@import "https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&display=swap";
*,:before,:after{box-sizing:border-box;margin:0;padding:0}:root{--primary:#2563eb;--primary-dark:#1d4ed8;--primary-light:#eff6ff;--primary-xlight:#dbeafe;--success:#16a34a;--success-light:#dcfce7;--gray-50:#f8fafc;--gray-100:#f1f5f9;--gray-200:#e2e8f0;--gray-300:#cbd5e1;--gray-400:#94a3b8;--gray-500:#64748b;--gray-600:#475569;--gray-700:#334155;--gray-800:#1e293b;--gray-900:#0f172a;--shadow-sm:0 2px 8px #00000012;--shadow-md:0 4px 16px #0000001a;--r-sm:8px;--r-md:12px;--r-lg:16px;--ease:.18s cubic-bezier(.4,0,.2,1)}body{background:var(--gray-100);color:var(--gray-800);font-family:Inter,-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Arial,sans-serif;line-height:1.6}header{color:#fff;z-index:200;background:linear-gradient(135deg,#1e40af 0%,#2563eb 60%,#3b82f6 100%);justify-content:center;align-items:center;width:100%;height:64px;margin:0;padding:0 20px;display:flex;position:sticky;top:0;box-shadow:0 2px 12px #2563eb4d}.floating-home-symbol{z-index:250;color:#fff;cursor:pointer;background:#ffffff38;border:1px solid #ffffff59;border-radius:12px;padding:8px 12px;font-size:26px;font-weight:700;line-height:1;text-decoration:none;transition:transform .15s,background .15s,box-shadow .15s;position:absolute;top:50%;left:12px;transform:translateY(-50%);box-shadow:0 4px 14px #00000040,inset 0 1px #ffffff59}.floating-home-symbol:hover{background:#ffffff59;transform:translateY(-50%)scale(1.08);box-shadow:0 6px 18px #0000004d}.site-header{justify-content:center;align-items:center;width:100%;padding:0 12px;display:flex;position:relative}.site-header span,.site-header h1,.site-header .title{letter-spacing:1.2px;text-transform:uppercase;background:linear-gradient(135deg,#ffffff47,#ffffff1a);border:1px solid #ffffff59;border-radius:10px;padding:6px 14px;font-size:24px;font-weight:900;box-shadow:0 4px 18px #00000040,inset 0 1px #ffffff59}.site-header .title{text-align:center;white-space:nowrap;position:absolute;left:50%;transform:translate(-50%)}.auth-btn{color:#fff;transition:var(--ease);-webkit-backdrop-filter:blur(4px);backdrop-filter:blur(4px);background:#ffffff2e;border:1px solid #ffffff40;border-radius:99px;padding:7px 14px;font-size:14px;font-weight:500;text-decoration:none;position:absolute;top:50%;right:12px;transform:translateY(-50%)}.auth-btn:hover{background:#ffffff4d}.page-wrapper{padding:0 16px 24px}.container{max-width:900px;margin:0 auto}.card{border-radius:var(--r-lg);border:1px solid var(--gray-200);box-shadow:var(--shadow-sm);background:#fff;margin-bottom:18px;padding:24px}.subject-title{color:var(--gray-900);margin-bottom:6px;font-size:26px;font-weight:700}.topic-subtitle{color:var(--primary);margin-bottom:18px;font-size:15px;font-weight:500}.question-text{margin-bottom:10px;font-size:19px;font-weight:600}.exam-info{color:var(--gray-500);margin-bottom:20px;font-size:13px}.option-card{border:1.5px solid var(--gray-200);border-radius:var(--r-sm);transition:all var(--ease);background:#fff;margin-bottom:10px;padding:14px 16px}.option-card:hover{border-color:var(--primary-xlight);background:var(--primary-light)}.option-correct{background:var(--success-light);border-color:var(--success);font-weight:600;position:relative}.option-correct:after{content:"✓";background:var(--success);color:#fff;border-radius:50%;justify-content:center;align-items:center;width:20px;height:20px;font-size:12px;display:flex;position:absolute;top:50%;right:14px;transform:translateY(-50%)}.answer-highlight{background:var(--success-light);border-left:4px solid var(--success);border-radius:var(--r-sm);margin-top:14px;padding:14px 18px;font-weight:600}.explanation-card{background:var(--gray-50);border-left:4px solid var(--primary);border-radius:var(--r-sm);margin-top:18px;padding:18px}.explanation-title{color:var(--gray-900);margin-bottom:6px;font-weight:700}.explanation-text{color:var(--gray-700);line-height:1.7}.cta-practice{background:var(--primary);color:#fff;border-radius:var(--r-sm);transition:background var(--ease);margin-top:24px;padding:12px 22px;font-weight:600;text-decoration:none;display:inline-block}.cta-practice:hover{background:var(--primary-dark)}.breadcrumb{color:var(--gray-500);margin-bottom:12px;font-size:13px}.options-list{margin-bottom:25px;padding:0;list-style:none}.answer-box{background:var(--success-light);border-left:4px solid var(--success);border-radius:var(--r-sm);margin-bottom:15px;padding:10px 14px;font-weight:600}.cta-wrapper{text-align:center;margin-top:30px}.css #bottomNav{border-bottom:1px solid var(--gray-200);background:#fff;justify-content:space-around;align-items:center;width:100%;padding:10px 0;font-size:14px;display:flex}#bottomNav a{color:var(--gray-500);transition:color var(--ease);padding:6px 8px;font-weight:500;text-decoration:none}#bottomNav a:hover{color:var(--primary)}