/* ==========================================================================
   rational.business — swiss typography clean
   Palette: #FAFAFA #1A1A1A #2C2C2C #666666 #E0E0E0 #0066CC #F5F5F5 #CC0000
   Hover bg: #F0F5FF · Alt tile: #F5F5F5 · Accent: #0066CC · Signal: #CC0000
   Fonts: Space Grotesk (700/500/200), Inter (400), JetBrains Mono (400)
   Grid: 6 columns, 24px gutter, 80px row height
   ========================================================================== */

:root {
    --c-bg: #FAFAFA;
    --c-bg-alt: #F5F5F5;
    --c-bg-hover: #F0F5FF;
    --c-ink: #1A1A1A;
    --c-text: #2C2C2C;
    --c-meta: #666666;
    --c-line: #E0E0E0;
    --c-accent: #0066CC;
    --c-signal: #CC0000;

    --gutter: 24px;
    --row: 80px;
    --header-h: 64px;

    --f-display: "Space Grotesk", "Helvetica Neue", Arial, sans-serif;
    --f-body: "Inter", "Helvetica Neue", Arial, sans-serif;
    --f-mono: "JetBrains Mono", "Menlo", "Consolas", monospace;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { font-size: 15px; }
html, body {
    background: var(--c-bg);
    color: var(--c-text);
    font-family: var(--f-body);
    font-weight: 400;
    line-height: 1.65;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    padding: 0 var(--gutter);
}

a { color: var(--c-accent); text-decoration: none; }

/* --- Background grid scaffold ---------------------------------------------*/

.grid-overlay {
    position: fixed;
    inset: 0;
    pointer-events: none;
    z-index: 0;
    background-image:
        linear-gradient(to right, var(--c-line) 1px, transparent 1px);
    background-size: calc((100vw - 5 * var(--gutter)) / 6 + var(--gutter)) 100%;
    background-position: var(--gutter) 0;
    opacity: 0.5;
}

/* --- Header ---------------------------------------------------------------*/

.site-header {
    position: relative;
    z-index: 2;
    border-bottom: 1px solid var(--c-line);
    height: var(--header-h);
}

.header-row {
    height: var(--header-h);
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(0, 2fr) minmax(0, 1fr);
    align-items: center;
    gap: var(--gutter);
}

.brand { display: flex; align-items: center; gap: 12px; }
.brand-mark {
    width: 8px; height: 8px;
    background: var(--c-accent);
    display: inline-block;
}
.brand-name {
    font-family: var(--f-display);
    font-weight: 700;
    font-size: 16px;
    letter-spacing: -0.01em;
    color: var(--c-ink);
}

.primary-nav {
    display: flex;
    justify-content: center;
    gap: 28px;
}

.nav-link {
    font-family: var(--f-mono);
    font-size: 12px;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--c-meta);
    position: relative;
    padding: 4px 0;
    transition: color 200ms ease;
}

.nav-link::after {
    content: "";
    position: absolute;
    left: 0; right: 100%;
    bottom: 0;
    height: 1px;
    background: var(--c-accent);
    transition: right 200ms ease;
}
.nav-link:hover { color: var(--c-accent); }
.nav-link:hover::after { right: 0; }
.nav-link.is-active { color: var(--c-ink); }
.nav-link.is-active::after { right: 0; background: var(--c-ink); }

.header-meta {
    display: flex;
    justify-content: flex-end;
    gap: 20px;
}

.meta-pair {
    display: inline-flex;
    align-items: baseline;
    gap: 6px;
    font-family: var(--f-mono);
    font-size: 12px;
    letter-spacing: 0.02em;
}
.meta-key { color: var(--c-meta); }
.meta-val { color: var(--c-ink); }

/* --- Grid canvas ----------------------------------------------------------*/

.grid-canvas {
    position: relative;
    z-index: 1;
    flex: 1 0 auto;
    display: grid;
    grid-template-columns: repeat(6, minmax(0, 1fr));
    grid-auto-rows: var(--row);
    gap: var(--gutter);
    padding: var(--gutter) 0;
}

/* tile sizing */
.tile-1x1 { grid-column: span 1; grid-row: span 1; }
.tile-2x1 { grid-column: span 2; grid-row: span 1; }
.tile-1x2 { grid-column: span 1; grid-row: span 2; }
.tile-2x2 { grid-column: span 2; grid-row: span 2; }
.tile-3x2 { grid-column: span 3; grid-row: span 2; }

/* tile shell */
.tile {
    position: relative;
    background: var(--c-bg);
    border: 1px solid var(--c-line);
    padding: 20px;
    display: flex;
    flex-direction: column;
    gap: 12px;
    overflow: hidden;
    transition: background 200ms ease, border-color 200ms ease, box-shadow 200ms ease;
    border-left: 2px solid var(--c-line);
}
.tile.tile-alt { background: var(--c-bg-alt); }
.tile:hover {
    background: var(--c-bg-hover);
    border-left-color: var(--c-accent);
}

/* shared tile header */
.tile-head {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    gap: 12px;
    font-family: var(--f-mono);
    font-size: 12px;
    letter-spacing: 0.06em;
    text-transform: uppercase;
}
.tile-id { color: var(--c-meta); }
.tile-status { color: var(--c-ink); }
.tile-status.accent-blue { color: var(--c-accent); }

.tile-foot {
    margin-top: auto;
    display: flex;
    gap: 24px;
    border-top: 1px solid var(--c-line);
    padding-top: 12px;
}

.tile-watermark {
    position: absolute;
    right: 16px;
    bottom: -28px;
    font-family: var(--f-display);
    font-weight: 200;
    font-size: 200px;
    line-height: 1;
    color: var(--c-ink);
    opacity: 0.03;
    pointer-events: none;
    user-select: none;
    letter-spacing: -0.04em;
}

/* --- Typography blocks ----------------------------------------------------*/

.lead-heading {
    font-family: var(--f-display);
    font-weight: 700;
    font-size: 48px;
    line-height: 1.04;
    letter-spacing: -0.01em;
    color: var(--c-ink);
    margin-top: 8px;
}

.sec-heading {
    font-family: var(--f-display);
    font-weight: 500;
    font-size: 24px;
    line-height: 1.2;
    color: #333333;
    letter-spacing: -0.01em;
}

.lead-body {
    max-width: 52ch;
    color: var(--c-text);
    font-size: 15px;
    line-height: 1.65;
}

/* --- Indicator tile -------------------------------------------------------*/

.indicator-row {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-top: 4px;
}
.indicator-dot {
    width: 8px; height: 8px;
    background: var(--c-ink);
    display: inline-block;
}
.indicator-dot-blue { background: var(--c-accent); }
.indicator-label {
    font-family: var(--f-display);
    font-weight: 500;
    font-size: 20px;
    color: var(--c-ink);
}
.indicator-note {
    font-family: var(--f-mono);
    font-size: 12px;
    color: var(--c-meta);
    letter-spacing: 0.02em;
}

/* --- Big number tiles -----------------------------------------------------*/

.big-number {
    font-family: var(--f-display);
    font-weight: 700;
    font-size: 56px;
    line-height: 1;
    color: var(--c-ink);
    letter-spacing: -0.02em;
    font-variant-numeric: tabular-nums;
    margin-top: auto;
}
.metric-label {
    font-family: var(--f-mono);
    font-size: 11px;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--c-meta);
    border-top: 1px solid var(--c-line);
    padding-top: 8px;
}

/* --- Service list ---------------------------------------------------------*/

.service-list { list-style: none; display: flex; flex-direction: column; }
.service-row {
    display: grid;
    grid-template-columns: 64px 1fr auto;
    align-items: baseline;
    gap: 16px;
    padding: 12px 0;
    border-top: 1px solid var(--c-line);
    transition: background 200ms ease, color 200ms ease;
}
.service-row:first-child { border-top: 1px solid var(--c-ink); }
.service-row:hover { background: var(--c-bg-hover); }
.service-row:hover .svc-name { color: var(--c-accent); }

.svc-num {
    font-family: var(--f-mono);
    font-size: 12px;
    color: var(--c-meta);
    letter-spacing: 0.02em;
}
.svc-name {
    font-family: var(--f-display);
    font-weight: 500;
    font-size: 18px;
    color: var(--c-ink);
    transition: color 200ms ease;
}
.svc-dur {
    font-family: var(--f-mono);
    font-size: 12px;
    color: var(--c-meta);
    letter-spacing: 0.02em;
}

/* --- Bar chart ------------------------------------------------------------*/

.bar-chart {
    display: flex;
    flex-direction: column;
    gap: 8px;
    margin-top: auto;
}
.bar-row {
    display: grid;
    grid-template-columns: 84px 1fr 36px;
    align-items: center;
    gap: 12px;
    font-family: var(--f-mono);
    font-size: 11px;
    letter-spacing: 0.04em;
    text-transform: uppercase;
}
.bar-cat { color: var(--c-meta); }
.bar-track {
    height: 8px;
    background: var(--c-line);
    position: relative;
    overflow: hidden;
}
.bar-fill {
    position: absolute;
    inset: 0 100% 0 0;
    background: var(--c-accent);
    transition: right 600ms ease;
}
.bar-row:nth-child(4) .bar-fill { background: var(--c-ink); }
.bar-row:nth-child(5) .bar-fill { background: var(--c-accent); }
.bar-val { color: var(--c-ink); text-align: right; }

/* --- Method grid ----------------------------------------------------------*/

.method-grid {
    list-style: none;
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 0;
    margin-top: 8px;
}
.method-step {
    padding: 16px 16px 16px 0;
    border-top: 1px solid var(--c-line);
    border-right: 1px solid var(--c-line);
    display: flex;
    flex-direction: column;
    gap: 6px;
    transition: background 200ms ease;
}
.method-step:nth-child(2n) { border-right: none; padding-right: 0; padding-left: 16px; }
.method-step:nth-child(1), .method-step:nth-child(2) { border-top: 1px solid var(--c-ink); }
.method-step:hover { background: var(--c-bg-hover); }
.step-num {
    font-family: var(--f-mono);
    font-size: 11px;
    letter-spacing: 0.06em;
    color: var(--c-accent);
}
.step-title {
    font-family: var(--f-display);
    font-weight: 700;
    font-size: 22px;
    color: var(--c-ink);
    letter-spacing: -0.01em;
}
.step-text {
    font-size: 14px;
    line-height: 1.55;
    color: var(--c-text);
}

/* --- Quote ----------------------------------------------------------------*/

.quote-text {
    font-family: var(--f-display);
    font-weight: 500;
    font-size: 22px;
    line-height: 1.3;
    color: var(--c-ink);
    margin-top: 8px;
}
.quote-attr {
    font-family: var(--f-mono);
    font-size: 12px;
    color: var(--c-meta);
    margin-top: auto;
    border-top: 1px solid var(--c-line);
    padding-top: 8px;
}

/* --- Status board ---------------------------------------------------------*/

.status-list { list-style: none; display: flex; flex-direction: column; gap: 0; }
.status-row {
    display: grid;
    grid-template-columns: 12px 1fr auto;
    align-items: center;
    gap: 10px;
    padding: 10px 0;
    border-top: 1px solid var(--c-line);
    font-family: var(--f-mono);
    font-size: 12px;
    letter-spacing: 0.02em;
}
.status-row:first-child { border-top: 1px solid var(--c-ink); }
.status-dot { width: 8px; height: 8px; background: var(--c-meta); }
.status-dot-blue { background: var(--c-accent); }
.status-dot-dark { background: var(--c-ink); }
.status-dot-red { background: var(--c-signal); }
.status-key { color: var(--c-text); text-transform: uppercase; font-size: 11px; }
.status-val { color: var(--c-ink); font-weight: 500; }

/* --- Scatter plot ---------------------------------------------------------*/

.scatter-plot {
    position: relative;
    flex: 1;
    min-height: 140px;
    border-left: 1px solid var(--c-line);
    border-bottom: 1px solid var(--c-line);
    margin-top: 8px;
}
.scatter-svg {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
}
.axis-line { stroke: var(--c-ink); stroke-width: 1; }
.grid-line-faint { stroke: var(--c-line); stroke-width: 1; stroke-dasharray: 2 3; }

.scatter-dot {
    position: absolute;
    width: 8px; height: 8px;
    background: var(--c-accent);
    transform: translate(-50%, 50%);
    transition: transform 200ms ease;
}
.scatter-dot.flagged { background: var(--c-signal); }
.scatter-dot:hover { transform: translate(-50%, 50%) scale(1.6); }

.axis-label {
    position: absolute;
    font-family: var(--f-mono);
    font-size: 10px;
    color: var(--c-meta);
    letter-spacing: 0.04em;
    text-transform: uppercase;
}
.axis-x { right: 0; bottom: -16px; }
.axis-y { left: -8px; top: -14px; }

.legend-row {
    display: flex;
    gap: 18px;
    font-family: var(--f-mono);
    font-size: 11px;
    letter-spacing: 0.04em;
    color: var(--c-meta);
    text-transform: uppercase;
    border-top: 1px solid var(--c-line);
    padding-top: 8px;
}
.legend-key { display: inline-flex; align-items: center; gap: 6px; }
.legend-mark { width: 8px; height: 8px; display: inline-block; background: var(--c-accent); }
.legend-mark-blue { background: var(--c-accent); }
.legend-mark-red { background: var(--c-signal); }

/* --- Principles -----------------------------------------------------------*/

.principle-list { list-style: none; display: flex; flex-direction: column; }
.principle-row {
    display: grid;
    grid-template-columns: 56px 1fr;
    gap: 12px;
    padding: 8px 0;
    border-top: 1px solid var(--c-line);
    font-family: var(--f-body);
    font-size: 14px;
}
.principle-row:first-child { border-top: 1px solid var(--c-ink); }
.prn-num {
    font-family: var(--f-mono);
    font-size: 12px;
    color: var(--c-accent);
    letter-spacing: 0.02em;
}
.prn-text { color: var(--c-text); }

/* --- Ledger table ---------------------------------------------------------*/

.ledger-table {
    width: 100%;
    border-collapse: collapse;
    font-family: var(--f-mono);
    font-size: 12px;
    letter-spacing: 0.02em;
    margin-top: 8px;
}
.ledger-table th {
    text-align: left;
    font-weight: 500;
    color: var(--c-meta);
    text-transform: uppercase;
    font-size: 11px;
    padding: 8px 8px 8px 0;
    border-bottom: 1px solid var(--c-ink);
}
.ledger-table td {
    padding: 10px 8px 10px 0;
    border-bottom: 1px solid var(--c-line);
    color: var(--c-text);
    vertical-align: top;
}
.ledger-table td:first-child { color: var(--c-meta); }
.ledger-table .num { text-align: right; color: var(--c-ink); }
.ledger-table .accent-blue { color: var(--c-accent); }
.ledger-table .accent-red { color: var(--c-signal); }
.ledger-table tbody tr { transition: background 200ms ease; }
.ledger-table tbody tr:hover { background: var(--c-bg-hover); }

/* --- Flow diagram ---------------------------------------------------------*/

.flow-svg {
    width: 100%;
    height: auto;
    margin-top: auto;
}
.flow-node {
    fill: var(--c-bg);
    stroke: var(--c-ink);
    stroke-width: 1;
}
.flow-node-accent { fill: var(--c-accent); stroke: var(--c-accent); }
.flow-text {
    font-family: "Space Grotesk", sans-serif;
    font-size: 12px;
    font-weight: 500;
    fill: var(--c-ink);
    letter-spacing: 0.04em;
    text-transform: uppercase;
}
.flow-text-light { fill: #FAFAFA; }
.flow-line {
    stroke: var(--c-ink);
    stroke-width: 1;
    fill: none;
}
.flow-dot { fill: var(--c-ink); }
.flow-dot.accent { fill: var(--c-accent); }

/* --- Contact tile ---------------------------------------------------------*/

.contact-line {
    font-size: 14px;
    color: var(--c-text);
    max-width: 48ch;
}
.contact-link {
    margin-top: auto;
    font-family: var(--f-display);
    font-weight: 500;
    font-size: 22px;
    color: var(--c-ink);
    border-top: 1px solid var(--c-line);
    padding-top: 12px;
    display: inline-flex;
    align-items: baseline;
    justify-content: space-between;
    gap: 12px;
    transition: color 200ms ease;
}
.contact-link:hover { color: var(--c-accent); }
.link-arrow {
    font-family: var(--f-mono);
    font-size: 18px;
    transition: transform 200ms ease;
    display: inline-block;
}
.contact-link:hover .link-arrow { transform: translateX(4px); color: var(--c-accent); }

/* --- Archive list ---------------------------------------------------------*/

.archive-list { list-style: none; display: flex; flex-direction: column; }
.archive-row {
    display: grid;
    grid-template-columns: 64px 1fr 48px;
    gap: 12px;
    align-items: baseline;
    padding: 10px 0;
    border-top: 1px solid var(--c-line);
    transition: background 200ms ease;
    font-size: 14px;
}
.archive-row:first-child { border-top: 1px solid var(--c-ink); }
.archive-row:hover { background: var(--c-bg-hover); }
.archive-row:hover .arc-title { color: var(--c-accent); }
.arc-id, .arc-date {
    font-family: var(--f-mono);
    font-size: 12px;
    color: var(--c-meta);
    letter-spacing: 0.02em;
}
.arc-date { text-align: right; }
.arc-title {
    font-family: var(--f-body);
    color: var(--c-ink);
    transition: color 200ms ease;
}

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

.site-footer {
    position: relative;
    z-index: 2;
    border-top: 1px solid var(--c-line);
    padding: 16px 0;
}
.foot-row {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    gap: var(--gutter);
    align-items: center;
    font-family: var(--f-mono);
    font-size: 11px;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--c-meta);
}
.foot-mid { text-align: center; }
.foot-end { text-align: right; }

/* --- Responsive collapse (preserves modular spirit) -----------------------*/

@media (max-width: 1100px) {
    .grid-canvas { grid-template-columns: repeat(4, minmax(0, 1fr)); }
    .tile-3x2 { grid-column: span 4; }
    .tile-2x2 { grid-column: span 2; }
    .tile-2x1 { grid-column: span 2; }
    .grid-overlay {
        background-size: calc((100vw - 3 * var(--gutter)) / 4 + var(--gutter)) 100%;
    }
    .lead-heading { font-size: 40px; }
}

@media (max-width: 720px) {
    body { padding: 0 16px; }
    .grid-canvas { grid-template-columns: repeat(2, minmax(0, 1fr)); }
    .tile-3x2, .tile-2x2, .tile-2x1, .tile-1x2 { grid-column: span 2; grid-row: auto; }
    .tile-1x1 { grid-column: span 1; grid-row: span 1; }
    .grid-overlay {
        background-size: calc((100vw - 16px) / 2 + 16px) 100%;
        background-position: 16px 0;
    }
    .header-row {
        grid-template-columns: 1fr auto;
        height: auto;
        padding: 16px 0;
    }
    .primary-nav { grid-column: 1 / -1; flex-wrap: wrap; gap: 14px; justify-content: flex-start; }
    .header-meta { grid-column: 2; }
    .site-header { height: auto; }
    .lead-heading { font-size: 32px; }
    .method-grid { grid-template-columns: 1fr; }
    .method-step:nth-child(n) { border-right: none; padding-left: 0; padding-right: 0; }
    .foot-row { grid-template-columns: 1fr; }
    .foot-mid, .foot-end { text-align: left; }
}