/* ======================================================================
   Has Inequality Killed the Azzurri? —
   BEE2041 · Data Science in Economics · University of Exeter
   ======================================================================*/

:root {
    --ink: #1e1e23;
    --rule: #c2c2d6;
    --bg: #ffffff;
    --bg-alt: #f5f5f7;
    --bg-blur: rgba(251, 251, 253, 0.72);
    --panel: #ffffff;
    --link: #359aff;
    --link-hover: #0077ed;
    --accent: #1d1d1f;





    --sans: -apple-system, BlinkMacSystemFont, "SF Pro Text", "SF Pro Display",
        "Helvetica Neue", "Helvetica", "Arial", system-ui, sans-serif;
    --mono: "SF Mono", "Menlo", "Consolas", monospace;

    /* layout */
    --max-width: 600px;
    --wide: 980px;
    --nav-h: 48px;
    --radius: 18px;
    --radius-sm: 12px;
    --radius-lg: 28px;
}

* {
    box-sizing: border-box;
}

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

body {
    margin: 0;
    background: var(--bg);
    color: var(--ink);
    font-family: var(--sans);
    font-size: 17px;
    line-height: 1.47;
    letter-spacing: -0.01em;
    font-feature-settings: "kern", "liga";
    text-rendering: optimizeLegibility;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}


section[id],
header[id] {
    scroll-margin-top: calc(var(--nav-h) + 20px);
}

/* =============================================================
   SCROLL PROGRESS BAR
   ============================================================= */
.progress-bar {
    position: fixed;
    top: 0;
    left: 0;
    height: 1px;
    width: 0%;
    background: var(--accent);
    z-index: 200;
    transition: width 0.08s linear;
}

/* =============================================================
   STICKY TOP NAV
   ============================================================= */
.topbar {
    position: sticky;
    top: 0;
    z-index: 100;
    height: var(--nav-h);
    padding: 0 22px;
    background: var(--bg-blur);
    backdrop-filter: saturate(180%) blur(20px);
    -webkit-backdrop-filter: saturate(180%) blur(20px);
    border-bottom: 1px solid rgba(0, 0, 0, 0.06);
    font-size: 12px;
    letter-spacing: -0.01em;
    display: flex;
    align-items: center;
    gap: 28px;
    justify-content: center;
}

.topbar .brand {
    font-weight: 600;
    color: var(--link);
    text-decoration: none;
    white-space: nowrap;
    margin-right: 14px;
}

.topbar .toc {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    gap: 26px;
    align-items: center;
}

.topbar .toc a {
    color: var(--ink-soft);
    text-decoration: none;
    opacity: 0.88;
    padding: 2px 0;
    transition: opacity .2s, color .2s;
}

.topbar .toc a:hover {
    color: var(--ink);
    opacity: 1;
}

/* --- Figures dropdown --- */
.fig-menu {
    position: relative;
    margin-left: 14px;
}

.fig-menu>summary {
    list-style: none;
    cursor: pointer;
    padding: 4px 10px;
    border-radius: 980px;
    background: rgba(0, 0, 0, 0.04);
    color: var(--ink);
    font-size: 12px;
    font-weight: 500;
    user-select: none;
    transition: background .15s;
}

.fig-menu>summary::-webkit-details-marker {
    display: none;
}

.fig-menu>summary:hover {
    background: rgba(0, 0, 0, 0.08);
}

.fig-menu[open]>summary {
    background: var(--ink);
    color: #fff;
}

.fig-menu .chev {
    display: inline-block;
    margin-left: 2px;
    transition: transform .2s;
    font-size: 9px;
}

.fig-menu[open] .chev {
    transform: rotate(180deg);
}

.fig-menu>ul {
    position: absolute;
    top: calc(100% + 10px);
    right: 0;
    min-width: 260px;
    margin: 0;
    padding: 8px 0;
    list-style: none;
    background: rgba(255, 255, 255, 0.92);
    backdrop-filter: saturate(180%) blur(20px);
    -webkit-backdrop-filter: saturate(180%) blur(20px);
    border: 1px solid rgba(0, 0, 0, 0.08);
    border-radius: var(--radius-sm);
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.14);
    font-size: 13px;
}

.fig-menu>ul li {
    margin: 0;
}

.fig-menu>ul a {
    display: block;
    padding: 9px 16px;
    color: var(--ink);
    text-decoration: none;
    transition: background .1s;
}

.fig-menu>ul a:hover {
    background: rgba(0, 0, 0, 0.05);
}

/* =============================================================
   SECTIONS 
   ============================================================= */
.hero,
main>section,
.site-footer {
    padding-left: 15px;
    padding-right: 15px;
}
.hero-image {
    display: block;
    width: 100%;
    max-width: var(--wide) !important;
    height: auto;
    max-height: 440px;
    object-fit: cover;
    margin: 0 auto 36px auto;
    border-radius: 6px;
    will-change: opacity;
    transition: opacity 0.06s linear;
}

/*even sections light-grey, odd sections white */
main>section:nth-of-type(even) {
    background: var(--bg-alt);
}

/* constrain the inner text column, centred */
.hero>*,
main>section>*,
.site-footer>* {
    max-width: var(--max-width);
    margin-left: auto;
    margin-right: auto;
}

/* figures and model grid can be wider */
main>section>details.fig,
main>section>.model-grid {
    max-width: var(--wide);
}

/* =============================================================
   HERO
   ============================================================= */
.hero {
    padding-top: 120px;
    padding-bottom: 120px;
    text-align: center;
    background: var(--bg);
}

.kicker {
    font-size: 14px;
    font-weight: 600;
    letter-spacing: -0.01em;
    color: var(--accent);
    margin: 0 auto 18px auto;
    max-width: none !important;
    text-align: center;
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}

h1 {
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    margin: 0 0 18px 0;
    color: var(--ink);
    max-width: 95% !important;
}

.subtitle {
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    color: var(--ink-soft);
    font-weight: 400;
    max-width: 95% !important;
    margin: 0 auto 28px;
    font-style: normal;
    letter-spacing: -0.015em;
}

.byline {
    font-size: 14px;
    color: var(--muted);
    margin: 0;
    letter-spacing: 0;
}

/* =============================================================
   SECTION HEADINGS
   ============================================================= */
main>section {
    padding-top: 100px;
    padding-bottom: 100px;
}

h2 {
    font-size: clamp(21px, 4.2vw, 38px);
    line-height: 1.1;
    letter-spacing: -0.022em;
    font-weight: 700;
    margin: 0 0 28px 0;
    color: var(--ink);
    text-align: center;
    max-width: 90% !important;
}

h3 {
    font-size: 14px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--muted);
    margin: 2rem 0 0.6rem 0;
}
h4 {
    font-size: 14px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--muted);
    margin: 2rem 0 0.6rem 0;
    text-align: center;
    }

p {
    margin: 0 0 10px 0;
    font-size: 19px;
    /* Apple body copy is generous */
    line-height: 1.52;
    letter-spacing: -0.015em;
    color: var(--ink-soft);
    style: normal;
    text-align: justify;
    text-align-last: center;
    max-width: 80% !important;
}

strong {
    font-weight: 600;
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}

em {
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}

a {
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    text-decoration: none;
    transition: color .15s;
}

a:hover {
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}

code {
    font-family: var(--mono);
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    background: rgba(0, 0, 0, 0.05);
    padding: 2px 6px;
    border-radius: 6px;
    color: var(--ink);
}

.three-column {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 40px;
    width: 100%;
    max-width: 1100px;
    margin: 0 auto;
    padding: 20px;
    box-sizing: border-box;
}

.column p {
    max-width: 100% !important;
    width: 100%;
    margin: 0 0 10px 0;
}

.column:first-child p {
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}

.column:nth-child(2) p {
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}


.column:last-child p {
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}

.column h3 {
    margin-bottom: 16px;
    text-align: center;
}

/* =============================================================
   INTRODUCTION PARAGRAPHS
   ============================================================= */
.intro-lead {
    max-width: 85%;
    font-size: 20px;
    font-weight: 500;
}

.intro-secondary {
    opacity: 0.50;
    max-width: 80%;
}


/* =============================================================
   FIGURES 
   ============================================================= */
details.fig {
    margin: 40px auto;
    padding: 0;
    background: var(--panel);
    border-radius: var(--radius);
    overflow: hidden;
    transition: box-shadow .25s ease;
    border: 1px solid rgba(0, 0, 0, 0.06);
}

details.fig:hover {
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.07);
}

details.fig>summary {
    cursor: pointer;
    padding: 22px 28px;
    font-weight: 500;
    font-size: 17px;
    color: var(--ink);
    letter-spacing: -0.015em;
    list-style: none;
    user-select: none;
    display: flex;
    align-items: center;
    gap: 14px;
    transition: background .15s;
}

details.fig>summary::-webkit-details-marker {
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}

details.fig>summary:hover {
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}

details.fig>summary::after {
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    margin-left: auto;
    color: var(--muted);
    font-size: 22px;
    line-height: 1;
    transition: transform .2s;
}

details.fig[open]>summary::after {
    transform: rotate(90deg);
}

.fig-label {
    display: inline-block;
    padding: 4px 11px;
    border-radius: 980px;
    background: var(--ink);
    color: #fff;
    font-size: 11px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.06em;
}

details.fig>figure {
    margin: 0;
    padding: 0 28px 28px;
}

details.fig img {
    display: block;
    width: 100%;
    height: auto;
    border-radius: var(--radius-sm);
    background: var(--bg-alt);
}

details.fig figcaption {
    font-size: 14px;
    color: var(--muted);
    line-height: 1.5;
    margin-top: 18px;
    padding-left: 0;
    border-left: none;
    text-align: center;
    letter-spacing: -0.01em;
}

details.fig figcaption strong {
    display: block;
    color: var(--ink);
    font-weight: 600;
    margin-bottom: 4px;
}


main>section:nth-of-type(even) details.fig {
    background: #fff;
}

/* =============================================================
   MODEL CARDS 
   ============================================================= */
.model-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 14px;
    margin: 36px auto;
}

.model-card {
    background: var(--panel);
    border-radius: var(--radius);
    padding: 28px 24px;
    border: 1px solid rgba(0, 0, 0, 0.06);
    transition: transform .2s, box-shadow .2s;
}

.model-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 28px rgba(0, 0, 0, 0.06);
}

.model-card h3 {
    margin: 0 0 6px 0;
    font-size: 11px;
    letter-spacing: 0.08em;
    color: var(--link);
    text-transform: uppercase;
    font-weight: 600;
    text-align: center !important;
}

.model-card .model-spec {
    font-family: var(--mono);
    font-size: 13px;
    color: var(--ink);
    margin: 0 0 14px 0;
    font-weight: 500;
    line-height: 1.4;
}

main>section:nth-of-type(even) .model-card {
    background: #fff;
}

/* =============================================================
   CAVEATS
   ============================================================= */
ul.caveats {
    padding-left: 0;
    margin: 12px auto 20px auto;
    max-width: 600px;
    font-size: 17px;
    color: var(--ink-soft);
    text-align: center;
    opacity: 0.5;
}

ul.caveats li {
    margin-bottom: 12px;
}

/* =============================================================
   FOOTER
   ============================================================= */
.site-footer {
    padding-top: 40px;
    padding-bottom: 48px;
    background: var(--bg-alt);
    color: var(--muted);
    font-size: 12px;
    text-align: center;
    border-top: 1px solid rgba(0, 0, 0, 0.06);
}

.site-footer p {
    margin: 0 0 6px 0;
    font-size: 12px;
    color: var(--muted);
}

.site-footer a {
    color: var(--muted);
}

.site-footer a:hover {
    color: var(--link);
}

/* =============================================================
   FADE-IN ON SCROLL
   ============================================================= */
.fade-in {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity .7s cubic-bezier(0.22, 1, 0.36, 1),
        transform .7s cubic-bezier(0.22, 1, 0.36, 1);
}

.fade-in.is-visible {
    opacity: 1;
    transform: none;
}

@media (prefers-reduced-motion: reduce) {
    html {
        scroll-behavior: auto;
    }

    .fade-in {
        opacity: 1;
        transform: none;
        transition: none;
    }
}

/* =============================================================
   RESPONSIVE
   ============================================================= */
@media (max-width: 820px) {
    .topbar {
        gap: 14px;
        padding: 0 14px;
        overflow-x: auto;
    }

    .topbar .toc {
        gap: 18px;
    }

    .topbar .toc a {
        font-size: 11px;
    }

    details.fig>summary {
        padding: 18px 20px;
        font-size: 15px;
    }

    details.fig>figure {
        padding: 0 20px 22px;
    }

    .model-card {
        padding: 22px 18px;
    }
}

@media (max-width: 540px) {
    .hero {
        padding-top: 80px;
        padding-bottom: 80px;
    }

    main>section {
        padding-top: 70px;
        padding-bottom: 70px;
    }

    h1 {
        font-size: 38px;
    }

    h2 {
        font-size: 28px;
    }

    p {
        font-size: 17px;
    }

    .topbar .toc {
        display: none;
    }

    .topbar {
        justify-content: space-between;
    }
}

/* =============================================================
   PRINT
   ============================================================= */
@media print {
    body {
        background: #eceee6;
        font-size: 11pt;
        color: #000;
    }

    .topbar,
    .progress-bar,
    .fig-menu {
        display: none !important;
    }

    main>section:nth-of-type(even) {
        background: #fff;
    }

    details.fig,
    .model-card {
        box-shadow: none;
        border: 1px solid #ccc;
        break-inside: avoid;
    }

    details.fig>summary::after {
        display: none;
    }

    details.fig:not([open])>figure {
        display: block;
    }

    a {
        color: #000;
        text-decoration: none;
    }
}