/* Lezioni a cartone — stile condiviso.
   Contorni spessi, ombre piene e colori pieni: l'aspetto di un fumetto.
   I colori sono token: le tele (canvas) li rileggono da qui, così il tema
   scuro vale anche per i disegni. */

:root {
  --carta: #fff8e7;
  --carta-2: #fff1cc;
  --pannello: #ffffff;
  --inchiostro: #1d1b2c;
  --inchiostro-2: #4a4760;
  --tenue: #8a86a0;
  --giallo: #ffd23f;
  --arancio: #ff9f1c;
  --rosso: #ee4266;
  --verde: #0ead69;
  --azzurro: #3bceac;
  --blu: #2f6fed;
  --viola: #7b4ddb;
  --rosa: #ff70a6;
  --cielo-alto: #8fd3ff;
  --cielo-basso: #e6f6ff;
  --prato: #7ed957;
  --prato-2: #4caf50;
  --griglia: rgba(29, 27, 44, 0.10);
  --griglia-forte: rgba(29, 27, 44, 0.28);
  --ombra: 4px 4px 0 var(--inchiostro);
  --ombra-piccola: 2px 2px 0 var(--inchiostro);
  --bordo: 3px solid var(--inchiostro);
  --raggio: 16px;
  --font: "Nunito", "Segoe UI Rounded", "Segoe UI", system-ui, -apple-system, sans-serif;
  --font-titolo: "Baloo 2", "Comic Sans MS", "Chalkboard SE", "Segoe UI", system-ui, sans-serif;
  --font-formula: "Cambria Math", "Cambria", "STIX Two Math", "Times New Roman", serif;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --carta: #1b1a28;
    --carta-2: #242236;
    --pannello: #2a2840;
    --inchiostro: #0b0a12;
    --inchiostro-2: #cfcbe6;
    --tenue: #9d99b8;
    --cielo-alto: #1c2a55;
    --cielo-basso: #34406b;
    --prato: #3f8f3a;
    --prato-2: #2e6b2b;
    --griglia: rgba(255, 255, 255, 0.08);
    --griglia-forte: rgba(255, 255, 255, 0.25);
    color-scheme: dark;
  }
  :root:not([data-theme="light"]) body { color: #f2efff; }
}
:root[data-theme="dark"] {
  --carta: #1b1a28;
  --carta-2: #242236;
  --pannello: #2a2840;
  --inchiostro: #0b0a12;
  --inchiostro-2: #cfcbe6;
  --tenue: #9d99b8;
  --cielo-alto: #1c2a55;
  --cielo-basso: #34406b;
  --prato: #3f8f3a;
  --prato-2: #2e6b2b;
  --griglia: rgba(255, 255, 255, 0.08);
  --griglia-forte: rgba(255, 255, 255, 0.25);
  color-scheme: dark;
}
:root[data-theme="dark"] body { color: #f2efff; }

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.5;
  color: var(--inchiostro);
  background: var(--carta);
  background-image: radial-gradient(var(--griglia) 1.2px, transparent 1.2px);
  background-size: 22px 22px;
  min-height: 100vh;
  overflow-x: hidden;
}
a { color: var(--blu); }
h1, h2, h3 { font-family: var(--font-titolo); line-height: 1.15; margin: 0 0 .4em; }
h1 { font-size: clamp(1.7rem, 4vw, 2.6rem); }
h2 { font-size: clamp(1.3rem, 3vw, 1.8rem); }
h3 { font-size: 1.15rem; }
p { margin: 0 0 .8em; }

.contenitore { max-width: 1280px; margin: 0 auto; padding: 0 16px; }

/* ---------- testata ---------- */
.testata {
  display: flex; align-items: center; gap: 14px; flex-wrap: wrap;
  padding: 18px 0 10px;
}
.testata .indietro {
  display: inline-flex; align-items: center; gap: 6px;
  font-weight: 800; text-decoration: none; color: var(--inchiostro);
  background: var(--giallo); border: var(--bordo); border-radius: 999px;
  padding: 6px 14px; box-shadow: var(--ombra-piccola);
}
.testata .indietro:hover { transform: translate(-1px, -1px); box-shadow: 3px 3px 0 var(--inchiostro); }
.testata h1 { margin: 0; }
.testata .sottotitolo { color: var(--tenue); font-weight: 700; width: 100%; }
.titolo-cartone {
  display: inline-block; background: var(--pannello); color: var(--inchiostro);
  border: var(--bordo); border-radius: 12px; padding: 2px 14px; box-shadow: var(--ombra);
  transform: rotate(-1.2deg);
}
[data-theme="dark"] .titolo-cartone, [data-theme="dark"] .scheda { color: #f2efff; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .titolo-cartone { color: #f2efff; }
}

/* ---------- schede ---------- */
.scheda {
  background: var(--pannello); border: var(--bordo); border-radius: var(--raggio);
  box-shadow: var(--ombra); padding: 16px;
}
.scheda + .scheda { margin-top: 18px; }
.scheda h2, .scheda h3 { margin-top: 0; }
.etichetta-colore {
  display: inline-block; font-weight: 800; font-size: .8rem; letter-spacing: .02em;
  border: 2px solid var(--inchiostro); border-radius: 999px; padding: 1px 10px;
  background: var(--giallo); color: #1d1b2c;
}

/* ---------- impaginazione lezione ---------- */
.palco-griglia {
  display: grid; grid-template-columns: minmax(0, 1fr) 340px; gap: 18px; align-items: start;
}
@media (max-width: 960px) { .palco-griglia { grid-template-columns: minmax(0, 1fr); } }

.palco {
  position: relative; border: var(--bordo); border-radius: var(--raggio);
  box-shadow: var(--ombra); overflow: hidden; background: var(--cielo-basso);
}
.palco canvas { display: block; width: 100%; height: clamp(320px, 58vh, 620px); touch-action: none; }
.palco.basso canvas { height: clamp(300px, 50vh, 520px); }

/* ---------- comandi ---------- */
.barra-comandi {
  display: flex; flex-wrap: wrap; gap: 8px 12px; align-items: center;
  padding: 10px 12px; margin-top: 12px;
  background: var(--pannello); border: var(--bordo); border-radius: var(--raggio); box-shadow: var(--ombra-piccola);
}
.barra-comandi label { display: inline-flex; align-items: center; gap: 6px; font-weight: 700; font-size: .9rem; }
.barra-comandi .vel-valore { min-width: 3.4em; font-variant-numeric: tabular-nums; font-weight: 800; }

.bottone {
  font: inherit; font-weight: 800; cursor: pointer;
  display: inline-flex; align-items: center; gap: 6px; justify-content: center;
  border: var(--bordo); border-radius: 12px; padding: 7px 14px;
  background: var(--pannello); color: var(--inchiostro); box-shadow: var(--ombra-piccola);
  transition: transform .08s, box-shadow .08s;
}
.bottone:hover { transform: translate(-1px, -1px); box-shadow: 3px 3px 0 var(--inchiostro); }
.bottone:active { transform: translate(2px, 2px); box-shadow: 0 0 0 var(--inchiostro); }
.bottone:disabled { opacity: .5; cursor: not-allowed; transform: none; }
.bottone.primario { background: var(--giallo); color: #1d1b2c; }
.bottone.verde { background: var(--verde); color: #fff; }
.bottone.blu { background: var(--blu); color: #fff; }
.bottone.rosso { background: var(--rosso); color: #fff; }
.bottone.piccolo { padding: 4px 10px; font-size: .88rem; border-width: 2px; }
.bottone.attivo { background: var(--inchiostro-2); color: var(--pannello); }

select, input[type="text"], input[type="search"], input[type="number"] {
  font: inherit; color: var(--inchiostro); background: var(--carta);
  border: 2px solid var(--inchiostro); border-radius: 10px; padding: 5px 9px;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) select,
  :root:not([data-theme="light"]) input { color: #f2efff; }
}
[data-theme="dark"] select, [data-theme="dark"] input { color: #f2efff; }
input[type="range"] { accent-color: var(--blu); width: 100%; }

.cursore { display: grid; gap: 2px; margin-bottom: 10px; }
.cursore .riga { display: flex; justify-content: space-between; font-weight: 800; }
.cursore output { font-variant-numeric: tabular-nums; }
.interruttore { display: flex; align-items: center; gap: 8px; font-weight: 700; margin: 4px 0; cursor: pointer; }
.interruttore input { width: 18px; height: 18px; accent-color: var(--verde); }

.linguette { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 12px; }

/* ---------- formule ---------- */
.f {
  font-family: var(--font-formula); font-size: 1.22em; line-height: 1.9;
  white-space: nowrap; display: inline-flex; align-items: center; flex-wrap: wrap; gap: 0 .18em;
}
.f i { font-style: italic; }
.f sub, .f sup { font-size: .68em; line-height: 0; }
.f .op { margin: 0 .12em; }
.fr { display: inline-flex; flex-direction: column; align-items: center; vertical-align: middle; font-size: .92em; line-height: 1.15; margin: 0 .1em; }
.fr > span:first-child { border-bottom: 2px solid currentColor; padding: 0 .2em .05em; }
.fr > span:last-child { padding: .05em .2em 0; }
.rad { display: inline-flex; align-items: stretch; }
.rad-in { border-top: 2px solid currentColor; padding: 0 .15em; margin-left: 1px; }
.num {
  font-family: var(--font); font-style: normal; font-weight: 900; font-size: .9em;
  background: var(--giallo); color: #1d1b2c; border-radius: 6px; padding: 0 .25em;
  border: 2px solid var(--inchiostro); line-height: 1.3;
}
.ris {
  font-family: var(--font); font-weight: 900; font-size: .95em;
  background: var(--verde); color: #fff; border-radius: 8px; padding: 0 .35em;
  border: 2px solid var(--inchiostro); box-shadow: var(--ombra-piccola); line-height: 1.35;
}
.u { font-family: var(--font); font-size: .78em; font-weight: 700; color: var(--tenue); margin-left: .12em; }
.c-x { color: var(--rosso); }
.c-y { color: var(--verde); }
.c-v { color: var(--blu); }
.c-a { color: var(--viola); }
.c-b { color: var(--arancio); }
.c-g { color: var(--rosa); }
.c-r { color: var(--viola); }

.lavagna {
  background: #214a3a; color: #f4f1e6; border: var(--bordo); border-radius: var(--raggio);
  box-shadow: var(--ombra); padding: 12px 14px; font-size: .95rem; overflow-x: auto;
}
.lavagna h3 { color: var(--giallo); font-size: 1rem; margin: 0 0 6px; }
.lavagna .riga-f { padding: 3px 0; border-bottom: 1px dashed rgba(255,255,255,.18); }
.lavagna .riga-f:last-child { border-bottom: 0; }
.lavagna .c-x { color: #ff8fa6; }
.lavagna .c-y { color: #7ff0b6; }
.lavagna .c-v { color: #9cc0ff; }
.lavagna .c-a { color: #c7a8ff; }
.lavagna .c-b { color: #ffc46b; }
.lavagna .c-r { color: #c7a8ff; }
.lavagna .u { color: #b9c9bf; }
.lavagna .num { background: #ffe680; }
.lavagna .fr > span:first-child { border-color: #f4f1e6; }

/* ---------- il fumetto: le formule "in sospensione" ---------- */
.fumetto {
  position: absolute; left: 14px; top: 14px; max-width: min(560px, calc(100% - 28px));
  background: var(--pannello); color: var(--inchiostro);
  border: var(--bordo); border-radius: 20px; box-shadow: var(--ombra);
  padding: 12px 16px 12px; z-index: 5;
  transform-origin: 20px 100%;
  animation: fumetto-entra .35s cubic-bezier(.2, 1.6, .5, 1);
  max-height: calc(100% - 28px); overflow: auto;
}
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) .fumetto { color: #f2efff; } }
[data-theme="dark"] .fumetto { color: #f2efff; }
.fumetto.esce { animation: fumetto-esce .25s ease-in forwards; }
.fumetto .f-titolo {
  font-family: var(--font-titolo); font-weight: 800; font-size: 1.1rem; margin-bottom: 4px;
  display: flex; align-items: center; gap: 8px;
}
.fumetto .f-titolo .badge {
  font-family: var(--font); font-size: .72rem; font-weight: 900; letter-spacing: .06em;
  background: var(--rosso); color: #fff; border: 2px solid var(--inchiostro); border-radius: 999px; padding: 0 8px;
}
.fumetto .passo { opacity: 0; transform: translateY(6px) scale(.97); transition: opacity .3s, transform .3s; padding: 2px 0; }
.fumetto .passo.visibile { opacity: 1; transform: none; }
.fumetto .passo .spiega { font-size: .92rem; color: var(--inchiostro-2); font-weight: 600; }
.fumetto .passo.visibile .num { animation: pop .45s cubic-bezier(.2, 1.8, .5, 1) both; }
.fumetto .passo.visibile .ris { animation: pop .5s .25s cubic-bezier(.2, 1.8, .5, 1) both; }
.fumetto .f-piede { display: flex; gap: 8px; justify-content: flex-end; align-items: center; margin-top: 8px; flex-wrap: wrap; }
.fumetto .f-piede .suggerimento { font-size: .78rem; color: var(--tenue); margin-right: auto; }
.fumetto .barra-lettura { height: 4px; background: var(--griglia-forte); border-radius: 4px; overflow: hidden; margin-top: 6px; }
.fumetto .barra-lettura > div { height: 100%; width: 0; background: var(--blu); }

.segnale-slowmo {
  position: absolute; right: 12px; top: 46px; z-index: 4;
  font-weight: 900; font-size: .85rem; letter-spacing: .05em;
  background: var(--rosso); color: #fff; border: 2px solid var(--inchiostro); border-radius: 999px;
  padding: 2px 10px; box-shadow: var(--ombra-piccola); display: none;
}
.segnale-slowmo.on { display: block; animation: lampeggia 1s infinite; }

@keyframes fumetto-entra { from { opacity: 0; transform: scale(.6) rotate(-4deg); } to { opacity: 1; transform: none; } }
@keyframes fumetto-esce { to { opacity: 0; transform: scale(.85) translateY(8px); } }
@keyframes pop { 0% { transform: scale(.3); opacity: 0; } 100% { transform: scale(1); opacity: 1; } }
@keyframes lampeggia { 50% { opacity: .55; } }

/* ---------- quaderno delle formule ---------- */
.quaderno { max-height: 340px; overflow: auto; font-size: .92rem; }
.quaderno .voce { border-left: 4px solid var(--giallo); padding: 4px 10px; margin: 8px 0; background: var(--carta); border-radius: 0 10px 10px 0; }
.quaderno .voce .quando { font-size: .75rem; font-weight: 800; color: var(--tenue); }
.quaderno .vuoto { color: var(--tenue); font-style: italic; }

/* ---------- teoria ---------- */
.teoria { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 18px; margin: 22px 0; }
.teoria .scheda { margin: 0; }
.teoria .scheda + .scheda { margin-top: 0; }
.riquadro-formula {
  background: var(--carta-2); border: 2px dashed var(--inchiostro-2); border-radius: 12px;
  padding: 6px 12px; margin: 8px 0; overflow-x: auto;
}
.nuvoletta-nota {
  position: relative; background: var(--giallo); color: #1d1b2c; border: var(--bordo); border-radius: 14px;
  padding: 8px 12px; font-weight: 700; box-shadow: var(--ombra-piccola); margin: 10px 0;
}

.video-rif { display: flex; flex-wrap: wrap; gap: 12px; }
.video-rif a {
  display: flex; gap: 10px; align-items: center; text-decoration: none; color: inherit;
  border: 2px solid var(--inchiostro); border-radius: 12px; padding: 6px 10px 6px 6px; background: var(--carta);
  font-weight: 700; box-shadow: var(--ombra-piccola);
}
.video-rif img { width: 96px; height: 54px; object-fit: cover; border-radius: 8px; border: 2px solid var(--inchiostro); }

.piede { color: var(--tenue); font-size: .85rem; text-align: center; padding: 30px 0 40px; }

.nascosto { display: none !important; }

@media (max-width: 600px) {
  .f { font-size: 1.08em; }
  .fumetto { left: 8px; top: 8px; max-width: calc(100% - 16px); padding: 10px 12px; }
  .scheda { padding: 12px; }
}
@media (prefers-reduced-motion: reduce) {
  .fumetto, .fumetto .passo, .fumetto .num, .fumetto .ris { animation: none !important; transition: none !important; }
}