/* ============================================================
   PCB Trace Width Calculator v4 — full 3-in-1 (Sierra-function)
   F.Robin Technologies · scoped to .ptwc-wrap
   ============================================================ */
.ptwc-wrap {
  --cyan:#00BFFF; --cyan-d:#0099CC; --dark:#0d0d0d; --dark2:#0a1628;
  --white:#fff; --off:#f5f7fa; --border:#e5e7eb; --grey:#6b7280;
  --text:#1a1a1a; --green:#10b981; --red:#e05a4d; --radius:10px;
  --font:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  font-family:var(--font); color:var(--text); background:var(--white);
  border:1px solid var(--border); border-radius:var(--radius);
  box-shadow:0 4px 24px rgba(0,0,0,.09); max-width:920px; margin:2em auto; overflow:hidden;
}

.ptwc-header { background:linear-gradient(135deg,#0d0d0d 0%,#0a1628 100%); color:#fff; padding:24px 28px 20px; text-align:center; }
.ptwc-icon { margin-bottom:8px; }
.ptwc-title { margin:0 0 5px; font-size:1.3rem; font-weight:800; color:#fff; border:none; padding:0; line-height:1.2; }
.ptwc-subtitle { margin:0; font-size:.82rem; color:rgba(255,255,255,.6); line-height:1.5; }

.ptwc-body { padding:22px 22px 24px; }

/* Toggles */
.ptwc-toggle-grid { display:grid; grid-template-columns:1fr 1fr; gap:14px; margin-bottom:18px; }
.ptwc-toggle-lbl { font-size:.68rem; font-weight:800; text-transform:uppercase; letter-spacing:.07em; color:var(--grey); margin-bottom:6px; }
.ptwc-layer-tabs, .ptwc-std-tabs { display:flex; gap:6px; }
.ptwc-layer-tab, .ptwc-std-tab {
  flex:1; padding:9px 6px; border:1.5px solid var(--border); border-radius:8px;
  background:var(--off); color:var(--grey); font-size:.82rem; font-weight:700;
  cursor:pointer; font-family:var(--font); transition:all .16s; text-align:center;
}
.ptwc-layer-tab:hover, .ptwc-std-tab:hover { border-color:var(--cyan); color:var(--cyan); }
.ptwc-layer-active, .ptwc-std-active { background:var(--dark); color:var(--cyan); border-color:var(--cyan); }

/* Panels */
.ptwc-panels { display:grid; grid-template-columns:1fr 1fr; gap:18px; margin-bottom:14px; }
.ptwc-panel { background:var(--off); border:1px solid var(--border); border-radius:var(--radius); padding:16px 16px 18px; }
.ptwc-panel-title { font-size:1rem; font-weight:800; color:var(--text); padding-bottom:10px; margin-bottom:14px; border-bottom:2px solid var(--cyan); }
.ptwc-panel-output .ptwc-panel-title { border-bottom-color:var(--grey); }

/* Fields */
.ptwc-field { display:flex; flex-direction:column; gap:5px; margin-bottom:13px; }
.ptwc-field:last-child { margin-bottom:0; }
.ptwc-label { font-size:.74rem; font-weight:700; color:var(--text); display:flex; align-items:center; gap:6px; flex-wrap:wrap; }

.ptwc-input-row { display:flex; align-items:stretch; border:1.5px solid var(--border); border-radius:7px; background:var(--white); overflow:hidden; transition:border-color .16s, box-shadow .16s; }
.ptwc-input-row:focus-within { border-color:var(--cyan); box-shadow:0 0 0 3px rgba(0,191,255,.13); }
.ptwc-input { flex:1; border:none; outline:none; background:transparent; font-size:.95rem; font-weight:700; font-family:var(--font); color:var(--text); padding:9px 10px; min-width:0; -moz-appearance:textfield; }
.ptwc-input::-webkit-outer-spin-button,.ptwc-input::-webkit-inner-spin-button{ -webkit-appearance:none; margin:0; }
.ptwc-input::placeholder { color:#b8bfc9; font-weight:400; font-size:.82rem; }
.ptwc-unit-sel { border:none; outline:none; background:var(--off); font-size:.78rem; font-weight:700; color:var(--grey); font-family:var(--font); padding:0 8px; cursor:pointer; border-left:1px solid var(--border); }
.ptwc-unit-badge { padding:0 12px; font-size:.8rem; font-weight:700; color:var(--grey); background:var(--off); display:flex; align-items:center; border-left:1px solid var(--border); white-space:nowrap; }

/* Solve row */
.ptwc-solve-row { display:flex; gap:8px; align-items:stretch; }
.ptwc-solve-row .ptwc-input-row { flex:1; }
.ptwc-solve-btn { flex:0 0 auto; padding:0 14px; border:none; border-radius:7px; background:var(--cyan); color:#000; font-size:.78rem; font-weight:800; cursor:pointer; font-family:var(--font); white-space:nowrap; transition:background .16s; box-shadow:0 2px 6px rgba(0,191,255,.25); }
.ptwc-solve-btn:hover { background:var(--cyan-d); }
.ptwc-solve-btn:active { transform:scale(.97); }

/* Solved highlight */
.ptwc-solved-field .ptwc-input-row { border-color:var(--green); background:#f0faf4; box-shadow:0 0 0 3px rgba(16,185,129,.12); }
.ptwc-solved-field .ptwc-input { color:#059669; }

/* Output */
.ptwc-output-row { background:var(--white); }
.ptwc-output { color:var(--cyan-d); font-family:"Courier New",monospace; cursor:default; }

/* Advanced */
.ptwc-advanced-btn { width:100%; margin-top:6px; padding:11px 14px; border:none; border-radius:8px; background:#c8925a; color:#fff; font-size:.85rem; font-weight:700; cursor:pointer; font-family:var(--font); transition:background .16s; }
.ptwc-advanced-btn:hover { background:#b5824c; }
.ptwc-advanced-btn.ptwc-adv-open { background:#a5763f; }
.ptwc-advanced { display:none; margin-top:10px; padding:14px; background:var(--white); border:1px solid var(--border); border-radius:8px; }
.ptwc-adv-note { font-size:.72rem; color:var(--grey); margin:10px 0 0; line-height:1.5; }
.ptwc-reset-link { width:100%; margin-top:12px; padding:8px; border:none; background:none; color:var(--grey); font-size:.8rem; font-weight:700; cursor:pointer; font-family:var(--font); text-decoration:underline; text-underline-offset:2px; transition:color .15s; }
.ptwc-reset-link:hover { color:var(--red); }

/* Message + note */
.ptwc-msg { border-radius:7px; font-size:.86rem; font-weight:600; }
.ptwc-msg:not(:empty){ padding:.65em 1em; margin-bottom:14px; }
.ptwc-msg.ptwc-error { background:#fce8e6; color:#c0392b; border:1px solid #f5c6c2; }
.ptwc-note { display:flex; align-items:flex-start; gap:8px; background:rgba(0,191,255,.06); border:1px solid rgba(0,191,255,.22); border-radius:8px; padding:12px 14px; font-size:.79rem; color:var(--grey); line-height:1.6; }
.ptwc-note strong { color:var(--text); }
.ptwc-note svg { flex-shrink:0; margin-top:1px; }

/* Responsive */
@media (max-width:720px){ .ptwc-panels{grid-template-columns:1fr;} .ptwc-toggle-grid{grid-template-columns:1fr;} .ptwc-body{padding:14px 12px 16px;} }
@media (max-width:420px){ .ptwc-solve-row{flex-direction:column;} .ptwc-solve-btn{padding:10px;} }