/* =========================================================
   Laboratorio filtri RC — stile
   I colori sono tutti qui sotto: cambiandoli si aggiornano
   anche i grafici (che leggono le stesse variabili).
   ========================================================= */
:root {
  --carta: #E9EFEC;          /* sfondo pagina */
  --superficie: #F8FAF9;     /* sfondo dei pannelli */
  --inchiostro: #1B2936;     /* testo e fili dello schema */
  --tenue: #586976;          /* testo secondario */
  --griglia: #DDE5E1;        /* griglia fine dei grafici */
  --griglia-forte: #BFCDC6;  /* griglia principale */
  --bordo: #BDCAC3;
  --in: #2152C0;             /* segnale in ingresso */
  --out: #B3205F;            /* segnale in uscita */
  --filtro: #0B7A62;         /* filtro e diagramma di Bode */
  --disturbo: #B87400;       /* componenti indesiderate */
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root {
    --carta: #121A20;
    --superficie: #18222A;
    --inchiostro: #E2E9E5;
    --tenue: #93A4AE;
    --griglia: #24313A;
    --griglia-forte: #33444F;
    --bordo: #33434D;
    --in: #7AA2FF;
    --out: #F27AB0;
    --filtro: #41C9A2;
    --disturbo: #F0B43C;
    color-scheme: dark;
  }
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }

html { background: var(--carta); }
body {
  margin: 0;
  font-family: "Atkinson Hyperlegible", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  font-size: 16px;
  line-height: 1.5;
  color: var(--inchiostro);
  background: var(--carta);
}

.sr { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); }

:focus-visible { outline: 3px solid var(--in); outline-offset: 2px; }

/* ---------- testata ---------- */
.testata {
  max-width: 1320px;
  margin: 0 auto;
  padding: 32px 24px 16px 84px;
  display: flex;
  flex-wrap: wrap;
  gap: 16px 40px;
  align-items: flex-end;
  justify-content: space-between;
}
.testata h1 {
  font-size: clamp(1.9rem, 3.4vw, 2.7rem);
  line-height: 1.05;
  margin: 0 0 10px;
  letter-spacing: -0.015em;
}
.testata p { margin: 0; max-width: 64ch; color: var(--tenue); }
.volume { display: flex; align-items: center; gap: 10px; font-weight: 700; }
.volume input { width: 150px; accent-color: var(--inchiostro); }

/* ---------- percorso del segnale ---------- */
.percorso {
  max-width: 1320px;
  margin: 0 auto;
  padding: 12px 24px 8px 84px;
}
.stadio { position: relative; margin-bottom: 32px; --tinta: var(--in); }
#sez-filtro { --tinta: var(--filtro); }
#sez-uscita { --tinta: var(--out); }

/* la traccia verticale: il segnale cambia colore attraversando il filtro */
.stadio::before {
  content: "";
  position: absolute;
  left: -39px;
  top: 16px;
  bottom: -34px;
  width: 4px;
  border-radius: 2px;
  background: var(--tinta);
}
#sez-uscita::before { display: none; }

.nodo {
  position: relative;
  font-size: 1.4rem;
  line-height: 30px;
  margin: 0 0 12px;
}
.nodo .num {
  position: absolute;
  left: -52px;
  top: 0;
  width: 30px;
  height: 30px;
  border-radius: 50%;
  border: 4px solid var(--tinta);
  background: var(--carta);
  display: grid;
  place-items: center;
  font-size: 0.85rem;
  line-height: 1;
}

.griglia {
  display: grid;
  grid-template-columns: minmax(260px, 320px) minmax(0, 1fr);
  gap: 24px;
  background: var(--superficie);
  border: 1px solid var(--bordo);
  border-radius: 8px;
  padding: 20px;
}

/* ---------- comandi ---------- */
.comandi { display: flex; flex-direction: column; gap: 14px; min-width: 0; }
fieldset { border: 0; padding: 0; margin: 0; min-width: 0; }
legend { font-weight: 700; font-size: 0.95rem; padding: 0; margin-bottom: 6px; }
.scelta label { display: flex; gap: 10px; align-items: center; padding: 4px 0; cursor: pointer; }

input[type="number"], select {
  font: inherit;
  font-size: 0.95rem;
  color: inherit;
  background: var(--carta);
  border: 1px solid var(--bordo);
  border-radius: 4px;
  padding: 5px 7px;
  min-width: 0;
}
input[type="file"] { font: inherit; font-size: 0.9rem; max-width: 100%; }
input[type="range"] { accent-color: var(--tinta); width: 100%; }
input[type="checkbox"], input[type="radio"] { accent-color: var(--tinta); width: 18px; height: 18px; margin: 0; }

.campo { display: flex; flex-direction: column; gap: 4px; font-weight: 700; font-size: 0.95rem; }
.campo select, .campo input { font-weight: 400; }
.spunta { display: flex; align-items: center; gap: 10px; cursor: pointer; }
.riga { display: flex; flex-wrap: wrap; gap: 8px 16px; }
.riga label { display: flex; align-items: center; gap: 6px; }
.riga input { width: 6em; }
.riga-slider { display: flex; align-items: center; gap: 10px; font-weight: 400; }

.nota { margin: 0; font-size: 0.87rem; color: var(--tenue); }
.nota:empty { display: none; }

table.disturbi { border-collapse: collapse; width: 100%; }
.disturbi th { font-size: 0.82rem; color: var(--tenue); text-align: left; font-weight: 700; padding-bottom: 4px; }
.disturbi td { padding: 3px 6px 3px 0; }
.disturbi td:first-child { width: 26px; }
.disturbi input[type="number"] { width: 100%; }
.disturbi td.multiplo { color: var(--tenue); font-size: 0.85rem; white-space: nowrap; font-variant-numeric: tabular-nums; padding-right: 0; }
.disturbi tr.spento input[type="number"] { opacity: 0.45; }

.ascolto { display: flex; flex-direction: column; gap: 8px; }
button { font: inherit; cursor: pointer; color: inherit; }
.play {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 14px;
  border: 2px solid var(--tinta);
  border-radius: 6px;
  background: transparent;
  font-weight: 700;
  text-align: left;
}
.play .icona { width: 1.1em; color: var(--tinta); }
.play[aria-pressed="true"] { background: var(--tinta); color: var(--superficie); }
.play[aria-pressed="true"] .icona { color: inherit; }
#sez-ingresso .play[data-play="pulito"] { border-style: dashed; }
.secondario {
  align-self: flex-start;
  padding: 6px 12px;
  border: 1px solid var(--bordo);
  border-radius: 4px;
  background: var(--carta);
}

/* ---------- viste e grafici ---------- */
.vista { display: flex; flex-direction: column; gap: 10px; min-width: 0; }
.schede {
  display: inline-flex;
  align-self: flex-start;
  border: 1px solid var(--bordo);
  border-radius: 6px;
  overflow: hidden;
}
.schede button { border: 0; background: transparent; padding: 7px 14px; color: var(--tenue); font-weight: 700; }
.schede button + button { border-left: 1px solid var(--bordo); }
.schede button[aria-selected="true"] { background: var(--tinta); color: var(--superficie); }

canvas.grafico { display: block; width: 100%; height: 310px; touch-action: pan-y; }
#cv-modulo { height: 230px; }
#cv-fase { height: 180px; }

.legenda { display: flex; flex-wrap: wrap; gap: 6px 18px; font-size: 0.87rem; color: var(--tenue); }
.legenda span { display: inline-flex; align-items: center; gap: 7px; }
.legenda i { display: inline-block; width: 22px; height: 0; border-top: 3px solid var(--c); }
.legenda i.tratteggio { border-top: 2px dashed var(--c); }
.legenda i.chiaro { border-top-width: 7px; opacity: 0.35; }
.legenda i.punto { width: 10px; height: 10px; border: 0; border-radius: 50%; background: var(--c); }

.opzioni {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 22px;
  align-items: center;
  padding-top: 10px;
  border-top: 1px solid var(--griglia);
  font-size: 0.92rem;
}
.opzioni label { display: flex; align-items: center; gap: 8px; }
.opzioni input[type="range"] { width: 120px; }
output { font-variant-numeric: tabular-nums; min-width: 3.2em; }

/* ---------- filtro ---------- */
.schema { margin: 0; padding: 6px 8px; background: var(--carta); border-radius: 6px; }
.schema svg { display: block; width: 100%; height: auto; max-height: 240px; }
.schema .filo { stroke: var(--inchiostro); stroke-width: 2; fill: none; }
.schema .comp { stroke: var(--filtro); stroke-width: 2.6; fill: none; stroke-linejoin: round; stroke-linecap: round; }
.schema .piastra { stroke-width: 4; stroke-linecap: butt; }
.schema .buf { fill: var(--superficie); }
.schema .punto { fill: var(--inchiostro); }
.schema .morsetto { fill: var(--superficie); stroke: var(--inchiostro); stroke-width: 2; }
.schema text { fill: var(--inchiostro); font-family: inherit; font-size: 15px; }
.schema .morsetto-testo { font-weight: 700; font-size: 16px; }
.schema .buf-testo { font-size: 13px; fill: var(--tenue); }

.gruppo-rc {
  border: 1px solid var(--bordo);
  border-radius: 6px;
  padding: 8px 12px 12px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.gruppo-rc legend { padding: 0 6px; margin: 0; }
.rc { display: grid; grid-template-columns: 2.4em minmax(0, 1fr) auto; gap: 4px 8px; align-items: center; }
.rc label { font-weight: 700; font-size: 1.05rem; }
.rc input[type="range"] { grid-column: 1 / -1; }
.fc { display: flex; align-items: center; justify-content: space-between; gap: 8px; font-size: 0.92rem; padding-top: 6px; border-top: 1px dashed var(--bordo); }
.fc input { width: 6.5em; }
.esito { margin: 0; font-size: 0.92rem; line-height: 1.55; padding: 10px 12px; background: var(--carta); border-radius: 6px; }

.lettura { margin: 0; min-height: 1.5em; font-size: 0.9rem; color: var(--tenue); display: flex; flex-wrap: wrap; gap: 4px 18px; }
.lettura b { color: var(--inchiostro); }

.scorri { overflow-x: auto; }
table.effetto { width: 100%; border-collapse: collapse; font-size: 0.9rem; font-variant-numeric: tabular-nums; }
.effetto caption { text-align: left; font-weight: 700; padding-bottom: 6px; }
.effetto th, .effetto td { padding: 6px 8px; border-bottom: 1px solid var(--griglia); text-align: right; white-space: nowrap; }
.effetto thead th { color: var(--tenue); font-size: 0.82rem; }
.effetto th:first-child { text-align: left; }
.effetto tbody th { font-weight: 400; }
.effetto tbody th i { display: inline-block; width: 10px; height: 10px; border-radius: 50%; margin-right: 8px; background: var(--disturbo); }
.effetto tr.utile th i { background: var(--in); }

/* ---------- uscita ---------- */
.risultato {
  margin: 0;
  padding: 12px 14px;
  border-left: 4px solid var(--out);
  border-radius: 0 6px 6px 0;
  background: var(--carta);
}

/* ---------- formule ---------- */
.formule { max-width: 1320px; margin: 0 auto; padding: 8px 24px 48px 84px; }
.formule-testa {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  justify-content: space-between;
  gap: 12px 24px;
  margin-bottom: 16px;
}
.formule h2 { font-size: 1.4rem; margin: 0 0 4px; }
.scarica {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 11px 18px;
  border-radius: 6px;
  background: var(--filtro);
  color: var(--superficie);
  font-weight: 700;
  text-decoration: none;
}
.scarica:hover { filter: brightness(1.1); }
.scarica svg { width: 20px; height: 20px; fill: none; stroke: currentColor; stroke-width: 2.4; stroke-linecap: round; stroke-linejoin: round; }

.carte { display: grid; grid-template-columns: repeat(auto-fill, minmax(310px, 1fr)); gap: 16px; }
.carta {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 16px 18px 18px;
  background: var(--superficie);
  border: 1px solid var(--bordo);
  border-top: 4px solid var(--filtro);
  border-radius: 8px;
}
.carta h3 { margin: 0; font-size: 1.05rem; }
.carta p { margin: 0; font-size: 0.92rem; line-height: 1.5; }

/* formula in evidenza */
.eq {
  display: block;
  padding: 12px 14px;
  border-radius: 6px;
  background: var(--carta);
  font-family: "Cambria Math", "STIX Two Math", "Latin Modern Math", Georgia, serif;
  font-size: 1.3rem;
  line-height: 1.2;
}
.eq.piccola { font-size: 1.08rem; padding: 8px 14px; }
.eq sub, .eq sup { font-size: 0.65em; }
.eq .commento { font-family: "Atkinson Hyperlegible", system-ui, sans-serif; font-size: 0.8rem; color: var(--tenue); margin-left: 6px; }
.eq .sep { display: inline-block; width: 22px; }
.eq .nw { display: inline-block; white-space: nowrap; }

/* frazione: numeratore sopra, denominatore sotto */
.fr { display: inline-flex; flex-direction: column; align-items: center; vertical-align: middle; margin: 0 2px; }
.fr > span { padding: 1px 5px; white-space: nowrap; }
.fr > span:first-child { border-bottom: 1.6px solid currentColor; }

/* radice quadrata con barra sopra */
.rad { display: inline-flex; align-items: stretch; vertical-align: middle; white-space: nowrap; }
.rad::before {
  content: "";
  flex: none;
  width: 0.62em;
  background: currentColor;
  -webkit-mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 12 24' preserveAspectRatio='none'%3E%3Cpath d='M0.5 14.5 L3.5 12.5 L7 23 L11.6 0.8' fill='none' stroke='black' stroke-width='1.4'/%3E%3C/svg%3E") no-repeat 0 0 / 100% 100%;
          mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 12 24' preserveAspectRatio='none'%3E%3Cpath d='M0.5 14.5 L3.5 12.5 L7 23 L11.6 0.8' fill='none' stroke='black' stroke-width='1.4'/%3E%3C/svg%3E") no-repeat 0 0 / 100% 100%;
}
.rad > span { border-top: 1.6px solid currentColor; padding: 3px 4px 1px 2px; line-height: 1.15; }

.carta .esempio {
  margin-top: auto;
  padding: 8px 12px;
  border-left: 3px solid var(--in);
  background: var(--carta);
  border-radius: 0 6px 6px 0;
  font-size: 0.88rem;
}
.carta .esempio b { margin-right: 6px; }

table.db { border-collapse: collapse; font-size: 0.88rem; font-variant-numeric: tabular-nums; }
.db th, .db td { padding: 4px 9px; border-bottom: 1px solid var(--griglia); text-align: center; }
.db th { text-align: left; color: var(--tenue); font-weight: 700; }

.piede { margin-top: 20px; max-width: 82ch; }

/* ---------- schermi stretti ---------- */
@media (max-width: 920px) {
  .griglia { grid-template-columns: 1fr; }
}
@media (max-width: 600px) {
  .testata, .percorso, .formule { padding-left: 52px; padding-right: 14px; }
  .stadio::before { left: -27px; }
  .nodo .num { left: -40px; }
  .griglia { padding: 14px; }
  canvas.grafico { height: 250px; }
  .schede button { padding: 7px 10px; }
  .carte { grid-template-columns: 1fr; }
}