.topbar:has(.header-theme){display:grid;grid-template-columns:minmax(0,1fr) auto 40px;gap:18px;align-items:center}.topbar .header-theme{width:40px;height:40px;border:1px solid var(--line);background:var(--surface);border-radius:11px}.topbar .project-credit{margin-left:auto;width:auto}.header-theme:hover{background:var(--surface-alt)}.practice-header-actions .header-theme{order:2;margin-left:4px}.advanced-content>.page-heading .page-description{max-width:880px;font-size:15px;line-height:1.85}.advanced-tools{margin:35px 0 48px}.advanced-tools>h2,.advanced-topics>h2{margin-bottom:22px}.advanced-credits{margin-top:22px}.advanced-topics{padding-top:30px;border-top:1px solid var(--line)}.advanced-tools .tool-card p{line-height:1.85}.redox-picker{max-width:800px;margin:24px 0}.redox-picker select{max-width:100%}
.feedback{flex-wrap:wrap}.reveal-answer{margin-left:auto;font-size:14px;text-decoration:underline;text-underline-offset:4px}.feedback.revealed,.review-state.peeked{color:#c35252}.task-dot.revealed{color:#c35252;background:#c3525214;box-shadow:inset 0 0 0 1px #c3525240}.revealed-answer{padding:20px 24px;margin:16px 0 2px;background:var(--surface);border:1px solid var(--line);border-radius:14px}.revealed-answer>h3{font-size:14px;color:var(--muted);margin-bottom:14px}.revealed-answer .bank-equation{flex-wrap:wrap;justify-content:center;font-size:24px;gap:8px}.revealed-answer .bank-term{white-space:normal;overflow-wrap:anywhere}.result-metrics{grid-template-columns:repeat(auto-fit,minmax(130px,1fr))}
.local-chain-players{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:22px;margin:25px 0}.local-player{min-width:0;padding:25px;border:1px solid var(--line);border-radius:20px;background:var(--surface)}.local-player>header{display:flex;align-items:center;justify-content:space-between;gap:16px}.local-player>header h2{font-size:21px}.local-player>header span{font-variant-numeric:tabular-nums;font-size:15px;color:var(--muted)}.local-player>p{color:var(--muted);line-height:1.75;font-size:14px}.local-player .player-transition{font-size:25px;margin:14px 0;overflow-wrap:anywhere}.local-player .chain-options{display:grid;gap:10px;margin-top:20px}.local-player .chain-option{font-size:14px;padding:15px}.local-player .chain-option:disabled{opacity:1;color:var(--muted)}.local-player .player-selected{border-color:var(--blue);background:var(--blue-soft);color:var(--ink)!important}.local-player .player-status{min-height:50px;margin:18px 0 0;font-size:14px}.local-player.player-correct{border-color:var(--green)}.local-player.player-correct .player-status{color:var(--green)}.local-player.player-wrong{border-color:#c77070}.local-player.player-wrong .player-status{color:#c77070}.local-final-score{display:block;font-size:40px;margin:20px 0 8px;font-variant-numeric:tabular-nums}.chain-round-result{padding:25px;border-radius:16px;background:var(--surface-alt)}.chain-round-result>h3{margin-bottom:10px}.chain-round-result>p{font-size:14px;color:var(--muted);line-height:1.8;margin-bottom:18px}.chain-round-result .btn{margin-top:25px}.chain-round-result .bank-equation{justify-content:flex-start}
.laboratory-content{max-width:1500px}.laboratory-content .page-heading{gap:20px;flex-wrap:wrap}.laboratory-content .page-heading>.pill{font-size:12px}.laboratory-grid{display:grid;grid-template-columns:minmax(235px,.75fr) minmax(0,1.6fr);gap:24px;align-items:start}.laboratory-grid .tool-panel{margin-top:0}.lab-shelf{padding:22px}.lab-shelf>h2{font-size:21px}.lab-shelf .tool-field{font-size:13px;margin-bottom:15px}.lab-inventory-count{color:var(--muted);font-size:12px;margin:17px 0 10px}.lab-inventory{display:grid;gap:8px;max-height:730px;overflow:auto;padding-right:5px;scrollbar-width:thin}.lab-substance{display:flex;align-items:center;gap:12px;width:100%;border:1px solid var(--line);border-radius:12px;background:var(--surface);padding:12px;text-align:left;min-width:0;color:var(--ink)}.lab-substance>span{min-width:0;display:grid;gap:3px}.lab-substance strong{font-size:19px;font-weight:550;overflow-wrap:anywhere}.lab-substance>span>span{font-size:12px;line-height:1.65}.lab-substance small{font-size:11px;color:var(--muted)}.lab-substance:hover{background:var(--surface-alt);border-color:var(--muted)}.lab-substance.on-bench{border-color:var(--blue);background:var(--blue-soft)}.lab-vessel{width:35px;height:43px;flex:none;color:var(--muted)}.lab-workspace{display:grid;gap:24px;min-width:0}.lab-bench{padding:25px}.lab-bench-hint{font-size:13px!important;line-height:1.8!important;margin:0 0 20px!important}.lab-slots{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px}.lab-slot{background:var(--surface-alt);border:1px solid var(--line);border-radius:16px;padding:15px;min-width:0}.lab-slot.slot-active{border-color:var(--blue);box-shadow:inset 0 0 0 1px var(--blue)}.lab-slot-target{display:flex;flex-direction:column;align-items:center;gap:7px;border:0;background:none;width:100%;padding:0 0 10px;min-width:0;text-align:center}.lab-slot-target>span{font-size:12px;color:var(--muted)}.lab-slot-target .lab-vessel{width:48px;height:57px;margin:5px 0}.lab-slot-target>strong{font-size:26px;line-height:1.3;max-width:100%;overflow-wrap:anywhere}.lab-slot-target>small{font-size:12px;line-height:1.7;min-height:40px}.lab-slot .tool-field{font-size:11px;margin:8px 0 0}.lab-slot select{font-size:12px;max-width:100%;text-overflow:ellipsis;min-width:0;padding:10px 8px}.lab-conditions{border:0;padding:0;margin:23px 0 20px;display:flex;flex-wrap:wrap;gap:8px}.lab-conditions>legend{margin-bottom:12px;font-size:13px;font-weight:500}.lab-condition{display:inline-flex;align-items:center;gap:6px;border:1px solid var(--line);border-radius:9px;background:var(--surface);color:var(--muted);padding:10px 12px;font-size:12px;line-height:1.4}.lab-condition:hover{background:var(--surface-alt)}.lab-condition[aria-pressed=true]{color:var(--blue);background:var(--blue-soft);border-color:var(--blue)}.lab-indicator-controls{display:flex;align-items:end;gap:15px}.lab-indicator-controls .tool-field{flex:1;min-width:0;margin:0}.lab-indicator-controls .btn{min-height:46px;flex:none}.lab-presets{margin-top:25px;border-top:1px solid var(--line);padding-top:16px}.lab-presets>summary{cursor:pointer;color:var(--blue);font-size:14px}.lab-presets .tool-field{margin:15px 0 0}.lab-presets select{max-width:100%;text-overflow:ellipsis}.lab-result{text-align:center;min-width:0;padding:28px}.lab-result h3{font-size:21px;line-height:1.55;text-wrap:pretty;margin:5px 0 18px}.lab-result>p{font-size:14px;line-height:1.8;color:var(--muted);margin:12px 0}.lab-experiment-visual{width:100%;max-width:320px;margin:0 auto 8px}.lab-experiment-visual svg{display:block;width:100%;max-height:230px}.lab-glass{fill:var(--surface-alt)}.lab-glass-outline,.lab-glass-shine,.lab-table-line{fill:none;stroke:var(--muted);stroke-width:2;stroke-linejoin:round}.lab-glass-shine{stroke:var(--surface);stroke-width:5;opacity:.6}.lab-table-line{stroke:var(--line)}.lab-fluid{fill:var(--lab-liquid);fill-opacity:.82;transition:fill .45s}.lab-sediment{fill:var(--lab-solid);opacity:0;stroke:var(--muted);stroke-width:.4}.lab-precipitate .lab-sediment{opacity:1;animation:lab-settle 1.1s ease-out}.lab-bubbles{fill:var(--surface);stroke:var(--muted);stroke-width:.5;opacity:0}.lab-gas .lab-bubbles{opacity:.75}.lab-gas circle{animation:lab-bubble 1.7s infinite ease-out;transform-origin:center}.lab-gas circle:nth-child(2){animation-delay:-.7s}.lab-gas circle:nth-child(3){animation-delay:-1.2s}.is-mixing .lab-flask{transform-origin:160px 180px;animation:lab-mix .18s ease-in-out infinite alternate}.is-mixing .lab-fluid{animation:lab-wave .3s ease-in-out infinite alternate;transform-origin:160px 170px}.lab-result .lab-result-title{font-size:17px;color:var(--ink);font-weight:500}.lab-equation{font-size:21px;justify-content:center;flex-wrap:wrap;gap:8px;margin:20px 0}.lab-equation .bank-side{flex-wrap:wrap;justify-content:center}.lab-equation .bank-term{white-space:normal;overflow-wrap:anywhere}.lab-observation-tags{display:flex;justify-content:center;flex-wrap:wrap;gap:8px;margin:18px 0}.lab-observation-tags>span{display:inline-flex;align-items:center;gap:7px;background:var(--surface-alt);border:1px solid var(--line);padding:7px 10px;border-radius:8px;font-size:12px;line-height:1.6}.lab-observation-tags i{display:inline-block;width:13px;height:13px;border-radius:50%;border:1px solid #aaa6}.lab-indicator-result{color:var(--ink)!important}.lab-experiment-sources{text-align:left;border-top:1px solid var(--line);padding-top:15px;margin-top:25px;font-size:12px;line-height:1.8;color:var(--muted)}.lab-experiment-sources summary{cursor:pointer}.lab-experiment-sources a{display:block;margin:10px 0}.lab-suggested-conditions{display:flex;justify-content:center;gap:9px;flex-wrap:wrap;margin-top:20px}.lab-added-medium{font-size:12px!important}
@keyframes lab-mix{from{transform:rotate(-5deg)}to{transform:rotate(5deg)}}@keyframes lab-wave{from{transform:rotate(-5deg)}to{transform:rotate(5deg)}}@keyframes lab-bubble{from{transform:translateY(15px);opacity:0}30%{opacity:.9}to{transform:translateY(-65px);opacity:0}}@keyframes lab-settle{from{transform:translateY(-65px);opacity:0}to{transform:translateY(0);opacity:1}}
[data-theme=dark] .feedback.revealed,[data-theme=dark] .review-state.peeked,[data-theme=dark] .task-dot.revealed{color:#e69c9c}
@media(max-width:1100px){.laboratory-grid{grid-template-columns:minmax(210px,.7fr) minmax(0,1.5fr);gap:16px}.lab-bench,.lab-result{padding:20px}.lab-slots{gap:10px}.lab-slot{padding:12px}.lab-indicator-controls{flex-wrap:wrap}.lab-indicator-controls .tool-field{min-width:190px}.advanced-tools .tool-grid{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media(max-width:1000px){.topbar:has(.header-theme){grid-template-columns:minmax(0,1fr) 40px;gap:10px 15px}.topbar .header-theme{grid-column:2;grid-row:1}.topbar .project-credit{grid-column:1/-1;grid-row:2;justify-content:space-between;width:100%}.topbar .project-credit-copy{text-align:left}.local-chain-players{gap:14px}.local-player{padding:18px}.local-player .player-transition{font-size:22px}.local-player .chain-option{font-size:13px}}
@media(max-width:780px){.laboratory-grid{display:block}.lab-shelf{margin-bottom:20px!important}.lab-inventory{grid-template-columns:repeat(2,minmax(0,1fr));max-height:230px}.lab-substance{padding:10px;gap:8px}.lab-substance strong{font-size:17px}.lab-vessel{width:29px;height:38px}.local-chain-players{grid-template-columns:1fr}.local-player .player-status{min-height:0}.advanced-tools .tool-grid{grid-template-columns:1fr}.practice-topbar{flex-wrap:wrap;height:auto;min-height:82px;padding:15px 22px;gap:12px}.practice-title{flex:1}.practice-header-actions{width:100%;justify-content:flex-end;flex-wrap:wrap}.reveal-answer{margin-left:0}.revealed-answer{padding:18px}.revealed-answer .bank-equation{font-size:21px}.lab-slot select,.lab-indicator-controls select,.lab-presets select,.lab-shelf input,.redox-picker select{font-size:16px}.lab-slot .tool-field>span{font-size:11px}.lab-slot-target>strong{font-size:23px}.lab-result h3{font-size:19px}.lab-indicator-controls{gap:14px}.lab-indicator-controls .btn{width:100%}.lab-equation{font-size:19px}.laboratory-content .page-heading>.pill{font-size:11px}.lab-conditions{gap:7px}.lab-condition{font-size:12px;padding:10px}}
@media(prefers-reduced-motion:reduce){.lab-experiment-visual *{animation:none!important;transition:none!important}}

.formula-editor.revealed-input[contenteditable=false]{color:#c35252;border-color:#c35252}[data-theme=dark] .formula-editor.revealed-input[contenteditable=false]{color:#e69c9c;border-color:#e69c9c}

/* Paired tabs keep the bench and the observation in one frame. */
.laboratory-grid .lab-tab-frame{padding:0;overflow:hidden}.lab-workspace.lab-tab-frame{display:block}.lab-tabs{display:flex;gap:3px;padding:10px 10px 0;background:var(--surface-alt);border-bottom:1px solid var(--line)}.lab-tabs>[role=tab]{flex:1;min-width:0;position:relative;border:1px solid transparent;border-bottom:0;border-radius:11px 11px 0 0;padding:14px 10px;font-size:14px;font-weight:500;line-height:1.5;background:none;color:var(--muted);margin-bottom:-1px}.lab-tabs>[role=tab]:hover{color:var(--ink)}.lab-tabs>[aria-selected=true]{background:var(--surface);border-color:var(--line);color:var(--ink)}.lab-tabs>[role=tab]:focus-visible{outline-offset:-5px}.lab-tab-panel{padding:23px;min-width:0}.lab-tab-panel[hidden]{display:none}.lab-workspace .lab-tab-panel{min-height:550px}.lab-result-panel{display:flex;flex-direction:column}.lab-result-panel .lab-result{padding:0}.lab-result-actions{margin-top:auto;padding-top:24px;display:flex;justify-content:center}.lab-result-actions .btn{font-size:14px;min-height:43px}.lab-preset-list{display:grid;gap:9px;max-height:620px;overflow:auto;scrollbar-width:thin;padding-right:4px}.lab-preset-card{width:100%;text-align:left;padding:14px;border:1px solid var(--line);border-radius:12px;background:var(--surface);display:grid;gap:9px;color:var(--ink);min-width:0}.lab-preset-card:hover{background:var(--surface-alt)}.lab-preset-card.selected{background:var(--blue-soft);border-color:var(--blue)}.lab-preset-card>strong{font-size:14px;line-height:1.65;font-weight:500;overflow-wrap:anywhere}.lab-preset-card>span{font-size:18px;line-height:1.6;overflow-wrap:anywhere}.lab-preset-card>small{font-size:11px;line-height:1.6;color:var(--muted)}.lab-list-empty{font-size:13px;line-height:1.8;color:var(--muted)}
.chain-mode-picker{margin-top:32px}.chain-mode-picker>h2{font-size:23px;margin-bottom:23px}.chain-mode-cards{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:23px}.chain-mode-card{display:flex;flex-direction:column;align-items:flex-start;gap:23px;text-align:left;padding:32px;border:1px solid var(--line);border-radius:20px;background:var(--surface);color:var(--ink);min-width:0}.chain-mode-card>svg{color:var(--blue)}.chain-mode-card>strong{font-size:24px;line-height:1.3;font-weight:550;letter-spacing:-.5px}.chain-mode-card>span{font-size:15px;line-height:1.85;color:var(--muted)}.chain-mode-card .chain-mode-start{margin-top:auto;padding-top:16px;color:var(--blue);display:flex;gap:12px;align-items:center;font-size:15px}.chain-mode-card:hover{border-color:var(--blue);background:var(--blue-soft)}.chain-game-header{display:flex;justify-content:space-between;align-items:center;gap:20px;margin-bottom:25px}.chain-game-header>span{font-size:15px;font-weight:500}.chain-game-header>.text-link{font-size:14px}.chain-game>.tool-field{max-width:650px;font-size:14px}.chain-controls{position:sticky;bottom:14px;z-index:3;display:flex;justify-content:space-between;align-items:center;gap:15px;flex-wrap:wrap;margin-top:25px;padding:16px;border:1px solid var(--line);border-radius:14px;background:var(--surface);box-shadow:0 8px 25px #0000000b}.chain-controls .btn{font-size:14px;min-height:45px}.chain-controls .btn[disabled]{opacity:.48}
@media(max-width:1100px){.lab-tab-panel{padding:20px}.lab-shelf .lab-tabs>[role=tab]{font-size:12px;padding:14px 6px}.chain-mode-card{padding:26px}.chain-mode-card>strong{font-size:22px}}
@media(max-width:780px){.lab-preset-list{max-height:300px}.lab-tabs>[role=tab],.lab-shelf .lab-tabs>[role=tab]{font-size:14px}.lab-tab-panel{padding:20px}.lab-workspace .lab-tab-panel{min-height:530px}.chain-mode-cards{grid-template-columns:1fr;gap:16px}.chain-mode-card{gap:18px;padding:25px}.chain-mode-card>strong{font-size:23px}.chain-mode-card>span{font-size:14px}.chain-controls{bottom:10px;padding:12px;gap:10px}.chain-controls .btn{font-size:13px;padding:12px 14px;flex:1;justify-content:center}.chain-game-header{align-items:flex-start;gap:12px}.chain-game-header>span{font-size:14px}.chain-game-header>.text-link{font-size:13px;white-space:nowrap}}

@media(min-width:781px){.lab-preset-list,.lab-shelf .lab-inventory{max-height:clamp(260px,44vh,480px)}}

.lab-shelf .lab-tabs>[role=tab]{padding:16px 4px;font-size:13px;white-space:nowrap}.lab-tabs>[role=tab]{min-height:59px}.lab-result-panel .lab-experiment-visual{max-width:260px}.lab-result-panel .lab-experiment-visual svg{max-height:190px}.chain-controls{margin-right:55px}@media(max-width:780px){.chain-controls{margin-right:0;padding-right:65px}.chain-controls .btn{flex-basis:100%}.lab-shelf .lab-tabs>[role=tab]{font-size:14px}}