/* Accessible local SVG lessons. Playback is user-initiated, never infinite. */
.vb-block{margin:30px 0 38px;background:#fff;border:1px solid #c7dcd5;border-radius:12px;overflow:hidden;scroll-margin-top:85px;min-width:0}
.vb-intro{padding:23px 25px 16px;background:linear-gradient(135deg,#eef7f2,#f7f9f4)}
.vb-kicker{font-size:12px;font-weight:750;letter-spacing:.09em;color:#166c69;margin-bottom:8px}
.vb-intro h2,.vb-intro h3{border:0;margin:4px 0 12px;padding:0;font-size:23px;line-height:1.6}
.vb-intro p{font-size:17px;line-height:1.95;margin:10px 0}.vb-question{font-weight:650;color:#234844}
.vb-terms{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:12px;margin:18px 0 10px}.vb-term{background:#fff;border:1px solid #dce8e2;border-radius:7px;padding:11px 13px;font-size:15px;line-height:1.8}.vb-term strong{display:block;color:#166c69}
.vb-scenario{padding:15px 24px;border-top:1px solid #e0eae4;border-bottom:1px solid #e0eae4;background:#faf9f3;font-size:15px;line-height:1.9}.vb-scenario strong{color:#795719}
.vb-player{padding:20px 23px;background:#fff;min-width:0}.vb-player:focus-visible{outline:3px solid #9f692b;outline-offset:-3px}
.vb-player h3{margin:0 0 13px;font-size:21px}.vb-controls{display:flex;flex-wrap:wrap;align-items:center;gap:7px;margin:14px 0 11px}.vb-controls button,.vb-controls select{font:inherit;font-size:14px;padding:7px 12px;min-height:38px;border:1px solid #aecac0;border-radius:6px;background:#f6faf7;color:#234844}.vb-controls button[data-vb-action=play]{background:#166c69;color:white;border-color:#166c69;min-width:84px}.vb-controls button:disabled{opacity:.4;cursor:not-allowed}.vb-speed{font-size:13px;margin-left:auto;white-space:nowrap}.vb-status{font-variant-numeric:tabular-nums;color:#5c756d;font-size:13px}
.vb-range-row{display:flex;gap:14px;align-items:center;margin:8px 0 15px}.vb-range{flex:1;min-width:80px;accent-color:#166c69}.vb-range-row label{font-size:13px;color:#516961}.vb-art{max-width:100%;overflow-x:auto;overscroll-behavior-x:contain;background:#fcfdfc;border:1px solid #e1e9e5;border-radius:9px;-webkit-overflow-scrolling:touch}.vb-svg{width:100%;height:auto;display:block;min-width:610px;font-family:system-ui,-apple-system,"PingFang SC","Microsoft YaHei",sans-serif}.vb-caption{margin:13px 0 0;padding:15px 18px;background:#eff6f2;border-left:3px solid #166c69;font-size:17px;line-height:1.95}.vb-state{display:block;padding:10px 13px;margin:10px 0;font-size:14px;background:#f4f6f4;white-space:pre-wrap;overflow-wrap:anywhere;line-height:1.85}.vb-equation{margin:10px 0;padding:12px 15px;background:#f8f3e9;border-radius:6px;font-size:15px;white-space:pre-wrap;overflow-wrap:anywhere}.vb-hint{font-size:12px;color:#61727d;line-height:1.8;margin-top:11px}.vb-transcript{padding:8px 25px 23px}.vb-transcript h2{font-size:22px;margin:20px 0;border-top:1px solid #dfebe5}.vb-step{border-left:2px solid #bcd6ca;padding:7px 0 12px 20px;margin:18px 0}.vb-step h3{font-size:18px;margin:0 0 8px}.vb-step p{font-size:16px;line-height:1.95;margin:8px 0}.vb-frame-link{font-size:13px}.vb-reasons{display:grid;grid-template-columns:1fr 1fr;gap:12px;padding:18px 24px 22px}.vb-reason{border:1px solid #dce6df;background:#fafcf9;border-radius:8px;padding:14px 16px}.vb-reason h3{font-size:16px;margin:0 0 9px;color:#166c69}.vb-reason p{font-size:15px;line-height:1.9;margin:0}.vb-reason.risk{background:#fff8f1;border-color:#e6d7c5}.vb-reason.risk h3{color:#8d4e23}
.vb-related{padding:14px 24px 20px;font-size:14px;line-height:2}.vb-related a{display:inline-block;margin-right:16px}.vb-bridge{padding:19px 22px;background:#eef6f1;border-left:3px solid #41877a;margin:24px 0}.vb-bridge h2{font-size:22px;border:0;margin:0 0 10px;padding:0}.vb-bridge p{font-size:16px;line-height:1.9;margin:10px 0}
.vb-gallery{display:grid;grid-template-columns:1fr 1fr;gap:16px}.vb-card{border:1px solid #d6e4dc;border-radius:10px;overflow:hidden;background:#fff;min-width:0}.vb-card>div{padding:17px 20px}.vb-card h3{font-size:19px;line-height:1.7;margin:7px 0}.vb-card p{font-size:14px;line-height:1.8;color:#61727d}.vb-card svg{display:block;width:100%;height:170px;background:#f6faf6;object-fit:contain}.vb-number{font-size:12px;color:#166c69;font-weight:700}.vb-home-link{padding:17px 21px;border:1px solid #cadfd5;border-radius:8px;background:#f1f7f3;line-height:1.9;margin:24px 0}.vb-home-link a{font-weight:650}.vb-home-link p{font-size:15px;margin:6px 0}
.vb-dialog{width:min(98vw,1250px);max-height:94vh;border:1px solid #bdcfc6;border-radius:12px;padding:20px;background:#fcfdfb;color:#203344;box-shadow:0 10px 90px #0003}.vb-dialog::backdrop{background:#203344bb}.vb-dialog>header{display:flex;align-items:center;justify-content:space-between;gap:18px}.vb-dialog h2{border:0;margin:0;font-size:20px}.vb-dialog .vb-art{margin-top:15px;max-height:72vh}.vb-dialog .vb-svg{min-width:800px}.vb-dialog button{min-height:40px}.vb-long-table td{font-size:14px;line-height:1.85}.vb-scope{border-left:3px solid #9c5818;padding:15px 20px;background:#fcf5e9;margin:20px 0;font-size:15px;line-height:1.95}
@media(max-width:780px){.vb-block{margin:23px 0;border-radius:9px}.vb-intro{padding:19px 16px 12px}.vb-intro h2,.vb-intro h3{font-size:22px}.vb-intro p{font-size:16px}.vb-scenario{padding:14px 16px}.vb-player{padding:16px 12px}.vb-player h3{font-size:19px}.vb-controls{gap:6px}.vb-controls button,.vb-controls select{font-size:13px;padding:7px 9px}.vb-speed{margin-left:0}.vb-terms{grid-template-columns:1fr}.vb-caption{font-size:16px;padding:12px 14px}.vb-reasons{grid-template-columns:1fr;padding:12px 16px 18px}.vb-gallery{grid-template-columns:1fr}.vb-transcript{padding:8px 16px 18px}.vb-related{padding:12px 16px}.vb-dialog{padding:13px}.vb-dialog h2{font-size:18px}.vb-bridge{padding:16px}.vb-long-table{overflow-x:auto}.vb-home-link{padding:14px 17px}}
@media(prefers-reduced-motion:reduce){.vb-block *{scroll-behavior:auto!important;animation:none!important;transition:none!important}}
@media print{.vb-controls,.vb-range-row,.vb-dialog,.vb-hint{display:none!important}.vb-svg{min-width:0;width:100%}.vb-art{overflow:visible}.vb-block{break-inside:auto}.vb-intro,.vb-scenario,.vb-caption,.vb-reason{background:#fff}.vb-gallery{display:block}.vb-card{break-inside:avoid}.vb-reasons{display:block}.vb-reason{margin:10px 0}}

.vb-scroll-tip{font-size:12px;color:#607b70;line-height:1.7;margin:6px 0}.vb-range-row label{display:flex;flex:1;gap:12px;align-items:center}.vb-range-row .vb-range{width:100%}.vb-range-row .vb-status{white-space:nowrap}.vb-art:focus-visible{outline:3px solid #9f692b;outline-offset:-3px}