.ib-lab{max-width:1320px;margin:auto;padding:clamp(14px,3vw,38px);font-family:Helvetica,Arial,sans-serif;color:#173c4a}.ib-lab *{box-sizing:border-box}.ib-heading>span{color:#358f87;font-size:13px;font-weight:800;letter-spacing:.11em;text-transform:uppercase}.ib-heading h2{margin:5px 0;font-size:clamp(34px,5vw,55px);letter-spacing:-.045em}.ib-heading p{margin:0;color:#607984;font-size:17px;line-height:1.55}.ib-layout{display:grid;grid-template-columns:minmax(290px,.72fr) minmax(420px,1.1fr) minmax(250px,.6fr);gap:16px;margin-top:25px;align-items:start}.ib-periodic,.ib-builder,.ib-results{border:1px solid #d4e3e7;border-radius:23px;background:#fff;box-shadow:0 12px 35px rgba(35,75,86,.07);padding:19px;min-width:0}.ib-section-head{display:flex;justify-content:space-between;gap:12px;align-items:center}.ib-section-head small{color:#328d83;font-weight:800;text-transform:uppercase;letter-spacing:.08em}.ib-section-head h3{margin:2px 0;font-size:20px}.ib-section-head>span{color:#67808b;font-size:12px}.ib-table{display:grid;grid-template-columns:repeat(18,minmax(13px,1fr));grid-template-rows:repeat(4,58px);gap:3px;margin-top:18px;overflow-x:auto}.ib-table button{grid-row:var(--row);grid-column:var(--col);min-width:34px;padding:3px 1px;border:1px solid #cbdde2;border-radius:7px;background:#f2f8f8;color:#244b5a;cursor:pointer;transition:transform .18s,background .18s,box-shadow .18s}.ib-table button:hover{transform:translateY(-2px);background:#dff2ee}.ib-table button[aria-selected=true]{background:#258c7e;color:#fff;border-color:#258c7e;box-shadow:0 5px 13px rgba(37,140,126,.24)}.ib-table small,.ib-table strong,.ib-table span{display:block}.ib-table small{font-size:8px}.ib-table strong{font-size:14px}.ib-table span{font-size:8px}.ib-table-note,.ib-tip{color:#6b818a;font-size:12px;line-height:1.45}.ib-reset{border:1px solid #bcd2d7;border-radius:10px;background:#fff;color:#3b6873;padding:8px 11px;cursor:pointer}.ib-stage{position:relative;border-radius:18px;background:radial-gradient(circle at 50% 48%,#f7fbf9,#eaf5f4 70%,#dcecee);overflow:hidden;margin:14px 0}.ib-stage svg{display:block;width:100%;height:auto;max-height:490px}.ib-shell{fill:none;stroke:#aacbd0;stroke-width:2}.ib-shell-label{fill:#729099;font:700 11px Helvetica,Arial,sans-serif}.ib-nucleus-symbol{fill:#fff;font:800 28px Helvetica,Arial,sans-serif}.ib-nucleus-count{fill:#fff;font:700 12px Helvetica,Arial,sans-serif}.ib-electron{cursor:pointer}.ib-electron circle,.ib-flyer circle{fill:#237ba5;stroke:#fff;stroke-width:3;filter:url(#ibGlow)}.ib-electron text,.ib-flyer text{fill:#fff;font:800 14px Helvetica,Arial,sans-serif;pointer-events:none}.ib-electron:hover circle,.ib-electron:focus circle{fill:#e36d55}.ib-flyer{will-change:transform}.ib-electron-bank{position:absolute;right:13px;bottom:11px;display:flex;align-items:center;gap:6px;color:#65808a;font-size:10px}.ib-electron-bank i{display:grid;place-items:center;width:31px;height:31px;border-radius:50%;background:#237ba5;color:#fff;font-style:normal;font-weight:800}.ib-actions{display:grid;grid-template-columns:1fr 1fr;gap:9px}.ib-actions button,.ib-challenge{min-height:54px;padding:9px;border:1px solid #bcd4d9;border-radius:13px;background:#f7fbfb;color:#265262;font:700 14px Helvetica,Arial,sans-serif;cursor:pointer}.ib-actions button:first-child{border-color:#e8b6aa;background:#fff6f2}.ib-actions button:last-child{border-color:#9dcfc7;background:#edf9f5}.ib-actions button>span{font-size:20px;margin-right:5px}.ib-actions small{display:block;color:#72868d}.ib-actions button:disabled{opacity:.4}.ib-results{text-align:center;position:sticky;top:18px}.ib-ion-tile{width:145px;height:155px;margin:4px auto 14px;border:1px solid #bad4d8;border-radius:18px;background:linear-gradient(145deg,#f7fbfa,#e6f3f1);display:flex;flex-direction:column;align-items:center;justify-content:center}.ib-ion-tile>small{font-size:11px;color:#66828c}.ib-ion-tile>strong{font-size:62px;line-height:1}.ib-ion-tile sup{font-size:25px;vertical-align:top;margin-left:3px}.ib-ion-tile>span{font-size:12px;color:#57737c;margin-top:5px}.ib-charge{padding:8px;border-radius:10px;font-size:13px;font-weight:800}.ib-charge.positive{background:#fff0e9;color:#bd573d}.ib-charge.negative{background:#e8f3ff;color:#286eaa}.ib-charge.neutral{background:#eef5f2;color:#35776c}.ib-results dl{margin:14px 0;text-align:left}.ib-results dl>div{display:flex;justify-content:space-between;gap:10px;padding:9px 0;border-bottom:1px solid #e2ecee}.ib-results dt{font-size:12px;color:#667f88}.ib-results dd{margin:0;font-weight:800}.ib-equation{padding:12px;border-radius:11px;background:#f2f6f7;font-size:13px}.ib-equation b{font-size:18px}.ib-results article{text-align:left;margin:13px 0;font-size:13px;line-height:1.5;color:#465f69}.ib-results article span{color:#68818a}.ib-challenge{width:100%;background:#245f72;color:#fff}.ib-feedback{font-size:12px;color:#758991}.ib-feedback.correct{color:#218866;font-weight:800}.ib-lab button:focus-visible,.ib-electron:focus-visible{outline:3px solid #57b4b0;outline-offset:3px}@media(max-width:1050px){.ib-layout{grid-template-columns:1fr 1fr}.ib-periodic{grid-column:1/-1}.ib-results{position:static}}@media(max-width:690px){.ib-layout{grid-template-columns:1fr}.ib-periodic{grid-column:auto}.ib-table{grid-template-columns:repeat(18,36px);padding-bottom:8px}.ib-builder,.ib-periodic,.ib-results{padding:14px}.ib-actions{grid-template-columns:1fr}.ib-heading p{font-size:15px}}@media(prefers-reduced-motion:reduce){.ib-table button{transition:none}}