:root {
  --bg: #f3f4f8;
  --card: #ffffff;
  --ink: #1e2330;
  --muted: #5f6677;
  --line: #e2e5ee;
  --accent: #4338ca;
  --accent-soft: #eef0ff;
  --up: #d9412b;
  --down: #2563eb;
  --size: #7c3aed;
  --ok: #15803d;
  --ok-soft: #e8f7ee;
  --err: #b42318;
  --err-soft: #fdecea;
  --radius: 14px;
  --shadow: 0 1px 2px rgba(20, 24, 40, .05), 0 4px 16px rgba(20, 24, 40, .05);
  --font: "Segoe UI", Roboto, -apple-system, BlinkMacSystemFont, Helvetica, Arial, sans-serif;
  --mono: "Cascadia Code", "JetBrains Mono", Consolas, "SF Mono", Menlo, monospace;
}

* { box-sizing: border-box; }

[hidden] { display: none !important; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 15px/1.5 var(--font);
}

h1, h2, h3 { margin: 0; line-height: 1.2; }

code {
  font-family: var(--mono);
  font-size: .88em;
  background: #f1f2f7;
  border: 1px solid var(--line);
  border-radius: 5px;
  padding: 0 .3em;
}

/* ------------------------------------------------------------------ header */

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  max-width: 1440px;
  margin: 0 auto;
  padding: 18px 24px 8px;
}

.brand { display: flex; align-items: center; gap: 12px; }
.brand h1 { font-size: 1.35rem; letter-spacing: -.01em; }
.brand p { margin: 2px 0 0; color: var(--muted); font-size: .92rem; }

.gh-link {
  color: var(--muted);
  font-size: .9rem;
  text-decoration: none;
  border: 1px solid var(--line);
  background: var(--card);
  padding: 6px 12px;
  border-radius: 999px;
  white-space: nowrap;
}
.gh-link:hover { color: var(--accent); border-color: #c9cdf5; }

main {
  max-width: 1440px;
  margin: 0 auto;
  padding: 8px 24px 24px;
  display: grid;
  gap: 16px;
}

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 18px 20px;
  min-width: 0;
}

/* ------------------------------------------------------------------- input */

.input-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 8px;
}
.input-head label { font-weight: 600; }

.expr {
  width: 100%;
  font: 500 1.45rem/1.3 var(--mono);
  color: var(--ink);
  padding: 12px 16px;
  border: 1.5px solid #cfd3e0;
  border-radius: 10px;
  background: #fbfbfe;
  outline: none;
  transition: border-color .15s, box-shadow .15s;
}
.expr:focus { border-color: var(--accent); box-shadow: 0 0 0 4px rgba(67, 56, 202, .12); background: #fff; }
.expr.invalid { border-color: var(--err); box-shadow: 0 0 0 4px rgba(180, 35, 24, .1); }

.error {
  margin-top: 8px;
  padding: 8px 12px;
  border-radius: 8px;
  background: var(--err-soft);
  color: var(--err);
  font-size: .93rem;
}
.error pre {
  margin: 6px 0 0;
  font: .95rem/1.3 var(--mono);
  color: var(--ink);
  white-space: pre-wrap;
  word-break: break-all;
}
.error mark { background: #f8c7c1; color: var(--err); border-radius: 3px; padding: 0 1px; }

.examples { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 12px; }
.chip {
  font: 500 .85rem var(--font);
  border: 1px solid var(--line);
  background: #f7f8fb;
  color: var(--ink);
  border-radius: 999px;
  padding: 4px 11px;
  cursor: pointer;
}
.chip:hover { border-color: #c9cdf5; background: var(--accent-soft); color: var(--accent); }
.chip.active { background: var(--accent); border-color: var(--accent); color: #fff; }

.options {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px 28px;
  margin-top: 16px;
  padding-top: 14px;
  border-top: 1px solid var(--line);
}
.opt { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.opt-label { font-weight: 600; font-size: .92rem; }
.check { display: inline-flex; align-items: center; gap: 8px; cursor: pointer; font-size: .92rem; }
.check input { width: 16px; height: 16px; accent-color: var(--accent); margin: 0; }
.sizing { gap: 14px; }
.ratio { font-size: .92rem; color: var(--muted); display: inline-flex; align-items: center; gap: 6px; }
.ratio input {
  width: 64px;
  font: inherit;
  color: var(--ink);
  padding: 3px 6px;
  border: 1px solid #cfd3e0;
  border-radius: 6px;
}
.ratio.disabled { opacity: .45; }

.segmented {
  display: inline-flex;
  background: #eef0f5;
  border-radius: 9px;
  padding: 3px;
  gap: 2px;
}
.segmented button {
  font: 500 .88rem var(--font);
  border: 0;
  background: transparent;
  color: var(--muted);
  padding: 5px 12px;
  border-radius: 7px;
  cursor: pointer;
}
.segmented button[aria-checked="true"] { background: #fff; color: var(--ink); box-shadow: 0 1px 3px rgba(0, 0, 0, .12); }

.syntax { margin-top: 14px; font-size: .92rem; }
.syntax summary { cursor: pointer; color: var(--accent); font-weight: 500; }
.syntax table { border-collapse: collapse; margin: 10px 0 4px; }
.syntax th { text-align: left; padding: 3px 14px 3px 0; color: var(--muted); font-weight: 600; vertical-align: top; }
.syntax td { padding: 3px 0; }
.syntax td code { margin-right: 4px; }
.syntax ul { margin: 8px 0 0; padding-left: 20px; color: var(--muted); }

/* ------------------------------------------------------------ layout/cards */

.layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(300px, 400px);
  gap: 16px;
  align-items: start;
}
.side { display: grid; gap: 16px; min-width: 0; }

.card-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
  margin-bottom: 12px;
}
.card h2 { font-size: 1.05rem; }
.tools { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }

.btn {
  font: 600 .88rem var(--font);
  border: 1px solid var(--accent);
  background: var(--accent);
  color: #fff;
  border-radius: 8px;
  padding: 7px 14px;
  cursor: pointer;
}
.btn:hover { filter: brightness(1.08); }
.btn.ghost { background: #fff; color: var(--ink); border-color: #cfd3e0; }
.btn.ghost:hover { border-color: var(--accent); color: var(--accent); filter: none; }
.btn.small { padding: 5px 11px; font-size: .84rem; }
.btn.icon { display: inline-flex; align-items: center; gap: 6px; }

.switch { display: inline-flex; align-items: center; gap: 8px; cursor: pointer; font-size: .9rem; font-weight: 500; margin-right: 6px; user-select: none; }
.switch input { position: absolute; opacity: 0; pointer-events: none; }
.switch .track {
  width: 36px; height: 20px; border-radius: 999px; background: #cfd3e0; position: relative; transition: background .15s;
}
.switch .track::after {
  content: ""; position: absolute; top: 2px; left: 2px; width: 16px; height: 16px; border-radius: 50%;
  background: #fff; box-shadow: 0 1px 2px rgba(0, 0, 0, .2); transition: transform .15s;
}
.switch input:checked + .track { background: var(--accent); }
.switch input:checked + .track::after { transform: translateX(16px); }
.switch input:focus-visible + .track { outline: 2px solid var(--accent); outline-offset: 2px; }

/* --------------------------------------------------------------- schematic */

.schematic {
  border: 1px solid var(--line);
  border-radius: 10px;
  background: #fff;
  padding: 12px;
  overflow: auto;
  min-height: 240px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: opacity .15s;
}
.schematic.stale { opacity: .35; }
.schematic svg { display: block; width: 100%; height: auto; max-height: 72vh; margin: 0 auto; }

.legend { display: flex; flex-wrap: wrap; gap: 6px 18px; margin-top: 10px; color: var(--muted); font-size: .85rem; }
.legend span { display: inline-flex; align-items: center; gap: 6px; }
.legend svg { color: var(--ink); }
.legend .sw { width: 22px; height: 4px; border-radius: 2px; display: inline-block; }
.legend .sw.up { background: var(--up); }
.legend .sw.down { background: var(--down); }
.legend .sw.size { background: var(--size); }
.legend .sim-only, .legend .size-only { display: none; }
.legend .move-hint { margin-left: auto; font-style: italic; }

/* MOSFET spostabili */
.schematic .cm-tr[data-movable] { cursor: pointer; }
.schematic .cm-tr[data-movable]:hover .cm-w,
.schematic .cm-tr[data-movable]:hover .cm-bubble { stroke: var(--accent); }
.schematic .cm-tr[data-movable]:hover .cm-txt { fill: var(--accent); }

.order-panel {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 14px;
  padding: 8px 12px;
  margin-bottom: 12px;
  background: var(--accent-soft);
  border: 1px solid #d5d9fb;
  border-radius: 10px;
}
.order-info { display: flex; align-items: center; flex-wrap: wrap; gap: 4px 8px; font-size: .92rem; }
.order-info .math { font-size: 1.05rem; }
.order-info .where { color: var(--muted); font-size: .88rem; }
.order-actions { display: flex; flex-wrap: wrap; gap: 6px; margin-left: auto; }
.btn:disabled, .btn:disabled:hover { opacity: .4; cursor: default; color: var(--ink); border-color: #cfd3e0; }
.sim-on .legend .sim-only, .size-on .legend .size-only { display: inline-flex; }

.sim-panel {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 18px;
  padding: 10px 12px;
  margin-bottom: 12px;
  background: #f7f8fb;
  border: 1px solid var(--line);
  border-radius: 10px;
}
.sim-panel .bits { display: flex; flex-wrap: wrap; gap: 6px; }
.sim-panel .hint { color: var(--muted); font-size: .85rem; }
.bit {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font: 600 .95rem var(--font);
  border: 1px solid #cfd3e0;
  background: #fff;
  border-radius: 8px;
  padding: 4px 6px 4px 10px;
  cursor: pointer;
}
.bit .v {
  min-width: 24px;
  text-align: center;
  border-radius: 5px;
  padding: 1px 0;
  color: #fff;
  font-family: var(--mono);
}
.bit .v.b0 { background: var(--down); }
.bit .v.b1 { background: var(--up); }
.sim-out { display: flex; align-items: center; gap: 10px; margin-left: auto; font-size: .9rem; color: var(--muted); }
.sim-out .val {
  font: 700 1.05rem var(--font);
  padding: 3px 12px;
  border-radius: 8px;
  color: #fff;
  background: var(--muted);
}
.sim-out .val.v1 { background: var(--up); }
.sim-out .val.v0 { background: var(--down); }
.sim-out .val.vx { background: #b45309; }

/* ---------------------------------------------------------------- analysis */

.math { font-size: 1.05rem; letter-spacing: .01em; }
.math.big { font-size: 1.45rem; font-weight: 600; margin: 6px 0 4px; }
.ol {
  display: inline-block;
  border-top: .075em solid currentColor;
  padding-top: .06em;
  line-height: 1.05;
}
.math sub, .ol sub { font-size: .65em; }

#analysis h3 { font-size: .95rem; margin: 16px 0 4px; display: flex; align-items: center; gap: 8px; }
#analysis p { margin: 4px 0; color: var(--muted); font-size: .92rem; }
#analysis .formula {
  background: #f7f8fb;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 6px 10px;
  margin: 6px 0;
  overflow-x: auto;
}
.tag {
  font-size: .72rem;
  font-weight: 700;
  letter-spacing: .03em;
  text-transform: uppercase;
  padding: 2px 7px;
  border-radius: 999px;
}
.tag.p { background: #fdeceb; color: var(--up); }
.tag.n { background: #e8effe; color: var(--down); }

.stats { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 8px; margin-top: 14px; }
.stat { background: #f7f8fb; border: 1px solid var(--line); border-radius: 10px; padding: 8px 10px; }
.stat b { display: block; font-size: 1.35rem; line-height: 1.2; }
.stat span { font-size: .78rem; color: var(--muted); }
.note { font-size: .86rem !important; }

.table-wrap.effort { margin: 8px 0; max-height: none; }
.effort .tt tbody tr { cursor: default; }
.effort .tt tbody tr:hover { background: none; }
.effort .tt td.math { font-family: var(--font); font-weight: 600; }
.effort .tt td.g b { color: var(--size); }
.effort .tt .approx { color: var(--muted); font-size: .82rem; margin-left: 4px; }
.effort-hint { margin-top: 12px !important; }

/* ------------------------------------------------------------- truth table */

.verify {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 10px;
  border-radius: 8px;
  font-size: .9rem;
  font-weight: 500;
  margin-bottom: 10px;
}
.verify.ok { background: var(--ok-soft); color: var(--ok); }
.verify.bad { background: var(--err-soft); color: var(--err); }

.table-wrap { max-height: 460px; overflow: auto; border: 1px solid var(--line); border-radius: 8px; }
table.tt { border-collapse: collapse; width: 100%; font-size: .9rem; text-align: center; }
.tt th {
  position: sticky;
  top: 0;
  background: #f1f2f7;
  font-weight: 600;
  padding: 6px 8px;
  border-bottom: 1px solid var(--line);
}
.tt td { padding: 4px 8px; border-bottom: 1px solid #f0f1f5; font-family: var(--mono); }
.tt th.sep, .tt td.sep { border-left: 2px solid var(--line); }
.tt tbody tr { cursor: pointer; }
.tt tbody tr:hover { background: #f5f6ff; }
.tt tr.current { background: #e9ebff !important; box-shadow: inset 3px 0 0 var(--accent); }
.tt .on { color: var(--ok); font-weight: 700; font-family: var(--font); font-size: .8rem; }
.tt .off { color: #9aa1b2; font-family: var(--font); font-size: .8rem; }
.tt .y1 { color: var(--up); font-weight: 700; }
.tt .y0 { color: var(--down); font-weight: 700; }

/* ------------------------------------------------------------------ varie */

footer { text-align: center; color: var(--muted); font-size: .85rem; padding: 8px 24px 28px; }

.toast {
  position: fixed;
  left: 50%;
  bottom: 24px;
  transform: translate(-50%, 20px);
  background: var(--ink);
  color: #fff;
  padding: 8px 16px;
  border-radius: 8px;
  font-size: .9rem;
  opacity: 0;
  pointer-events: none;
  transition: opacity .2s, transform .2s;
}
.toast.show { opacity: 1; transform: translate(-50%, 0); }

/* schermo intero: solo lo schema, il più grande possibile */
.schematic-card:fullscreen {
  border-radius: 0;
  border: 0;
  padding: 20px 28px;
  display: flex;
  flex-direction: column;
  background: #fff;
}
.schematic-card:fullscreen .schematic { flex: 1; border: 0; padding: 0; }
.schematic-card:fullscreen .schematic svg { max-height: calc(100vh - 150px); }
.schematic-card:fullscreen #export-svg,
.schematic-card:fullscreen #export-png { display: none; }

@media (max-width: 1020px) {
  .layout { grid-template-columns: minmax(0, 1fr); }
}

@media (max-width: 640px) {
  body { font-size: 14px; }
  .topbar { padding: 14px 16px 4px; }
  .brand p { display: none; }
  main { padding: 8px 16px 20px; }
  .card { padding: 14px; }
  .expr { font-size: 1.15rem; padding: 10px 12px; }
  .segmented button { padding: 5px 8px; font-size: .82rem; }
  .sim-out { margin-left: 0; }
  .schematic { padding: 6px; }
}