*{box-sizing:border-box}body{margin:0;font-family:Inter,system-ui,-apple-system,Segoe UI,Roboto,Arial,sans-serif;background:#eef6fb;color:#173042;line-height:1.55}.top{position:sticky;top:0;z-index:50;background:#fff;border-bottom:1px solid #d8e5ee;box-shadow:0 3px 18px #12304a12}.nav{max-width:1250px;margin:auto;padding:10px 16px;min-height:62px;display:flex;align-items:center;justify-content:space-between}.brand{font-size:1.2rem;font-weight:900;color:#1769aa}.ds{display:inline-grid;place-items:center;background:#1769aa;color:#fff;border-radius:10px;width:40px;height:40px;margin-right:7px}.dot{color:#f0a11a}.badge,.eyebrow{font-weight:800;color:#1769aa;font-size:.78rem}.hero{max-width:1250px;margin:22px auto;padding:25px 16px;display:grid;grid-template-columns:1fr 310px;gap:20px;align-items:center}.hero h1{font-size:clamp(2rem,5vw,4rem);line-height:1.05;margin:8px 0}.hero h1 strong{color:#1769aa}.hero p{max-width:800px;color:#5d7182;font-size:1.05rem}.hero-card{background:linear-gradient(145deg,#1769aa,#12304a);color:#fff;border-radius:20px;padding:20px;display:grid;grid-template-columns:1fr 1fr;gap:6px 12px;box-shadow:0 16px 35px #12304a2a}.hero-card b{font-size:1.6rem}.hero-card span{align-self:center;opacity:.85}.panel,.paper-wrap{max-width:1250px;margin:16px auto;padding:20px;background:#fff;border:1px solid #dbe8f1;border-radius:18px;box-shadow:0 10px 28px #12304a10}.panel h2{margin-top:0}.grid{display:grid;grid-template-columns:repeat(3,1fr);gap:12px}.grid.two{grid-template-columns:repeat(2,1fr)}.grid.four{grid-template-columns:repeat(4,1fr)}.field{display:flex;flex-direction:column;gap:5px}.field.full{grid-column:1/-1}.field label{font-size:.82rem;font-weight:800;color:#516879}.field input,.field select{width:100%;padding:11px 12px;border:1px solid #cbdce7;border-radius:10px;background:#fbfdff;font:inherit}.checks,.topics{display:grid;grid-template-columns:repeat(2,1fr);gap:8px}.check{padding:10px;border:1px solid #dce7ee;border-radius:11px;background:#f8fbfd}.check input{margin-right:7px}.subtopic{font-size:.86rem;padding:8px 10px;border:1px solid #e2ebf0;border-radius:9px;background:#fff}.section-config{margin-top:18px;padding:15px;border:1px solid #dce8ef;border-radius:14px;background:#f8fbfd}.actions{display:flex;flex-wrap:wrap;gap:9px;margin-top:18px}.actions button{border:0;border-radius:11px;padding:11px 15px;font-weight:800;cursor:pointer}.primary{background:#1769aa;color:#fff}.secondary{background:#e8f1f7;color:#173042}.dark{background:#173042;color:#fff}.danger{background:#fff0f0;color:#a72f2f}.paper{background:#fff;max-width:850px;margin:auto;padding:38px;box-shadow:0 0 0 1px #d7e1e8,0 10px 25px #12304a12}.paper-head{text-align:center;border-bottom:2px solid #173042;padding-bottom:15px;margin-bottom:18px}.paper-head h2{margin:4px 0}.meta{display:flex;justify-content:space-between;gap:10px;flex-wrap:wrap;font-size:.9rem}.sec-title{background:#173042;color:#fff;padding:8px 12px;margin:24px 0 12px;font-weight:900}.q{padding:13px 0;border-bottom:1px dashed #cfdde5}.qtext{font-weight:650}.answer{display:none;margin-top:9px;padding:10px;border-left:4px solid #1769aa;background:#eef7ff}.answer.show{display:block}.q button{margin-top:8px;border:1px solid #b8d0df;background:#fff;border-radius:8px;padding:7px 10px;cursor:pointer;font-weight:700}.mcq{margin:8px 0 0 18px}.guide h3{color:#1769aa}.guide .chapter{padding:14px;border:1px solid #dfebf2;border-radius:13px;margin:10px 0;background:#fbfdff}.guide .formula{background:#eef7ff;border-left:4px solid #1769aa;padding:10px;margin:8px 0}.empty{padding:30px;text-align:center;color:#607587}footer{text-align:center;padding:28px;color:#5e7384}@media(max-width:800px){.hero{grid-template-columns:1fr;padding:18px 12px}.grid,.grid.four,.checks,.topics{grid-template-columns:1fr}.grid.two{grid-template-columns:1fr}.panel,.paper-wrap{margin:10px 8px;padding:14px}.paper{padding:20px 15px}.nav{padding:8px 10px}.badge{display:none}.actions button{width:100%}}@media print{body{background:#fff}.top,.hero,.controls,.guide,footer{display:none!important}.paper-wrap{border:0;box-shadow:none;margin:0;padding:0}.paper{box-shadow:none;max-width:none}.answer{display:block!important}.q button{display:none}}

.mcqopt{display:block;padding:7px 9px;margin:5px 0;border:1px solid #dce7ee;border-radius:8px;background:#fff;cursor:pointer}
.mcqopt:hover{background:#f4faff}
.mcq-check{margin-top:8px!important;background:#1769aa!important;color:#fff;border:0!important}
.mcq-feedback{margin-top:7px;font-weight:800}
.mcq-feedback.ok{color:#16834b}.mcq-feedback.bad{color:#b02a2a}
.answer{display:none!important}.answer.show{display:block!important}