amberfork-layout 1.0.0

      /* DESIGN.md tokens — dark is the primary/default theme (DD5); light follows the OS via
         prefers-color-scheme (#31), no manual toggle. Fonts are the metrics-compatible
         fallbacks; the latin-subset Monaspace/General Sans woff2 land in a later slice with
         no layout shift. */
      :root {
        color-scheme: dark;
        --bg: #0a0a0b;
        --surface: #121214;
        --raised: #17171b;
        --hair: #26262b;
        --text: #e6e6e9;
        --muted: #8a8a93;
        --faint: #55555c;
        --amber: #ff7a1a;
        --warning: #f5a623;
        --error: #ff5c5c;
        --error-bg: #ff5c5c14;
        --success: #46d39a;
        --success-bg: #46d39a14;
        --mono: ui-monospace, "SF Mono", SFMono-Regular, Menlo, monospace;
        --sans: ui-sans-serif, system-ui, -apple-system, sans-serif;
      }

      /* Light palette (DESIGN.md "Light mode"). --raised coincides with --surface (both read
         as the elevated/white layer against the --bg canvas — the dark scale's bg<surface<raised
         progression has no headroom above white). --faint has no explicit light spec; it's
         decorative-only (DD4), so it's picked for a low, ~faint-in-dark contrast against --bg
         rather than lifted from the doc. */
      @media (prefers-color-scheme: light) {
        :root {
          color-scheme: light;
          --bg: #f7f7f5;
          --surface: #ffffff;
          --raised: #ffffff;
          --hair: #e2e2dd;
          --text: #16161a;
          --muted: #6b6b72;
          --faint: #a3a39c;
          --amber: #e0570b;
          --error: #c7382f;
          --error-bg: #c7382f14;
          --success: #1e9e6a;
          --success-bg: #1e9e6a14;
        }
      }

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

      body {
        height: 100vh; /* exact viewport height so the CANVAS scrolls, never the whole page */
        display: flex;
        flex-direction: column;
        overflow: hidden;
        background: var(--bg);
        color: var(--text);
        font-family: var(--sans);
        font-size: 0.875rem;
        line-height: 1.5;
        -webkit-font-smoothing: antialiased;
      }

      /* The two-pane body: canvas flexes, attribution holds a fixed 320px on the right. Fills
         the height below the header so the pane's border-left runs the full column. */
      .body {
        display: flex;
        flex: 1;
        min-height: 0;
      }

      /* --- The app shell: never a blank page before wasm mounts (D20). The boot node is
             removed by the csr entry once the app is alive; if it survives, boot failed and
             the error state below is revealed in its place. --- */
      .boot {
        display: flex;
        flex-direction: column;
        align-items: center;
        justify-content: center;
        gap: 0.5rem;
        min-height: 100vh;
        padding: 2rem;
        text-align: center;
        color: var(--muted);
      }

      .boot-glyph {
        font-family: var(--mono);
        font-size: 1.5rem;
        color: var(--faint);
      }

      .boot p {
        max-width: 34rem;
      }

      .boot-hint {
        color: var(--muted);
        font-size: 0.8125rem;
      }

      .boot code {
        font-family: var(--mono);
        color: var(--text);
      }

      .boot--error .boot-glyph {
        color: var(--warning);
      }

      [hidden] {
        display: none !important;
      }

      @media (prefers-reduced-motion: no-preference) {
        .boot-glyph {
          animation: boot-pulse 1.6s ease-in-out infinite;
        }
      }

      @keyframes boot-pulse {
        0%,
        100% {
          opacity: 0.55;
        }
        50% {
          opacity: 1;
        }
      }

      /* --- Header bar. Mono, compact, quiet: the verdict is the protagonist through the
             `text` token and its position, not color. Zero amber in the header frame. --- */
      .hdr {
        display: flex;
        align-items: baseline;
        gap: 1rem;
        padding: 0.5rem 0.875rem;
        border-bottom: 1px solid var(--hair);
        background: var(--surface);
        font-family: var(--mono);
        font-size: 0.75rem;
      }

      .logo {
        color: var(--text);
        font-weight: 700;
        letter-spacing: -0.01em;
      }

      .logo-glyph {
        color: var(--muted); /* never amber — amber is spent only in the canvas */
      }

      .pair {
        color: var(--text);
      }

      .pair b {
        font-weight: 600;
      }

      .role {
        color: var(--muted);
      }

      .vs {
        color: var(--faint);
      }

      .verdict {
        color: var(--text);
        font-variant-numeric: tabular-nums;
        text-decoration: none;
      }

      .verdict--fork:hover {
        text-decoration: underline;
        text-underline-offset: 3px;
      }

      .verdict:focus-visible {
        outline: 1px solid var(--hair);
        outline-offset: 2px;
        border-radius: 2px;
      }

      .meta {
        margin-left: auto;
        color: var(--muted);
        font-variant-numeric: tabular-nums;
      }

      /* --- The alignment canvas: side-by-side runs on the shared spine. Sameness recedes
             (muted), divergence glows (amber on the fork + every downstream row). Amber is
             spent here and nowhere else. DOM rows carry selectable text; the SVG overlay
             draws the timeline rail, the amber divergent-path segment, and the fork node,
             both keyed to the 30px row pitch so they line up. --- */
      .canvas {
        flex: 1;
        min-width: 0; /* let the flex child shrink so its own overflow engages */
        min-height: 12rem;
        overflow: auto; /* the canvas is the scroll container — header + pane stay fixed */
      }

      /* Fills the canvas viewport (dotted field), with the bounded rows left-anchored on top.
         When the rows are wider than the canvas the canvas alone scrolls (DD4 canvas-only
         horizontal scroll) — the header and attribution pane never move. */
      .track {
        position: relative;
        min-height: 100%;
        background-image: radial-gradient(circle, var(--hair) 1px, transparent 1px);
        background-size: 22px 22px;
      }

      .spine {
        position: absolute;
        top: 0;
        left: 0;
        pointer-events: none;
      }
      .spine-rail {
        stroke: var(--faint); /* the quiet shared timeline */
        stroke-width: 1;
      }
      .spine-path {
        stroke: var(--amber); /* the divergent path made literal; the ignition beat animates it */
        stroke-width: 2;
      }
      .fork-node {
        fill: var(--amber);
      }

      .rows {
        list-style: none;
        width: fit-content; /* hug the two bounded runs; the fork band never spans dead space */
        margin-left: 28px; /* clear the 28px SVG spine strip */
        padding: 18px 0; /* 18px top pad matches the geometry's TOP_PAD */
      }

      /* Fixed side columns, not 1fr: the two runs sit adjacent as one comparison instead of
         stretching to opposite edges, and the layout anchors left — leaving the right open for
         the attribution pane (slice 2). Same template on every row keeps the columns aligned. */
      .row {
        display: grid;
        grid-template-columns: 104px 300px 300px auto;
        align-items: center;
        column-gap: 18px;
        height: 30px; /* == ROW_H; the SVG overlay is computed from the same pitch */
        padding: 0 14px;
        font-family: var(--mono);
        font-size: 0.75rem;
        color: var(--muted);
        font-variant-numeric: tabular-nums;
        cursor: pointer;
        scroll-margin-top: 96px; /* auto-scroll lands the fork in the upper third, not the edge */
      }
      /* Hover tint (never on the selected row) and a clear focus-visible ring. The ring is a
         box-shadow, not an outline, so it never overrides the fork's dashed amber cue. */
      .row:hover:not(.row--selected) {
        background: var(--surface);
      }
      .row:focus-visible {
        outline: none;
        box-shadow: inset 0 0 0 2px var(--muted);
      }

      .gutter {
        display: flex;
        align-items: baseline;
        gap: 8px;
      }
      .cue {
        width: 0.9em;
        display: inline-block;
        text-align: center;
        color: var(--faint);
      }
      .idx {
        color: var(--muted);
      }

      .cell {
        display: flex;
        align-items: baseline;
        gap: 8px;
        min-width: 0;
      }
      .kind {
        width: 40px;
        color: var(--faint);
      }
      .name {
        width: 104px;
        color: var(--muted);
        white-space: nowrap;
        overflow: hidden;
        text-overflow: ellipsis;
      }
      .sum {
        flex: 1;
        min-width: 0;
        color: var(--muted);
        white-space: nowrap;
        overflow: hidden;
        text-overflow: ellipsis;
      }
      /* The honest cut mark (issue #17) and, when the slot carries a resolvable address, a real
         click-to-expand affordance (issue #30) — same element, same class, so idle appearance
         never changes: only interaction reveals whether there's anything behind it to fetch.
         Never amber (DESIGN.md) — this is not divergence, and must not compete with the fork's
         one scarce accent. */
      .slot-trunc {
        border: none;
        background: none;
        padding: 0;
        margin: 0;
        font: inherit;
        color: var(--muted);
      }
      button.slot-trunc {
        cursor: pointer;
        transition: color 150ms ease-out;
      }
      button.slot-trunc:hover {
        color: var(--text);
        text-decoration: underline dotted;
      }
      button.slot-trunc:focus-visible {
        color: var(--text);
        text-decoration: underline dotted;
        outline: 2px solid var(--muted);
        outline-offset: 1px;
      }
      button.slot-trunc:disabled {
        cursor: default;
        opacity: 0.6;
        text-decoration: none;
      }
      @media (prefers-reduced-motion: reduce) {
        button.slot-trunc {
          transition: none;
        }
      }

      /* Divergence glows: the fork and every downstream row in one uniform amber (no intensity
         grading — one scarce accent). The dashed outline is the fork's redundant non-color cue;
         `outline` never shifts layout, so the row stays 30px and the SVG stays aligned. */
      .row--fork {
        color: var(--amber);
        background: rgba(255, 122, 26, 0.05);
        border-radius: 4px;
        outline: 1px dashed var(--amber);
        outline-offset: -1px;
      }
      .row--down {
        color: var(--amber);
      }
      .row--fork .idx,
      .row--fork .kind,
      .row--fork .name,
      .row--fork .sum,
      .row--fork .cue,
      .row--down .idx,
      .row--down .kind,
      .row--down .name,
      .row--down .sum,
      .row--down .cue {
        color: var(--amber);
      }
      .tag {
        justify-self: end;
        white-space: nowrap; /* the [FORK · conf] tag stays on the fork's single 30px row */
        color: var(--amber);
        font-variant-numeric: tabular-nums;
      }

      /* Selection is the neutral frame: raised surface + a hairline ring (inset box-shadow, so
         no layout shift). Never amber (DD2) — the default-selected fork keeps its amber role via
         `row--fork` and only gains the raised surface + hairline on top. Placed after the role
         rules so its raised background wins over the fork's amber tint. */
      .row--selected {
        background: var(--raised);
        box-shadow: inset 0 0 0 1px var(--hair);
      }

      /* --- Motion: the ONE expressive beat (DESIGN.md §Motion). On load the amber ignites at
             the fork node and flows down the divergent path — the fork node pops, the amber
             spine segment draws downward from the fork, and the divergent rows kindle to full
             amber. Medium 250–400ms, ease-out (enter easing); the beat spans 0–380ms. Each
             animation's `to` state IS the static markup, so with `prefers-reduced-motion:
             reduce` this whole block is off and the lit end state simply shows with no motion.
             The glow is the saturated stroke — no blur halo. Fires on load; slice 3a already
             scrolls the fork into view first, so the beat plays where the eye is. --- */
      @media (prefers-reduced-motion: no-preference) {
        .fork-node {
          transform-box: fill-box;
          transform-origin: center;
          animation: fork-ignite 200ms ease-out both;
        }
        .spine-path {
          transform-box: fill-box;
          transform-origin: top; /* the fork end: the segment runs fork_y → y_last */
          animation: path-flow 300ms ease-out 80ms both;
        }
        .row--fork,
        .row--down {
          animation: row-kindle 300ms ease-out 80ms both;
        }
      }

      @keyframes fork-ignite {
        from {
          opacity: 0;
          transform: scale(0.2);
        }
        to {
          opacity: 1;
          transform: scale(1);
        }
      }
      @keyframes path-flow {
        from {
          transform: scaleY(0);
        }
        to {
          transform: scaleY(1);
        }
      }
      @keyframes row-kindle {
        from {
          opacity: 0.4;
        }
        to {
          opacity: 1;
        }
      }

      /* --- Attribution pane: the diff's one answer in DR5 order. No amber, no red/green — a
             statement ABOUT the divergence, not the divergence itself. --- */
      .attr {
        flex: 0 0 320px;
        border-left: 1px solid var(--hair);
        background: var(--surface);
        padding: 16px 18px;
        font-family: var(--mono);
        font-size: 0.75rem;
        overflow-y: auto;
      }
      .attr-title {
        margin-bottom: 14px;
        font-size: 0.625rem;
        font-weight: 600;
        text-transform: uppercase;
        letter-spacing: 0.08em;
        color: var(--muted);
      }
      .attr-list {
        display: flex;
        flex-direction: column;
        gap: 10px;
      }
      .attr-row {
        display: flex;
        align-items: baseline;
        justify-content: space-between;
        gap: 14px;
      }
      .attr-row dt {
        color: var(--muted);
      }
      .attr-row dd {
        color: var(--text);
        text-align: right;
        font-variant-numeric: tabular-nums;
      }
      .attr-empty {
        color: var(--muted);
        line-height: 1.6;
      }

      /* A division of the SAME pane (issue #40), not a new one — a hairline divider plus a
             heading-level step-down (h3, still styled as .attr-title) carry the hierarchy, so
             this reads as "more of the same voice," never a competing header. */
      .attr-section {
        margin-top: 20px;
        padding-top: 16px;
        border-top: 1px solid var(--hair);
      }
      .attr-section .attr-title {
        margin-bottom: 10px;
      }

      /* --- Content-diff pane: the selected pair's field-level -/+ evidence (issue #27). The
             ONLY red/green in any surface (DESIGN.md containment) — removed red, added green,
             kept deliberately distinct from the amber fork. Lives inside the attribution aside,
             below the answer; a card per field, monospace, values wrapping so long payloads stay
             readable and copyable (never a canvas draw). --- */
      .content-diff,
      .content-diff-empty {
        margin-top: 18px;
        padding-top: 14px;
        border-top: 1px solid var(--hair);
      }
      .content-diff {
        display: flex;
        flex-direction: column;
        gap: 12px;
      }
      .content-diff-empty {
        color: var(--muted);
        line-height: 1.6;
      }
      .content-diff-field {
        display: flex;
        flex-direction: column;
        gap: 3px;
      }
      .content-diff-path {
        color: var(--muted);
        font-size: 0.6875rem;
      }
      .content-diff-del,
      .content-diff-add {
        display: flex;
        gap: 6px;
        padding: 2px 6px;
        border-radius: 3px;
        white-space: pre-wrap;
        overflow-wrap: anywhere;
      }
      .content-diff-del {
        color: var(--error);
        background: var(--error-bg);
      }
      .content-diff-add {
        color: var(--success);
        background: var(--success-bg);
      }
      .content-diff-sign {
        flex: 0 0 auto;
        font-variant-numeric: tabular-nums;
        opacity: 0.85;
      }
      .content-diff-val {
        flex: 1;
        min-width: 0;
      }
      /* The copy affordance (issue #27 evidence-out). Quiet neutral at rest — buttons are never
         amber (DESIGN.md), and it must not compete with the card's scarce red/green, so the
         confirmed state stays neutral too. Sits top-right of the card; hover = surface tint;
         focus-visible = hairline ring, matching the canvas rows. */
      .content-diff-copy {
        align-self: flex-end;
        margin-bottom: -4px;
        padding: 2px 8px;
        border: 1px solid var(--hair);
        border-radius: 4px;
        background: var(--surface);
        color: var(--muted);
        font-family: var(--mono);
        font-size: 0.6875rem;
        cursor: pointer;
        transition:
          color 150ms ease-out,
          background 150ms ease-out,
          border-color 150ms ease-out;
      }
      .content-diff-copy:hover {
        background: var(--raised);
        color: var(--text);
        border-color: var(--muted);
      }
      .content-diff-copy:focus-visible {
        outline: 2px solid var(--muted);
        outline-offset: 1px;
      }
      @media (prefers-reduced-motion: reduce) {
        .content-diff-copy {
          transition: none;
        }
      }

      /* --- Disconnect banner: the server that fed this view stopped (D-decision 2026-07-12).
             A slim strip docked at the bottom edge, `warning` — never amber: a system-status
             message is not a divergence. Fixed, so it annunciates without reflowing the canvas;
             no spinner — the state is terminal until the user restarts + reloads. --- */
      .banner {
        position: fixed;
        left: 0;
        right: 0;
        bottom: 0;
        padding: 0.5rem 0.875rem;
        border-top: 1px solid var(--warning);
        background: rgba(245, 166, 35, 0.08); /* faint warning wash over the surface */
        font-family: var(--mono);
        font-size: 0.75rem;
        color: var(--warning);
      }

      .banner code {
        color: var(--text); /* the restart command reads as copy-ready, brighter than the label */
      }