.fl-body{max-width:920px}.fl-body h2{margin:20px 0}.fl-content{font-size:15px;line-height:1.9;min-height:230px}.fl-content>p{margin:0 0 18px}.fl-lead{font-size:21px;color:#245e80}.fl-intro,.fl-summary{background:#f2f8fc;padding:24px;border:1px solid #dcebf4;border-radius:14px}.fl-intro p{font-size:13px;color:#668294;margin:12px 0 0}.fl-formula{font-size:19px;font-weight:600;padding:20px;background:#edf6fb;border-left:3px solid #5ba0c6;border-radius:6px;overflow-wrap:anywhere;margin:20px 0;color:#1b587b}.fl-example{list-style:none;counter-reset:example;padding:0;display:grid;gap:17px}.fl-example li{counter-increment:example;position:relative;padding:19px 20px 19px 62px;background:#f7fafc;border:1px solid #e2edf4;border-radius:12px}.fl-example li:before{content:counter(example);position:absolute;left:19px;top:19px;display:grid;place-items:center;width:27px;height:27px;background:#e1eff8;border-radius:50%;color:#33789e;font-size:12px}.fl-interactive{background:#f7fbfd;padding:24px;border:1px solid #d7e8f3;border-radius:15px}.fl-controls{display:grid;gap:23px;margin:25px 0}.fl-controls label{display:block}.fl-controls label>span{display:flex;justify-content:space-between;gap:15px;font-size:13px}.fl-controls b{color:#277da9}.fl-controls input[type=range]{width:100%;display:block;margin:16px 0 4px;accent-color:#3c91bd;min-height:30px}.fl-choices{display:flex;flex-wrap:wrap;gap:10px;margin:20px 0}.fl-choices button[aria-pressed=true]{background:#235c7e;color:#fff}.fl-live{background:#fff;border:1px solid #dfeaf2;padding:20px;border-radius:12px;min-height:95px}.fl-live h3{font-size:17px;margin:0 0 8px}.fl-live p{font-size:14px}.fl-values{display:grid;grid-template-columns:repeat(auto-fit,minmax(160px,1fr));gap:18px}.fl-values>div{display:flex;flex-direction:column;gap:6px}.fl-values span{font-size:11px;color:#718a9b}.fl-values strong{font-size:23px;color:#215f83;line-height:1.5;overflow-wrap:anywhere}.fl-values small{font-size:12px;font-weight:400}.fl-note{font-size:12px;color:#718797;line-height:1.8}.fl-plot{width:100%;max-height:100px}.fl-bar{font-size:11px;color:#668496;margin-bottom:20px}.fl-bar>div{height:14px;background:#e9f2f8;margin:8px 0;border-radius:8px;overflow:hidden}.fl-bar i{display:block;background:#5bafd1;height:100%}.fl-question{border:1px solid #dfeaf2;border-radius:12px;margin:23px 0;padding:18px}.fl-question legend{font-size:14px;font-weight:600;padding:0 7px;color:#214b65;line-height:1.7}.fl-question label{display:flex;align-items:flex-start;gap:10px;padding:10px 12px;border-radius:8px;margin:5px 0;background:#f7fafc;cursor:pointer;font-size:13px}.fl-question input{accent-color:#3487b5;flex-shrink:0;margin-top:6px}.fl-question label:has(input:checked){background:#e5f2fb;outline:1px solid #a6cde4}.fl-result{padding:25px;background:#fff6e9;border:1px solid #ecdbbe;border-radius:13px}.fl-result.passed{background:#ebf8f2;border-color:#c2e3d4}.fl-result>strong{font-size:30px;color:#245b76}.fl-result h3{font-size:20px;margin:10px 0}.fl-result p{font-size:12px}.fl-review{display:grid;gap:15px;margin-top:22px}.fl-review article{border:1px solid #e2eaf0;border-left:3px solid #d6a66b;border-radius:8px;padding:18px}.fl-review article.correct{border-left-color:#65ae91}.fl-review strong{font-size:14px}.fl-review p{font-size:12px;margin:8px 0 0}.fl-summary h3{font-size:20px;margin:0 0 14px}.fl-summary ul{padding-left:22px}.fl-sources{font-size:12px;color:#657f91;margin-top:25px}.fl-sources summary,.fl-history summary{cursor:pointer}.fl-sources a{display:block;margin-top:10px;color:#2e79a3}.fl-history{padding:15px;border-bottom:1px solid #e2ebf1}.fl-body .actions{flex-wrap:wrap}@media(max-width:650px){.fl-content{font-size:14px}.fl-lead{font-size:18px}.fl-interactive,.fl-intro,.fl-summary{padding:17px}.fl-values{grid-template-columns:1fr}.fl-formula{font-size:16px;padding:15px}.fl-question{padding:13px}.fl-example li{padding-left:53px}.fl-controls input[type=range]{min-height:40px}}

/* v28.3 teaching typography, fractions and responsive laboratory controls. */
.fl-fraction{display:inline-flex;flex-direction:column;vertical-align:middle;text-align:center;line-height:1.35;margin:.2em .2em;max-width:100%;font-variant-numeric:tabular-nums;font-weight:500}
.fl-fraction>span{display:block;padding:.12em .35em;overflow-wrap:anywhere}
.fl-fraction>span:first-child{border-bottom:1.4px solid currentColor}
.fl-formula{line-height:2.1;font-size:18px}
.fl-intro p{font-size:15px;line-height:1.9}
.fl-intro .fx-intro-use{border-top:1px solid #dcebf4;padding-top:14px}
.fx-control{display:grid;grid-template-columns:minmax(0,1fr) 130px;align-items:center;gap:10px}
.fx-control>label{font-size:14px}
.fx-control input[type=number],.fx-unit-selects select,.fx-material select{box-sizing:border-box;width:100%;border:1px solid #c4dbe9;background:white;color:#245d7d;border-radius:8px;padding:10px;font:inherit;min-width:0}
.fx-control input[type=range]{grid-column:1/-1;width:100%;margin:0}
.fx-unit-selects{display:grid;grid-template-columns:1fr 1fr;gap:16px}
.fx-unit-selects label,.fx-material{display:grid;gap:8px;font-size:14px}
.fx-material{max-width:450px;margin-bottom:20px}
.fx-table-wrap{overflow-x:auto;margin:22px 0;border:1px solid #dce8f0;border-radius:10px}
.fx-table{width:100%;border-collapse:collapse;font-size:14px;line-height:1.6}
.fx-table caption{text-align:left;padding:15px;background:#edf6fb;font-weight:600;color:#275c7b}
.fx-table th,.fx-table td{padding:12px;text-align:left;border-bottom:1px solid #e1ebf1;white-space:normal}
.fx-table th{background:#f3f8fb;font-weight:600}
.fx-explanation{background:#edf7fb;border-left:3px solid #6aa9ca;padding:17px 20px;border-radius:7px;margin-top:18px;font-size:14px;line-height:1.9;color:#355c74}
.fx-plot{display:block;width:100%;max-height:190px;margin:20px 0}
.fl-values span{font-size:13px}
.fl-review .fl-fraction{font-size:14px}
@media(max-width:650px){.fx-control{grid-template-columns:minmax(0,1fr) 105px}.fx-unit-selects{grid-template-columns:1fr}.fx-explanation{padding:14px}.fx-table th,.fx-table td{padding:8px}.fl-formula{font-size:16px}.fl-intro p{font-size:14px}}

.fx-derivation th:first-child,.fx-derivation td:first-child{width:55px;text-align:center}.fx-derivation td:last-child{min-width:180px;color:#245d7d}.fx-derivation td{vertical-align:middle}