/* ------------------------------------------------------------------
   transactology.org -- Standards Document Stylesheet
   Swiss typography clean. Institutional. RFC/W3C-inspired.
   Palette: #1e40af #ffffff #d1d5db #059669 #1f2937 #dc2626 #f9fafb #d97706
   Fonts:   Inter (display), Source Sans 3 (body), Source Code Pro (code)
   ------------------------------------------------------------------ */

:root {
    --color-white:       #ffffff;
    --color-text:        #1f2937;
    --color-primary:     #1e40af;
    --color-active:      #059669;
    --color-draft:       #d97706;
    --color-deprecated:  #dc2626;
    --color-border:      #d1d5db;
    --color-surface:     #f9fafb;

    --font-display: "Inter", "Helvetica Neue", Arial, sans-serif;
    --font-body:    "Source Sans 3", "Inter", "Helvetica Neue", Arial, sans-serif;
    --font-code:    "Source Code Pro", "SFMono-Regular", Menlo, Consolas, monospace;

    --max-doc:     1100px;
    --sidebar-w:   220px;
}

* { box-sizing: border-box; }

html, body {
    margin: 0;
    padding: 0;
    background: var(--color-white);
    color: var(--color-text);
    font-family: var(--font-body);
    font-size: 16px;
    line-height: 1.6;
    font-weight: 400;
}

body {
    background:
        linear-gradient(var(--color-white), var(--color-white));
}

a {
    color: var(--color-primary);
    text-decoration: underline;
    text-decoration-style: dotted;
    text-underline-offset: 2px;
}
a:hover { text-decoration-style: solid; }

a.xref {
    color: var(--color-primary);
    text-decoration: underline dotted;
    text-underline-offset: 3px;
}

code, pre {
    font-family: var(--font-code);
    font-size: 0.85rem;
}

code {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    padding: 0.05rem 0.35rem;
    border-radius: 2px;
    color: var(--color-text);
}

pre.codeblock {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-left: 3px solid var(--color-primary);
    padding: 1rem 1.1rem;
    margin: 1.25rem 0;
    overflow-x: auto;
    line-height: 1.5;
}
pre.codeblock code {
    background: transparent;
    border: 0;
    padding: 0;
    color: var(--color-text);
}

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

.masthead {
    border-bottom: 2px solid var(--color-primary);
    background: var(--color-white);
}

.masthead-inner {
    max-width: var(--max-doc);
    margin: 0 auto;
    padding: 1.5rem 1.5rem 1rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 2rem;
    flex-wrap: wrap;
}

.brand {
    display: flex;
    align-items: center;
    gap: 0.85rem;
}

.brand-mark {
    width: 42px;
    height: 42px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background: var(--color-primary);
    color: var(--color-white);
    font-family: var(--font-display);
    font-weight: 700;
    font-size: 1.2rem;
    letter-spacing: 0.02em;
    border-radius: 2px;
}

.brand-text {
    display: flex;
    flex-direction: column;
    line-height: 1.15;
}

.brand-title {
    font-family: var(--font-display);
    font-weight: 600;
    font-size: clamp(1.05rem, 1.6vw, 1.25rem);
    color: var(--color-text);
    letter-spacing: -0.005em;
}

.brand-subtitle {
    font-family: var(--font-body);
    font-size: 0.82rem;
    color: #4b5563;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    margin-top: 2px;
}

.masthead-nav {
    display: flex;
    gap: 1.4rem;
    flex-wrap: wrap;
}

.masthead-nav a {
    font-family: var(--font-display);
    font-weight: 500;
    font-size: 0.92rem;
    color: var(--color-text);
    text-decoration: none;
    padding-bottom: 2px;
    border-bottom: 1px solid transparent;
}
.masthead-nav a:hover {
    color: var(--color-primary);
    border-bottom-color: var(--color-primary);
}

.masthead-meta {
    max-width: var(--max-doc);
    margin: 0 auto;
    padding: 0.55rem 1.5rem 0.8rem;
    display: flex;
    flex-wrap: wrap;
    gap: 1.25rem;
    font-size: 0.82rem;
    color: #4b5563;
    border-top: 1px solid var(--color-border);
    background: var(--color-surface);
}

.meta-tag strong {
    color: var(--color-text);
    font-weight: 600;
}
.meta-tag code {
    margin-left: 0.25rem;
    font-size: 0.78rem;
}

/* ----------------------- Document grid ----------------------- */

.document {
    max-width: var(--max-doc);
    margin: 0 auto;
    padding: 2.5rem 1.5rem 3rem;
    display: grid;
    grid-template-columns: var(--sidebar-w) 1fr;
    column-gap: 2.5rem;
    align-items: start;
}

/* ----------------------- Sidebar ----------------------- */

.sidebar {
    position: sticky;
    top: 1.25rem;
    align-self: start;
    max-height: calc(100vh - 2rem);
    overflow-y: auto;
    padding-right: 0.5rem;
    border-right: 1px solid var(--color-border);
}

.sidebar-inner > * + * { margin-top: 1.75rem; }

.sidebar-heading {
    font-family: var(--font-display);
    font-weight: 600;
    font-size: 0.78rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--color-primary);
    margin: 0 0 0.6rem;
    padding-bottom: 0.4rem;
    border-bottom: 1px solid var(--color-border);
}

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

.toc li { margin: 0.2rem 0; }

.toc a {
    display: flex;
    gap: 0.5rem;
    font-size: 0.88rem;
    color: var(--color-text);
    text-decoration: none;
    padding: 0.25rem 0.4rem;
    border-left: 2px solid transparent;
    line-height: 1.35;
}
.toc a:hover {
    color: var(--color-primary);
    background: var(--color-surface);
}
.toc a.is-current {
    color: var(--color-primary);
    border-left-color: var(--color-primary);
    background: var(--color-surface);
    font-weight: 600;
}

.toc-num {
    color: var(--color-primary);
    font-weight: 600;
    font-variant-numeric: tabular-nums;
    min-width: 1.6em;
}

.legend {
    list-style: none;
    margin: 0;
    padding: 0;
    font-size: 0.85rem;
}
.legend li {
    display: flex;
    align-items: center;
    gap: 0.55rem;
    margin: 0.4rem 0;
}

.docinfo {
    margin: 0;
    font-size: 0.85rem;
    display: grid;
    grid-template-columns: max-content 1fr;
    column-gap: 0.75rem;
    row-gap: 0.25rem;
}
.docinfo dt {
    color: #4b5563;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    font-size: 0.72rem;
    padding-top: 0.15rem;
}
.docinfo dd { margin: 0; }

/* ----------------------- Status badges ----------------------- */

.badge {
    display: inline-block;
    font-family: var(--font-display);
    font-weight: 600;
    font-size: 0.72rem;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    padding: 0.18rem 0.55rem;
    border-radius: 2px;
    border: 1px solid currentColor;
    line-height: 1.2;
    white-space: nowrap;
    background: var(--color-white);
}

.badge-active     { color: var(--color-active);     background: rgba(5, 150, 105, 0.08); }
.badge-draft      { color: var(--color-draft);      background: rgba(217, 119, 6, 0.08); }
.badge-deprecated { color: var(--color-deprecated); background: rgba(220, 38, 38, 0.08); }

/* ----------------------- Content ----------------------- */

.content {
    min-width: 0;
}

.doc-header {
    border-bottom: 1px solid var(--color-border);
    padding-bottom: 1.5rem;
    margin-bottom: 2rem;
}

.doc-kicker {
    margin: 0 0 0.4rem;
    font-family: var(--font-display);
    font-weight: 600;
    font-size: 0.78rem;
    text-transform: uppercase;
    letter-spacing: 0.12em;
    color: var(--color-primary);
}

.doc-title {
    font-family: var(--font-display);
    font-weight: 600;
    font-size: clamp(1.6rem, 3.2vw, 2.25rem);
    line-height: 1.2;
    color: var(--color-text);
    margin: 0 0 1rem;
    letter-spacing: -0.015em;
}

.doc-abstract {
    margin: 0 0 1rem;
    font-size: 1.02rem;
    color: var(--color-text);
    max-width: 60ch;
}

.doc-status {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem 0.9rem;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-left: 3px solid var(--color-active);
}
.doc-status .status-line {
    font-size: 0.92rem;
    color: var(--color-text);
    flex: 1 1 320px;
}

/* ----------------------- Sections ----------------------- */

.section {
    padding-top: 1.75rem;
    margin-bottom: 0.5rem;
    scroll-margin-top: 1rem;
}

.section + .section {
    border-top: 1px solid var(--color-border);
}

.section h2 {
    font-family: var(--font-display);
    font-weight: 600;
    font-size: clamp(1.25rem, 2vw, 1.5rem);
    color: var(--color-text);
    margin: 0 0 0.85rem;
    letter-spacing: -0.005em;
}

.sec-num {
    font-weight: 600;
    color: var(--color-primary);
    margin-right: 0.45rem;
    font-variant-numeric: tabular-nums;
}

.section p,
.section li {
    max-width: 68ch;
}

.section p { margin: 0.7rem 0; }

/* ----------------------- Tables ----------------------- */

.table-wrap {
    margin: 1.25rem 0;
    overflow-x: auto;
    border: 1px solid var(--color-border);
    background: var(--color-white);
}

.spec-table {
    width: 100%;
    border-collapse: collapse;
    border: 1px solid var(--color-border);
    font-size: 0.92rem;
    background: var(--color-white);
}

.spec-table caption {
    caption-side: top;
    text-align: left;
    font-family: var(--font-display);
    font-weight: 600;
    font-size: 0.82rem;
    color: var(--color-primary);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    padding: 0.6rem 0.8rem;
    border-bottom: 1px solid var(--color-border);
    background: var(--color-surface);
}

.spec-table th,
.spec-table td {
    border: 1px solid var(--color-border);
    padding: 0.55rem 0.75rem;
    text-align: left;
    vertical-align: top;
}

.spec-table thead th {
    background: var(--color-surface);
    font-family: var(--font-display);
    font-weight: 600;
    font-size: 0.82rem;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--color-text);
    border-bottom: 2px solid var(--color-primary);
}

.spec-table tbody tr:nth-child(even) td {
    background: var(--color-surface);
}

.spec-table tbody tr.is-hidden { display: none; }

.spec-table tbody tr td code {
    font-size: 0.82rem;
}

/* ----------------------- Filter bar ----------------------- */

.filter-bar {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 0.5rem;
    padding: 0.6rem 0.75rem;
    border: 1px solid var(--color-border);
    background: var(--color-surface);
    margin-top: -1px;
    font-size: 0.88rem;
}

.filter-label {
    font-family: var(--font-display);
    font-weight: 600;
    font-size: 0.78rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--color-text);
    margin-right: 0.5rem;
}

.filter-btn {
    font-family: var(--font-display);
    font-weight: 500;
    font-size: 0.82rem;
    padding: 0.25rem 0.7rem;
    background: var(--color-white);
    color: var(--color-text);
    border: 1px solid var(--color-border);
    border-radius: 2px;
    cursor: pointer;
}

.filter-btn:hover {
    border-color: var(--color-primary);
    color: var(--color-primary);
}

.filter-btn.is-active {
    background: var(--color-primary);
    color: var(--color-white);
    border-color: var(--color-primary);
}

/* ----------------------- Lists ----------------------- */

.termlist {
    margin: 1rem 0;
    display: grid;
    grid-template-columns: max-content 1fr;
    column-gap: 1rem;
    row-gap: 0.5rem;
}
.termlist dt {
    font-weight: 600;
    color: var(--color-primary);
    font-family: var(--font-display);
    padding-top: 0.1rem;
}
.termlist dd { margin: 0; }

.lifecycle-list {
    list-style: none;
    margin: 1rem 0;
    padding: 0;
    display: grid;
    gap: 0.6rem;
}
.lifecycle-list > li {
    display: grid;
    grid-template-columns: 7.5rem 1fr;
    align-items: start;
    gap: 1rem;
    padding: 0.75rem 0.9rem;
    border: 1px solid var(--color-border);
    background: var(--color-surface);
}
.lifecycle-list > li p { margin: 0; }

.wg-list {
    list-style: none;
    margin: 1rem 0;
    padding: 0;
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 0.5rem 1.25rem;
}
.wg-list li {
    border-left: 2px solid var(--color-primary);
    padding: 0.25rem 0.75rem;
    font-size: 0.92rem;
}

.process-list {
    margin: 1rem 0 1rem 1.25rem;
    padding: 0;
}
.process-list li { margin: 0.5rem 0; }

.reflist {
    margin: 1rem 0 1rem 1.25rem;
    padding: 0;
    font-size: 0.92rem;
}
.reflist li { margin: 0.35rem 0; }

/* ----------------------- Colophon ----------------------- */

.colophon {
    border-top: 1px solid var(--color-border);
    background: var(--color-surface);
    margin-top: 2rem;
}

.colophon-inner {
    max-width: var(--max-doc);
    margin: 0 auto;
    padding: 1.25rem 1.5rem;
    font-size: 0.85rem;
    color: #4b5563;
}

.colophon-line {
    margin: 0.25rem 0;
    display: flex;
    flex-wrap: wrap;
    gap: 1.5rem;
}

.colophon-line code {
    font-size: 0.78rem;
}

/* ----------------------- Responsive ----------------------- */

@media (max-width: 880px) {
    .document {
        grid-template-columns: 1fr;
    }
    .sidebar {
        position: static;
        max-height: none;
        overflow: visible;
        border-right: 0;
        border-bottom: 1px solid var(--color-border);
        padding-right: 0;
        padding-bottom: 1.25rem;
        margin-bottom: 0.5rem;
    }
    .masthead-nav { gap: 1rem; }
    .lifecycle-list > li {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 520px) {
    .masthead-inner { padding: 1.1rem 1rem 0.85rem; }
    .masthead-meta  { padding: 0.5rem 1rem 0.7rem; gap: 0.75rem; }
    .document       { padding: 1.75rem 1rem 2rem; }
    .colophon-inner { padding: 1rem; }
    .doc-title      { font-size: 1.5rem; }
    .doc-abstract   { font-size: 0.98rem; }
}

/* ----------------------- Print ----------------------- */

@media print {
    .masthead-nav,
    .filter-bar,
    .colophon { display: none; }
    .sidebar { position: static; border-right: 0; }
    body { font-size: 12pt; }
    .document { display: block; padding: 0; }
}