.doppler-intro,.doppler-meaning,.doppler-lab-section{padding-top:84px}.doppler-derive-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:10px;margin-top:24px}.doppler-card{min-width:0;padding:19px;border:1px solid var(--line);border-radius:18px;background:linear-gradient(180deg,color-mix(in srgb,var(--panel) 95%,transparent),color-mix(in srgb,var(--bg) 84%,transparent))}.doppler-card>span{color:var(--accent);font-size:.68rem;font-weight:900;letter-spacing:.08em;text-transform:uppercase}.doppler-card h2{margin:7px 0 10px;font-size:1.08rem}.doppler-card p{margin:0;color:var(--muted);font-size:.82rem;line-height:1.58}.doppler-card-key{border-top:2px solid color-mix(in srgb,var(--accent) 72%,var(--line))}.doppler-equation-stack{display:grid;gap:8px;margin:13px 0;font-family:ui-monospace,SFMono-Regular,Consolas,monospace;font-size:.91rem}.doppler-equation-stack span{overflow-wrap:anywhere}.doppler-equation{margin:14px 0;font-family:ui-monospace,SFMono-Regular,Consolas,monospace;line-height:1.55;overflow-wrap:anywhere}.doppler-equation-large{font-size:1.14rem}.doppler-frac{display:inline-grid;vertical-align:middle;text-align:center;line-height:1.08}.doppler-frac>span:first-child{padding:0 6px 3px;border-bottom:1px solid currentColor}.doppler-frac>span:last-child{padding-top:3px}.doppler-sign-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:8px;margin-top:12px}.doppler-sign-grid article{min-width:0;padding:15px;border-top:2px solid color-mix(in srgb,var(--accent) 40%,var(--line));background:linear-gradient(180deg,color-mix(in srgb,var(--accent) 4%,transparent),transparent)}.doppler-sign-grid span{color:var(--accent);font-family:ui-monospace,SFMono-Regular,Consolas,monospace;font-size:.72rem;font-weight:800}.doppler-sign-grid strong{display:block;margin:6px 0 5px;font-size:.9rem}.doppler-sign-grid p{margin:0;color:var(--muted);font-size:.76rem;line-height:1.5}.doppler-model-note{margin-top:14px;padding:16px 18px;border-left:3px solid var(--accent);border-radius:0 14px 14px 0;background:color-mix(in srgb,var(--accent) 6%,var(--panel));color:var(--muted);font-size:.83rem;line-height:1.55}.doppler-model-note strong{color:var(--text)}.doppler-model-note p{display:inline;margin-left:6px}.doppler-concept-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:10px;margin-top:22px}.doppler-concept-grid .doppler-card strong{display:block;margin:7px 0 6px;font-size:.91rem;line-height:1.45}.doppler-lab-shell{display:grid;grid-template-columns:minmax(245px,300px) minmax(0,1fr);gap:16px;align-items:start;margin-top:22px}.doppler-controls{position:sticky;top:calc(var(--header-h) + 14px);min-width:0;padding:17px;border:1px solid var(--line);border-radius:18px;background:var(--panel)}.doppler-presets{display:grid;grid-template-columns:1fr;gap:7px;margin:0 0 14px;padding:0;border:0}.doppler-presets legend{margin-bottom:7px;color:var(--muted);font-size:.7rem;font-weight:850;letter-spacing:.06em;text-transform:uppercase}.doppler-presets button{width:100%;padding:9px 10px;border:1px solid var(--line);border-radius:10px;background:var(--panel-solid);color:var(--text);font:inherit;font-size:.76rem;text-align:left;cursor:pointer}.doppler-presets button.is-active{border-color:color-mix(in srgb,var(--accent) 72%,var(--line));background:color-mix(in srgb,var(--accent) 12%,var(--panel-solid))}.doppler-controls>label{display:grid;grid-template-columns:1fr auto;gap:6px 9px;align-items:center;margin:13px 0;color:var(--muted);font-size:.75rem}.doppler-controls output{color:var(--text);font-family:ui-monospace,SFMono-Regular,Consolas,monospace;font-size:.71rem}.doppler-controls input[type=range]{grid-column:1/-1;width:100%}.doppler-reset{width:100%;margin-top:2px}.doppler-assumption{margin-top:14px;padding:12px;border:1px solid var(--line);border-radius:12px;background:var(--panel-solid);color:var(--muted);font-size:.71rem;line-height:1.48}.doppler-assumption strong{color:var(--text)}.doppler-assumption p{margin:5px 0 0}.doppler-stage{min-width:0;display:grid;gap:12px}.doppler-panel{min-width:0;padding:16px;border:1px solid var(--line);border-radius:18px;background:var(--panel);overflow:hidden}.doppler-panel-head{display:flex;justify-content:space-between;align-items:flex-start;gap:12px;margin-bottom:10px}.doppler-panel-head span{display:block;color:var(--muted);font-size:.68rem;text-transform:uppercase;letter-spacing:.07em}.doppler-panel-head strong{display:block;margin-top:3px;font-size:.9rem}.doppler-status{max-width:52%;padding:5px 8px;border:1px solid var(--line);border-radius:999px;background:var(--panel-solid);color:var(--muted);font-size:.67rem;text-align:right;white-space:normal}.doppler-front-svg,.doppler-spacetime-svg,.doppler-ratio-svg{display:block;width:100%;height:auto;overflow:visible}.doppler-axis,.doppler-grid{stroke:var(--line);stroke-width:1.5}.doppler-front{stroke:#53c7ff;stroke-width:3;opacity:.9}.doppler-front-old{stroke:#53c7ff;stroke-width:2;opacity:.45}.doppler-source-body{fill:#ffb45a;stroke:var(--bg);stroke-width:2}.doppler-observer-body{fill:#9b8cff;stroke:var(--bg);stroke-width:2}.doppler-velocity-line.source{stroke:#ffb45a;stroke-width:4;stroke-linecap:round}.doppler-velocity-line.observer{stroke:#9b8cff;stroke-width:4;stroke-linecap:round}.doppler-bracket{stroke:#ff6f91;stroke-width:2}.doppler-wave-ray{stroke:#53c7ff;stroke-width:2;opacity:.46}.doppler-worldline{fill:none;stroke-width:4;stroke-linecap:round}.doppler-worldline.source{stroke:#ffb45a}.doppler-worldline.observer{stroke:#9b8cff}.doppler-event{fill:#ff6f91;stroke:var(--bg);stroke-width:2}.doppler-ratio-curve{fill:none;stroke:#53c7ff;stroke-width:4;stroke-linecap:round;stroke-linejoin:round}.doppler-ratio-unity{stroke:#ffb45a;stroke-width:2;stroke-dasharray:8 6}.doppler-ratio-marker{fill:#ff6f91;stroke:var(--bg);stroke-width:2}.doppler-svg-label,.doppler-grid-label{fill:var(--muted);font-size:15px;font-family:ui-monospace,SFMono-Regular,Consolas,monospace}.doppler-svg-label.emphasis{fill:var(--text);font-weight:800}.doppler-svg-legend{display:flex;gap:9px 16px;flex-wrap:wrap;margin-top:7px;color:var(--muted);font-size:.7rem}.doppler-svg-legend span{display:flex;align-items:center;gap:6px}.doppler-svg-legend i{width:16px;height:3px;border-radius:4px;background:var(--line)}.doppler-svg-legend i.source{background:#ffb45a}.doppler-svg-legend i.front{background:#53c7ff}.doppler-svg-legend i.observer{background:#9b8cff}.doppler-metrics{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:8px}.doppler-metrics>div{min-width:0;padding:12px;border:1px solid var(--line);border-radius:13px;background:var(--panel)}.doppler-metrics span{display:block;color:var(--muted);font-size:.66rem}.doppler-metrics strong{display:block;margin-top:5px;font-family:ui-monospace,SFMono-Regular,Consolas,monospace;font-size:.84rem;overflow-wrap:anywhere}.doppler-checks{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:7px}.doppler-checks>div{min-width:0;padding:9px;border-top:1px solid var(--line);font-size:.68rem;color:var(--muted)}.doppler-checks strong{display:block;margin-top:4px;color:var(--text);font-family:ui-monospace,SFMono-Regular,Consolas,monospace;font-size:.72rem;overflow-wrap:anywhere}.doppler-reading{padding:16px 18px;border:1px solid var(--line);border-radius:14px;background:var(--panel)}.doppler-reading strong{display:block;margin-bottom:6px;font-size:.94rem}.doppler-reading p{margin:0;color:var(--muted);font-size:.8rem;line-height:1.58}.doppler-intro :is(h1,h2),.doppler-meaning h2,.doppler-lab-section h2{overflow-wrap:anywhere;hyphens:auto}
@media(max-width:1100px){.doppler-derive-grid{grid-template-columns:1fr}.doppler-lab-shell{grid-template-columns:1fr}.doppler-controls{position:static}.doppler-metrics{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media(max-width:680px){.doppler-intro,.doppler-meaning,.doppler-lab-section{padding-top:64px}.doppler-sign-grid,.doppler-concept-grid,.doppler-metrics,.doppler-checks{grid-template-columns:1fr}.doppler-card,.doppler-panel,.doppler-controls{padding:14px}.doppler-panel-head{flex-direction:column}.doppler-status{max-width:100%;text-align:left}.doppler-model-note p{display:block;margin:6px 0 0}.doppler-svg-label,.doppler-grid-label{font-size:24px}.doppler-equation-large{font-size:.98rem}.doppler-presets button{font-size:.74rem}}
.doppler-cross-reference{margin:18px auto 0;padding:16px 18px;border:1px solid var(--line);border-radius:14px;background:var(--panel);color:var(--muted);font-size:.84rem;line-height:1.55}.doppler-cross-reference a{color:var(--text)}.doppler-takeaways{padding-top:72px;padding-bottom:88px}.doppler-takeaway-grid{display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:8px}.doppler-takeaway-grid article{min-width:0;padding:15px;border-top:2px solid color-mix(in srgb,var(--accent) 42%,var(--line));background:linear-gradient(180deg,color-mix(in srgb,var(--accent) 3%,transparent),transparent)}.doppler-takeaway-grid span{color:var(--accent);font-size:.66rem;font-weight:900}.doppler-takeaway-grid strong{display:block;margin:6px 0 5px;font-size:.84rem}.doppler-takeaway-grid p{margin:0;color:var(--muted);font-size:.73rem;line-height:1.5}@media(max-width:1100px){.doppler-takeaway-grid{grid-template-columns:repeat(3,minmax(0,1fr))}}@media(max-width:680px){.doppler-takeaway-grid{grid-template-columns:1fr}}
