/* ============================================================
   CALCOLATORE RETTA — stile locale
   La disposizione è quella del Calcolatore Parabola (scheda dei dati,
   grafico con la tabella accanto, svolgimento), ma i colori e i font
   sono quelli di math-base.css: niente palette propria (guida, cap. 3).
   ============================================================ */

.app-container {
    max-width: 1000px;
    width: 100%;
    margin: 32px auto;
    padding: 0 20px;
    flex: 1;
}

.calculator-card {
    background: var(--card);
    padding: 28px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    border: 1px solid var(--line);
    margin-bottom: 28px;
}

.app-title {
    text-align: center;
    margin: 0 0 8px;
    font-weight: 800;
    color: var(--brand);
}

.sommario {
    text-align: center;
    color: var(--ink-2);
    max-width: 680px;
    margin: 0 auto 24px;
}

.calculator-card h2 { color: var(--brand); font-size: 1.25rem; margin: 0 0 14px; }
.calculator-card h3 { color: var(--ink); font-size: 1.05rem; margin: 22px 0 6px; }

/* ---------- I tre modi ---------- */
.mode-selector {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 24px;
}

.modo-btn {
    min-height: 44px;
    padding: 8px 20px;
    border: 2px solid var(--line);
    background: var(--card);
    color: var(--ink);
    border-radius: 999px;
    font-weight: 700;
    font-size: 1rem;
    cursor: pointer;
    transition: background .2s, border-color .2s, color .2s;
}

.modo-btn:hover { border-color: var(--brand); }
.modo-btn.attivo { background: var(--brand); border-color: var(--brand); color: #fff; }

/* ---------- I campi ---------- */
.campi { max-width: 560px; margin: 0 auto; }

.etichetta { display: block; font-weight: 700; color: var(--ink-2); margin-bottom: 6px; }

/* 16px almeno: sotto, iOS ingrandisce la pagina al tocco (guida, cap. 4) */
.campo {
    width: 100%;
    min-height: 48px;
    padding: 10px 14px;
    border: 2px solid var(--line);
    border-radius: var(--radius-sm);
    font-family: var(--font-mono);
    font-size: 1.1rem;
    color: var(--ink);
    background: #fff;
    box-sizing: border-box;
}

.campo:focus { border-color: var(--brand); outline: 3px solid var(--ring); outline-offset: 1px; }
.campo-eq { font-size: 1.25rem; text-align: center; }

.aiuto { color: var(--ink-2); font-size: .92rem; margin: 8px 0 0; }

.esempi { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 12px; justify-content: center; }

.esempio {
    min-height: 44px;
    padding: 6px 14px;
    border: 1px solid var(--line);
    background: var(--brand-light);
    color: var(--brand-deep);
    border-radius: 999px;
    font-family: var(--font-mono);
    font-size: .95rem;
    cursor: pointer;
}

.esempio:hover { border-color: var(--brand); }

.griglia-punti { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }

.punto-campi {
    border: 1px solid var(--line);
    border-radius: var(--radius-sm);
    padding: 10px 14px 14px;
    margin: 0;
    display: grid;
    gap: 10px;
}

.punto-campi legend { font-weight: 700; color: var(--brand); padding: 0 6px; }

.punto-campi label {
    display: grid;
    grid-template-columns: 2.4rem 1fr;
    align-items: center;
    font-family: var(--font-mono);
    font-weight: 600;
    color: var(--ink-2);
}

.calculate-btn {
    display: block;
    width: 100%;
    max-width: 320px;
    min-height: 48px;
    margin: 22px auto 0;
    padding: 12px;
    background: var(--brand);
    color: #fff;
    border: none;
    border-radius: 999px;
    font-size: 1.05rem;
    font-weight: 700;
    cursor: pointer;
    transition: background .2s, transform .2s;
}

.calculate-btn:hover { background: var(--brand-2); transform: translateY(-1px); }

.errore {
    max-width: 560px;
    margin: 16px auto 0;
    padding: 12px 16px;
    border-radius: var(--radius-sm);
    background: #fef2f2;
    border-left: 4px solid #dc2626;
    color: #7f1d1d;
}

.errore::before { content: "⚠️ "; }

/* ---------- I risultati ---------- */
.results-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 14px;
    margin-top: 26px;
    padding-top: 20px;
    border-top: 1px solid var(--line);
}

.result-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
    background: var(--bg);
    padding: 14px 10px;
    border-radius: var(--radius-sm);
    min-width: 0;
}

.res-label { font-size: .88rem; color: var(--ink-2); text-align: center; }

/* Scorre in orizzontale se la formula è lunga, ma mai in verticale: una
   frazione è più alta della riga, e con overflow-y lasciato ad «auto»
   accanto a ogni frazione compariva una barra di scorrimento sottile. */
.res-value {
    font-weight: 700;
    font-size: 1.1rem;
    color: var(--brand);
    max-width: 100%;
    overflow-x: auto;
    overflow-y: hidden;
    padding: 4px 2px;
    text-align: center;
}

/* ---------- Grafico e tabella ---------- */
.visual-section {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 280px;
    gap: 24px;
    align-items: start;
    margin-bottom: 28px;
}

.canvas-wrapper {
    position: relative;
    background: var(--card);
    padding: 14px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    border: 1px solid var(--line);
}

#grafico {
    width: 100%;
    aspect-ratio: 1 / 1;
    display: block;
    border: 1px solid var(--line);
    border-radius: 8px;
    /* di norma il dito sul grafico fa scorrere la pagina */
    touch-action: pan-y pinch-zoom;
}

#grafico.spostabile { touch-action: none; cursor: grab; }
#grafico.spostabile:active { cursor: grabbing; }

.graph-controls {
    position: absolute;
    bottom: 24px;
    left: 24px;
    display: flex;
    gap: 8px;
    background: rgba(255, 255, 255, .95);
    padding: 8px;
    border-radius: 12px;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--line);
}

.ctrl-btn {
    width: 44px;
    height: 44px;
    border: 1px solid var(--line);
    background: #fff;
    border-radius: 10px;
    color: var(--ink);
    font-size: 1.25rem;
    font-weight: 700;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0;
}

.ctrl-btn:hover { background: var(--brand-light); }
.ctrl-btn.attivo { background: var(--brand); color: #fff; border-color: var(--brand); }

.table-wrapper {
    background: var(--card);
    padding: 16px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    border: 1px solid var(--line);
}

.table-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 8px;
}

.table-header h2 { margin: 0; font-size: 1.05rem; }

.ctrl-btn.text-btn {
    width: auto;
    min-height: 44px;
    height: auto;
    padding: 6px 12px;
    font-size: .88rem;
}

#tabella { width: 100%; border-collapse: collapse; font-family: var(--font-mono); }
#tabella th, #tabella td { padding: 9px 8px; border-bottom: 1px solid var(--line); text-align: center; }
#tabella th { background: var(--bg); color: var(--ink-2); }

/* La riga di un punto sugli assi: colore e segno, mai solo colore (guida, cap. 7) */
#tabella tr.sull-asse td { background: var(--accent-soft); }
#tabella tr.sull-asse td:first-child::before { content: "◆ "; color: #b45309; font-size: .8em; }

.tabella-perche { color: var(--ink-2); font-size: .9rem; margin: 12px 0 0; }

.legenda { font-size: .85rem; color: var(--ink-2); margin: 10px 0 0; display: flex; flex-wrap: wrap; gap: 4px 12px; align-items: center; }
.pallino { display: inline-block; width: 11px; height: 11px; border-radius: 50%; margin-right: 4px; vertical-align: middle; }
.pallino.oro { background: var(--accent); }
.pallino.rosso { background: #dc2626; }

/* ---------- Lo svolgimento ---------- */
.steps-title {
    text-align: center;
    margin: 0 auto 20px;
    padding-bottom: 8px;
    border-bottom: 3px solid var(--accent);
    width: fit-content;
}

.passo {
    border-left: 5px solid var(--brand);
    background: var(--bg);
    padding: 14px 16px;
    border-radius: 4px var(--radius-sm) var(--radius-sm) 4px;
    margin-bottom: 14px;
}

.passo:nth-child(3n+2) { border-left-color: var(--accent); }
.passo:nth-child(3n+3) { border-left-color: var(--brand-2); }

.passo h3 { margin: 0 0 6px; font-size: 1rem; color: var(--ink); }

/* Una formula lunga scorre da sola, la pagina no (guida, cap. 4) */
.passo-formula {
    overflow-x: auto;
    overflow-y: hidden;
    -webkit-overflow-scrolling: touch;
    padding: 4px 0;
    font-family: var(--font-mono);
}

.passo-perche { margin: 6px 0 0; color: var(--ink-2); font-size: .95rem; }

/* ---------- Le formule e la teoria ---------- */
.formula-list { display: flex; flex-wrap: wrap; gap: 12px; }

.formula-item {
    background: var(--bg);
    padding: 10px 14px;
    border-radius: var(--radius-sm);
    max-width: 100%;
    overflow-x: auto;
    overflow-y: hidden;
}

.formula-item strong { color: var(--ink-2); margin-right: 6px; font-weight: 600; }

.teoria p, .teoria li { color: var(--ink); line-height: 1.65; }
.teoria ul { padding-left: 1.2rem; }
.teoria li { margin-bottom: 6px; }

.lessico dt { font-weight: 700; color: var(--brand); margin-top: 10px; }
.lessico dd { margin: 2px 0 0; color: var(--ink); }

.mono { font-family: var(--font-mono); }

/* ---------- Telefono e tablet ---------- */
@media (max-width: 860px) {
    .visual-section { grid-template-columns: minmax(0, 1fr); }
}

@media (max-width: 600px) {
    .app-container { margin: 18px auto; padding: 0 12px; }
    .calculator-card { padding: 18px 14px; }
    .griglia-punti { grid-template-columns: 1fr; }
    .modo-btn { flex: 1 1 100%; }
    .graph-controls { left: 20px; bottom: 20px; }
}

@media (prefers-reduced-motion: reduce) {
    * { animation: none !important; transition: none !important; }
}