/* Thinkering — shared stylesheet (v3)
   ----------------------------------------------------------------
   Hard-panel design system. Pure white, pure black, constructivist
   red (#c8102e). System sans (Helvetica Neue / Helvetica / Arial).
   Every visible structural element is bordered with a 3px black
   rule and shares edges with its neighbours. No webfonts, no
   off-whites, no rounded corners, no shadows, no gradients.

   Canonical reference: thinkering-style-guide-v2.html at repo root.
   ---------------------------------------------------------------- */

:root {
    /* Palette */
    --black: #000000;
    --white: #ffffff;
    --red: #c8102e;

    /* Structure */
    --rule: 3px;
    --border: var(--rule) solid var(--black);

    /* Measures */
    --measure-page: 64rem;
    --measure-read: 38rem;

    /* Type scale */
    --t-display: clamp(2.5rem, 6vw, 5rem);
    --t-h1: 2.5rem;
    --t-h2: 1.5rem;
    --t-h3: 1.125rem;
    --t-body: 1rem;
    --t-small: 0.875rem;
    --t-caption: 0.75rem;
    --t-label: 0.8125rem;

    /* Spacing */
    --s-1: 0.25rem;
    --s-2: 0.5rem;
    --s-3: 1rem;
    --s-4: 1.5rem;
    --s-5: 2rem;
    --s-6: 3rem;
    --s-7: 4rem;
}

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

html {
    background: var(--white);
    -webkit-text-size-adjust: 100%;
}

body {
    margin: 0;
    background: var(--white);
    color: var(--black);
    font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
    font-size: 16px;
    line-height: 1.45;
    font-weight: 400;
}

/* ---------- Page shell ---------- */

.page {
    max-width: var(--measure-page);
    margin: 0 auto;
    padding: var(--s-4);
}

/* ---------- Masthead ---------- */

.masthead {
    border: var(--border);
    display: grid;
    grid-template-columns: 1fr auto;
    align-items: stretch;
}

.wordmark {
    display: block;
    line-height: 0;
    color: inherit;
    text-decoration: none;
    border-bottom: none;
    padding: 0;
}

.wordmark img,
.wordmark svg {
    display: block;
    width: auto;
    height: 120px;
    max-width: 100%;
}

.nav {
    display: flex;
    align-items: center;
    padding: 0 var(--s-4);
    border-left: var(--border);
    font-size: var(--t-small);
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    gap: var(--s-4);
}

.nav a {
    color: var(--black);
    text-decoration: none;
    border-bottom: none;
    padding: 0;
    transition: background-color 180ms ease-out, color 180ms ease-out;
}

.nav a:hover {
    color: var(--white);
}

.nav a[aria-current="page"] {
    color: var(--red);
}

/* ---------- Hero block ---------- */

.hero {
    border: var(--border);
    border-top: none;
    padding: var(--s-6) var(--s-4) 3.5rem;
}

.hero h1,
.hero .hero-title {
    font-size: var(--t-display);
    line-height: 0.95;
    font-weight: 700;
    letter-spacing: -0.025em;
    margin: 0;
    color: var(--black);
    max-width: 16ch;
}

.hero h1 em,
.hero .hero-title em {
    font-style: normal;
    color: var(--red);
}

.hero-meta {
    font-size: var(--t-label);
    font-weight: 700;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: var(--black);
    margin: 0 0 var(--s-4);
    display: flex;
    flex-wrap: wrap;
    gap: var(--s-2) var(--s-4);
}

.hero-lede {
    font-size: var(--t-h3);
    line-height: 1.5;
    margin: var(--s-4) 0 0;
    max-width: 50ch;
}

/* Hero call-to-action: a bordered box that inverts to red on hover, the
   same interaction as the nav and the entry cards. Overrides the default
   red link underline with a full black rule. */
.hero-cta {
    display: inline-block;
    margin-top: var(--s-5);
    padding: var(--s-3) var(--s-4);
    border: var(--border);
    font-size: var(--t-small);
    font-weight: 700;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--black);
    text-decoration: none;
}

.hero-cta::after {
    content: " \2192"; /* → */
}

.hero-cta:hover {
    background: var(--red);
    color: var(--white);
}

.hero-cta:focus-visible {
    outline: 2px solid var(--red);
    outline-offset: 2px;
}

/* Hero with portrait: h1 on the left, portrait on the right.
   Mobile collapses to single column with portrait below the heading. */
.hero--with-portrait > img.portrait,
.hero--with-portrait > .hero-figure {
    display: block;
    width: 300px;
    max-width: 100%;
    height: auto;
    border: var(--border);
    background: var(--white);
    margin: var(--s-4) 0 0;
}

@media (min-width: 44rem) {
    .hero--with-portrait {
        display: grid;
        grid-template-columns: 1fr auto;
        column-gap: var(--s-5);
        align-items: start;
    }
    .hero--with-portrait > img.portrait,
    .hero--with-portrait > .hero-figure {
        margin: 0;
    }
}

/* ---------- Panel ---------- */

.panel {
    border: var(--border);
    border-top: none;
    display: grid;
    grid-template-columns: 1fr;
}

@media (min-width: 44rem) {
    .panel {
        grid-template-columns: 11rem 1fr;
    }
}

.panel .label {
    padding: var(--s-4) var(--s-4);
    font-size: var(--t-label);
    font-weight: 700;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    line-height: 1.3;
    color: var(--black);
}

/* Founder panel layout: bio text on the left, portrait on the right.
   Bordered square portrait matches the panel system. On narrow
   viewports the grid collapses to single-column, text above image. */
.panel .content--with-portrait > img.portrait {
    display: block;
    width: 280px;
    max-width: 100%;
    height: auto;
    border: var(--border);
    margin: var(--s-4) 0 0;
}

@media (min-width: 44rem) {
    .panel .content--with-portrait {
        display: grid;
        grid-template-columns: 1fr 280px;
        column-gap: var(--s-5);
        align-items: start;
    }
    .panel .content--with-portrait > * {
        max-width: none;
    }
    .panel .content--with-portrait .bio > * {
        max-width: var(--measure-read);
    }
    .panel .content--with-portrait > img.portrait {
        margin: 0;
    }
}

.panel .content {
    padding: var(--s-4) var(--s-4) 1.75rem;
    border-top: var(--border);
}

@media (min-width: 44rem) {
    .panel .content {
        border-top: none;
        border-left: var(--border);
    }
}

.panel .content > * {
    max-width: var(--measure-read);
}

.panel .content > .wide,
.panel .content > figure,
.panel .content > table {
    max-width: none;
}

/* ---------- Type within content ---------- */

.panel .content p {
    margin: 0 0 var(--s-3);
}

.panel .content p:last-child {
    margin-bottom: 0;
}

.panel .content h2 {
    font-size: var(--t-h2);
    font-weight: 700;
    margin: var(--s-5) 0 var(--s-3);
    color: var(--black);
    letter-spacing: -0.01em;
}

.panel .content h2:first-child {
    margin-top: 0;
}

.panel .content h3 {
    font-size: var(--t-h3);
    font-weight: 700;
    margin: var(--s-4) 0 var(--s-2);
    color: var(--black);
}

.panel .content ul:not([class]),
.panel .content ol:not([class]) {
    margin: 0 0 var(--s-3);
    padding-left: 1.25rem;
}

.panel .content ul:not([class]) li,
.panel .content ol:not([class]) li {
    margin-bottom: var(--s-1);
    line-height: 1.5;
}

.panel .content blockquote {
    margin: var(--s-4) 0;
    padding: 0 0 0 var(--s-4);
    border-left: var(--border);
    font-size: var(--t-h3);
    line-height: 1.5;
    max-width: 56ch;
}

/* ---------- Links ---------- */

a {
    color: var(--black);
    text-decoration: none;
    border-bottom: var(--rule) solid var(--red);
    padding-bottom: 1px;
}

a:hover {
    background: var(--red);
    color: var(--white);
}

a:focus-visible {
    outline: 2px solid var(--red);
    outline-offset: 2px;
}

/* Contact list (home page) */

ul.contact-list {
    list-style: none;
    margin: 0;
    padding: 0;
    font-size: var(--t-h3);
}

ul.contact-list li {
    padding: var(--s-1) 0;
}

/* ---------- Footer ---------- */

.site-footer {
    border: var(--border);
    border-top: none;
    padding: var(--s-3) var(--s-4);
    font-size: var(--t-small);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    display: flex;
    flex-wrap: wrap;
    gap: var(--s-2) var(--s-4);
    justify-content: space-between;
}

.site-footer p {
    margin: 0;
}

.site-footer a {
    color: var(--black);
    border-bottom-color: var(--red);
}

/* ---------- Analytics hub: piece index ---------- */

ul.piece-index {
    list-style: none;
    padding: 0;
    margin: 0;
    width: 100%;
    max-width: none;
}

ul.piece-index > li + li {
    border-top: var(--border);
}

.piece-link {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--s-1);
    padding: var(--s-4) 0;
    text-decoration: none;
    color: var(--black);
    border-bottom: none;
}

.piece-link:hover {
    background: var(--red);
    color: var(--white);
    padding-left: var(--s-3);
    padding-right: var(--s-3);
    margin-left: calc(var(--s-3) * -1);
    margin-right: calc(var(--s-3) * -1);
}

.piece-date {
    font-size: var(--t-label);
    font-weight: 700;
    letter-spacing: 0.15em;
    text-transform: uppercase;
}

.piece-title {
    font-size: 1.25rem;
    font-weight: 700;
    line-height: 1.2;
    letter-spacing: -0.01em;
}

.piece-dek {
    font-size: var(--t-body);
    line-height: 1.45;
    max-width: 56ch;
}

@media (min-width: 44rem) {
    .piece-link {
        grid-template-columns: 8rem 1fr;
        column-gap: var(--s-4);
        align-items: baseline;
    }
}

/* ---------- Article body ---------- */

.article-body h2 {
    font-size: var(--t-h2);
    font-weight: 700;
    margin: var(--s-6) 0 var(--s-3);
    letter-spacing: -0.01em;
}

.article-body h2:first-child {
    margin-top: 0;
}

.article-body h3 {
    font-size: var(--t-h3);
    font-weight: 700;
    margin: var(--s-4) 0 var(--s-2);
}

.article-body p {
    margin: 0 0 var(--s-3);
}

.article-body blockquote {
    margin: var(--s-4) 0;
    padding: 0 0 0 var(--s-4);
    border-left: var(--border);
    font-size: var(--t-h3);
    line-height: 1.5;
}

/* Figures */

figure {
    margin: var(--s-5) 0;
}

figure svg {
    display: block;
    width: 100%;
    height: auto;
    border: var(--border);
    background: var(--white);
}

figcaption {
    margin-top: var(--s-3);
    font-size: var(--t-small);
    line-height: 1.5;
    max-width: 56ch;
}

.figcaption-label {
    font-weight: 700;
    font-size: var(--t-label);
    letter-spacing: 0.15em;
    text-transform: uppercase;
    margin-right: var(--s-2);
}

/* Data tables */

table.data {
    width: 100%;
    border-collapse: collapse;
    border: var(--border);
    font-size: var(--t-small);
    font-variant-numeric: tabular-nums;
    margin: var(--s-5) 0;
}

table.data caption {
    text-align: left;
    font-size: var(--t-label);
    font-weight: 700;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    padding: 0 0 var(--s-2);
}

table.data th,
table.data td {
    text-align: left;
    padding: var(--s-2) var(--s-3);
    border-bottom: 1px solid var(--black);
}

table.data thead th {
    font-weight: 700;
    font-size: var(--t-label);
    letter-spacing: 0.1em;
    text-transform: uppercase;
    border-bottom: var(--border);
}

table.data td.num,
table.data th.num {
    text-align: right;
}

table.data tbody tr:last-child th,
table.data tbody tr:last-child td {
    border-bottom: none;
}

table.data tfoot th,
table.data tfoot td {
    font-weight: 700;
    border-top: var(--border);
    border-bottom: none;
}

/* Footnotes */

ol.footnotes {
    padding-left: 1.25rem;
    margin: 0;
    font-size: var(--t-small);
    line-height: 1.5;
}

ol.footnotes li {
    margin-bottom: var(--s-2);
}

/* ================================================================
   Frameworks mock — extensions on top of the v3 stylesheet.
   Adds: expanded persistent nav, entry-points block, sticky-TOC
   document layout. Same hard-panel grammar, no new motion, no
   rounded corners, no shadows.
   ================================================================ */

/* ---------- Masthead nav: extended item set ---------- */

.nav a[aria-current="page"] {
    color: var(--red);
    border-bottom: var(--rule) solid var(--red);
    padding-bottom: 2px;
}

.nav a[aria-current="page"]:hover {
    background: transparent;
    color: var(--red);
}

/* Stack the masthead vertically on narrow viewports so an expanded
   nav (4+ items) does not squeeze the wordmark out. The wordmark
   sits in its own row with a bottom rule; the nav row sits below. */
@media (max-width: 44rem) {
    .masthead {
        grid-template-columns: 1fr;
    }
    .nav {
        border-left: none;
        border-top: var(--border);
        padding: var(--s-3) var(--s-4);
        flex-wrap: wrap;
        gap: var(--s-3) var(--s-4);
    }
    .wordmark img,
    .wordmark svg {
        height: auto;
        max-height: 96px;
        width: 100%;
    }
}

/* ---------- Entry-points block (frameworks landing) ---------- */

.entry-points {
    border: var(--border);
    border-top: none;
    display: grid;
    grid-template-columns: 1fr;
}

@media (min-width: 56rem) {
    .entry-points {
        grid-template-columns: 1fr 1fr 1fr;
    }
    .entry-points--two {
        grid-template-columns: 1fr 1fr;
    }
}

.entry {
    display: grid;
    grid-template-rows: auto auto 1fr auto;
    gap: var(--s-3);
    padding: var(--s-5) var(--s-4) var(--s-4);
    text-decoration: none;
    color: var(--black);
    border-bottom: none;
    border-top: var(--border);
}

.entry:first-child {
    border-top: none;
}

@media (min-width: 56rem) {
    .entry {
        border-top: none;
        border-left: var(--border);
    }
    .entry:first-child {
        border-left: none;
    }
}

.entry:hover {
    background: var(--red);
    color: var(--white);
}

.entry-eyebrow {
    font-size: var(--t-label);
    font-weight: 700;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    margin: 0;
}

.entry-title {
    font-size: 1.5rem;
    font-weight: 700;
    line-height: 1.1;
    letter-spacing: -0.015em;
    margin: 0;
    max-width: 18ch;
}

.entry-dek {
    font-size: var(--t-body);
    line-height: 1.45;
    margin: 0;
    max-width: 32ch;
}

.entry-cta {
    font-size: var(--t-label);
    font-weight: 700;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    margin: 0;
}

.entry-cta::after {
    content: " \2192"; /* → */
}

/* ---------- Document layout: sticky left-rail TOC ---------- */

.panel--doc {
    border: var(--border);
    border-top: none;
    display: grid;
    grid-template-columns: 1fr;
}

@media (min-width: 56rem) {
    .panel--doc {
        grid-template-columns: 16rem 1fr;
    }
}

.panel--doc .toc {
    padding: var(--s-4);
    font-size: var(--t-label);
    line-height: 1.4;
}

@media (min-width: 56rem) {
    .panel--doc .toc {
        position: sticky;
        top: var(--s-3);
        align-self: start;
        max-height: calc(100vh - var(--s-5));
        overflow-y: auto;
    }
}

.toc-eyebrow {
    font-size: var(--t-caption);
    font-weight: 700;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    margin: 0 0 var(--s-3);
    color: var(--black);
}

.toc ol {
    list-style: none;
    margin: 0;
    padding: 0;
    counter-reset: toc;
}

.toc li {
    counter-increment: toc;
    margin: 0;
}

.toc li + li {
    margin-top: var(--s-2);
}

.toc a {
    display: block;
    color: var(--black);
    border-bottom: none;
    padding: var(--s-1) 0 var(--s-1) var(--s-3);
    font-size: var(--t-label);
    font-weight: 700;
    letter-spacing: 0.04em;
    text-transform: uppercase;
    line-height: 1.3;
    border-left: var(--rule) solid transparent;
}

.toc a::before {
    content: counter(toc, decimal-leading-zero) "  ";
    color: var(--red);
    font-variant-numeric: tabular-nums;
    margin-right: var(--s-1);
}

.toc a:hover {
    background: var(--black);
    color: var(--white);
}

.toc a:hover::before {
    color: var(--white);
}

.toc a[aria-current="true"] {
    color: var(--red);
    border-left: var(--rule) solid var(--red);
    background: transparent;
}

.panel--doc .doc-content {
    padding: var(--s-5) var(--s-4) var(--s-5);
    border-top: var(--border);
}

@media (min-width: 56rem) {
    .panel--doc .doc-content {
        border-top: none;
        border-left: var(--border);
        padding: var(--s-6) var(--s-5) var(--s-6);
    }
}

.panel--doc .doc-content > * {
    max-width: var(--measure-read);
}

.panel--doc .doc-content .wide,
.panel--doc .doc-content figure,
.panel--doc .doc-content table {
    max-width: none;
}

.doc-content section + section {
    margin-top: var(--s-7);
}

.doc-content h2 {
    font-size: 1.75rem;
    font-weight: 700;
    letter-spacing: -0.015em;
    margin: 0 0 var(--s-3);
    scroll-margin-top: var(--s-3);
}

.doc-content h3 {
    font-size: var(--t-h3);
    font-weight: 700;
    margin: var(--s-5) 0 var(--s-2);
}

.doc-content p {
    margin: 0 0 var(--s-3);
}

.doc-content ul:not([class]),
.doc-content ol:not([class]) {
    margin: 0 0 var(--s-3);
    padding-left: 1.25rem;
}

.doc-content ul:not([class]) li,
.doc-content ol:not([class]) li {
    margin-bottom: var(--s-1);
    line-height: 1.5;
}

.doc-content table.attribute-map {
    width: 100%;
    border-collapse: collapse;
    border: var(--border);
    margin: var(--s-5) 0;
    font-size: var(--t-small);
}

.doc-content table.attribute-map th,
.doc-content table.attribute-map td {
    text-align: left;
    padding: var(--s-2) var(--s-3);
    border-bottom: 1px solid var(--black);
    vertical-align: top;
}

.doc-content table.attribute-map thead th {
    font-weight: 700;
    font-size: var(--t-label);
    letter-spacing: 0.1em;
    text-transform: uppercase;
    border-bottom: var(--border);
}

.doc-content table.attribute-map tbody tr:last-child th,
.doc-content table.attribute-map tbody tr:last-child td {
    border-bottom: none;
}

/* Evidence tags inside the vocabulary section. The markdown source
   marks them as **TESTED**, **GROUNDED**, **EMERGING**; here they
   become small tracked-uppercase badges with a 2px black outline. */
.evidence {
    display: inline-block;
    font-size: var(--t-caption);
    font-weight: 700;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    padding: 0.1rem 0.4rem;
    border: 2px solid var(--black);
    margin-right: var(--s-2);
    line-height: 1.2;
    vertical-align: 1px;
}

.research,
.what-to-try,
.co-occurs {
    margin: var(--s-3) 0 var(--s-2);
    font-size: var(--t-caption);
    font-weight: 700;
    letter-spacing: 0.15em;
    text-transform: uppercase;
}

.entry-locator {
    font-style: italic;
    color: var(--black);
    margin: 0 0 var(--s-3);
    max-width: var(--measure-read);
}

.vocab-entry + .vocab-entry {
    margin-top: var(--s-6);
    padding-top: var(--s-5);
    border-top: var(--border);
}

.vocab-cluster {
    margin-top: var(--s-6);
    padding-top: var(--s-4);
    border-top: var(--border);
}

.vocab-cluster-label {
    font-size: var(--t-label);
    font-weight: 700;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: var(--red);
    margin: 0 0 var(--s-3);
}

/* References list (full-treatment framework page). Alphabetical by
   author, unnumbered, with a hanging indent so author surnames line
   up at the left rule. */
ol.references,
ul.references {
    list-style: none;
    margin: 0;
    padding: 0;
    font-size: var(--t-small);
    line-height: 1.5;
}

.references li {
    margin-bottom: var(--s-3);
    padding-left: 1.5rem;
    text-indent: -1.5rem;
}

.references li:last-child {
    margin-bottom: 0;
}