:root{
  --navy:#1B3A6B;
  --navy-dark:#12294f;
  --orange:#C2410C;
  --green:#15803D;
  --red:#B91C1C;
  --offwhite:#F8F9FA;
  --lightbg:#F0F4FF;
  --calloutbg:#EFF6FF;
  --dkgray:#111827;
  --midgray:#6B7280;
  --border:#E2E8F0;
  --bg:#0a0e14;
}
*{box-sizing:border-box;}
html,body{margin:0;padding:0;height:100%;}
body{
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  background:var(--bg);
  color:var(--dkgray);
  -webkit-font-smoothing:antialiased;
}
#app-shell{
  max-width:520px;
  margin:0 auto;
  min-height:100vh;
  background:var(--offwhite);
  display:flex;
  flex-direction:column;
}
#topbar{
  position:sticky; top:0; z-index:20;
  background:var(--navy);
  color:#fff;
  display:flex;
  align-items:center;
  gap:8px;
  padding:14px 12px;
  min-height:24px;
}
#back-btn{
  background:none;border:none;color:#fff;font-size:20px;
  cursor:pointer;padding:2px 8px 2px 0;line-height:1;visibility:hidden;
}
#topbar-title{
  font-size:15px;font-weight:700;letter-spacing:.2px;
  white-space:nowrap;overflow:hidden;text-overflow:ellipsis;
}
#app{flex:1; padding-bottom:70px;}
.view{padding:16px;}

/* Tab bar */
#tabbar{
  position:sticky; bottom:0; z-index:20;
  display:flex;
  background:#fff;
  border-top:1px solid var(--border);
  max-width:520px;
  margin:0 auto;
}
.tabbar-btn{
  flex:1; background:none; border:none; padding:10px 4px 8px;
  font-size:10.5px; color:var(--midgray); cursor:pointer;
  display:flex; flex-direction:column; align-items:center; gap:3px;
}
.tabbar-btn .tab-ico{font-size:17px;}
.tabbar-btn.active{color:var(--navy); font-weight:700;}

/* ===== Home / Nav Map ===== */
.home-intro h1{font-size:19px;margin:0 0 4px;color:var(--navy);}
.home-intro p{font-size:12.5px;color:var(--midgray);margin:0 0 14px;line-height:1.4;}
.navmap-scroll{
  position:relative;
  overflow-x:auto;
  overflow-y:hidden;
  background:#fff;
  border:1px solid var(--border);
  border-radius:10px;
  padding:0;
}
.navmap-svg{
  width:1040px; max-width:none; display:block;
}
.navmap-nodes{
  position:absolute; top:0; left:0;
  width:1040px; height:770px;
}
.navnode-landmark{
  position:absolute; transform:translate(-50%,-50%);
  font-size:10px; color:var(--midgray); text-align:center;
  width:110px;
}
.navnode-landmark .navnode-label{font-style:italic;}
.navnode{
  position:absolute; transform:translate(-50%,-50%);
  width:118px;
  background:#fff;
  border:2px solid var(--cat-color, var(--navy));
  border-radius:9px;
  padding:6px 4px 5px;
  cursor:pointer;
  text-align:center;
  box-shadow:0 1px 3px rgba(0,0,0,.08);
  font-family:inherit;
}
.navnode:active{ background:var(--lightbg); }
.navnode-num{
  font-size:9px; font-weight:700; color:#fff;
  background:var(--cat-color, var(--navy));
  display:inline-block; border-radius:8px; padding:1px 6px;
  margin-bottom:3px;
}
.navnode-label{font-size:11px; font-weight:700; color:var(--dkgray); line-height:1.2;}
.navnode-angle{font-size:9.5px; color:var(--midgray); margin-top:2px;}
.navmap-edge{stroke:#c3cbe0; stroke-width:2;}

.navmap-legend{
  display:flex; gap:14px; flex-wrap:wrap;
  margin:10px 2px 4px; font-size:11px; color:var(--midgray);
}
.legend-item{display:flex; align-items:center; gap:5px;}
.legend-item i{width:10px;height:10px;border-radius:3px;display:inline-block;}

.home-quicklinks{
  display:flex; flex-direction:column; gap:8px; margin-top:16px;
}
.quicklink{
  background:#fff; border:1px solid var(--border); border-left:4px solid var(--navy);
  border-radius:8px; padding:12px 14px; text-align:left;
  font-size:13.5px; font-weight:600; color:var(--navy);
  cursor:pointer;
}

/* ===== Card detail ===== */
.card-topbar{
  display:flex; align-items:center; gap:8px; margin-bottom:10px;
  font-size:11px; color:var(--midgray);
}
.card-badge{
  background:var(--navy); color:#fff; font-weight:700;
  border-radius:6px; padding:2px 8px; font-size:11px;
}
.card-cat{margin-left:auto; background:var(--lightbg); border-radius:6px; padding:2px 8px; font-weight:700; color:var(--navy);}
.card-image-wrap{
  background:#fff; border:1px solid var(--border); border-radius:10px;
  padding:8px; margin-bottom:12px; text-align:center;
}
.card-image{max-width:100%; height:auto; border-radius:4px;}
.card-titleblock{margin-bottom:12px;}
.card-subtitle{font-size:11.5px; color:var(--midgray); margin-bottom:2px;}
.card-title{font-size:20px; margin:0; color:var(--navy);}
.card-sections{display:flex; flex-direction:column; gap:10px;}
.section-block{border-radius:8px; overflow:hidden; border:1px solid var(--border);}
.section-hdr{color:#fff; font-size:11px; font-weight:700; letter-spacing:.3px; padding:6px 10px;}
.section-body{background:var(--lightbg); padding:10px 14px;}
.bullets{margin:0; padding-left:18px;}
.bullets li{font-size:12.5px; line-height:1.5; margin-bottom:4px; color:var(--dkgray);}
.bullets li:last-child{margin-bottom:0;}
.card-prevnext{display:flex; gap:8px; margin-top:16px;}
.pn-btn{
  flex:1; background:#fff; border:1px solid var(--border); border-radius:8px;
  padding:10px 8px; font-size:11px; color:var(--navy); font-weight:600; cursor:pointer;
}

/* ===== Probe reference ===== */
.view-probe h1, .view-sweep h1, .view-appendix h1{font-size:18px; color:var(--navy); margin:0 0 12px;}
.probe-table{border:1px solid var(--border); border-radius:8px; overflow:hidden;}
.probe-row{display:flex; flex-direction:column; padding:9px 12px; background:#fff;}
.probe-row.alt{background:var(--lightbg);}
.probe-sym{font-size:12.5px; font-weight:700; color:var(--navy); margin-bottom:2px;}
.probe-desc{font-size:12px; color:var(--dkgray); line-height:1.4;}
.callout{background:var(--calloutbg); border-radius:8px; padding:12px 14px; margin-top:14px;}
.callout-hdr{font-size:11px; font-weight:700; color:var(--navy); margin-bottom:6px; letter-spacing:.3px;}
.callout-body{font-size:11.5px; color:var(--dkgray); line-height:1.5;}

/* ===== Sweep ===== */
.sweep-intro{font-size:12.5px; color:var(--midgray); line-height:1.5; margin-bottom:14px;}
.phase-card{border-radius:8px; overflow:hidden; border:1px solid var(--border); margin-bottom:10px;}
.phase-hdr{color:#fff; font-size:11.5px; font-weight:700; padding:8px 12px;}
.phase-body{background:var(--lightbg); padding:10px 14px;}
.phase-body p{font-size:12px; margin:0 0 6px; line-height:1.45; color:var(--dkgray);}
.phase-mapping{color:var(--navy) !important; font-size:11.5px !important;}

/* ===== Appendix ===== */
.appendix-item{margin-bottom:20px;}
.appendix-item h3{font-size:13px; color:var(--navy); margin:0 0 6px;}
.appendix-image{width:100%; height:auto; border:1px solid var(--border); border-radius:8px; background:#fff;}

@media (prefers-reduced-motion: reduce){
  *{transition:none !important; animation:none !important;}
}

/* ===== Map gutter: node #4 sits at x=20, so half of it hung off the left edge ===== */
.navmap-svg{margin-left:60px;}
.navmap-nodes{left:60px;}

/* ===== Tab bar spans the shell (margin:auto in a flex column was shrinking it) ===== */
#tabbar{width:100%;}

/* ===== Desktop ===== */
@media (min-width:900px){
  #app-shell{max-width:1180px;box-shadow:0 0 0 1px rgba(255,255,255,.04);}
  #topbar{padding:16px 32px;}
  #topbar-title{font-size:17px;}
  #tabbar{max-width:none;}
  .tabbar-btn{flex-direction:row;justify-content:center;gap:8px;font-size:13px;padding:14px 8px;}
  .tabbar-btn:hover{color:var(--navy);background:var(--lightbg);}
  .view{padding:28px 32px;}

  .home-intro h1{font-size:24px;}
  .home-intro p{font-size:14px;}
  .navmap-scroll{max-width:1102px;margin:0 auto;}
  .navnode:hover{background:var(--lightbg);}
  .home-quicklinks{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;}
  .quicklink:hover{background:var(--lightbg);}

  /* Card: image left, text right */
  .view-card{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);column-gap:28px;align-items:start;}
  .card-topbar,.card-prevnext{grid-column:1 / -1;}
  .card-image-wrap{grid-column:1;grid-row:2 / span 2;position:sticky;top:76px;margin-bottom:0;}
  .card-titleblock{grid-column:2;grid-row:2;}
  .card-sections{grid-column:2;grid-row:3;}
  .card-title{font-size:26px;}
  .bullets li{font-size:14px;}
  .pn-btn{font-size:13px;padding:12px;}
  .pn-btn:hover{background:var(--lightbg);}

  .view-probe h1,.view-sweep h1,.view-appendix h1{font-size:24px;}
  .probe-row{display:grid;grid-template-columns:260px 1fr;gap:16px;align-items:baseline;}
  .probe-sym{font-size:14px;margin:0;}
  .probe-desc{font-size:14px;}
  .callout-body{font-size:13.5px;}

  .view-sweep{display:grid;grid-template-columns:1fr 1fr;gap:0 16px;align-items:start;}
  .view-sweep > h1,.view-sweep > .sweep-intro{grid-column:1 / -1;}
  .sweep-intro,.phase-body p{font-size:14px;}

  .view-appendix{display:grid;grid-template-columns:1fr 1fr;gap:0 24px;align-items:start;}
  .view-appendix > h1{grid-column:1 / -1;}
  .appendix-item h3{font-size:15px;}
}