:root{--navy:#13365d;--ink:#172c42;--blue:#1c7896;--teal:#0a9c9a;--sky:#edf6fc;--mist:#f5f8fc;--line:#dde7ee;--muted:#66798c;--white:#fff;--success:#18835e;--fail:#bc4a48;--shadow:0 10px 32px #12315d09;font-family:Inter,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;color:var(--ink);background:var(--mist);font-size:15px}
*{box-sizing:border-box}body{margin:0;min-height:100vh}button{font:inherit;cursor:pointer}button:disabled{cursor:not-allowed;opacity:.53}a{color:var(--blue)}.wrap{max-width:1120px;margin:0 auto;padding-left:24px;padding-right:24px}.site-header{background:var(--white);border-bottom:1px solid var(--line)}.header-inner{height:83px;display:flex;justify-content:space-between;align-items:center;gap:16px}.brand{display:flex;align-items:center;gap:13px;text-decoration:none;color:var(--navy);font-size:23px;font-weight:850;letter-spacing:-.9px;line-height:1}.brand em{font-style:normal;color:#16839d}.brand small{display:block;font-weight:750;font-size:10px;text-transform:uppercase;letter-spacing:2px;color:#758a9b;margin-top:6px}.brand-mark{width:45px;height:45px;background:#123c6a;color:#fff;border-radius:13px;display:grid;place-items:center;font-size:25px;letter-spacing:-2px}.brand-mark span{color:#42d4ca}.header-right{display:flex;align-items:center;gap:18px}.version-mark{font-size:11px;color:#607d92;background:#edf5f9;padding:8px 12px;border-radius:999px;font-weight:700}.header-home{text-decoration:none;font-weight:750;font-size:14px}.site-footer{display:flex;gap:16px;justify-content:space-between;flex-wrap:wrap;padding-top:62px;padding-bottom:24px;color:#8696a6;font-size:12px}.hero{padding:53px 0 22px}.eyebrow{font-size:11px;letter-spacing:1.7px;text-transform:uppercase;color:var(--blue);font-weight:800;margin-bottom:11px}h1{font-size:clamp(32px,5vw,48px);letter-spacing:-1.5px;line-height:1.14;margin:5px 0 13px;color:var(--navy)}h2{font-size:25px;letter-spacing:-.65px;color:var(--navy);margin:0 0 14px}h3{margin:10px 0;font-size:19px;color:var(--navy)}p{color:#54677b;line-height:1.6;margin:10px 0}.lead{max-width:730px;font-size:17px}.hero-cta{display:flex;gap:12px;flex-wrap:wrap;margin-top:25px}.stat-row{display:flex;gap:14px;flex-wrap:wrap;margin:28px 0 32px}.stat{background:#fff;border:1px solid var(--line);border-radius:13px;padding:13px 21px;min-width:137px}.stat strong{display:block;font-size:23px;color:var(--navy)}.stat span{font-size:12px;color:var(--muted)}.subject-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:15px;margin:20px 0 32px}.card,.panel{background:var(--white);border:1px solid var(--line);border-radius:18px;box-shadow:var(--shadow)}.card{padding:22px;display:flex;flex-direction:column;min-height:228px}.card h3{margin:14px 0 4px}.card p{font-size:13px;flex:1}.card .subject-icon{display:grid;place-items:center;width:50px;height:50px;background:#ebf5fa;border-radius:12px;font-size:28px}.card .btn{margin-top:14px;align-self:flex-start}.card.muted-card{box-shadow:none;background:#fcfdff}.card.muted-card .subject-icon{background:#f0f3f6}.btn{border:0;border-radius:10px;background:var(--navy);color:#fff;padding:12px 17px;font-weight:760;display:inline-flex;align-items:center;justify-content:center;text-decoration:none;gap:7px;line-height:1.2}.btn:hover:not(:disabled){background:#215287}.btn.secondary{color:#1b567f;background:#eaf3f9}.btn.secondary:hover:not(:disabled){background:#dcebf5}.btn.outline{background:#fff;color:#214b6d;border:1px solid #cbdce9}.btn.outline:hover:not(:disabled){background:#f3f8fc}.btn.small{font-size:13px;padding:9px 13px}.btn.full{width:100%}.link-button{border:0;background:none;color:var(--blue);font-weight:770;padding:6px 0}.breadcrumb{display:flex;align-items:center;gap:9px;flex-wrap:wrap;padding:29px 0 18px;color:#7d8b99;font-size:13px}.breadcrumb button{border:none;background:none;color:#457493;font:inherit;font-weight:700;padding:0}.breadcrumb strong{color:#34516a;font-weight:700}.section-header{padding:8px 0 10px}.section-header p{max-width:780px}.topics{display:grid;gap:11px;margin:22px 0}.topic-row{background:#fff;border:1px solid var(--line);border-radius:14px;display:flex;justify-content:space-between;align-items:center;gap:15px;padding:17px 20px}.topic-row h3{font-size:16px;margin:0 0 5px}.topic-row p{margin:0;font-size:13px;color:var(--muted)}.topic-row .topic-right{display:flex;align-items:center;gap:12px;flex-shrink:0}.topic-row.pending{background:#fbfcfd;box-shadow:none}.count-pill{display:inline-flex;align-items:center;padding:5px 9px;border-radius:999px;background:#e8f4f6;color:#116c76;font-weight:800;font-size:11px;white-space:nowrap}.count-pill.gray{background:#eef1f4;color:#8594a1}.three-cols{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:17px;margin-top:24px}.mode-card{padding:25px;display:flex;flex-direction:column;gap:8px;border-top:4px solid var(--teal)}.mode-card .mode-icon{font-size:31px}.mode-card h3{margin:5px 0 0}.mode-card p{flex:1;font-size:14px}.notice{background:#edf5f9;border:1px solid #d9e8f2;border-radius:13px;padding:15px 18px;color:#486780;line-height:1.55;font-size:13px;margin:20px 0}.notice.success{border-color:#c7e8dc;background:#ecfaf4;color:#19674d}.notice.error{border-color:#f0cacc;background:#fff1f1;color:#944548}.panel{padding:26px}.lesson-panel{padding:20px;min-height:490px}.lesson-panel iframe{display:block;width:100%;height:clamp(390px,68vw,690px);border:1px solid #dde7ec;border-radius:12px;background:#f2f5f7}.mode-head{display:flex;justify-content:space-between;align-items:center;flex-wrap:wrap;gap:12px;margin:12px 0 17px}.mode-head h2{margin:0}.question-panel{padding:26px}.source-label{color:#8294a4;text-transform:uppercase;letter-spacing:1.1px;font-size:10px;font-weight:750}.question-figure{background:#fff;border:1px solid #e6ecf0;border-radius:11px;overflow:hidden;margin:18px 0 13px}.question-figure img{display:block;width:100%;height:auto}.zoom-row{display:flex;justify-content:flex-end}.question-options{display:grid;grid-template-columns:repeat(5,1fr);gap:10px;margin:20px 0}.option-button{padding:15px 9px;border:2px solid #d6e3eb;background:#fff;border-radius:12px;font-size:17px;font-weight:820;color:#294560;text-align:center;cursor:pointer}.option-button:hover:not(:disabled){border-color:#61a6c6}.option-button.is-selected{background:#edf8fc;border-color:#1d82a0;color:#125775}.option-button.is-correct{background:#e5f7ed;border-color:#199065;color:#14684a}.option-button.is-incorrect{background:#fff1ef;border-color:#c45a52;color:#983d36}.option-button:focus-visible,.btn:focus-visible,a:focus-visible,button:focus-visible{outline:3px solid #79bdd5;outline-offset:2px}.question-progress{height:8px;border-radius:999px;background:#e1eaf0;overflow:hidden;margin:17px 0 27px}.question-progress>span{height:100%;display:block;background:linear-gradient(90deg,#166c93,#1ca4a1);border-radius:999px;transition:width .18s}.actions-row{display:flex;justify-content:space-between;align-items:center;flex-wrap:wrap;gap:12px;margin-top:20px}.answer-note{margin:18px 0;padding:19px;border:1px solid #cde8d7;background:#f0faf5;border-radius:12px}.answer-note.incorrect{background:#fff4f2;border-color:#f0d0ca}.answer-note strong{color:#22513b}.answer-note.incorrect strong{color:#923f38}.answer-note p{margin:7px 0 0;color:#334e43}.answer-note.incorrect p{color:#5c4543}.result-score{font-size:50px;color:var(--navy);font-weight:900;line-height:1.15;margin:5px 0}.review-item{padding:17px 20px;background:#fff;border:1px solid var(--line);border-radius:13px;margin:10px 0}.review-item summary{display:flex;justify-content:space-between;align-items:center;gap:14px;cursor:pointer;list-style:none;font-weight:720}.review-item summary::-webkit-details-marker{display:none}.review-item summary:after{content:'⌄';color:#57778e;font-size:24px}.review-item[open] summary:after{content:'⌃'}.review-item img{width:100%;border:1px solid #e1e6ec;margin-top:15px;border-radius:10px}.review-item p{margin-top:8px}.review-item .result-icon{white-space:nowrap}.review-item .result-icon.ok{color:var(--success)}.review-item .result-icon.no{color:var(--fail)}.loading{padding:100px 0;color:var(--muted);text-align:center}.empty-panel{background:#fff;border:1px dashed #cbdbe6;border-radius:15px;padding:30px;margin:22px 0}.empty-panel h3{margin-top:0}.section-split{margin-top:42px}.icon-button{border:0;border-radius:9px;padding:9px 12px;background:#e7edf4;color:#34526c}dialog{width:min(95vw,1200px);max-height:93vh;border:0;border-radius:16px;box-shadow:0 15px 90px #0004;padding:16px;background:#fff}dialog::backdrop{background:#112b4299}dialog img{width:100%;height:auto}dialog p{font-size:12px;margin:8px}.zoom-top{display:flex;align-items:center;justify-content:space-between;margin-bottom:10px}.sr-only{border:0;clip:rect(0,0,0,0);height:1px;width:1px;overflow:hidden;position:absolute;white-space:nowrap}
@media(max-width:950px){.subject-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.three-cols{grid-template-columns:repeat(2,minmax(0,1fr))}.three-cols .mode-card:last-child{grid-column:1/-1}}
@media(max-width:630px){.wrap{padding-left:16px;padding-right:16px}.header-inner{height:72px}.brand{font-size:20px}.brand-mark{width:38px;height:38px}.version-mark{display:none}.hero{padding:37px 0 15px}h1{font-size:32px}.subject-grid{grid-template-columns:1fr 1fr;gap:10px}.subject-grid .card{padding:16px;min-height:220px}.card h3{font-size:16px}.three-cols{grid-template-columns:1fr}.three-cols .mode-card:last-child{grid-column:auto}.panel,.question-panel{padding:17px}.question-options{gap:7px}.option-button{padding:14px 5px}.topic-row{padding:14px;align-items:flex-start}.topic-row .topic-right{flex-direction:column;align-items:flex-end}.topic-row h3{font-size:15px}.site-footer{padding-top:34px}.stat{min-width:0;flex:1;padding:11px}.stat strong{font-size:21px}.lesson-panel iframe{height:430px}}
/* Mobile-friendly text rendering supplements original image questions. */
.mobile-prompt{display:none}.option-text{display:none}.option-letter{font-weight:850}
@media(max-width:630px){
 .mobile-prompt{display:block;font-size:16px;font-weight:720;color:#1f3852;line-height:1.55}
 .mobile-prompt:empty{display:none}
 .question-figure{overflow-x:auto;overscroll-behavior-x:contain;scrollbar-color:#80adbd #f4f8fa}
 .question-figure img{width:720px;max-width:none}
 .question-options.has-labels{grid-template-columns:1fr}
 .question-options.has-labels .option-button{display:flex;align-items:center;justify-content:flex-start;gap:14px;padding:12px 14px;text-align:left;font-size:14px;min-height:49px}
 .question-options.has-labels .option-letter{font-size:17px;flex:0 0 22px}
 .question-options.has-labels .option-text{display:inline;font-size:15px;line-height:1.35;font-weight:570}
 dialog{overflow:auto}
 dialog img{min-width:800px;width:800px;max-width:none}
}