.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}.gs-head{padding:30px 0 24px;max-width:1120px;margin:auto}.gs-head .back-link{display:inline-block;margin:0 0 18px}.gs-heading{display:flex;justify-content:space-between;align-items:start;gap:24px}.gs-heading h1{font-size:clamp(30px,4vw,48px);line-height:1.08;font-weight:600;letter-spacing:-1.7px;margin:0 0 12px}.gs-heading p{color:var(--muted);font-size:14px;max-width:690px;margin:0;line-height:1.6}.gs-progress-label{display:flex;justify-content:space-between;font-size:12px;color:#6c7465;margin:23px 0 8px}.gs-progress{height:5px;background:#e7e9e0;border-radius:20px;overflow:hidden}.gs-progress i{display:block;height:100%;background:#819b76;transition:width .3s}.gs-layout{display:grid;grid-template-columns:minmax(0,1fr) 280px;gap:24px;align-items:start;max-width:1120px;margin:0 auto 55px}.gs-play{background:#fff;border:1px solid var(--line);border-radius:28px;padding:30px;min-width:0}.gs-play h2{font-size:clamp(23px,3vw,32px);line-height:1.25;letter-spacing:-.8px;margin:0 0 24px;font-weight:600}.gs-guide{background:#f0ede5;border-radius:24px;padding:25px 23px}.gs-guide-icon{font-size:35px;color:#81866f;line-height:1}.gs-guide h2{font-size:20px;line-height:1.2;letter-spacing:-.5px;margin:20px 0 15px}.gs-guide p{font-size:13px;color:#616956;line-height:1.75}.gs-guide .gs-conditions{font-size:11px;line-height:1.7;margin-top:24px}.gs-guide .gs-footnote{font-size:12px;border-top:1px solid #dadbce;padding-top:18px;margin-top:24px;color:#737a68}.gs-source{font-size:10px;text-decoration:underline;color:#747a6c;display:block;margin-top:20px;line-height:1.5}.gs-primary,.gs-quiet{border:1px solid var(--line);border-radius:24px;padding:11px 19px;font:500 13px var(--font);cursor:pointer;line-height:1.4}.gs-primary{background:var(--ink);color:#fff;border-color:var(--ink)}.gs-primary:hover{background:#3d4b37}.gs-quiet{background:transparent;color:var(--ink);flex-shrink:0}.gs-quiet:hover{background:#eeeee8}.gs-quiet:disabled{opacity:.4}.gs-actions{display:flex;gap:12px;flex-wrap:wrap;margin-top:20px}.gs-compound{display:grid;place-items:center;min-height:170px;background:linear-gradient(135deg,#f0e7dc,#f8f2eb);font-size:clamp(45px,6vw,72px);font-weight:500;letter-spacing:-2px;border-radius:20px;margin:18px 0 25px}.gs-options{display:grid;grid-template-columns:1fr 1fr;gap:12px}.gs-option{background:#fafbf8;border:1px solid #e0e4d8;border-radius:16px;padding:16px 18px;text-align:left;font-size:14px;line-height:1.4;display:flex;align-items:center;justify-content:space-between;gap:12px;min-height:65px;color:var(--ink);transition:background .15s,border-color .15s}.gs-option:hover:not(:disabled){background:#eef2e8;border-color:#a2b295}.gs-option.gs-selected{background:#e6ebdf;border:2px solid #758e68;padding:15px 17px}.gs-option:disabled{opacity:1;cursor:default}.gs-option.gs-right-answer{background:#e5eedc;border-color:#7b986c}.gs-option.gs-wrong-answer{background:#f8ebe3;border-color:#c08b6b}.gs-option span{font-size:18px;color:#567344}.gs-feedback{font-size:14px;line-height:1.65;border-radius:14px;margin-top:20px;min-height:8px}.gs-feedback:not(:empty){padding:15px 18px}.gs-feedback.gs-success{background:#e6eedf;color:#35482c}.gs-feedback.gs-error{background:#f8ece4;color:#774a30}.gs-feedback.gs-notice{background:#f5f0da;color:#655a30}.gs-result-equation{font-size:17px;font-weight:500;margin-top:13px;overflow-wrap:anywhere}.gs-input-label{display:block;font-size:12px;color:var(--muted);margin-bottom:9px}.gs-name-input{width:100%;font-size:18px;padding:15px 18px;border:1px solid #cbd3c3;border-radius:15px;background:#fafbf8;color:var(--ink)}.gs-name-input:disabled{opacity:1}.gs-equation{display:flex;justify-content:center;align-items:center;gap:10px;flex-wrap:wrap;background:#f2eee5;border-radius:20px;padding:23px 16px;margin-bottom:25px;min-height:130px}.gs-term{display:flex;align-items:center;gap:7px;white-space:nowrap}.gs-term>span:last-child{font-size:25px;letter-spacing:-.6px}.gs-term sub{font-size:.6em}.gs-term select{padding:9px 6px;border:1px solid #d1d7c7;border-radius:12px;background:#fff;color:var(--ink);font-size:20px;min-width:46px}.gs-term select:disabled{opacity:1}.gs-plus,.gs-arrow{color:#8b917f;font-size:23px}.gs-atoms{border-collapse:collapse;width:100%;text-align:center;font-size:15px}.gs-atoms th,.gs-atoms td{padding:12px 15px;border-bottom:1px solid #e9ece3}.gs-atoms thead{font-size:11px;color:var(--muted)}.gs-atoms th:first-child{text-align:left}.gs-atoms .gs-unequal td:last-child{color:#a56b4c}.gs-atoms .gs-equal td:last-child{color:#5a7845}.gs-atoms .gs-equal{background:#f1f6ec}.gs-faint{color:#9ba08f;font-weight:400}.gs-lab-scene,.gs-metal-scene{display:flex;flex-direction:column;align-items:center;justify-content:center;background:#eef1e9;border-radius:22px;padding:20px;margin:16px 0 22px;min-height:255px;position:relative;overflow:hidden}.gs-lab-scene{background:linear-gradient(130deg,#f0eee2,#f1f4eb)}.gs-reagents{display:flex;justify-content:center;gap:12px;align-items:center;margin-bottom:7px}.gs-reagents span{border:1px solid #d7dece;padding:5px 13px;border-radius:20px;background:#fff9;font-size:13px}.gs-reagents b{font-size:18px;color:#a1aa92;font-weight:400}.gs-beaker{height:155px;width:150px;overflow:visible}.gs-lab-label{font-size:12px;color:#667457;text-align:center;margin:6px 0 0;min-height:20px}.gs-model{font-size:10px;color:#858b7c;text-align:center;margin:9px 0 0}.gs-sediment{animation:gs-settle .7s ease-out}.gs-deposit{animation:gs-appear .6s ease-out}.gs-bubbles{animation:gs-rise 2.2s infinite ease-out}.gs-series{font-size:12px;font-weight:500;line-height:1.7;margin:18px 0;background:#ffffff70;padding:12px;border-radius:12px}.gs-scene{height:235px;display:grid;place-items:center;border-radius:22px;background:linear-gradient(120deg,#f0ede0,#e7eddf);margin-top:10px;overflow:hidden}.gs-scene svg{height:210px;width:100%;max-width:400px}.gs-play>.gs-model{margin:10px 0 22px}.gs-ice{animation:gs-ice 4s infinite alternate ease-in-out;transform-origin:center}.gs-droplet{animation:gs-appear 2.5s infinite alternate}.gs-flame{animation:gs-flame .85s infinite alternate;transform-origin:150px 135px}.gs-steam{animation:gs-rise 3s infinite ease-out}.gs-dissolve{animation:gs-spread 3s infinite alternate ease-in-out;transform-origin:center}.gs-mystery{float:left;width:112px;height:140px;display:flex;flex-direction:column;justify-content:space-between;padding:13px 17px;background:#e7e0ee;border:1px solid #dbd0e5;border-radius:20px;margin:0 22px 18px 0}.gs-mystery>span{font-size:12px;color:#7a6d87}.gs-mystery strong{font-size:46px;line-height:1;font-weight:600}.gs-mystery small{font-size:10px;overflow-wrap:anywhere;color:#7a6d87}.gs-clues{list-style:none;padding:0;margin:0 0 25px;min-height:148px}.gs-clues li{margin-bottom:14px}.gs-clues small{font-size:10px;color:#8c8278;text-transform:uppercase;letter-spacing:1.3px}.gs-clues p{font-size:14px;line-height:1.6;margin:5px 0 0}.gs-element-options{clear:both;grid-template-columns:repeat(5,1fr);gap:9px}.gs-element-options .gs-option{font-size:23px;font-weight:500;min-height:65px;text-align:center;justify-content:center;padding:10px}.gs-element-options .gs-option.gs-selected{padding:9px}.gs-element-options .gs-option span{font-size:13px}.gs-finish{max-width:800px;text-align:center;background:#fff;border:1px solid var(--line);border-radius:30px;padding:40px;margin:45px auto}.gs-medal{background:var(--sage);height:75px;width:75px;border-radius:50%;display:grid;place-items:center;font-size:37px;margin:0 auto 24px}.gs-finish h1{font-size:clamp(32px,4vw,50px);letter-spacing:-1.8px;line-height:1.1;margin:20px 0}.gs-finish>p{font-size:14px;color:var(--muted);line-height:1.7;max-width:580px;margin:0 auto}.gs-score{display:grid;gap:5px;margin:28px 0}.gs-score strong{font-size:48px;font-weight:500;letter-spacing:-2px}.gs-score>span{font-size:12px;color:var(--muted)}.gs-finish>.back-link{display:block;margin:20px auto}.gs-review{text-align:left;border-top:1px solid var(--line);padding-top:22px;margin-top:30px}.gs-review summary{cursor:pointer;font-size:15px;font-weight:500}.gs-review ol{padding-left:22px;margin-top:22px}.gs-review li{font-size:13px;padding:0 0 16px 5px;margin-bottom:16px;border-bottom:1px solid var(--line)}.gs-review li>span{display:block;font-size:10px;color:var(--muted);margin-top:5px}.gs-review p{font-size:12px;line-height:1.6;color:#6a735f}.gs-art{position:relative;overflow:hidden;min-height:160px}.gs-art>span{font-size:clamp(25px,3vw,39px);letter-spacing:-1px;font-weight:500;z-index:1;transform:rotate(-6deg)}.gs-art:before,.gs-art:after{content:'';width:90px;height:90px;border:1px solid #fff9;border-radius:25px;position:absolute;transform:rotate(25deg);left:15%;top:27%}.gs-art:after{left:auto;right:12%;top:15%;transform:rotate(-15deg)}.gs-names{background:#eae1ed}.gs-balance{background:#f1d1b7}.gs-precip{background:#e5e9cd}.gs-metals{background:#d7e4e3}.gs-physical{background:#f0e4bf}.gs-elements{background:#deddef}.gs-card h3{line-height:1.2}.gs-card .card-copy p{min-height:65px}@keyframes gs-settle{from{transform:translateY(-17px);opacity:0}to{transform:translateY(0);opacity:1}}@keyframes gs-appear{from{opacity:.2}to{opacity:1}}@keyframes gs-rise{0%{transform:translateY(8px);opacity:0}30%{opacity:1}100%{transform:translateY(-22px);opacity:0}}@keyframes gs-ice{from{opacity:1}to{opacity:.55}}@keyframes gs-flame{from{transform:scaleX(.95) scaleY(.9)}to{transform:scaleX(1.05) scaleY(1.05)}}@keyframes gs-spread{from{transform:scale(.7)}to{transform:scale(1.15)}}@media(max-width:1000px){.gs-layout{grid-template-columns:minmax(0,1fr) 240px;gap:17px}.gs-play{padding:24px}.gs-guide{padding:22px 18px}.gs-equation{gap:7px}.gs-term>span:last-child{font-size:22px}}@media(max-width:760px){.gs-layout{grid-template-columns:1fr}.gs-head{padding-top:23px}.gs-heading{gap:14px}.gs-heading .gs-quiet{max-width:110px;white-space:normal;padding:9px 12px;flex-shrink:1}.gs-heading h1{font-size:32px}.gs-play{padding:23px 19px}.gs-guide{padding:25px}.gs-options{gap:10px}.gs-option{padding:13px 14px;font-size:13px}.gs-option.gs-selected{padding:12px 13px}.gs-finish{padding:30px 22px;margin:25px auto}.gs-compound{min-height:145px}.gs-equation{padding:20px 12px}.gs-term>span:last-child{font-size:23px}.gs-beaker{height:145px}.gs-element-options .gs-option{font-size:21px;padding:10px}.gs-element-options .gs-option.gs-selected{padding:9px}}@media(max-width:420px){.gs-options:not(.gs-element-options){grid-template-columns:1fr}.gs-compound{font-size:48px}.gs-mystery{width:88px;height:116px;margin-right:15px;padding:11px 13px}.gs-mystery strong{font-size:38px}.gs-clues p{font-size:13px}.gs-element-options{grid-template-columns:repeat(5,1fr);gap:6px}.gs-element-options .gs-option{font-size:19px;min-height:54px}.gs-play{padding:21px 16px}.gs-atoms th,.gs-atoms td{padding:10px}.gs-heading h1{font-size:29px;letter-spacing:-1.2px}}@media(prefers-reduced-motion:reduce){.gs-progress i{transition:none}.gs-sediment,.gs-deposit,.gs-bubbles,.gs-ice,.gs-droplet,.gs-flame,.gs-steam,.gs-dissolve{animation:none}}

/* Generated illustration assets share a crop-safe 8:5 frame. */
.cards:has(.gs-card) .card-art{height:auto;aspect-ratio:8/5}.gs-art:before,.gs-art:after{display:none}.gs-art img{display:block;width:100%;height:100%;object-fit:cover}