.isotope-hub-hero{border-bottom:1px solid #c9d9dc;background:linear-gradient(135deg,#eef7f7 0%,#fff 60%,#fff5ed 100%)}
.isotope-hero-grid{display:grid;grid-template-columns:minmax(0,1.4fr) minmax(270px,.6fr);gap:42px;align-items:center}.isotope-hero-demo{border:1px solid #bfd2d6;background:#fff;border-radius:20px;padding:24px;box-shadow:0 16px 36px rgba(18,56,69,.08);display:grid;gap:13px}.isotope-demo-nuclides{display:flex;gap:13px;align-items:end;justify-content:center;font-family:Georgia,"Times New Roman",serif;color:var(--navy);font-size:1.65rem}.isotope-demo-nuclides span{min-width:54px;text-align:center}.isotope-demo-bars{height:110px;border-left:2px solid #8eabad;border-bottom:2px solid #8eabad;display:flex;align-items:end;justify-content:space-around;gap:18px;padding:0 18px}.isotope-demo-bars i{display:block;width:38px;height:var(--h);background:linear-gradient(180deg,#0b8b9d,#0b6476);border-radius:7px 7px 0 0}.isotope-hero-demo>strong{text-align:center;color:var(--navy);font-family:Georgia,"Times New Roman",serif}.isotope-hero-demo>small{text-align:center;color:var(--muted);line-height:1.35}
.isotope-board-strip{padding-top:30px;padding-bottom:10px;display:flex;align-items:end;justify-content:space-between;gap:26px}.isotope-board-strip h2{margin-bottom:5px}.isotope-board-strip p{margin:0;color:var(--muted);max-width:760px}.isotope-board-strip nav{display:flex;gap:6px;flex-wrap:wrap;justify-content:flex-end}.isotope-board-strip nav a{border:1px solid #a9c2c7;border-radius:999px;padding:8px 12px;text-decoration:none;font-weight:800;color:var(--navy);background:#fff}.isotope-board-strip nav a.is-active{background:#0b7180;color:#fff;border-color:#0b7180}
.isotope-picker{padding-top:36px}.isotope-tool-list{border-top:1px solid #c8d7da}.isotope-tool-row{display:grid;grid-template-columns:54px minmax(0,1fr) auto;gap:18px;align-items:center;padding:18px 4px;border-bottom:1px solid #c8d7da;text-decoration:none;color:var(--ink)}.isotope-tool-row:hover{background:#f4f9f9;color:var(--ink)}.isotope-row-icon{width:44px;height:44px;border-radius:12px;background:#e9f5f5;display:grid;place-items:center}.isotope-row-icon svg{width:26px;height:26px}.isotope-row-copy{display:grid;gap:4px}.isotope-row-copy strong{font-family:Georgia,"Times New Roman",serif;color:var(--navy);font-size:1.08rem}.isotope-row-copy small{color:var(--muted);line-height:1.4}.isotope-tool-row>b{color:#087487;font-size:.86rem;white-space:nowrap}
.isotope-tof-callout .split-callout{align-items:center}.isotope-method-grid{display:grid;grid-template-columns:minmax(0,1.25fr) minmax(280px,.75fr);gap:38px;align-items:start}.isotope-equation{padding:16px 18px;border:1px solid #c8d7da;background:#f8fbfb;border-radius:12px;color:var(--navy);font-size:1.08rem}.isotope-exam-notes{border-left:4px solid #0b8797;background:#f1f8f8;padding:22px 24px}.isotope-exam-notes h3{margin-top:0;color:var(--navy)}.isotope-exam-notes p:last-child{margin-bottom:0}.isotope-hard-note{display:flex;align-items:center;justify-content:space-between;gap:34px}.isotope-hard-note>div{max-width:820px}.isotope-hard-note h2{margin-bottom:6px}.isotope-hard-note p{margin:0;color:var(--muted)}
.isotope-practice-hero{background:linear-gradient(180deg,#f2f8f8,#fff);border-bottom:1px solid #c8d7da}.isotope-breadcrumb{display:flex;gap:8px;align-items:center;font-size:.83rem;color:var(--muted);margin-bottom:13px}.isotope-breadcrumb a{color:#087384}.isotope-hero-skills{display:flex;gap:7px;flex-wrap:wrap;margin-top:16px}.isotope-hero-skills span{border:1px solid #c7d8da;background:#fff;border-radius:999px;padding:5px 9px;font-size:.75rem;font-weight:800;color:#49636c}
.isotope-practice-shell{max-width:1060px}.isotope-app{border:1px solid #bad0d4;border-radius:22px;overflow:hidden;background:#fff;box-shadow:0 18px 48px rgba(20,59,70,.09)}.isotope-app-header{display:flex;justify-content:space-between;align-items:center;gap:20px;padding:24px 30px;border-top:6px solid #176b7c;border-bottom:1px solid #c8d8db}.isotope-app-header h2{margin:0;color:var(--navy);font-family:Georgia,"Times New Roman",serif}.isotope-app-header .eyebrow{margin-bottom:6px}.isotope-session-summary{display:flex;gap:8px}.isotope-session-summary span{min-width:104px;border:1px solid #c6d7da;border-radius:13px;padding:10px;text-align:center}.isotope-session-summary strong{display:block;font-size:1.35rem;color:var(--navy)}.isotope-session-summary small{font-size:.68rem;color:var(--muted)}
.isotope-toolbar{display:grid;grid-template-columns:minmax(250px,1.25fr) minmax(150px,.6fr) auto;gap:16px;align-items:end;padding:20px 30px;background:#f2f7f7;border-bottom:1px solid #c8d8db}.isotope-toolbar label{display:grid;gap:6px;font-weight:800;color:var(--navy);font-size:.83rem}.isotope-toolbar label small{font-weight:500;color:var(--muted);line-height:1.35;max-width:430px}.isotope-toolbar select{min-height:42px;border:1px solid #9eb9bf;border-radius:10px;background:#fff;padding:0 12px;font:inherit;color:var(--ink)}
.isotope-question-stage{padding:26px 30px 30px}.isotope-question-meta{display:flex;gap:7px;flex-wrap:wrap;margin-bottom:16px}.isotope-question-meta span{font-size:.72rem;font-weight:800;background:#edf4f3;border:1px solid #d0dfdd;color:#49636b;border-radius:999px;padding:5px 9px}.isotope-question{border:1px solid #d4dfde;background:#fafbf9;border-radius:15px;padding:22px 24px;line-height:1.5}.isotope-question h3{font-family:Georgia,"Times New Roman",serif;color:var(--navy);margin:0 0 12px}.isotope-question p:first-child{margin-top:0}.isotope-question p:last-child{margin-bottom:0}.isotope-symbol{white-space:nowrap;font-family:Georgia,"Times New Roman",serif;font-size:1.06em}.isotope-symbol sup{font-size:.68em;vertical-align:.62em;margin-right:1px}.isotope-data-table{width:100%;border-collapse:collapse;margin:14px 0 5px;background:#fff}.isotope-data-table th,.isotope-data-table td{border:1px solid #cbdada;padding:9px 11px;text-align:center}.isotope-data-table th{background:#edf5f5;color:var(--navy);font-size:.82rem}.isotope-spectrum{display:grid;grid-template-columns:repeat(var(--peaks,4),1fr);align-items:end;gap:10px;height:150px;border-left:2px solid #9db7bc;border-bottom:2px solid #9db7bc;padding:12px 12px 0;margin:18px 0 8px;background:#fff}.isotope-spectrum .peak{height:calc(var(--height)*1%);min-height:3px;background:#0b8292;position:relative;border-radius:3px 3px 0 0}.isotope-spectrum .peak span{position:absolute;bottom:-27px;left:50%;transform:translateX(-50%);font-size:.72rem;color:#526b73;white-space:nowrap}.isotope-spectrum-wrap{padding-bottom:25px}.isotope-ratio-strip{display:flex;gap:12px;align-items:end;height:130px;margin:18px 0 4px}.isotope-ratio-strip span{flex:1;display:grid;align-items:end;justify-items:center;gap:5px;height:100%}.isotope-ratio-strip i{display:block;width:42px;height:calc(var(--h)*1%);background:#0b8292;border-radius:4px 4px 0 0}.isotope-ratio-strip b{font-size:.72rem;color:var(--muted)}
.isotope-answer{display:flex;gap:18px;align-items:end;justify-content:space-between;margin-top:22px}.isotope-answer-control{flex:1}.isotope-number-answer{display:grid;gap:7px;font-weight:800;color:var(--navy);max-width:430px}.isotope-number-entry{display:flex;border:1px solid #9db7bc;border-radius:10px;overflow:hidden;background:#fff}.isotope-number-entry input{flex:1;min-width:0;border:0;padding:12px 14px;font:inherit}.isotope-number-entry b{display:grid;place-items:center;padding:0 13px;color:#536a72;background:#f4f7f7;font-size:.83rem}.isotope-options{border:0;padding:0;margin:0;display:grid;gap:9px}.isotope-options legend{font-weight:800;color:var(--navy);margin-bottom:8px}.isotope-options label{display:flex;gap:10px;align-items:flex-start;border:1px solid #c5d7d9;border-radius:10px;padding:11px 13px;background:#fff;cursor:pointer}.isotope-options label:hover{background:#f4f9f9}.isotope-options input{margin-top:3px}.isotope-help-row{display:flex;gap:24px;margin:15px 2px 0}.isotope-solution{margin-top:18px}.isotope-solution .math-line{display:block;margin:8px 0;padding:9px 12px;background:#fff;border-left:3px solid #8bbdc3}.isotope-next-step,.isotope-progress-nudge{margin-top:22px;border:1px solid #b9d4d8;background:#eef8f8;border-radius:14px;padding:18px 20px}.isotope-next-step{display:flex;align-items:center;justify-content:space-between;gap:20px}.isotope-next-step h3{margin:0 0 4px;color:var(--navy)}.isotope-next-step p,.isotope-progress-nudge p{margin:0;color:var(--muted)}.isotope-progress-nudge{display:flex;justify-content:space-between;align-items:center;gap:18px}.isotope-progress-nudge a{font-weight:800;color:#087384}.isotope-app-footer{display:flex;justify-content:space-between;gap:20px;padding:17px 30px;background:#f7faf9;border-top:1px solid #c8d8db;font-size:.82rem}.isotope-app-footer a{font-weight:800;color:#087384}.isotope-app-footer span{color:var(--muted);text-align:right}
.isotope-related-grid{display:grid;grid-template-columns:repeat(4,1fr);border-top:1px solid #c8d7da;border-left:1px solid #c8d7da}.isotope-related-grid a{display:grid;gap:5px;padding:18px;border-right:1px solid #c8d7da;border-bottom:1px solid #c8d7da;text-decoration:none;background:#fff;color:var(--ink)}.isotope-related-grid a:hover{background:#f4f9f9}.isotope-related-grid strong{color:var(--navy)}.isotope-related-grid small{color:var(--muted)}
@media(max-width:900px){.isotope-hero-grid{grid-template-columns:1fr}.isotope-hero-demo{max-width:460px}.isotope-board-strip{align-items:start;flex-direction:column}.isotope-board-strip nav{justify-content:flex-start}.isotope-tool-row{grid-template-columns:48px 1fr auto}.isotope-method-grid{grid-template-columns:1fr}.isotope-toolbar{grid-template-columns:1fr 1fr}.isotope-toolbar>.button{grid-column:2}.isotope-related-grid{grid-template-columns:repeat(2,1fr)}}
@media(max-width:620px){.isotope-app-header{align-items:flex-start;flex-direction:column;padding:20px}.isotope-session-summary{width:100%}.isotope-session-summary span{flex:1;min-width:0}.isotope-toolbar{grid-template-columns:1fr;padding:18px 20px}.isotope-toolbar>.button{grid-column:auto;width:100%}.isotope-question-stage{padding:20px}.isotope-answer{align-items:stretch;flex-direction:column}.isotope-answer>.button{width:100%}.isotope-next-step,.isotope-progress-nudge,.isotope-hard-note{align-items:stretch;flex-direction:column}.isotope-app-footer{flex-direction:column;padding:16px 20px}.isotope-app-footer span{text-align:left}.isotope-tool-row{grid-template-columns:44px 1fr}.isotope-tool-row>b{grid-column:2}.isotope-related-grid{grid-template-columns:1fr}.isotope-demo-bars{height:90px}}
.isotope-multi-answer{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px;max-width:650px}@media(max-width:620px){.isotope-multi-answer{grid-template-columns:1fr}}