:root{
  --bg:#0f1420;
  --panel:#161d2e;
  --panel-2:#1d2740;
  --border:#2a3654;
  --text:#e7ecf7;
  --text-dim:#9fb0cf;
  --accent:#4fb0ff;
  --accent-2:#ffb74f;
  --good:#4fd88a;
  --warn:#ff6b6b;
  --radius:10px;
}
*{box-sizing:border-box;}
body{
  margin:0;
  font-family:'Segoe UI', Roboto, Arial, sans-serif;
  background:var(--bg);
  color:var(--text);
  min-height:100vh;
}
.brand-title{font-size:1.05rem;font-weight:700;display:block;}
.brand-sub{font-size:0.72rem;color:var(--text-dim);}
main{
  flex:1;
  padding:24px;
  width:100%;
  max-width:100%;
}
.tool-panel{display:none;}
.tool-panel.active{display:block;animation:fadein .2s ease;}
@keyframes fadein{from{opacity:0;transform:translateY(4px);}to{opacity:1;transform:translateY(0);}}
h2{margin-top:0;font-size:1.3rem;}
.tool-desc{color:var(--text-dim);font-size:0.88rem;margin-bottom:18px;max-width:800px;}
.grid{
  display:grid;
  grid-template-columns:340px 1fr;
  gap:20px;
}
@media (max-width:850px){
  .grid{grid-template-columns:1fr;}
}
.card{
  background:var(--panel);
  border:1px solid var(--border);
  border-radius:var(--radius);
  padding:18px;
}
.field{margin-bottom:14px;}
.field label{
  display:block;
  font-size:0.78rem;
  color:var(--text-dim);
  margin-bottom:4px;
}
.field input, .field select{
  width:100%;
  padding:8px 10px;
  background:var(--panel-2);
  border:1px solid var(--border);
  border-radius:6px;
  color:var(--text);
  font-size:0.9rem;
}
.field input:focus, .field select:focus{outline:1px solid var(--accent);}
.row2{display:grid;grid-template-columns:1fr 1fr;gap:10px;}
.checkrow{display:flex;align-items:center;gap:8px;margin-bottom:10px;font-size:0.85rem;color:var(--text-dim);}
.checkrow input{width:auto;}
.results{
  margin-top:16px;
  padding-top:14px;
  border-top:1px solid var(--border);
}
.result-line{
  display:flex;
  justify-content:space-between;
  font-size:0.86rem;
  padding:4px 0;
  color:var(--text-dim);
}
.result-line b{color:var(--text);font-weight:600;}
.result-flag{
  margin-top:10px;
  padding:8px 10px;
  border-radius:6px;
  font-size:0.82rem;
  font-weight:600;
}
.flag-good{background:rgba(79,216,138,0.12);color:var(--good);}
.flag-warn{background:rgba(255,107,107,0.12);color:var(--warn);}
.chart-wrap{
  background:var(--panel);
  border:1px solid var(--border);
  border-radius:var(--radius);
  padding:16px;
  min-height:420px;
}
canvas{max-width:100%;}
table.ref-table{
  width:100%;
  border-collapse:collapse;
  font-size:0.82rem;
  margin-top:10px;
}
table.ref-table th, table.ref-table td{
  border:1px solid var(--border);
  padding:6px 8px;
  text-align:left;
}
table.ref-table th{background:var(--panel-2);color:var(--text-dim);}
.btn{
  background:var(--accent);
  color:#08131f;
  border:none;
  padding:9px 16px;
  border-radius:6px;
  font-weight:600;
  cursor:pointer;
  font-size:0.85rem;
}
.btn:hover{opacity:0.9;}
.btn-secondary{
  background:var(--panel-2);
  color:var(--text);
  border:1px solid var(--border);
}
.footer{
  text-align:center;
  padding:14px;
  font-size:0.72rem;
  color:var(--text-dim);
  border-top:1px solid var(--border);
  background:var(--panel);
}
.note{
  font-size:0.76rem;
  color:var(--text-dim);
  margin-top:8px;
  line-height:1.4;
}
.std-badge{
  display:inline-block;
  background:rgba(79,176,255,0.12);
  color:var(--accent);
  border-radius:4px;
  padding:2px 6px;
  font-size:0.7rem;
  font-weight:700;
  margin-left:6px;
}
.diagram-note{
  font-size:0.76rem;
  color:var(--text-dim);
  margin-top:12px;
  padding-top:10px;
  border-top:1px solid var(--border);
  line-height:1.4;
}
.fault-type-grid{
  display:grid;
  grid-template-columns:repeat(2,1fr);
  gap:8px;
  margin-bottom:14px;
}
.fault-type-btn{
  background:var(--panel-2);
  border:1px solid var(--border);
  color:var(--text-dim);
  padding:10px 8px;
  border-radius:6px;
  cursor:pointer;
  font-size:0.78rem;
  text-align:center;
}
.fault-type-btn.active{
  background:rgba(79,176,255,0.15);
  border-color:var(--accent);
  color:var(--accent);
  font-weight:600;
}
.compact-form{
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:10px 14px;
}
.compact-form .field{ margin-bottom:0; }
.compact-form .field.full{ grid-column:1 / -1; }
.ref-tabs{
  display:flex;
  gap:6px;
  flex-wrap:wrap;
  margin-bottom:14px;
}
.ref-tab-btn{
  background:var(--panel-2);
  border:1px solid var(--border);
  color:var(--text-dim);
  padding:7px 12px;
  border-radius:6px;
  cursor:pointer;
  font-size:0.8rem;
}
.ref-tab-btn.active{
  background:var(--accent);
  border-color:var(--accent);
  color:#08131f;
  font-weight:600;
}
.ref-panel{ display:none; }
.ref-panel.active{ display:block; }
.ref-doc-link{
  display:flex;
  justify-content:space-between;
  align-items:center;
  padding:8px 10px;
  background:var(--panel-2);
  border:1px solid var(--border);
  border-radius:6px;
  margin-bottom:6px;
  font-size:0.82rem;
}
.app-shell{
  display:flex;
  min-height:100vh;
  width:100%;
}
.sidebar{
  width:260px;
  min-width:260px;
  background:var(--panel);
  border-right:1px solid var(--border);
  display:flex;
  flex-direction:column;
  transition:margin-left .2s ease;
}
.sidebar.collapsed{
  margin-left:-260px;
}
.sidebar-header{
  padding:18px 20px;
  border-bottom:1px solid var(--border);
}
.side-nav{
  flex:1;
  overflow-y:auto;
  padding:12px 0;
}
.side-group{
  margin-bottom:4px;
}
.side-group-label{
  padding:10px 20px 6px;
  font-size:0.7rem;
  text-transform:uppercase;
  letter-spacing:0.06em;
  color:var(--text-dim);
  font-weight:700;
}
.side-link{
  display:block;
  width:100%;
  text-align:left;
  background:transparent;
  border:none;
  border-left:3px solid transparent;
  color:var(--text-dim);
  padding:10px 20px;
  font-size:0.86rem;
  cursor:pointer;
}
.side-link:hover{
  background:var(--panel-2);
  color:var(--text);
}
.side-link.active{
  background:rgba(79,176,255,0.1);
  border-left-color:var(--accent);
  color:var(--accent);
  font-weight:600;
}
.main-col{
  flex:1;
  display:flex;
  flex-direction:column;
  min-width:0;
}
.topbar{
  display:flex;
  align-items:center;
  gap:14px;
  padding:14px 24px;
  background:var(--panel);
  border-bottom:1px solid var(--border);
  position:sticky;
  top:0;
  z-index:10;
}
.sidebar-toggle{
  background:var(--panel-2);
  border:1px solid var(--border);
  color:var(--text);
  border-radius:6px;
  width:36px;
  height:36px;
  cursor:pointer;
  font-size:1rem;
}
.topbar-title{
  font-size:1rem;
  font-weight:600;
  color:var(--text);
}
@media (max-width:850px){
  .sidebar{
    position:fixed;
    top:0;
    left:0;
    bottom:0;
    z-index:200;
    margin-left:-260px;
  }
  .sidebar.mobile-open{
    margin-left:0;
    box-shadow:0 0 30px rgba(0,0,0,0.6);
  }
}
.results.centered .result-line{
  display:flex;
  flex-direction:row;
  align-items:baseline;
  justify-content:center;
  text-align:center;
  gap:6px;
  padding:8px 4px;
  border-bottom:1px solid rgba(159,176,207,0.15);
  font-size:1rem;
}
.results.centered .result-line:last-child{border-bottom:none;}
.results.centered .result-line span{font-weight:700;font-size:1rem;color:var(--text);}
.results.centered .result-line b{font-weight:400;color:var(--text-dim);font-size:1rem;}
.formula-block{color:var(--text);}
.symcomp-canvases{display:grid;grid-template-columns:1fr 1fr;gap:16px;}
.canvas-label{margin-top:0;font-size:0.95rem;color:var(--text-dim);}
@media (max-width:600px){.symcomp-canvases{grid-template-columns:1fr;}}
.save-load-card{margin-top:16px;}
.save-load-header{font-size:0.7rem;color:var(--text-dim);text-transform:uppercase;letter-spacing:0.06em;font-weight:700;margin-bottom:10px;}
.save-load-row{display:flex;gap:8px;margin-bottom:10px;}
.save-load-row .saveNameInput{flex:1;padding:8px 10px;background:var(--panel-2);border:1px solid var(--border);border-radius:6px;color:var(--text);font-size:0.85rem;}
.save-list{display:flex;flex-direction:column;gap:6px;}
.save-item{display:flex;align-items:center;gap:8px;padding:8px 10px;background:var(--panel-2);border:1px solid var(--border);border-radius:6px;font-size:0.82rem;}
.save-item-name{flex:1;font-weight:600;color:var(--text);overflow:hidden;text-overflow:ellipsis;white-space:nowrap;}
.save-item-date{color:var(--text-dim);font-size:0.72rem;white-space:nowrap;}
.btn-icon{background:transparent;border:1px solid var(--border);color:var(--text-dim);border-radius:5px;padding:4px 8px;font-size:0.72rem;cursor:pointer;}
.btn-icon:hover{color:var(--text);border-color:var(--accent);}