/* New v19 math + chemistry course styling: all selectors namespaced, previous lessons untouched. */
.tl-new-lesson{--tl-blue:#287fae;--tl-deep:#174b70;--tl-sky:#e9f6fc;--tl-line:#cee4ef;--tl-muted:#5b7f93;color:#365c73;font-size:13.5px;line-height:1.82;min-width:0}
.tl-extra-body{min-width:0}.tl-extra-nav .steps{max-height:calc(100vh - 240px);overflow-y:auto;scrollbar-width:thin}.tl-course-label{display:flex;flex-wrap:wrap;justify-content:space-between;gap:10px;align-items:center}.tl-course-label>span+span{font-size:11px;color:#7899ad}
.tl-new-lesson h3{color:#205c80;font-size:19px;line-height:1.5;margin:7px 0 12px}.tl-new-lesson h4{color:#205c80;font-size:15px;margin:7px 0}.tl-new-lesson strong{color:#255879}
.tl-new-lesson button{cursor:pointer}.tl-new-lesson button:disabled{cursor:not-allowed;opacity:.48}
.tl-new-lesson .tl-feature{background:linear-gradient(130deg,#e7f5fc,#fff 78%);border:1px solid #cee6f2;border-radius:17px;padding:24px;margin:0 0 26px;overflow:hidden}.tl-feature h3{font-size:21px;max-width:760px;margin:0 0 8px}.tl-feature p{margin:5px 0 10px;font-size:13px;line-height:1.85;color:#4c7790}.tl-feature-tags{display:flex;gap:7px;flex-wrap:wrap;margin:16px 0 0}.tl-feature-tags span{font-size:11px;background:#fff;color:#347ea5;padding:5px 11px;border-radius:100px;border:1px solid #cde5f0;font-weight:700}
.tl-widget{margin:0 0 26px;padding:20px 22px;background:#fff;border:1px solid var(--tl-line);border-radius:16px;box-shadow:0 9px 21px #8eb9ce13;min-width:0}.tl-widget h3{margin-top:0}.tl-widget-sub{font-size:12px;color:#5c839c;margin:3px 0 17px;line-height:1.85}.tl-widget-head{display:flex;justify-content:space-between;align-items:center;gap:9px;flex-wrap:wrap}.tl-widget-head b{font-size:11px;color:#4391b4;letter-spacing:.6px}.tl-grid-2{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:13px}.tl-grid-3{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:10px}.tl-control{display:block;padding:12px 14px;background:#f7fbfe;border:1px solid #dfedf4;border-radius:11px;min-width:0;color:#517892;font-size:12px;font-weight:700}.tl-control span{display:flex;justify-content:space-between;gap:8px}.tl-control output{font-weight:850;color:#2375a1}.tl-control input[type=range]{display:block;margin:11px 0 3px;width:100%;accent-color:#248dbb;cursor:pointer}.tl-control input[type=number],.tl-control select{display:block;width:100%;padding:9px 10px;margin-top:7px;border:1px solid #c2dbe9;border-radius:8px;background:#fff;color:#245c7d;font:inherit}.tl-result{background:linear-gradient(135deg,#edf8fe,#fafdfd);border:1px solid #d4e9f4;border-radius:12px;padding:16px;text-align:center;min-width:0;margin:12px 0}.tl-result span,.tl-result small{display:block;font-size:11px;color:#6288a0}.tl-result b{display:block;font-size:28px;line-height:1.48;word-break:break-word;color:#146b9b;font-variant-numeric:tabular-nums}.tl-step-note{font-size:12px;color:#52788e;margin:10px 0;line-height:1.8}.tl-note{background:#eff7fc;border-left:3px solid #69afd1;border-radius:8px;padding:12px 14px;font-size:12px;color:#4a7188;margin:15px 0}.tl-warn{background:#fff8ed;border-left-color:#e6b071;color:#84633d}.tl-good{background:#ecf9f3;border-left-color:#65b38d;color:#256b50}.tl-answer{min-height:38px;font-size:12px;padding:9px 12px;border-radius:9px;background:#f0f7fc;margin:12px 0;line-height:1.8}.tl-answer.correct{background:#eaf8f0;color:#266b4e}.tl-answer.wrong{background:#fff3eb;color:#945d3b}.tl-choice-list{display:grid;gap:8px;margin:12px 0}.tl-choice-list button{text-align:left;width:100%;padding:12px 15px;border-radius:10px;border:1px solid #d3e5ef;background:#fbfdff;color:#285977;font-size:13px;line-height:1.7}.tl-choice-list button:hover,.tl-choice-list button:focus-visible{background:#eaf6fc;border-color:#80b8d3}.tl-choice-list button.chosen{border-color:#348eb9;background:#e8f5fc}.tl-flex-actions{display:flex;gap:9px;flex-wrap:wrap;margin:13px 0}.tl-flex-actions .button{font-size:12px;padding:9px 13px}.tl-option-tab{display:inline-flex;border:1px solid #cfe4ee;border-radius:9px;background:#fff;font-size:12px;color:#307ba2;padding:8px 12px;margin:3px;cursor:pointer}.tl-option-tab.active{background:#227ba8;color:#fff;border-color:#227ba8}
.tl-area-diagram{display:block;max-width:100%;height:auto;margin:10px auto}.tl-tile{padding:14px 12px;border-radius:10px;border:1px solid #d1e5ef;text-align:center;background:#f4faff}.tl-tile b{display:block;color:#1f739d;font-size:19px;font-variant-numeric:tabular-nums}.tl-tile small{font-size:11px;color:#6b8ca2}.tl-tile.pos{background:#e5f5fb}.tl-tile.neg{background:#fff2e8;border-color:#efceab}.tl-formula-frame{padding:16px 12px;border:1px dashed #aad2e5;border-radius:10px;background:#f7fcff;text-align:center;color:#185f85;line-height:1.8;margin:11px 0;font-size:17px;overflow-wrap:anywhere}.tl-math-tag{font-weight:850;letter-spacing:.7px;color:#438eb4;font-size:10px}
.tl-beaker{max-width:350px;margin:13px auto;display:block;width:100%}.tl-beaker-label{text-anchor:middle;fill:#1b658b;font-weight:bold;font-size:15px;font-family:'Segoe UI',Arial,sans-serif}.tl-beaker-grid{display:grid;grid-template-columns:1fr 1fr;gap:15px;align-items:center}.tl-beaker-grid .tl-result{margin:0}
.tl-reading-head{display:flex;justify-content:space-between;gap:9px;align-items:center;border-bottom:1px solid #dceaf2;color:#408aaf;font-size:10px;font-weight:900;letter-spacing:1.4px;margin:29px 0 20px;padding-bottom:11px}.tl-reading-head small{font-size:10px;color:#88a3b3;font-weight:500;letter-spacing:0}
.tl-original-material{color:#365d74;overflow-wrap:break-word}.tl-original-material p{font-size:13.5px;line-height:1.85;margin:10px 0}.tl-original-material h3{font-size:17px;margin:22px 0 8px}.tl-original-material h4{font-size:14px;margin:15px 0 7px}.tl-original-material li{font-size:13px;line-height:1.8;padding-left:1px;margin:4px 0}.tl-original-material table{width:100%;display:block;overflow-x:auto;border-collapse:collapse;margin:18px 0;font-size:12px;white-space:normal}.tl-original-material th,.tl-original-material td{border:1px solid #d5e6ef;padding:10px 12px;min-width:115px}.tl-original-material th{color:#215d81;background:#eef7fc}.tl-original-material blockquote{border-left:3px solid #6facce;background:#f0f9fe;padding:12px 18px;border-radius:0 9px 9px 0;color:#41708a;margin:17px 0}.tl-original-material blockquote p{margin:3px 0}.tl-original-material hr{border:0;border-top:1px solid #e4edf3;margin:22px 0}.tl-original-material .tl-math-render{color:#1e638a}.tl-original-material .tl-math-render[display=true]{display:block;overflow-x:auto;text-align:center;background:#f7fbfe;border:1px solid #e0edf4;border-radius:9px;padding:12px 7px;margin:12px 0}.tl-original-material .tl-math-render:not([display=true]){display:inline-block;vertical-align:middle;line-height:1.2;max-width:100%}.tl-original-material .tl-math-render svg{max-width:none;vertical-align:middle}.tl-original-material .tl-math-render[display=true] svg{max-width:100%;height:auto;max-height:100px}.tl-original-material .tl-math-render:not([display=true]) svg{max-width:100%;height:auto}.tl-original-material li .tl-math-render svg{max-height:50px}.tl-original-material table .tl-math-render svg{max-height:52px}
.tl-q-menu{display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:5px;margin:10px 0 17px}.tl-q-menu button{padding:8px 4px;font-size:11px;color:#307ca2;border:1px solid #cde4f0;background:#f8fcfe;border-radius:8px;font-weight:700}.tl-q-menu button.sel{background:#287eaa;color:white}.tl-q-menu button.done{border-color:#7abe9c}.tl-q-score{font-size:12px;color:#547f98;margin:12px 0}.tl-order-line{display:flex;align-items:center;gap:9px;background:#f8fcfe;border:1px solid #d9e8f0;border-radius:9px;padding:9px;margin:7px 0}.tl-order-line span{flex:1;font-size:12px}.tl-order-line button{padding:6px 9px;background:#eaf5fc;border:1px solid #c9e1ef;color:#277baa;border-radius:7px}
@media(max-width:900px){.tl-extra-nav .steps{max-height:315px}.tl-widget{padding:16px}}
@media(max-width:720px){.tl-grid-3,.tl-grid-2,.tl-beaker-grid{grid-template-columns:1fr}.tl-widget{padding:15px}.tl-feature{padding:18px}.tl-reading-head small{display:none}.tl-q-menu{grid-template-columns:repeat(5,minmax(0,1fr))}.tl-original-material th,.tl-original-material td{min-width:88px}}

/* v20 microlearning: short readings, airy diagrams, focus on practice */
.tl-extra-body .tl-reading-head{margin:13px 0 12px}
.tl-extra-nav .steps{max-height:initial;overflow:visible}
.tl-new-lesson{line-height:1.62}.tl-original-material{padding:12px 16px 14px;background:#f8fcfe;border:1px solid #e3edf4;border-radius:14px;margin-bottom:12px}
.tl-original-material p{font-size:13px;line-height:1.7;margin:7px 0}.tl-original-material p:first-child{margin-top:2px}
.tl-mini-tip{margin:10px 0 0;background:#e9f5fc;border-left:3px solid #439ec7;border-radius:8px;padding:10px 13px;color:#39708b;font-size:12px}
.tl-key-points{margin:6px 0 4px;padding-left:18px}.tl-key-points li{margin:5px 0;font-size:12.8px}
.tl-geo-explorer{padding:18px 20px 15px;margin-bottom:14px}
.tl-geo-stage{background:radial-gradient(circle at 53% 40%,#fff 0%,#f4fbff 68%,#e9f5fd 100%);border:1px solid #e0edf5;border-radius:15px;margin:11px 0;padding:4px 8px;overflow:hidden;min-height:205px;display:flex;align-items:center;justify-content:center;flex-direction:column}
.tl-geo-svg{max-width:100%;width:min(100%,560px);height:auto;display:block}
.tl-geo-part{transition:transform .28s ease,opacity .24s ease}.tl-geo-face{transition:opacity .28s ease,fill .28s ease}
.tl-geo-choose{display:flex;align-items:center;justify-content:center;gap:5px;flex-wrap:wrap;margin:7px auto -4px;font-size:11px;color:#62869c}
.tl-geo-chip{padding:5px 8px;border-radius:6px;background:#fff;border:1.5px solid var(--chip);color:#38738f;font-size:11px}.tl-geo-chip.on{background:var(--chip);color:#123d5a;font-weight:750}
.tl-geo-insight{padding:11px 13px;background:#edf8fb;color:#296f8a;border-radius:10px;font-size:12px;line-height:1.65}
.tl-geo-explorer .tl-result{margin:7px 0}.tl-geo-explorer .tl-result b{font-size:22px}
.tl-practice-switch{display:flex;flex-wrap:wrap;gap:7px;margin:1px 0 13px}.tl-practice-switch .tl-option-tab{margin:0}
.tl-quick-start{margin-bottom:15px!important;padding:18px 20px!important}
.tl-quick-start h3{font-size:20px}.tl-quick-start .button{margin-top:12px}
.tl-recap-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:8px}.tl-recap-grid>div{padding:10px 12px;background:#fff;border:1px solid #dfedf3;border-radius:10px}.tl-recap-grid b{display:block;font-size:12px}.tl-recap-grid small{display:block;margin-top:4px;white-space:normal;overflow-wrap:anywhere;font-size:12px;color:#236b93}.tl-recap-grid span{display:inline-block;background:#d7ebfa;border-radius:100%;width:19px;text-align:center;font-size:10px;margin-right:5px}
@media(max-width:640px){.tl-recap-grid{grid-template-columns:1fr}.tl-geo-explorer{padding:13px 11px}.tl-geo-stage{min-height:155px;padding:2px}.tl-geo-svg{width:100%}.tl-original-material{padding:12px}}