:root{--bg:#f4f7fb;--card:#fff;--ink:#172033;--muted:#5d6b82;--brand:#0a5e75;--brand2:#0f8aa4;--line:#dce5ee;--soft:#eaf6f9;--bad:#b42318;--good:#157347;--warn:#9a6700;--shadow:0 18px 50px rgba(23,32,51,.10);--radius:22px}*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;font-family:Inter,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;color:var(--ink);background:radial-gradient(circle at top left,#d8f2f7 0,#f4f7fb 34rem)}.app-shell{max-width:1180px;margin:0 auto;padding:22px 16px 94px}.hero{display:grid;grid-template-columns:160px 1fr 270px;gap:18px;align-items:center;background:linear-gradient(135deg,#08394b,#0a6e86);color:#fff;border-radius:28px;padding:22px;box-shadow:var(--shadow);overflow:hidden;position:relative}.hero:after{content:"";position:absolute;right:-80px;top:-80px;width:240px;height:240px;border:2px solid rgba(255,255,255,.16);border-radius:50%}.brand-row{display:flex;gap:12px;align-items:center}.logo-card{background:#fff;color:#08394b;border-radius:18px;padding:12px;min-height:96px;width:94px;display:flex;flex-direction:column;justify-content:center;text-align:center;box-shadow:0 10px 25px rgba(0,0,0,.12)}.logo-card span{font-weight:900;font-size:26px;letter-spacing:.05em}.logo-card small{font-size:10px;line-height:1.15}.atom-mark svg{width:64px;height:64px;fill:none;stroke:#fff;stroke-width:3}.atom-mark svg circle{fill:#fff;stroke:none}.eyebrow{text-transform:uppercase;letter-spacing:.12em;font-size:12px;font-weight:700;opacity:.82;margin:0 0 8px}.hero h1{margin:0;font-size:clamp(30px,5vw,50px);line-height:1}.subtitle{margin:10px 0 0;max-width:680px;color:#d9f5fb}.attempt-card{background:rgba(255,255,255,.12);border:1px solid rgba(255,255,255,.25);border-radius:20px;padding:16px;backdrop-filter:blur(5px);z-index:1}.attempt-card span{display:block;font-size:12px;color:#d9f5fb}.attempt-card strong{display:block;font-size:22px;margin:6px 0;letter-spacing:.05em}.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:22px;margin-top:18px;box-shadow:0 8px 28px rgba(23,32,51,.06)}.section-heading{display:flex;align-items:flex-start;gap:13px;margin-bottom:16px}.step{flex:none;display:grid;place-items:center;width:42px;height:42px;border-radius:14px;background:var(--soft);color:var(--brand);font-weight:900}.section-heading h2{margin:0;font-size:24px}.section-heading p{margin:4px 0 0;color:var(--muted)}.grid{display:grid;gap:14px}.grid.two{grid-template-columns:repeat(2,minmax(0,1fr))}label,.full-label{font-weight:700;color:#263348}input,select,textarea{width:100%;margin-top:7px;border:1px solid #c8d4e1;border-radius:14px;padding:12px 13px;font:inherit;color:var(--ink);background:#fff}textarea{resize:none;overflow:hidden;line-height:1.45;min-height:80px}.mobile-note{display:none;background:#fff7e6;border:1px solid #ffe0a3;color:#7a5200;border-radius:14px;padding:10px 12px;margin:10px 0;font-size:14px}.table-wrap{width:100%;overflow-x:auto;border:1px solid var(--line);border-radius:18px;background:#fff}table{width:100%;border-collapse:separate;border-spacing:0;min-width:760px}th,td{border-bottom:1px solid var(--line);border-right:1px solid var(--line);padding:10px;vertical-align:middle;text-align:left}th{background:#f0f7fa;color:#123544;font-size:13px;text-transform:uppercase;letter-spacing:.04em}td:last-child,th:last-child{border-right:0}tr:last-child td{border-bottom:0}.given{background:#f8fbfd;font-weight:800}.small-input{min-width:96px;padding:9px 10px;border-radius:10px}.question-list{display:grid;gap:14px}.question{border:1px solid var(--line);border-radius:18px;padding:15px;background:#fbfdff}.question h3{font-size:16px;margin:0 0 10px}.options{display:grid;gap:8px}.option{display:flex;gap:10px;align-items:flex-start;padding:10px;border:1px solid #dbe5ee;border-radius:13px;background:#fff;cursor:pointer}.option input{width:auto;margin-top:2px}.formula-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;margin-bottom:14px}.formula-grid div{background:var(--soft);border-radius:16px;padding:13px}.formula-grid span{display:block;color:var(--muted);font-size:14px;margin-top:3px}.phet-card{background:linear-gradient(180deg,#fff,#f5fbfd)}.phet-link{display:inline-flex;align-items:center;gap:8px;text-decoration:none;background:var(--brand);color:#fff;border-radius:999px;padding:12px 18px;font-weight:800;margin-bottom:14px}.purpose{background:#f7fafc;border-left:5px solid var(--brand);padding:13px;border-radius:12px;color:#324258}.rubric-choice{display:flex;gap:8px;flex-wrap:wrap}.rubric-choice label{font-weight:600;font-size:13px;background:#fff;border:1px solid #d5e0eb;border-radius:999px;padding:8px 10px}.rubric-choice input{width:auto;margin:0 5px 0 0}.actions{display:flex;gap:10px;flex-wrap:wrap}button{border:0;border-radius:999px;background:var(--brand);color:#fff;font:inherit;font-weight:800;padding:13px 18px;cursor:pointer;box-shadow:0 10px 22px rgba(10,94,117,.22)}button.secondary{background:#fff;color:var(--brand);border:1px solid #bad6de}button.ghost{background:rgba(255,255,255,.18);box-shadow:none;border:1px solid rgba(255,255,255,.34)}button.mini{padding:8px 12px;font-size:13px}.sticky-actions{position:fixed;z-index:50;left:50%;bottom:calc(82px + env(safe-area-inset-bottom));transform:translateX(-50%);display:flex;gap:8px;align-items:center;justify-content:center;background:rgba(255,255,255,.96);border:1px solid var(--line);box-shadow:0 12px 35px rgba(0,0,0,.16);padding:8px;border-radius:22px;backdrop-filter:blur(8px);max-width:min(92vw,520px);width:max-content}footer{text-align:center;color:#68768b;font-size:13px;padding:18px 16px 160px}.score-summary{display:grid;grid-template-columns:repeat(4,1fr);gap:12px}.score-pill{border:1px solid var(--line);border-radius:18px;padding:15px;background:#fbfdff}.score-pill b{display:block;font-size:28px}.score-pill span{color:var(--muted);font-size:13px}.feedback-box{margin-top:14px;display:grid;gap:8px}.feedback-item{padding:12px;border-radius:13px}.ok{background:#eaf7ef;color:var(--good)}.review{background:#fff7e6;color:#775000}.missing{background:#fdecec;color:var(--bad)}.correct{outline:2px solid rgba(21,115,71,.25)}.incorrect{outline:2px solid rgba(180,35,24,.25)}@media(max-width:860px){.hero{grid-template-columns:1fr}.brand-row{justify-content:space-between}.attempt-card{max-width:100%}.grid.two,.formula-grid,.score-summary{grid-template-columns:1fr}.mobile-note{display:block}.card{padding:17px}.sticky-actions{left:10px;right:10px;bottom:calc(78px + env(safe-area-inset-bottom));transform:none;width:auto;max-width:none;display:grid;grid-template-columns:1fr 1fr;border-radius:18px;padding:8px}.sticky-actions button{padding:11px 10px;font-size:13px;line-height:1.1;box-shadow:none}.section-heading h2{font-size:20px}}@media print{body{background:#fff}.app-shell{max-width:none;padding:0}.hero,.sticky-actions,footer,.actions,.phet-link{display:none!important}.card{box-shadow:none;border:1px solid #ccc;break-inside:avoid;margin:10px 0}.table-wrap{overflow:visible}.mobile-note{display:none}table{min-width:0;font-size:11px}input,select,textarea{border:0;padding:0}.question{break-inside:avoid}}
.top-toolbar{position:fixed;z-index:80;top:10px;right:14px;display:flex;gap:8px;align-items:center;background:rgba(255,255,255,.94);border:1px solid var(--line);box-shadow:0 12px 30px rgba(0,0,0,.14);border-radius:999px;padding:8px;backdrop-filter:blur(10px)}
.small-btn{font-size:12px;padding:8px 11px;box-shadow:none;white-space:nowrap}.logos-row{gap:10px;flex-wrap:wrap}.logo-img-card{width:74px;min-height:88px;padding:8px}.logo-img-card img{width:100%;height:72px;object-fit:contain;display:block}.atom-mark{margin-left:2px}.parta-input{min-width:140px}
@media(max-width:860px){body{padding-bottom:132px}.app-shell{padding-top:60px;padding-bottom:120px}.top-toolbar{left:8px;right:8px;top:6px;justify-content:flex-start;border-radius:16px;overflow-x:auto;scrollbar-width:none;padding:6px}.top-toolbar::-webkit-scrollbar{display:none}.small-btn{font-size:11px;padding:7px 9px}.logo-img-card{width:68px;min-height:78px}.logo-img-card img{height:62px}.hero{padding-top:18px}}
@media print{.top-toolbar{display:none!important}}

@media(max-width:430px){
  .sticky-actions{grid-template-columns:1fr 1fr;gap:6px;left:8px;right:8px;bottom:calc(74px + env(safe-area-inset-bottom));}
  .sticky-actions button{font-size:12px;padding:10px 8px;}
  .top-toolbar .small-btn{font-size:10.5px;padding:7px 8px;}
  .app-shell{padding-left:10px;padding-right:10px;}
}