.toolbox-content{max-width:1460px}.toolbox-content .page-description{max-width:770px}.tool-category-nav{display:flex;gap:10px;flex-wrap:wrap;margin:28px 0 40px}.tool-category-nav a{display:flex;align-items:center;gap:17px;padding:12px 16px;background:var(--surface);border:1px solid var(--line);border-radius:11px;font-size:12px}.tool-category-nav a:hover{border-color:var(--blue);color:var(--blue)}.tool-category{margin:34px 0 40px;scroll-margin-top:25px}.tool-category>h2{font-size:22px;margin-bottom:19px;font-weight:550}.tool-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:17px}.tool-card{border:1px solid var(--line);background:var(--surface);border-radius:18px;overflow:hidden;display:flex;flex-direction:column;transition:border-color .15s,transform .15s}.tool-card:hover{border-color:#aabfe6;transform:translateY(-2px)}.tool-card-art{height:108px;display:flex;align-items:center;justify-content:center;color:#4468b7;background:#edf2fc;overflow:hidden}.tool-card-art>span{font-size:27px;font-weight:450;letter-spacing:-1px;white-space:nowrap}.art-editor{background:#e7efff}.art-editor>span{font-size:62px}.art-oc3d{background:radial-gradient(circle at 45% 55%,#e1dff4 2%,#f0effa 58%);color:#7565b0}.art-oc3d>span{font-size:37px;letter-spacing:6px}.art-fusion{background:#eaf5f1;color:#387e6c}.art-memory{background:#f6efe7;color:#9b7443}.art-quantity{background:#ecf0f9}.art-modeling{background:#e5f4f4;color:#338389}.art-atom-balance{background:#f3eefb;color:#8665b0}.art-redox>span{font-size:24px}.art-structures>span{font-size:33px}.tool-card-copy{padding:23px;display:flex;flex-direction:column;flex:1}.tool-card h3{font-size:17px;line-height:1.5;letter-spacing:-.3px;margin:0 0 9px;font-weight:550}.tool-card p{font-size:12px;line-height:1.85;color:var(--muted);margin:0 0 24px;flex:1}.tool-open{display:flex;align-items:center;justify-content:space-between;font-size:12px;color:var(--blue)}.tool-footer{border-top:1px solid var(--line);padding-top:22px;display:flex;gap:20px;justify-content:space-between;align-items:start;color:var(--muted);font-size:11px;line-height:1.8}.tool-footer p{max-width:620px}.tool-footer button{font-size:11px;white-space:nowrap}.tool-panel{margin-top:26px;padding:28px;border:1px solid var(--line);border-radius:18px;background:var(--surface);min-width:0}.tool-panel>h2{font-size:21px;margin-bottom:17px;letter-spacing:-.4px}.tool-panel>p{color:var(--muted);font-size:13px;line-height:1.8;margin:10px 0 17px}.tool-panel h3{font-size:17px;line-height:1.6}.tool-split{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1.2fr);gap:22px;align-items:start}.tool-form-row{display:flex;align-items:end;gap:13px;flex-wrap:wrap}.tool-form-row>.tool-field{flex:1;min-width:140px}.tool-form-row>.btn{margin-bottom:18px;flex-shrink:0}.tool-field{display:flex;flex-direction:column;gap:9px;margin:0 0 18px;font-size:12px;line-height:1.7;min-width:0}.tool-field>span{font-weight:500}.tool-input,.tool-field textarea{border:1px solid var(--line);border-radius:10px;background:var(--surface);color:var(--ink);font:inherit;padding:12px 13px;width:100%;min-width:0;outline-offset:3px}.tool-input:focus,.tool-field textarea:focus{outline:2px solid var(--blue)}.tool-field textarea{font-family:inherit;resize:vertical;font-size:11px;overflow-wrap:anywhere}.tool-field select{font:inherit}.tool-field input[type=range]{width:100%;accent-color:var(--blue);min-height:34px}.tool-small{font-size:11px!important;line-height:1.85!important;color:var(--muted);margin:14px 0}.tool-feedback{font-size:12px;line-height:1.8;margin:20px 0 0;overflow-wrap:anywhere;color:var(--muted)}.tool-feedback.correct{color:#298360}.tool-feedback.wrong{color:#bc645a}.tool-feedback:empty{display:none}.tool-result{margin:25px 0 0;font-size:13px;line-height:1.8}.tool-equation{font-size:20px;gap:10px;max-width:100%;flex-wrap:wrap}.tool-equation .bank-side{flex-wrap:wrap}.tool-equation .bank-term{white-space:normal;overflow-wrap:anywhere}.metric-value{font-size:34px;color:var(--ink);letter-spacing:-1px;font-weight:500}.metric-value>span{font-size:15px;font-weight:400;letter-spacing:0;color:var(--muted)}.metric-secondary{font-size:20px;margin:4px 0 12px}.tool-table{width:100%;border-collapse:collapse;text-align:left;font-size:12px}.tool-table th{font-weight:500;color:var(--muted)}.tool-table td,.tool-table th{padding:11px 8px;border-bottom:1px solid var(--line)}.table-scroll{overflow:auto;margin-top:16px}.mini-equation{margin:18px 0}.tool-toolbar{display:flex;flex-wrap:wrap;gap:10px;margin:24px 0 18px}.btn.compact{font-size:11px;padding:10px 15px;min-height:37px}.tool-frame-wrap{border:1px solid var(--line);border-radius:16px;overflow:hidden;background:white;margin-top:20px}.tool-frame{width:100%;height:730px;border:0;display:block;background:white}.oc3d-frame{height:820px}.tool-frame:fullscreen{height:100vh;background:white}.tool-notice{display:flex;align-items:center;justify-content:space-between;gap:20px;padding:19px 22px;background:var(--surface);border:1px solid var(--line);border-radius:14px;margin-top:24px}.tool-notice p{font-size:12px;line-height:1.8;color:var(--muted);max-width:800px}.tool-notice .btn{white-space:nowrap}.tool-source{font-size:11px;color:var(--muted);margin-top:19px;line-height:1.8}.tool-source a{color:var(--blue)}.editor-check>p{max-width:800px}.group-options{display:grid;gap:8px;margin-top:22px}.group-option,.chain-option{border:1px solid var(--line);border-radius:11px;background:var(--surface);color:var(--ink);padding:14px 16px;text-align:left;font-size:13px;line-height:1.6;width:100%}.group-option:hover,.chain-option:hover{background:var(--blue-soft);border-color:#b9ccef}.group-visual{text-align:center}.group-visual #group-drawing{min-height:280px;display:grid;place-items:center}.group-visual svg{max-width:100%;height:auto}.group-visual .muted{font-size:11px;line-height:1.8;margin-top:18px}.model-split{grid-template-columns:minmax(220px,.65fr) minmax(0,1.35fr)}.model-metrics{display:flex;justify-content:space-between;gap:20px}.model-metrics>div{display:grid;gap:10px;font-size:11px;color:var(--muted)}.model-metrics strong{font-size:30px;color:var(--ink);font-weight:500}.titration-chart{margin:25px 0}.titration-chart svg{width:100%;display:block;overflow:visible}.titration-chart text{font-size:12px;fill:var(--muted);font-family:inherit}.chart-grid{stroke:var(--line);stroke-width:1}.chart-curve{stroke:var(--blue);fill:none;stroke-width:3;stroke-linejoin:round}.chart-point{fill:var(--surface);stroke:var(--blue);stroke-width:3}.solution-visual{display:flex;gap:23px;align-items:center;border-top:1px solid var(--line);padding-top:22px}.solution-visual>div:last-child{min-width:0}.solution-visual p{font-size:12px;line-height:1.8;color:var(--muted);margin-top:7px}.solution-beaker{width:84px;height:92px;position:relative;border:2px solid #9aaec9;border-top:0;border-radius:0 0 15px 15px;overflow:hidden;flex-shrink:0;background:var(--bg)}.solution-beaker span{position:absolute;bottom:0;left:0;right:0;height:70%;background:var(--solution-color,#fb9e8c);opacity:.65;transition:background .25s}.atom-equation{display:flex;align-items:center;justify-content:center;flex-wrap:wrap;gap:15px;font-size:25px;margin:35px 0}.atom-term{display:flex;gap:7px;align-items:center;white-space:nowrap}.atom-term input{width:55px}.atom-chart{max-width:650px;margin:20px auto 25px}.atom-legend{display:flex;gap:25px;font-size:11px;color:var(--muted);justify-content:flex-end;margin-bottom:20px}.atom-legend span::before{content:'';display:inline-block;width:9px;height:9px;background:#6193df;margin-right:6px;border-radius:2px}.atom-legend span+span::before{background:#9a87cc}.atom-bar-row{display:grid;grid-template-columns:28px 1fr;gap:18px;align-items:center;margin:20px 0}.atom-bar-row>strong{font-size:18px;font-weight:500}.atom-bar{min-width:33px;height:25px;margin:4px 0;border-radius:5px;display:flex;align-items:center;justify-content:flex-end;padding:0 8px;font-size:11px;color:#fff;transition:width .2s}.atom-bar.left{background:#6193df}.atom-bar.right{background:#9a87cc}.chain-map{display:flex;flex-wrap:wrap;align-items:center;gap:8px;margin:26px 0 30px}.chain-node{padding:13px 16px;border:1px solid var(--line);border-radius:11px;font-size:18px;line-height:1.4}.chain-node.current{border-color:#b5c8ed;background:var(--blue-soft)}.chain-node.completed{border-color:#c6ded4;background:#f0f7f4;color:#2d735a}.chain-map-arrow{display:grid;gap:0;text-align:center;font-size:9px;color:var(--muted);min-width:21px}.chain-map-arrow small{font-size:23px;line-height:1.1}.chain-map-arrow.completed{color:#3e916e}.chain-question{margin:28px 0}.chain-question h2{font-size:32px;font-weight:500;letter-spacing:-.6px;line-height:1.6;margin:12px 0}.chain-question h2>span{color:var(--muted);margin:0 9px}.chain-question>p{font-size:13px;color:var(--muted)}.chain-options{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:11px;margin-top:23px}.chain-option{min-height:74px;font-size:12px}.chain-option:disabled{opacity:.45;cursor:default}.game-scores{display:flex;gap:13px;align-items:center;flex-wrap:wrap}.game-scores>span{display:flex;align-items:center;gap:28px;padding:11px 16px;border:1px solid var(--line);border-radius:10px;font-size:12px}.game-scores>span.current{border-color:#b6cbee;background:var(--blue-soft)}.game-scores strong{font-size:19px;font-weight:500}.game-scores small{color:var(--muted);font-size:11px}.chain-history{border-top:1px solid var(--line);padding-top:22px;margin-top:24px}.chain-history summary{cursor:pointer;font-size:12px;color:var(--blue)}.chain-history-row{padding:18px 0;border-bottom:1px solid var(--line)}.chain-complete{text-align:center;padding:24px 0}.chain-complete h2{font-size:25px;margin:15px 0 8px}.chain-complete p{font-size:13px;color:var(--muted)}.completion-mark{display:inline-grid;place-items:center;width:44px;height:44px;border-radius:50%;color:#378163;background:#e7f4ee;font-size:22px}.peer-panel[hidden]{display:none}.peer-code-grid{display:grid;grid-template-columns:1fr 1fr;gap:25px;margin-top:25px}.peer-code-grid>div>.btn{margin-bottom:16px}.tool-checkbox{font-size:12px;display:flex;align-items:center;gap:9px}.tool-checkbox input{accent-color:var(--blue)}.substance-inventory{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:9px}.substance-card{border:1px solid var(--line);background:var(--surface-alt);border-radius:11px;padding:13px 8px;text-align:center;color:var(--ink);min-width:0}.substance-card:hover{border-color:var(--blue)}.substance-card strong{font-size:19px;font-weight:500;display:block;overflow-wrap:anywhere;line-height:1.5}.substance-card>span{font-size:9px;line-height:1.65;display:block;color:var(--muted);margin-top:6px}.sandbox-inputs{display:grid;grid-template-columns:minmax(0,1fr) 14px minmax(0,1fr);gap:12px;align-items:center}.sandbox-plus{margin-top:8px;color:var(--muted)}.drop-active{outline:2px dashed var(--blue)}.sandbox-result{text-align:center;padding:28px 0 20px;min-height:260px;border-top:1px solid var(--line);margin-top:28px}.sandbox-result h3{margin:14px 0;font-size:19px}.sandbox-result>.tool-equation{justify-content:center}.sandbox-result p{font-size:12px;line-height:1.8;color:var(--muted)}.sandbox-result .observation-text{margin:17px 0}.empty-beaker{color:#8fa9d4;display:flex;justify-content:center;margin:13px 0 20px}.discovery-summary{padding-top:20px;border-top:1px solid var(--line);display:flex;align-items:center;justify-content:center;gap:10px;font-size:11px;color:var(--muted)}.discovery-summary strong{font-size:18px;font-weight:500;color:var(--ink)}.reaction-beaker{position:relative;overflow:hidden;width:95px;height:107px;border:2px solid #90a9c9;border-top:0;border-radius:0 0 18px 18px;margin:0 auto;background:#fbfdff}.beaker-liquid{position:absolute;inset:28px 0 0;background:#dfedf7}.beaker-solid{position:absolute;inset:auto 0 0;height:0;background:var(--precipitate)}.has-precipitate .beaker-solid{height:18px;box-shadow:0 -5px 8px var(--precipitate)}.reaction-beaker i{display:none}.has-gas i{position:absolute;display:block;border:1px solid #89aecd;border-radius:50%;width:9px;height:9px;left:20px;bottom:12px;animation:bubble-rise 2.2s infinite}.has-gas i:nth-last-child(2){left:58px;animation-delay:.7s;width:6px;height:6px}.has-gas i:last-child{left:39px;animation-delay:1.4s}@keyframes bubble-rise{to{transform:translateY(-75px);opacity:0}}.memory-workspace{text-align:center;padding:25px 0 15px;min-height:280px;border-top:1px solid var(--line);margin-top:20px}.memory-workspace h2{font-size:23px;margin:16px 0}.memory-workspace>p{font-size:13px;line-height:1.85;color:var(--muted)}.memory-question{display:flex;align-items:center;flex-wrap:wrap;justify-content:center;gap:16px;margin:28px 0;font-size:28px}.memory-question>strong{font-size:35px;color:var(--blue);font-weight:400}.memory-answer{margin:28px 0;padding:22px;background:var(--bg);border-radius:13px}.memory-answer .tool-equation{justify-content:center}.memory-ratings{display:flex;gap:9px;justify-content:center;flex-wrap:wrap;margin:22px 0}.memory-ratings .btn{font-size:12px;padding:12px 17px}
@media(min-width:1500px){.tool-grid{grid-template-columns:repeat(4,minmax(0,1fr))}}@media(max-width:1150px){.tool-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.tool-split{grid-template-columns:1fr}.model-split{grid-template-columns:minmax(220px,.7fr) minmax(0,1.3fr)}.model-visual{padding:22px}.model-metrics{flex-wrap:wrap}.chain-options{grid-template-columns:1fr}.chain-option{min-height:50px}.tool-frame{height:680px}}
@media(max-width:700px){.tool-category-nav{gap:8px;margin:22px 0 30px}.tool-category-nav a{font-size:10px;padding:10px 12px;gap:8px}.tool-category{margin:27px 0}.tool-category>h2{font-size:19px}.tool-grid{gap:12px}.tool-card{border-radius:14px}.tool-card-art{height:80px}.tool-card-art>span{font-size:21px}.art-editor>span{font-size:48px}.tool-card-copy{padding:16px}.tool-card h3{font-size:14px;line-height:1.6}.tool-card p{font-size:10px;line-height:1.85;margin-bottom:18px}.tool-open{font-size:10px}.tool-panel{padding:20px;margin-top:22px;border-radius:14px}.tool-panel>h2{font-size:19px}.tool-panel>p{font-size:12px}.tool-split,.model-split{grid-template-columns:1fr;gap:0}.tool-form-row{display:grid;grid-template-columns:1fr;gap:0}.tool-form-row>.tool-field{min-width:0}.tool-form-row>.btn{margin-bottom:4px}.tool-field{font-size:11px}.tool-input,.tool-field select{font-size:13px}.tool-equation{font-size:17px;gap:8px}.tool-footer{flex-direction:column;gap:15px;font-size:10px}.tool-footer button{white-space:normal}.tool-notice{display:block;padding:16px}.tool-notice p{font-size:11px}.tool-notice .btn{margin-top:15px}.tool-toolbar{gap:8px}.btn.compact{font-size:10px;padding:9px 12px}.tool-frame-wrap{margin-left:-8px;margin-right:-8px;border-radius:12px}.tool-frame{height:650px}.oc3d-frame{height:760px}.tool-source{font-size:10px}.group-visual #group-drawing{min-height:220px}.model-metrics strong{font-size:26px}.model-metrics>div{font-size:10px}.solution-visual{gap:15px}.solution-visual h3{font-size:15px}.solution-visual p{font-size:11px}.solution-beaker{width:65px;height:78px}.atom-equation{font-size:21px;gap:12px}.atom-term input{width:46px}.chain-map{gap:7px;margin:23px 0}.chain-node{font-size:15px;padding:10px 11px}.chain-question h2{font-size:25px}.chain-question>p{font-size:12px}.game-scores>span{padding:9px 12px;gap:17px;font-size:11px}.game-scores small{width:100%}.peer-code-grid{grid-template-columns:1fr;gap:13px}.substance-inventory{grid-template-columns:repeat(3,minmax(0,1fr));gap:8px}.substance-card{padding:11px 5px}.substance-card strong{font-size:18px}.substance-card>span{font-size:9px}.sandbox-inputs{grid-template-columns:1fr;gap:0}.sandbox-plus{display:none}.sandbox-bench .btn{width:100%}.memory-question{font-size:22px;gap:12px}.memory-workspace h2{font-size:20px}.memory-workspace>p{font-size:12px}.memory-ratings{display:grid;grid-template-columns:1fr 1fr}.memory-ratings .btn{font-size:11px;padding:11px}.metric-value{font-size:29px}.table-scroll{max-width:100%}}
@media(max-width:380px){.tool-grid{grid-template-columns:1fr}.tool-card{display:grid;grid-template-columns:78px minmax(0,1fr)}.tool-card-art{height:100%;min-height:160px}.tool-card-art>span{font-size:16px;writing-mode:horizontal-tb;letter-spacing:0;white-space:normal;overflow-wrap:anywhere;text-align:center}.art-editor>span{font-size:38px;writing-mode:horizontal-tb}.tool-card-copy{padding:16px}.tool-card p{font-size:11px}.tool-card h3{font-size:15px}}
@media(prefers-reduced-motion:reduce){.tool-card{transition:none}.tool-card:hover{transform:none}.has-gas i{animation:none}.atom-bar,.solution-beaker span{transition:none}}

.tool-card,.tool-card:hover{color:var(--ink);text-decoration:none}.tool-card h3{text-decoration:none}
/* Route introductions share the same controls as the tool catalog. */
.btn.compact{font-size:15px;min-height:44px;padding:11px 17px}.instruction-route-links{gap:11px}.tool-category-nav a{font-size:14px}.tool-open{font-size:14px}.tool-card p{font-size:13px}
.structure-group-workspace{display:grid;grid-template-columns:minmax(250px,.85fr) minmax(0,1.15fr);gap:22px;align-items:start;min-width:0}.structure-group-workspace .tool-panel{margin-top:0;max-width:100%;min-width:0}.structure-controls>h2{font-size:17px;margin:22px 0 12px}.structure-controls .group-options{grid-template-columns:repeat(2,minmax(0,1fr));gap:9px;margin:0}.structure-controls .group-option{padding:11px;font-size:13px;min-width:0;overflow-wrap:break-word}.structure-controls .group-option[aria-pressed=true]{background:var(--blue-soft);border-color:var(--blue);color:var(--blue)}.structure-controls .tool-field select{width:100%;min-width:0;max-width:100%;text-overflow:ellipsis}.structure-group-workspace .group-visual{overflow:hidden}.structure-group-workspace .group-visual h2{font-size:22px;overflow-wrap:break-word;margin-bottom:9px}.structure-group-workspace #group-formula{font-size:20px;margin:0 0 16px}.structure-group-workspace #group-drawing{display:block;height:clamp(230px,27vw,360px);min-height:0;width:100%;min-width:0;max-width:100%;overflow:hidden}.structure-group-workspace #group-drawing>.molecule-graphic{display:block;width:100%;height:100%;min-width:0;max-width:100%}.structure-group-workspace #group-drawing svg{display:block;width:100%;height:100%;min-width:0;max-width:100%;max-height:100%;overflow:hidden}.structure-group-workspace #group-source{display:inline-flex;align-items:center;gap:7px;font-size:13px;margin-top:18px}
@media(max-width:1050px){.structure-group-workspace{grid-template-columns:1fr}.structure-group-workspace #group-drawing{height:320px}.structure-controls .group-options{grid-template-columns:repeat(3,minmax(0,1fr))}}
@media(max-width:700px){.btn.compact{font-size:14px;min-height:44px;padding:11px 15px}.tool-category-nav a{font-size:13px}.tool-open{font-size:13px}.tool-card p{font-size:12px}.structure-group-workspace{gap:20px}.structure-group-workspace .tool-panel{padding:20px}.structure-controls .group-options{grid-template-columns:repeat(2,minmax(0,1fr))}.structure-controls .tool-field select{font-size:16px}.structure-group-workspace #group-drawing{height:270px}.structure-group-workspace .group-visual h2{font-size:20px}}
.instruction-route-links{display:flex;flex-wrap:wrap;gap:9px}.learn-content>.page-heading{align-items:flex-start;flex-wrap:wrap}.learn-content>.page-heading>[data-feature=tour]{white-space:normal;max-width:100%;text-align:center;flex-shrink:0}

.tool-footer button{font-size:14px}.tool-field{font-size:14px}.tool-field select{font-size:14px;min-height:44px}.structure-controls .group-option{font-size:14px}.assistant-intro .text-link{font-size:14px}
@media(max-width:700px){.tool-field input,.tool-field select{font-size:16px}}

.oc3d-launch{justify-content:flex-start;flex-wrap:wrap}.oc3d-launch .btn{font-size:15px;min-height:48px;padding:12px 22px}.oc3d-launch p{margin:0}