.voltage-definitions { display:grid; grid-template-columns:1fr 1fr; gap:18px; margin:26px 0; }
.voltage-page .lesson-concept h2 { margin:0 0 14px; font-size:20px; }
.voltage-formula { display:block; padding:12px; background:#edf6f2; border-radius:6px; color:#147c69; text-align:center; }
.voltage-lab { margin:30px 0; border:1px solid #d9e2e5; border-radius:12px; overflow:hidden; background:#fff; }
.voltage-bar { padding:18px 22px; background:#3d444c; }
.voltage-bar span { font-size:10px; letter-spacing:.1em; color:#b6c3cc; font-weight:700; }
body.site-subpage .voltage-page .voltage-bar h2 { margin:6px 0 0; font-size:21px; color:white; }
.voltage-controls { display:flex; align-items:center; gap:14px; padding:16px 22px; flex-wrap:wrap; }
.voltage-controls label { font-size:14px; font-weight:600; flex:0 0 185px; }
.voltage-controls input[type=range] { flex:1; min-width:110px; accent-color:#147c69; }
.voltage-controls output { min-width:65px; color:#137860; font-weight:700; text-align:right; }
body.site-subpage .voltage-page button[type] { border:1px solid #ccd5da; border-radius:5px; background:#f5f7f8; color:#25343a; padding:7px 12px; min-height:34px; font:600 13px Arial,sans-serif; box-shadow:none; cursor:pointer; }
.voltage-page input:focus-visible,.voltage-page button:focus-visible { outline:3px solid #149982; outline-offset:3px; }
.voltage-lab svg { display:block; width:100%; height:auto; }
.voltage-lab svg text { font:16px Arial,sans-serif; }
.voltage-lab .source-sign { fill:white; font-size:25px; font-weight:bold; }
.voltage-lab .source-value { fill:white; font-size:17px; }
.voltage-metrics { display:flex; flex-wrap:wrap; justify-content:space-around; gap:10px; padding:16px; background:#eef5f2; color:#147c69; font-size:14px; font-weight:600; }
.voltage-explanation { margin:0; padding:16px 22px; font-size:14px; line-height:1.7; color:#66747b; }
.arc-state { margin:0; padding:16px 22px; font-weight:600; color:#137860; background:#eef5f2; }
.arc-state[data-active=true] { background:#e7f1fb; color:#275b7e; }
@media(max-width:650px) { .voltage-definitions { grid-template-columns:1fr; } .voltage-controls { gap:10px; padding:14px; } .voltage-controls label { flex-basis:100%; } .voltage-explanation { padding:14px; } }

/* Simplified introduction, scoped to this lesson. */
.voltage-simplified .breadcrumb,.voltage-simplified .context-tags { display:none; }
.voltage-simplified .page-chrome:has(> .breadcrumb):not(:has(.topic-drawer)) { display:none; }
.voltage-page [hidden] { display:none !important; }
.voltage-definitions { grid-template-columns:1fr; }
.voltage-simple-definition { font-size:21px; line-height:1.65; margin-top:0; color:#253c44; }
.voltage-safety { margin:38px 0; }
.voltage-safety-grid { display:grid; grid-template-columns:1fr 1fr; gap:18px; margin:22px 0; }
.voltage-safety-grid article { border:1px solid #d9e2e5; border-radius:10px; padding:20px; background:#f5f8f9; }
.voltage-safety-grid h3 { margin:0 0 12px; }
.voltage-safety-grid p { margin:0; }
.voltage-safety-rule { border-left:4px solid #147c69; padding:14px 18px; background:#eef5f2; }
@media(max-width:650px) { .voltage-safety-grid { grid-template-columns:1fr; } .voltage-simple-definition { font-size:18px; } }