:root{--blue:#00a8e8;--blue-dark:#0078b5;--ink:#17232d;--muted:#697883;--bg:#f3f7f9;--card:#fff;--line:#dfe8ec;--green:#20a56b;--red:#e14e54;--shadow:0 18px 55px rgba(20,54,70,.12)}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--ink);font:15px/1.6 Arial,sans-serif;transition:.25s}body.dark{--ink:#e8f0f3;--muted:#a9b9c1;--bg:#101a20;--card:#18262e;--line:#2e414b;--shadow:0 18px 55px rgba(0,0,0,.3)}h1,h2,h3,p{margin-top:0}a{text-decoration:none;color:inherit}.site-header{height:78px;padding:0 max(5vw,24px);display:flex;align-items:center;justify-content:space-between;background:var(--card);border-bottom:1px solid var(--line)}.brand{display:flex;align-items:center;gap:11px;font-size:18px;font-weight:800;text-transform:uppercase;letter-spacing:.8px}.brand-mark{display:grid;place-items:center;width:38px;height:38px;background:var(--blue);color:white;font-size:14px}.theme-toggle{width:42px;height:42px;border:1px solid var(--line);background:transparent;color:var(--ink);border-radius:50%;font-size:20px;cursor:pointer}.header-actions{display:flex;align-items:center;gap:14px}.student-chip{color:var(--muted)}.hero{min-height:610px;padding:80px max(7vw,28px);display:grid;grid-template-columns:1.15fr .85fr;gap:8vw;align-items:center;background:linear-gradient(115deg,rgba(0,168,232,.96),rgba(0,106,158,.9)),url('../img/bg_sub-header.png') center/cover;color:white}.eyebrow{display:inline-block;text-transform:uppercase;letter-spacing:2.5px;font-size:30px;font-weight:800;color:var(--blue)}.hero .eyebrow{color:#d9f6ff}.hero h1,.quiz-top h1,.result-hero h1{font-size:clamp(42px,6vw,76px);line-height:1.02;margin:14px 0 25px;text-transform:uppercase;letter-spacing:-2px}.hero h1 em{font-style:normal;color:#a9eaff}.hero-copy>p{max-width:610px;font-size:18px;color:#e4f7ff}.hero-stats{display:flex;gap:45px;margin-top:45px}.hero-stats div{display:flex;flex-direction:column}.hero-stats strong{font-size:25px}.hero-stats span{font-size:12px;text-transform:uppercase;letter-spacing:1px}.start-card{background:var(--card);color:var(--ink);padding:36px;box-shadow:var(--shadow)}.card-heading{display:flex;gap:16px;border-bottom:1px solid var(--line);padding-bottom:22px;margin-bottom:24px}.number-badge{display:grid;place-items:center;width:44px;height:44px;background:#dcf5ff;color:var(--blue-dark);font-weight:bold}.card-heading h2{font-size:23px;margin:0}.card-heading p,.form-note{color:var(--muted);margin:2px 0 0}label{display:block;text-transform:uppercase;letter-spacing:.7px;font-size:11px;font-weight:bold;margin-bottom:17px}input,select{width:100%;margin-top:7px;padding:14px;border:1px solid var(--line);background:var(--bg);color:var(--ink);font-size:15px;outline:none}input:focus,select:focus{border-color:var(--blue);box-shadow:0 0 0 3px rgba(0,168,232,.13)}button,.primary-btn,.secondary-btn{font:inherit}.primary-btn,.secondary-btn{display:inline-flex;justify-content:center;align-items:center;gap:16px;padding:14px 22px;border:0;cursor:pointer;font-weight:bold}.primary-btn{background:var(--blue);color:white}.primary-btn:hover{background:var(--blue-dark)}.secondary-btn{background:var(--card);color:var(--ink);border:1px solid var(--line)}form .primary-btn{width:100%;margin-top:6px}.form-note{text-align:center;font-size:12px;margin-top:14px}.features{display:grid;grid-template-columns:repeat(3,1fr);gap:45px;padding:70px max(7vw,28px);background:var(--card)}.features article>span{color:var(--blue);font-weight:bold}.features h3{margin:9px 0;font-size:20px}.features p{color:var(--muted)}footer{text-align:center;padding:28px;color:var(--muted);background:var(--card);border-top:1px solid var(--line)}.quiz-shell,.result-shell{max-width:1050px;margin:auto;padding:55px 24px 80px}.quiz-top{display:flex;justify-content:space-between;align-items:end}.quiz-top h1{font-size:42px;margin:8px 0 0}.timer{padding:13px 22px;background:var(--card);border-left:4px solid var(--blue);box-shadow:var(--shadow)}.timer small{display:block;color:var(--muted);text-transform:uppercase}.timer strong{font-size:24px}.timer.danger{border-color:var(--red);color:var(--red)}.progress-wrap{margin:30px 0}.progress-copy{display:flex;justify-content:space-between;color:var(--muted);font-size:13px}.progress-track{height:7px;background:var(--line);margin-top:9px;overflow:hidden}.progress-track div{height:100%;background:var(--blue);transition:.3s}.question-card{background:var(--card);padding:42px;box-shadow:var(--shadow);min-height:400px}.question-meta{display:flex;align-items:center;gap:14px;color:var(--muted);font-size:12px;text-transform:uppercase;letter-spacing:1px}.question-meta span:first-child{display:grid;place-items:center;width:40px;height:40px;background:var(--blue);color:white;font-weight:bold;font-size:15px}.question-card h2{font-size:26px;margin:28px 0}.options{display:grid;grid-template-columns:1fr 1fr;gap:13px}.option{display:flex;align-items:center;gap:15px;padding:16px;border:1px solid var(--line);background:var(--bg);cursor:pointer;text-align:left;color:var(--ink)}.option:hover{border-color:var(--blue)}.option.selected{border-color:var(--blue);background:rgba(0,168,232,.1)}.option-letter{display:grid;place-items:center;flex:0 0 32px;height:32px;border:1px solid var(--line);background:var(--card);font-weight:bold}.option.selected .option-letter{background:var(--blue);color:white}.quiz-actions{display:flex;justify-content:space-between;margin-top:24px}.warning{min-height:24px;color:var(--red);margin:14px 0 0}.modal{position:fixed;inset:0;display:none;place-items:center;padding:20px;background:rgba(6,17,23,.7);z-index:10}.modal.open{display:grid}.modal-box{max-width:460px;padding:38px;background:var(--card);text-align:center;box-shadow:var(--shadow)}.modal-icon{display:grid;place-items:center;width:55px;height:55px;margin:0 auto 18px;border-radius:50%;background:#dcf7ec;color:var(--green);font-size:25px}.modal-box div{display:flex;gap:10px;justify-content:center}.result-hero{text-align:center;padding:35px}.result-hero h1{font-size:52px;margin-bottom:10px}
    .result-hero > p {
        color: var(--muted);
        font-size: 30px;
    }.score-ring{display:grid;place-items:center;width:220px;height:220px;border-radius:50%;margin:30px auto;background:conic-gradient(var(--blue) var(--score,0%),var(--line) 0);position:relative}.score-ring:before{content:'';position:absolute;inset:14px;background:var(--card);border-radius:50%}.score-ring div{position:relative;display:flex;flex-direction:column}.score-ring strong{font-size:50px;line-height:1}.score-ring span{color:var(--muted)}.grade-pill{display:inline-block;padding:8px 22px;background:var(--ink);color:var(--card);font-weight:bold}.best-score{margin:14px!important}.result-actions{display:flex;justify-content:center;gap:10px}.review-section{margin-top:45px}.section-title{display:flex;justify-content:space-between;align-items:end;margin-bottom:22px}.section-title h2{font-size:30px;margin:5px 0}.legend{display:flex;gap:15px;color:var(--muted)}.legend i{display:inline-block;width:9px;height:9px;border-radius:50%;margin-right:5px}.correct-dot{background:var(--green)}.wrong-dot{background:var(--red)}.review-item{background:var(--card);padding:25px;margin-bottom:12px;border-left:4px solid var(--red)}.review-item.correct{border-color:var(--green)}.review-item h3{margin-bottom:12px}.review-item p{margin:4px 0;color:var(--muted)}.review-item strong{color:var(--ink)}
@media(max-width:760px){.hero{grid-template-columns:1fr;padding-top:55px}.hero h1{font-size:46px}.hero-stats{gap:25px}.features{grid-template-columns:1fr;gap:20px}.student-chip{display:none}.quiz-top{align-items:center}.quiz-top h1{font-size:30px}.question-card{padding:25px}.options{grid-template-columns:1fr}.section-title{display:block}.legend{margin-top:12px}.result-hero h1{font-size:40px}}@media(max-width:440px){.hero-stats{justify-content:space-between;gap:8px}.start-card{padding:24px}.quiz-shell{padding:35px 15px}.timer{padding:9px 13px}.quiz-actions .primary-btn,.quiz-actions .secondary-btn{padding:12px;font-size:13px}.modal-box div,.result-actions{flex-direction:column}}