:root {
    --blu: #005792;
    --blu-scuro: #003f63;
    --blu-notte: #012a44;
    --blu-chiaro: #e8f0fe;
    --sfondo: #f0f4f8;
    --carta: #ffffff;
    --testo: #1f2d38;
    --testo-tenue: #5b6b78;
    --bordo: #d5dfe8;
    --ombra: 0 1px 2px rgba(1, 42, 68, 0.06), 0 8px 24px rgba(1, 42, 68, 0.08);
    --serif: 'Iowan Old Style', 'Palatino Linotype', Palatino, 'Book Antiqua', 'URW Palladio L', 'P052', Georgia, serif;
    --sans: system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    --mono: ui-monospace, 'DejaVu Sans Mono', Menlo, Consolas, 'Liberation Mono', monospace;
}

*,
*::before,
*::after {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: var(--sans);
    font-size: 1rem;
    line-height: 1.6;
    background-color: var(--sfondo);
    color: var(--testo);
}

h1,
h2,
p,
ol,
ul {
    margin: 0;
}

.contenitore {
    width: 100%;
    max-width: 960px;
    margin: 0 auto;
    padding: 0 24px;
}

/* Intestazione */
header {
    position: relative;
    overflow: hidden;
    color: white;
    background-color: var(--blu-scuro);
    background-image:
        linear-gradient(rgba(255, 255, 255, 0.05) 1px, transparent 1px),
        linear-gradient(90deg, rgba(255, 255, 255, 0.05) 1px, transparent 1px),
        linear-gradient(135deg, var(--blu-notte), var(--blu) 85%);
    background-size: 32px 32px, 32px 32px, 100% 100%;
}

/* Il logo ripetuto in grande, come filigrana */
header::after {
    content: "";
    position: absolute;
    top: 50%;
    right: -90px;
    width: 460px;
    height: 460px;
    transform: translateY(-50%);
    background: url("../img/tutanum-logo.png") center / contain no-repeat;
    opacity: 0.1;
    pointer-events: none;
}

header .contenitore {
    position: relative;
    z-index: 1;
    display: flex;
    align-items: center;
    gap: 28px;
    padding-top: 64px;
    padding-bottom: 64px;
}

.logo {
    flex: none;
    width: 120px;
    height: 120px;
    filter: drop-shadow(0 0 14px rgba(120, 200, 255, 0.45));
}

header h1 {
    font-family: var(--serif);
    font-size: clamp(2.75rem, 8vw, 4.5rem);
    font-weight: 600;
    line-height: 1;
    letter-spacing: -0.01em;
}

.sottotitolo {
    margin-top: 14px;
    font-family: var(--mono);
    font-size: 0.8rem;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: rgba(255, 255, 255, 0.75);
}

/* Sezioni */
main {
    padding-top: 16px;
    padding-bottom: 24px;
}

section {
    margin-top: 48px;
}

.label {
    display: flex;
    align-items: center;
    gap: 14px;
    margin-bottom: 18px;
    color: var(--testo-tenue);
    font-size: 0.95rem;
}

.label::after {
    content: "";
    flex: 1;
    height: 1px;
    background-color: var(--bordo);
}

h2 {
    font-family: var(--serif);
    font-weight: 600;
    line-height: 1.2;
    color: var(--blu);
}

.titolo-sezione {
    margin-bottom: 18px;
    padding-bottom: 10px;
    border-bottom: 1px solid var(--bordo);
    font-size: 1.75rem;
}

.bottone {
    display: inline-block;
    padding: 10px 22px;
    font-size: 1rem;
    font-weight: 600;
    text-decoration: none;
    white-space: nowrap;
    color: white;
    background-color: var(--blu);
    border-radius: 8px;
    transition: background-color 0.2s;
}

.bottone:hover {
    background-color: var(--blu-scuro);
}

a:focus-visible {
    outline: 3px solid #4aa8e0;
    outline-offset: 3px;
    border-radius: 8px;
}

/* Scelta della versione */
.choice-container {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 24px;
}

.choice-card {
    display: flex;
    flex-direction: column;
    overflow: hidden;
    background-color: var(--carta);
    border: 1px solid var(--bordo);
    border-radius: 14px;
    box-shadow: var(--ombra);
    transition: transform 0.2s, box-shadow 0.2s;
}

.choice-card:hover {
    transform: translateY(-3px);
    box-shadow: 0 2px 4px rgba(1, 42, 68, 0.08), 0 16px 36px rgba(1, 42, 68, 0.14);
}

.choice-card img {
    display: block;
    width: 100%;
    aspect-ratio: 16 / 10;
    object-fit: cover;
    background-color: var(--blu-notte);
}

.choice-card img.classico {
    object-position: 50% 35%;
}

.choice-card img.lieve {
    object-position: 50% 28%;
}

.choice-testo {
    display: flex;
    flex: 1;
    flex-direction: column;
    align-items: flex-start;
    padding: 22px 24px 24px;
}

.choice-card h2 {
    font-size: 1.75rem;
}

.descrizione {
    flex: 1;
    margin: 8px 0 20px;
}

/* Discussione */
.discussione {
    display: flex;
    align-items: center;
    gap: 32px;
    padding: 28px 28px 28px 30px;
    background-color: var(--carta);
    border: 1px solid var(--bordo);
    border-left: 5px solid var(--blu);
    border-radius: 12px;
    box-shadow: var(--ombra);
}

.discussione h2 {
    margin-bottom: 8px;
    font-size: 1.75rem;
}

/* Didattica e progetti futuri */
.elenco {
    display: grid;
    gap: 14px;
    padding: 0;
    list-style: none;
}

.didattica {
    grid-template-columns: repeat(2, 1fr);
    counter-reset: lezione;
}

.progetti-futuri {
    grid-template-columns: repeat(3, 1fr);
}

.riquadro {
    display: flex;
    flex-direction: column;
    gap: 10px;
    padding: 18px 20px;
    background-color: var(--carta);
    border: 1px solid var(--bordo);
    border-radius: 12px;
    transition: border-color 0.2s, background-color 0.2s;
}

.riquadro:hover {
    border-color: var(--blu);
    background-color: var(--blu-chiaro);
}

.riquadro p {
    flex: 1;
    font-weight: 600;
    line-height: 1.35;
}

.riquadro a {
    align-self: flex-start;
    font-size: 0.9rem;
    font-weight: 600;
    text-decoration: none;
    color: var(--blu);
}

.riquadro a::after {
    content: " \2192";
}

.riquadro a:hover {
    text-decoration: underline;
}

.didattica .riquadro {
    display: grid;
    grid-template-columns: auto 1fr auto;
    align-items: center;
    gap: 16px;
    counter-increment: lezione;
}

.didattica .riquadro a {
    align-self: center;
}

.didattica .riquadro::before {
    content: counter(lezione, decimal-leading-zero);
    font-family: var(--mono);
    font-size: 1.35rem;
    color: var(--blu);
}

/* Piè di pagina */
footer {
    margin-top: 40px;
    padding: 24px;
    border-top: 1px solid var(--bordo);
    font-size: 0.9rem;
    text-align: center;
    color: var(--testo-tenue);
}

footer a {
    color: inherit;
}

/* Presentazione in apertura */
.presentazione {
    max-width: 46rem;
    font-size: 1.1rem;
    line-height: 1.65;
}

.presentazione .percorsi {
    margin-top: 10px;
    font-size: 1rem;
    color: var(--testo-tenue);
}

.presentazione a,
.nota-sezione a {
    font-weight: 600;
    color: var(--blu);
}

.nota-sezione {
    margin: -6px 0 18px;
    color: var(--testo-tenue);
}

.riquadro small {
    display: block;
    margin-top: 3px;
    font-size: 0.82rem;
    font-weight: 400;
    color: var(--testo-tenue);
}

section[id] {
    scroll-margin-top: 16px;
}

/* I progetti futuri non hanno ancora una pagina: riquadri non cliccabili */
.progetti-futuri .riquadro {
    border-style: dashed;
    background-color: transparent;
}

.progetti-futuri .riquadro:hover {
    border-color: var(--bordo);
    background-color: transparent;
}

.stato {
    align-self: flex-start;
    padding: 3px 10px;
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.04em;
    text-transform: uppercase;
    color: var(--testo-tenue);
    border: 1px solid var(--bordo);
    border-radius: 999px;
}

.copyleft {
    display: inline-block;
    transform: rotate(180deg);
}

@media (max-width: 760px) {
    .progetti-futuri {
        grid-template-columns: repeat(2, 1fr);
    }

    .didattica {
        grid-template-columns: 1fr;
    }

    .discussione {
        flex-direction: column;
        align-items: flex-start;
        gap: 18px;
    }
}

@media (max-width: 560px) {
    header .contenitore {
        flex-direction: column;
        align-items: flex-start;
        gap: 20px;
        padding-top: 44px;
        padding-bottom: 44px;
    }

    .logo {
        width: 88px;
        height: 88px;
    }

    header::after {
        right: -160px;
    }

    .choice-container,
    .progetti-futuri {
        grid-template-columns: 1fr;
    }

    section {
        margin-top: 36px;
    }
}

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

    .choice-card:hover {
        transform: none;
    }
}

/* ======================================================================
   Tema scuro: attivabile con il pulsante (data-theme="dark" su <html>),
   con ripiego automatico sulle preferenze di sistema quando il JS è
   disattivato.
   ====================================================================== */
.tema-toggle {
    position: absolute;
    top: 18px;
    right: 24px;
    display: inline-flex;
    align-items: center;
    gap: 7px;
    padding: 6px 14px;
    font-family: var(--sans);
    font-size: 0.85rem;
    font-weight: 600;
    color: white;
    background: rgba(255, 255, 255, 0.08);
    border: 1px solid rgba(255, 255, 255, 0.4);
    border-radius: 999px;
    cursor: pointer;
    transition: background-color 0.2s, border-color 0.2s;
}

.tema-toggle:hover {
    background: rgba(255, 255, 255, 0.18);
    border-color: white;
}

.tema-toggle:focus-visible {
    outline: 3px solid #4aa8e0;
    outline-offset: 2px;
}

:root[data-theme="dark"] {
    --blu: #58b0e6;
    --blu-scuro: #9fd0f2;
    --blu-notte: #04141f;
    --blu-chiaro: #15314c;
    --sfondo: #0d1620;
    --carta: #16222e;
    --testo: #e4ecf2;
    --testo-tenue: #9fb1be;
    --bordo: #2b3b49;
    --ombra: 0 1px 2px rgba(0, 0, 0, 0.35), 0 8px 24px rgba(0, 0, 0, 0.5);
}

/* I bottoni restano leggibili: sfondo blu pieno, testo bianco */
:root[data-theme="dark"] .bottone {
    background-color: #1f6fa3;
}

:root[data-theme="dark"] .bottone:hover {
    background-color: #2a85c0;
}

@media (prefers-color-scheme: dark) {
    :root:not([data-theme="light"]) {
        --blu: #58b0e6;
        --blu-scuro: #9fd0f2;
        --blu-notte: #04141f;
        --blu-chiaro: #15314c;
        --sfondo: #0d1620;
        --carta: #16222e;
        --testo: #e4ecf2;
        --testo-tenue: #9fb1be;
        --bordo: #2b3b49;
        --ombra: 0 1px 2px rgba(0, 0, 0, 0.35), 0 8px 24px rgba(0, 0, 0, 0.5);
    }

    :root:not([data-theme="light"]) .bottone {
        background-color: #1f6fa3;
    }

    :root:not([data-theme="light"]) .bottone:hover {
        background-color: #2a85c0;
    }
}