*{box-sizing:border-box}body{margin:0;background:#f5f8fd;color:#18243a;font-family:Inter,Segoe UI,Arial,sans-serif;line-height:1.55}header{position:sticky;top:0;z-index:5;background:#fff;border-bottom:1px solid #dfe7f2;box-shadow:0 3px 14px #18243a12}nav{max-width:1180px;margin:auto;padding:9px 16px;display:flex;justify-content:space-between;align-items:center}nav a{margin-left:16px;text-decoration:none;color:#33425e;font-weight:850;font-size:.88rem}.logo{display:flex;align-items:center;margin-left:0!important;color:#15234a;font-weight:950}.logo span{display:grid;place-items:center;width:40px;height:40px;margin-right:9px;border-radius:12px;background:#15234a;color:#fff}.hero{max-width:1180px;margin:20px auto;padding:18px 16px;display:grid;grid-template-columns:205px 1fr;gap:24px;align-items:center}.art{height:170px;border-radius:28px;background:linear-gradient(135deg,#e4efff,#fff3d4);border:1px solid #d9e4f3;position:relative;overflow:hidden;font-size:34px}.art i{position:absolute;background:#fff;padding:5px 9px;border-radius:13px;font-size:18px;font-weight:900;box-shadow:0 5px 14px #18243a20;animation:f 3s infinite}.art i:nth-child(1){left:12px;top:15px}.art i:nth-child(2){right:10px;top:30px}.art i:nth-child(3){right:12px;bottom:16px}.art strong{position:absolute;font-size:72px;left:57px;bottom:3px;animation:b 2.5s infinite}@keyframes b{50%{transform:translateY(-7px)}}@keyframes f{50%{transform:translateY(-6px)}}.hero small{font-weight:950;color:#31509b}.hero h1{font-size:clamp(1.9rem,5vw,3.2rem);line-height:1.03;color:#15234a;margin:7px 0}.hero p{color:#5c6a81;font-size:1.05rem}.hero em{font-style:normal;font-size:.82rem}.panel{max-width:1180px;margin:14px auto;padding:18px;background:#fff;border:1px solid #dfe7f2;border-radius:18px;box-shadow:0 5px 22px #18243a0b}.grid{display:grid;grid-template-columns:repeat(3,1fr);gap:12px}.grid label{font-size:.86rem;font-weight:850;color:#3d4c66}.grid select{display:block;width:100%;margin-top:5px;padding:11px;border:1px solid #cad6e6;border-radius:10px;background:#fff;font:inherit}.actions{display:flex;flex-wrap:wrap;gap:9px;margin-top:15px}.actions button,.check,.show{border:0;border-radius:10px;padding:11px 14px;background:#edf2f9;color:#253654;font-weight:900;cursor:pointer}.actions .primary{background:#15234a;color:#fff}.note{margin-top:12px;background:#fff7da;border:1px solid #efd991;border-radius:10px;padding:10px}.stats{display:grid;grid-template-columns:repeat(4,1fr);gap:10px;text-align:center}.stats div{background:#f7f9fd;border-radius:12px;padding:9px}.stats b{display:block;font-size:1.3rem;color:#15234a}.stats small{color:#69768a}.progress{max-width:1180px;height:10px;margin:8px auto;background:#dce5f2;border-radius:99px;overflow:hidden}.progress span{display:block;height:100%;width:0;background:#15234a;transition:.3s}.qcard{max-width:1180px;margin:14px auto;padding:16px;background:#fff;border:1px solid #dfe7f2;border-radius:17px;box-shadow:0 4px 18px #18243a09}.qcard.correct{border-color:#299b56;animation:ok .45s}.qcard.wrong{border-color:#d9534f;animation:no .4s}@keyframes ok{50%{transform:scale(1.01)}}@keyframes no{25%,75%{transform:translateX(-5px)}50%{transform:translateX(5px)}}.qhead{display:flex;justify-content:space-between}.qnum{font-weight:950;color:#15234a}.tag,.subtopic{font-size:.72rem;color:#65738a}.tag{background:#edf2f9;padding:4px 8px;border-radius:99px}.qtext{font-size:1.02rem;font-weight:750;margin:9px 0}.subparts{background:#fafcff;border-left:4px solid #d5e0ef;padding:9px 11px;margin:8px 0}.choices{display:grid;grid-template-columns:1fr 1fr;gap:8px}.choice{padding:11px;text-align:left;border:1px solid #ccd7e7;border-radius:10px;background:#fff;font-weight:750;cursor:pointer}.choice.selected{outline:3px solid #dbe5ff;background:#f1f5ff}.answer{width:100%;padding:11px;border:2px solid #ccd7e7;border-radius:10px;font:inherit}.correct-input{border-color:#299b56;background:#eaf8ef}.wrong-input{border-color:#d9534f;background:#fff0ef}.feedback{min-height:24px;margin-top:8px;font-weight:900}.good{color:#19743b}.bad{color:#a52824}.show-answer{display:none;background:#f4f7fb;border-radius:10px;padding:9px;margin-top:8px}.result{text-align:center;background:#edf8f0;border-color:#b8dfc3}.hidden{display:none}.guide h2{color:#15234a}.guide h3{color:#304c79;margin-bottom:4px}.guide p,.guide li{font-size:.96rem}.formula{display:inline-block;background:#fff0a8;border:1px solid #e8cf63;border-radius:7px;padding:1px 7px;font-weight:900;color:#4c3a00}footer{text-align:center;padding:24px;color:#6b778b;font-size:.84rem}@media(max-width:720px){.hero{grid-template-columns:1fr;padding:15px}.art{height:135px}.art strong{font-size:60px;left:42%}.grid{grid-template-columns:1fr 1fr}.stats{grid-template-columns:1fr 1fr}.choices{grid-template-columns:1fr}.actions button{flex:1 1 45%}.panel{margin:10px 9px;padding:14px}.progress{margin:8px 9px}.qcard{margin:10px 9px;padding:13px}nav{padding:8px 10px}.logo span{width:34px;height:34px}nav a{font-size:.76rem;margin-left:8px}}@media(max-width:420px){.grid{grid-template-columns:1fr}.actions button{flex-basis:100%}}@media print{header,.hero,.controls,.stats,.progress,.guide,footer,.check,.show,.feedback{display:none!important}.qcard{box-shadow:none;break-inside:avoid;max-width:none}}