-index:10;backdrop-filter:blur(10px)}.brand{display:flex;align-items:center;gap:11px;color:var(--ink);text-decoration:none;font-size:18px;font-weight:800}.brand-mark{display:grid;place-items:center;width:36px;height:36px;border-radius:11px;background:var(--blue);color:#fff;font-size:26px;box-shadow:0 5px 0 var(--blue-dark)}.session-score{display:flex;align-items:center;gap:8px;background:var(--cream);border:1px solid #f3dfaf;border-radius:999px;padding:8px 14px;color:#735719}.score-dot{width:10px;height:10px;background:var(--yellow);border-radius:50%}main{max-width:1120px;margin:auto;padding:0 24px 72px}.hero{text-align:center;padding:70px 12px 46px}.eyebrow,.section-kicker,.mini-label{font-size:12px;font-weight:850;letter-spacing:.12em;color:var(--blue);margin:0 0 10px}.hero h1{font-size:clamp(40px,6vw,68px);line-height:1.03;letter-spacing:-.045em;margin:0}.hero h1 span{color:var(--blue)}.hero-copy{max-width:650px;margin:22px auto 0;color:var(--muted);font-size:18px}.mode-tabs{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;max-width:720px;margin:0 auto 44px;padding:7px;background:#e9eef6;border-radius:18px}.mode-tab{border:0;background:transparent;color:var(--muted);padding:12px;border-radius:13px;font:inherit;font-weight:800;cursor:pointer;display:flex;justify-content:center;align-items:center;gap:9px}.mode-tab span{display:grid;place-items:center;width:25px;height:25px;border-radius:50%;background:#d4ddea;font-size:13px}.mode-tab.active{background:#fff;color:var(--ink);box-shadow:0 4px 15px rgba(36,58,88,.09)}.mode-tab.active span{background:var(--blue);color:#fff}.mode-panel{display:none}.mode-panel.active{display:block;animation:rise .3s ease}@keyframes rise{from{opacity:0;transform:translateY(8px)}to{opacity:1;transform:none}}.panel-heading{margin-bottom:25px}.panel-heading h2{font-size:34px;letter-spacing:-.03em;margin:0 0 6px}.panel-heading p:not(.section-kicker){margin:0;color:var(--muted)}.panel-heading.split{display:flex;justify-content:space-between;gap:24px;align-items:end}.select-wrap{display:flex;flex-direction:column;gap:6px;font-size:13px;font-weight:800;color:var(--muted)}select{min-width:190px;padding:11px 38px 11px 13px;border:1px solid var(--line);border-radius:11px;background:#fff;color:var(--ink);font:inherit;font-weight:700}.number-choices{display:grid;grid-template-columns:repeat(10,1fr);gap:9px;margin-bottom:25px}.number-btn{aspect-ratio:1;border:1px solid var(--line);border-radius:14px;background:#fff;color:var(--ink);font:inherit;font-size:19px;font-weight:850;cursor:pointer;box-shadow:0 3px 0 #dce4ef}.number-btn:hover,.number-btn:focus-visible{border-color:var(--blue);transform:translateY(-1px)}.number-btn.active{background:var(--blue);color:#fff;border-color:var(--blue);box-shadow:0 4px 0 var(--blue-dark)}.learn-grid,.practice-layout{display:grid;grid-template-columns:minmax(0,1.6fr) minmax(260px,.8fr);gap:24px}.table-card,.tip-card,.quiz-card,.stats-card,.challenge-card{background:#fff;border:1px solid var(--line);border-radius:22px;box-shadow:var(--shadow)}.table-card{padding:28px}.table-card-head{display:flex;align-items:start;justify-content:space-between;gap:16px;border-bottom:1px solid var(--line);padding-bottom:20px}.table-card h3,.tip-card h3{font-size:24px;margin:0}.pattern-badge{background:var(--sky);color:var(--blue-dark);border-radius:999px;padding:7px 11px;font-size:12px;font-weight:800}.facts-list{display:grid;grid-template-columns:repeat(2,1fr);gap:0 28px;padding-top:14px}.fact{display:flex;justify-content:space-between;padding:10px 8px;border-bottom:1px dashed var(--line);font-size:18px}.fact strong{color:var(--blue)}.tip-card{padding:30px;background:var(--cream);border-color:#f0dfb9;display:flex;flex-direction:column;align-items:flex-start}.bulb{width:48px;height:48px;border-radius:50% 50% 45% 45%;display:grid;place-items:center;background:var(--yellow);color:#6e500a;font-size:25px;font-weight:900;margin-bottom:25px;box-shadow:0 5px 0 #d79a22}.tip-card .mini-label{color:#8c6815}.tip-card p:not(.mini-label){color:#685d45;flex:1}.primary-btn,.secondary-btn{border:0;border-radius:12px;padding:13px 18px;font:inherit;font-weight:850;cursor:pointer}.primary-btn{background:var(--blue);color:#fff;box-shadow:0 4px 0 var(--blue-dark)}.primary-btn:hover{background:#215ad3}.primary-btn:active{transform:translateY(3px);box-shadow:0 1px 0 var(--blue-dark)}.secondary-btn{background:var(--sky);color:var(--blue-dark)}.tip-card .primary-btn{width:100%;margin-top:18px}.quiz-card{padding:30px}.quiz-top,.challenge-status{display:flex;justify-content:space-between;color:var(--muted);font-weight:750}.equation{display:flex;justify-content:center;align-items:center;gap:18px;font-size:clamp(38px,7vw,64px);font-weight:900;letter-spacing:-.04em;padding:46px 12px}.answer-box{display:grid;place-items:center;min-width:90px;height:82px;border:3px dashed #b8c7dc;border-radius:17px;color:#8da0ba}.answer-form{max-width:480px;margin:auto}.answer-form label{display:block;margin-bottom:7px;font-weight:800;font-size:14px}.answer-row{display:flex;gap:10px}.answer-row input{width:100%;min-width:0;border:2px solid var(--line);border-radius:12px;padding:12px 14px;font:inherit;font-size:20px;font-weight:800;color:var(--ink);outline:none}.answer-row input:focus{border-color:var(--blue);box-shadow:0 0 0 4px var(--sky)}.feedback{min-height:48px;margin:18px auto 0;max-width:480px;border-radius:12px;padding:0;font-weight:750}.feedback.success,.feedback.error{padding:12px 14px}.feedback.success{background:#e8f7f1;color:#147453}.feedback.error{background:#fff0ef;color:#a83737}.quiz-card>.secondary-btn{display:block;margin:0 auto}.stats-card{padding:28px;height:max-content}.stats-card .mini-label{margin-bottom:18px}.stat-row{display:flex;justify-content:space-between;padding:13px 0;border-bottom:1px solid var(--line)}.stat-row strong{font-size:20px}.progress-track{height:10px;border-radius:10px;background:#e9eef5;margin:22px 0 14px;overflow:hidden}.progress-track div{height:100%;width:0;background:var(--green);transition:width .3s}.stats-note{color:var(--muted);font-size:14px}.challenge-card{text-align:center;max-width:720px;margin:auto;padding:42px}.challenge-card h3{font-size:28px;margin:20px 0 8px}.challenge-card p{color:var(--muted);max-width:480px;margin:0 auto 25px}.timer-illustration{width:92px;height:92px;border:8px solid var(--blue);border-radius:50%;margin:auto;display:grid;place-items:center;position:relative;color:var(--blue);font-size:27px;font-weight:900}.timer-illustration:before{content:"";position:absolute;width:22px;height:9px;background:var(--blue);border-radius:5px;top:-15px}.challenge-status{font-size:18px;padding-bottom:15px;border-bottom:1px solid var(--line)}.answer-form.compact{max-width:400px}.result-number{font-size:72px;font-weight:900;color:var(--blue);line-height:1}.hidden{display:none!important}footer{text-align:center;color:var(--muted);border-top:1px solid var(--line);padding:28px 16px;background:#fff}
@media(max-width:760px){.topbar{height:64px;padding:0 16px}.brand{font-size:15px}.session-score{font-size:13px;padding:7px 10px}main{padding:0 16px 50px}.hero{padding:48px 0 32px}.hero-copy{font-size:16px}.mode-tabs{margin-bottom:34px}.mode-tab{font-size:13px;padding:10px 5px}.mode-tab span{display:none}.number-choices{grid-template-columns:repeat(5,1fr)}.learn-grid,.practice-layout{grid-template-columns:1fr}.panel-heading.split{align-items:stretch;flex-direction:column}.select-wrap select{width:100%}.facts-list{grid-template-columns:1fr}.table-card,.tip-card,.quiz-card,.stats-card,.challenge-card{border-radius:17px}.table-card,.quiz-card,.challenge-card{padding:22px}.equation{gap:11px;padding:35px 4px}.answer-row{flex-direction:column}.answer-row .primary-btn{width:100%}}
@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;animation:none!important;transition:none!important}}
.round-review{text-align:left;margin:30px 0;padding-top:24px;border-top:1px solid var(--line)}.round-review h4{font-size:18px;margin:0 0 14px}.round-review ul{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:9px}.round-item{display:grid;grid-template-columns:24px 1fr;gap:1px 8px;padding:11px 12px;border:1px solid var(--line);border-radius:11px;background:#f8fafc}.round-item span:last-child{grid-column:2;font-size:12px;color:var(--muted)}.round-item.right{border-left:4px solid var(--green)}.round-item.wrong{border-left:4px solid var(--red)}.round-item.unanswered{border-left:4px solid #9aa8ba}.round-number{color:var(--muted);font-size:13px}
@media(max-width:760px){.round-review ul{grid-template-columns:1fr}}