:root{color-scheme:light;--paper:#f5f7fa;--white:#fff;--ink:#16283b;--muted:#556779;--line:#dce3ea;--navy:#102c46;--blue:#1760a2;--accent:#85dfd6;--red:#b32c3b;--green:#14614e}
*{box-sizing:border-box}body{margin:0;background:var(--paper);color:var(--ink);font:16px/1.55 system-ui,-apple-system,sans-serif}a{color:var(--blue)}header{background:#fff;border-bottom:1px solid var(--line)}.bar,main,footer{max-width:1120px;margin:auto;padding:0 28px}.bar{display:flex;justify-content:space-between;align-items:center;min-height:68px;gap:14px}.brand{display:flex;align-items:center;gap:7px;color:var(--ink);font-weight:850;text-decoration:none;white-space:nowrap}.cross{background:var(--navy);color:var(--accent);display:grid;place-items:center;width:34px;height:34px;border-radius:9px;margin-right:4px}.muted,.small{color:var(--muted)}.small{font-size:.87rem}nav{display:flex;gap:22px}nav a{text-decoration:none;font-size:.92rem;font-weight:650}main{min-height:75vh;padding-top:30px;padding-bottom:42px}.hero{background:var(--navy);color:#fff;border-radius:20px;padding:38px;position:relative;overflow:hidden}.hero-copy{position:relative;z-index:1;max-width:600px}.hero p{color:#d7e7f3;max-width:440px}.hero svg{position:absolute;right:0;top:0;height:100%;width:43%;opacity:.85}.kicker{font-size:.72rem;font-weight:850;letter-spacing:.15em;text-transform:uppercase;color:var(--blue);margin:0 0 8px}.hero .kicker{color:var(--accent)}h1,h2,h3,p{margin-top:0}h1{font-size:clamp(2rem,6vw,3.4rem);line-height:1.05;letter-spacing:-.045em;margin-bottom:14px}h2{font-size:1.55rem;letter-spacing:-.025em;margin-bottom:4px}h3{font-size:1.13rem;margin-bottom:5px}.btn,button{font:inherit;font-weight:740;cursor:pointer;border-radius:9px}.btn{display:inline-block;padding:11px 16px;background:var(--blue);color:#fff;text-decoration:none;border:1px solid transparent}.hero .btn{background:var(--accent);color:#102c46}.btn.secondary{background:white;color:var(--blue);border-color:var(--line)}.btn:hover,.mode:hover,.topic:hover{filter:brightness(.96)}:focus-visible{outline:3px solid #168d84;outline-offset:3px}.section{margin-top:26px}.grid,.stats{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px}.stats{margin-top:16px}.stat,.mode,.topic,.panel{background:#fff;border:1px solid var(--line);border-radius:13px;padding:17px}.stat strong{font-size:1.5rem;display:block;line-height:1.25}.mode,.topic{display:block;text-decoration:none;color:var(--ink);text-align:left;width:100%}.mode .small,.topic .small{display:block;font-weight:450}.mode .symbol{color:var(--blue);font-weight:850;margin-bottom:9px;display:block}.topic{padding:12px 15px}.topic strong{display:block}.panel{max-width:760px;margin:16px auto 0;padding:clamp(17px,4vw,32px)}.back{display:inline-block;margin-bottom:12px;text-decoration:none;font-weight:650}.row{display:flex;justify-content:space-between;align-items:center;gap:12px;flex-wrap:wrap}.progress{height:7px;background:#e5edf4;border-radius:20px;overflow:hidden;margin:12px 0 24px}.progress span{display:block;height:100%;background:var(--blue)}.question{font-size:clamp(1.3rem,4vw,1.9rem);line-height:1.25;margin:0 0 18px}.answers{display:grid;gap:9px}.answer{background:#fff;color:var(--ink);border:1px solid #c7d4df;text-align:left;padding:13px 15px;display:flex;align-items:center;gap:12px}.answer:not(:disabled):hover{background:#eef6fc}.answer:disabled{cursor:default}.answer .letter{display:grid;place-items:center;flex:none;width:27px;height:27px;border-radius:6px;background:#eaf1f7;color:var(--navy)}.answer.correct{border-color:#52a18f;background:#eaf8f1}.answer.wrong{border-color:#c57882;background:#fff1f2}.feedback{border-left:4px solid var(--green);padding:12px 14px;margin:16px 0;background:#edf8f3;border-radius:0 9px 9px 0}.feedback.incorrect{border-color:var(--red);background:#fff1f2}.feedback p{margin:5px 0}.actions{display:flex;flex-wrap:wrap;gap:10px;margin-top:16px}.source-list li{margin:10px 0}footer{display:flex;justify-content:space-between;gap:10px;border-top:1px solid var(--line);padding-top:17px;padding-bottom:22px;font-size:.8rem;color:var(--muted)}
@media(max-width:680px){.bar,main,footer{padding-left:16px;padding-right:16px}main{padding-top:17px}.hero{padding:25px 20px}.hero svg{opacity:.22;width:75%}.grid{grid-template-columns:repeat(2,minmax(0,1fr))}.stat{padding:11px}.stat strong{font-size:1.23rem}nav{gap:11px}.brand{gap:4px}.mode,.topic{padding:12px}.stats .small{font-size:.74rem}}@media(max-width:370px){.brand .muted{display:none}.grid{grid-template-columns:1fr}}