/* ==================================================================
   E‑Beam Lite – Professional UI
   ==================================================================*/
:root{--canvas-target: 600px; 
  --bg: #0b1020;           /* page background (dark navy) */
  --panel: #121a2f;        /* cards/panels */
  --panel-2:#0f1530;       /* alt panels */
  --text:#e8ecf6;          /* body text */
  --muted:#a9b3c9;         /* secondary text */
  --brand:#00baff;         /* accent */
  --brand-2:#8de4ff;       /* accent soft */
  --ok:#00c853;            /* success */
  --border: #1e2844;       /* borders */
  --shadow: 0 10px 24px rgba(0,0,0,.35);
  --radius: 16px;
}

@media (prefers-color-scheme: light){
  :root{ --bg:#f7f9fc; --panel:#ffffff; --panel-2:#fbfcff; --text:#0c1326; --muted:#4a5678; --border:#e5e9f3; }
}

*{box-sizing:border-box}
html,body{height:100%}
body{
  margin:0; font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif;
  color:var(--text); background: radial-gradient(1200px 800px at 20% -10%, rgba(0,186,255,.12), transparent 60%),
          radial-gradient(1000px 700px at 100% 10%, rgba(141,228,255,.08), transparent 60%), var(--bg);
}

/* Layout */
.container{max-width:1100px;margin:0 auto;padding:0 20px}
.site-header{position:sticky;top:0;z-index:50;background:rgba(5,8,20,.8);backdrop-filter: blur(8px);border-bottom:1px solid var(--border)}
.header-wrap{display:flex;align-items:center;justify-content:space-between;gap:1rem;padding:14px 0}
.brand{display:flex;align-items:center;gap:.6rem}
.brand-mark{display:inline-block;width:10px;height:10px;border-radius:50%;background:var(--brand)}
.brand-title{font-size:1.1rem;margin:0;font-weight:700;letter-spacing:.2px}
.brand-title .thin{font-weight:500;color:var(--muted)}

.tabs{display:flex;gap:.4rem}
.tab{appearance:none;border:1px solid var(--border);background:linear-gradient(180deg,var(--panel-2),var(--panel));color:var(--text);
  border-radius:999px;padding:.45rem .9rem;font-weight:600;cursor:pointer;transition:transform .08s ease, box-shadow .2s ease;}
.tab:hover{transform:translateY(-1px);box-shadow:var(--shadow)}
.tab.active, .tab:focus-visible{outline:none;border-color:var(--brand);box-shadow:0 0 0 3px rgba(0,186,255,.25)}

.site-footer{border-top:1px solid var(--border);padding:28px 0;margin-top:48px;color:var(--muted)}

/* Panes */
.pane{padding:24px 0}
.pane-grid{display:grid;grid-template-columns:1fr 1fr;gap:20px}
@media (max-width: 980px){ .pane-grid{grid-template-columns:1fr} }

/* Cards */
.card{background:linear-gradient(180deg,var(--panel-2),var(--panel));border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow);overflow:hidden}
.card-header{padding:16px 16px 4px;border-bottom:1px solid var(--border);background:linear-gradient(180deg,rgba(141,228,255,.08),transparent)}
.card-title{margin:0 0 4px;font-size:1.05rem}
.card-sub{margin:0;color:var(--muted);font-size:.95rem}
.canvas-wrap{padding:12px}

/* Buttons & controls */
.btn{appearance:none;background:linear-gradient(180deg,var(--brand-2),var(--brand));color:#001019;border:none;border-radius:10px;padding:.6rem 1rem;font-weight:700;cursor:pointer}
.btn:hover{filter:brightness(1.05)}
.btn:focus-visible{outline:3px solid rgba(0,186,255,.35)}
.btn-ghost{background:transparent;border:1px solid var(--border);color:var(--text)}
.actions{padding:0 16px 16px}
.toolbar{display:flex;gap:.6rem;align-items:center;padding:8px 12px;border-top:1px solid var(--border);background:rgba(255,255,255,.02)}
.control-inline{display:inline-flex;align-items:center;gap:.5rem}
.badge{display:inline-block;padding:.2rem .5rem;border-radius:999px;background:rgba(141,228,255,.15);border:1px solid var(--border)}

/* Forms */
.form{padding:0}
.form .grid{padding:12px 16px 4px;display:grid;gap:10px}
.form .grid.two{grid-template-columns:1fr 1fr}
@media (max-width:700px){ .form .grid.two{grid-template-columns:1fr} }
.form label{display:flex;flex-direction:column;gap:.35rem;font-size:.95rem}
.form input[type="number"],
.form input[type="range"],
.form input[type="text"]{appearance:none;width:100%;padding:.55rem .6rem;border-radius:10px;border:1px solid var(--border);background:#0b1431;color:var(--text)}
.form input[type="range"]{padding:0;height:8px}
.form input:focus{outline:2px solid rgba(0,186,255,.35);border-color:var(--brand)}
.output{margin:12px 16px 16px;max-height:220px;overflow:auto;background:#081028;border:1px solid var(--border);border-radius:12px;padding:10px}

/* Canvases & schematic */
#grid, #sim, #voltageScene, #emitterScene{display:block;width:100%;height:auto;border:1px solid var(--border);background:linear-gradient(180deg,#0b1431,#0b1226)}

.theory{display:flex;gap:16px;align-items:flex-start;padding:12px}
#systemSvg{border:1px solid var(--border);background:#0b1431;border-radius:12px}
svg .part{stroke:#6f7ba5;stroke-width:2;fill:#141d3a;cursor:pointer;transition:fill .15s, stroke .15s}
svg .part:hover{fill:#1c2855}
svg .selected{fill:#233064 !important;stroke:var(--brand)}

#infoBox{max-width:280px;padding:.75rem;background:linear-gradient(180deg,var(--panel),var(--panel-2));border:1px solid var(--border);border-radius:12px}
#infoBox h3{margin:.2rem 0 .4rem}
#ctrls label{display:flex;justify-content:space-between;font-size:.9em;margin:.4em 0;gap:.6rem}
#ctrls input{width:70px}

/* Voltage slider visuals */
input[type="range"]#voltageSlider{
  -webkit-appearance:none;appearance:none;width:100%;height:10px;border-radius:999px;
  background:linear-gradient(90deg,#ffffff 0%,#ff0000 100%);outline:none;margin:.6rem 0;border:1px solid var(--border)
}
input[type="range"]#voltageSlider::-webkit-slider-thumb{
  -webkit-appearance:none;appearance:none;width:16px;height:16px;border-radius:50%;background:#101935;cursor:pointer;border:2px solid #fff
}
input[type="range"]#voltageSlider::-moz-range-thumb{
  width:16px;height:16px;border-radius:50%;background:#101935;cursor:pointer;border:2px solid #fff
}

/* Emitter labels */
.emit-wrap{position:relative}
.emLabel{position:absolute;top:6px;transform:translateX(-50%);font-size:.85rem;color:var(--muted)}

/* Utility tweaks */
.canvas-wrap{isolation:isolate}
.hidden{display:none}

/* (unchanged base from v2) + minor additions for new pages */
/* --- keep your existing v2 CSS here as-is --- */

/* Additions for theory/emission pages */
.page-hero{display:flex;align-items:center;justify-content:space-between;gap:1rem;margin:8px 0 18px}
.page-hero h1{margin:0;font-size:1.4rem}
.help{color:var(--muted);font-size:.95rem}
.kv{display:grid;grid-template-columns:1fr 1fr;gap:12px}
@media (max-width:800px){.kv{grid-template-columns:1fr}}
.param{border:1px solid var(--border);border-radius:12px;padding:12px;background:linear-gradient(180deg,var(--panel),var(--panel-2))}
.param label{display:flex;justify-content:space-between;gap:.6rem;align-items:center}
.param input, .param select{max-width:220px}
.plot-card{padding:12px}

.note{padding:.6rem .8rem;border:1px dashed var(--border);border-radius:12px;background:rgba(141,228,255,.06)}


/* ================== Responsive layout & canvas sizing ================== */
.layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  align-items: start;
}
@media (max-width: 1100px) {
  .layout { grid-template-columns: 1fr; }
}

/* Keep canvases within viewport while preserving a crisp 1:1 aspect */
canvas.canvas, #grid, #sim {
  width: clamp(420px, var(--canvas-target), 720px);
  height: auto;
  max-width: clamp(420px, var(--canvas-target), 720px);
  aspect-ratio: 1 / 1;
  image-rendering: pixelated;
  border: 1px solid var(--border, #d9e0ef);
  border-radius: 8px;
}

/* Compact toolbars on narrow screens */
.toolbar { display: flex; gap: 12px; align-items: center; flex-wrap: wrap; }
.toolbar label { display: inline-flex; align-items: center; gap: 8px; }


:root{
  --canvas-target: 420px; /* JS will update this for "fit to screen" */
  --gap: 16px;
  --panel-pad: 12px;
  --pre-h: 88px;
}
body.compact * { letter-spacing: 0.01em; }


.layout {
  display: grid;
  grid-template-columns: minmax(280px, 1fr) minmax(340px, 1fr);
  gap: var(--gap);
  align-items: start;
}
@media (max-width: 1100px) {
  .layout { grid-template-columns: 1fr; }
}
.panel { padding: var(--panel-pad); }


/* Fit canvases while preserving aspect; JS will set --canvas-target based on vw/vh */
canvas.canvas, #grid, #sim {
  width: min(100%, var(--canvas-target));
  height: auto;
  aspect-ratio: 1/1;
  image-rendering: pixelated;
  border: 1px solid var(--border, #d9e0ef);
  border-radius: 8px;
  display: block;
}


.toolbar { display:flex; gap:12px; align-items:center; flex-wrap:wrap; margin-top:8px; }
.controls .grid { display:grid; grid-template-columns: 1fr 1fr; gap: 10px; }
@media (max-width: 900px){ .controls .grid { grid-template-columns: 1fr; } }
.controls label { font-size: 13px; display:flex; flex-direction:column; gap:6px; }
.controls input, .controls select { font-size: 14px; padding:8px 10px; border-radius:8px; border:1px solid var(--border, #d0d5dd); }
button.primary { margin-top:10px; }


#status { max-height: var(--pre-h); overflow:auto; padding:8px; border:1px solid #e5e7eb; border-radius:8px; background:#fafafa; }
#derived { max-height: calc(var(--pre-h) + 20px); overflow:auto; padding:8px; border:1px solid #e5e7eb; border-radius:8px; background:#fafafa; }
#debugger #dbgInfo { max-height: var(--pre-h); }


/* Painter pointer affordances */
#grid, #sim {
  touch-action: none;        /* prevent page scroll on drag */
  cursor: crosshair;         /* visual affordance for painting */
  -webkit-user-select: none; /* avoid text selection while dragging */
  user-select: none;
}

/* Embedded contrast safety: prevent light-on-light conflicts in status/derived panes */
#status, #derived, pre#status, pre.output, .output {
  background: var(--panel-2) !important;
  color: var(--text) !important;
  border-color: var(--border) !important;
}