/* Layout: Distill-style article grid — a 680px text column, figures break out to a wider "page" column, margin notes in the right gutter on wide screens. */
:root {
  --bg: #ffffff;
  --surface: #f5f5f3;
  --ink: #16191d;
  --ink-2: #4a4f57;
  --ink-3: #7a7f87;
  --rule: #dfe0e2;
  --grid: #ececec;
  --accent: #b3264a;
  --accent-soft: #f6e3e8;
  --pass: #1f7a3a;
  --fail: #b3261e;
  --m0: #2a78d6;  /* Ti-6Al-4V  */
  --m1: #1baf7a;  /* Al-2024    */
  --m2: #4a3aa7;  /* AISI 304   */
  --m3: #eb6834;  /* BeCu C17000 */
  --mesh: #b4bac2;
  --f-display: "Newsreader", "Iowan Old Style", Georgia, serif;
  --f-body: "Newsreader", "Iowan Old Style", Georgia, serif;
  --f-ui: "IBM Plex Sans", system-ui, -apple-system, "Segoe UI", sans-serif;
  --f-mono: "IBM Plex Mono", ui-monospace, Menlo, Consolas, monospace;
  color-scheme: light;
}
* { box-sizing: border-box; }
body { background: var(--bg); color: var(--ink); font-family: var(--f-body); font-size: 19px; line-height: 1.6; -webkit-font-smoothing: antialiased; }
a { color: var(--accent); text-decoration: underline; text-decoration-thickness: 1px; text-underline-offset: 2px; }
a:hover { text-decoration-thickness: 2px; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

.grid {
  display: grid;
  grid-template-columns: [screen-start] 1fr [page-start] minmax(0, 150px) [text-start] minmax(0, 680px) [text-end] minmax(0, 150px) [page-end] 1fr [screen-end];
  column-gap: 32px;
  padding-inline: 20px;
}
.grid > * { grid-column: text; min-width: 0; }
.grid > .l-page { grid-column: page; }
.grid > .l-screen { grid-column: screen; }
@media (max-width: 1000px) {
  .grid { grid-template-columns: [screen-start page-start text-start] minmax(0, 1fr) [text-end page-end screen-end]; column-gap: 0; padding-inline: 16px; }
  .grid > * , .grid > .l-page { grid-column: text; }
}

/* Title block */
header.hero { padding-block: 64px 28px; }
.kicker { font-family: var(--f-ui); font-size: 13px; letter-spacing: .08em; text-transform: uppercase; color: var(--ink-3); margin: 0 0 18px; }
h1 { font-family: var(--f-display); font-weight: 500; font-size: clamp(36px, 5.4vw, 58px); line-height: 1.06; letter-spacing: -0.015em; margin: 0 0 20px; text-wrap: balance; }
.dek { font-size: 22px; line-height: 1.45; color: var(--ink-2); margin: 0; max-width: 680px; text-wrap: pretty; }
.hero-fig { margin-top: 36px; }

.byline { border-top: 1px solid var(--rule); border-bottom: 1px solid var(--rule); padding-block: 18px; margin-block: 8px 40px;
  display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 16px 24px; font-family: var(--f-ui); font-size: 14px; line-height: 1.45; }
.byline h4 { font-size: 11px; letter-spacing: .08em; text-transform: uppercase; color: var(--ink-3); font-weight: 500; margin: 0 0 6px; }
.byline p { margin: 0; color: var(--ink); }
.byline .sub { color: var(--ink-3); }
@media (max-width: 700px) { .byline { grid-template-columns: repeat(2, minmax(0, 1fr)); } }

/* Prose */
article p, article li { text-wrap: pretty; }
article p { margin: 0 0 1.1em; }
article h2 { font-family: var(--f-display); font-weight: 500; font-size: 32px; line-height: 1.15; letter-spacing: -0.01em; margin: 56px 0 14px; padding-top: 28px; border-top: 1px solid var(--rule); text-wrap: balance; }
article h3 { font-family: var(--f-ui); font-weight: 600; font-size: 17px; margin: 32px 0 8px; }
article ul, article ol { padding-left: 1.2em; margin: 0 0 1.1em; }
.math { font-family: var(--f-display); font-style: italic; white-space: nowrap; }
.eq { font-family: var(--f-display); font-size: 21px; text-align: center; margin: 22px 0 26px; overflow-x: auto; }
.eq .lbl { font-family: var(--f-ui); font-style: normal; font-size: 13px; color: var(--ink-3); margin-left: 18px; }
code, .mono { font-family: var(--f-mono); font-size: 0.82em; }
code { background: var(--surface); padding: 1px 5px; border-radius: 3px; }
sup.fn a, a.cite { font-family: var(--f-ui); font-size: 12px; text-decoration: none; color: var(--accent); }
a.cite { vertical-align: super; line-height: 0; }
.swatch { display: inline-block; width: 10px; height: 10px; border-radius: 2px; vertical-align: baseline; margin-right: 4px; }

/* Margin notes */
.note-row { position: relative; }
aside.margin { font-family: var(--f-ui); font-size: 13px; line-height: 1.5; color: var(--ink-2); }
@media (min-width: 1001px) {
  aside.margin { grid-column: text-end / page-end !important; grid-row: span 3; align-self: start; padding-top: 4px; }
}
@media (max-width: 1000px) {
  aside.margin { border-left: 2px solid var(--rule); padding-left: 12px; margin: 0 0 1.1em; }
}

/* Callout */
.callout { background: var(--accent-soft); border-radius: 6px; padding: 18px 20px; margin: 8px 0 24px; font-size: 17px; line-height: 1.55; }
.callout strong { font-family: var(--f-ui); font-size: 12px; letter-spacing: .08em; text-transform: uppercase; color: var(--accent); display: block; margin-bottom: 6px; }
.callout p:last-child { margin-bottom: 0; }

/* Figures */
figure { margin: 18px 0 36px; }
.fig { font-family: var(--f-ui); font-size: 13px; color: var(--ink); }
.fig .controls { display: flex; flex-wrap: wrap; gap: 10px 22px; align-items: center; padding-bottom: 12px; margin-bottom: 8px; border-bottom: 1px solid var(--rule); }
.ctl { display: flex; align-items: center; gap: 8px; color: var(--ink-2); min-width: 0; max-width: 100%; }
.ctl label { white-space: nowrap; }
select, input[type=range] { font-family: var(--f-ui); font-size: 13px; }
select { max-width: 100%; min-width: 0; background: var(--bg); color: var(--ink); border: 1px solid var(--rule); border-radius: 4px; padding: 5px 8px; }
input[type=range] { accent-color: var(--accent); width: 130px; }
.val { font-family: var(--f-mono); font-size: 12.5px; color: var(--ink); min-width: 3.4em; display: inline-block; font-variant-numeric: tabular-nums; }
.chips { display: flex; flex-wrap: wrap; gap: 6px; }
.chip { font-family: var(--f-ui); font-size: 12.5px; display: inline-flex; align-items: center; gap: 6px; border: 1px solid var(--rule); background: var(--bg); color: var(--ink); border-radius: 999px; padding: 4px 10px 4px 8px; cursor: pointer; }
.chip[aria-pressed="false"] { color: var(--ink-3); }
.chip[aria-pressed="false"] svg { opacity: .3; }
.chip:hover { border-color: var(--ink-3); }
.check { display: inline-flex; gap: 6px; align-items: center; cursor: pointer; color: var(--ink-2); }
.check input { accent-color: var(--accent); }
.legend { display: flex; flex-wrap: wrap; gap: 6px 18px; color: var(--ink-2); font-size: 12.5px; margin: 6px 0 4px; }
.legend span { display: inline-flex; align-items: center; gap: 6px; }
.chart { position: relative; width: 100%; }
.chart svg { display: block; overflow: visible; }
.chart text { font-family: var(--f-ui); }
.axis text { fill: var(--ink-3); font-size: 11.5px; font-variant-numeric: tabular-nums; }
.axis path, .axis line { stroke: var(--rule); }
.gridline line { stroke: var(--grid); }
.gridline path { display: none; }
.axis-title { fill: var(--ink-2); font-size: 12px; }
.readout { font-family: var(--f-ui); font-size: 13px; color: var(--ink-2); margin-top: 8px; font-variant-numeric: tabular-nums; }
.readout b { color: var(--ink); font-weight: 600; }
figcaption { font-family: var(--f-ui); font-size: 13.5px; line-height: 1.55; color: var(--ink-2); margin-top: 12px; max-width: 760px; }
figcaption b { color: var(--ink); font-weight: 600; }
.fignum { font-weight: 600; color: var(--ink); }

/* Tables */
.tablewrap { overflow-x: auto; margin-top: 14px; }
table { border-collapse: collapse; width: 100%; font-family: var(--f-ui); font-size: 13px; font-variant-numeric: tabular-nums; }
th { text-align: right; font-weight: 500; color: var(--ink-3); font-size: 11.5px; letter-spacing: .02em; padding: 6px 10px; border-bottom: 1px solid var(--rule); white-space: nowrap; }
td { text-align: right; padding: 6px 10px; border-bottom: 1px solid var(--grid); white-space: nowrap; }
th:first-child, td:first-child, th.l, td.l { text-align: left; }
tbody tr.hl td { background: var(--surface); }
tbody tr[data-row] { cursor: pointer; }
.mat-cell { display: inline-flex; align-items: center; gap: 6px; }
.pill { display: inline-flex; align-items: center; gap: 4px; font-size: 11.5px; font-weight: 500; padding: 1px 8px 1px 6px; border-radius: 999px; border: 1px solid currentColor; }
.pill.pass { color: var(--pass); }
.pill.fail { color: var(--fail); }
.mt-table td, .mt-table th { padding: 7px 10px; }

/* Tooltip */
.tip { position: fixed; z-index: 50; pointer-events: none; background: var(--bg); color: var(--ink); border: 1px solid var(--rule); box-shadow: 0 6px 24px rgba(0,0,0,.12); border-radius: 6px; padding: 9px 11px; font-family: var(--f-ui); font-size: 12.5px; line-height: 1.45; max-width: 280px; font-variant-numeric: tabular-nums; }
.tip .t { font-weight: 600; margin-bottom: 4px; display: flex; align-items: center; gap: 6px; }
.tip .r { display: flex; justify-content: space-between; gap: 16px; color: var(--ink-2); }
.tip .r b { color: var(--ink); font-weight: 500; }

/* Bracket card */
.card-head { display: flex; flex-wrap: wrap; align-items: baseline; gap: 6px 14px; margin-top: 18px; font-family: var(--f-ui); }
.card-head h5 { font-size: 15px; margin: 0; font-weight: 600; }
.card-head span { color: var(--ink-3); font-size: 12.5px; }

/* Appendix & refs */
.appendix { font-family: var(--f-ui); font-size: 14px; line-height: 1.6; color: var(--ink-2); }
.appendix h3 { font-size: 13px; letter-spacing: .06em; text-transform: uppercase; color: var(--ink-3); font-weight: 500; margin: 28px 0 10px; }
ol.refs { padding-left: 1.4em; }
ol.refs li { margin-bottom: 8px; }
pre.bib { font-family: var(--f-mono); font-size: 12px; background: var(--surface); padding: 14px; border-radius: 6px; overflow-x: auto; color: var(--ink); line-height: 1.5; }
footer.end { border-top: 1px solid var(--rule); margin-top: 56px; padding-block: 28px 64px; }

/* Design thumbnails, gallery and inspector */
.thumb { display: inline-block; flex: none; background-repeat: no-repeat; }
.thumb.fill { display: block; height: 100%; width: auto; aspect-ratio: 1; margin: 0 auto; max-width: 100%; }
.tip .thumb { display: block; margin: -2px auto 6px; }
.insp { display: grid; grid-template-columns: minmax(0, 1.35fr) minmax(0, 1fr); gap: 20px 28px; margin-top: 18px; align-items: start; }
.insp.insp-stack { grid-template-columns: minmax(0, 1fr); margin-top: 0; }
@media (max-width: 700px) { .insp { grid-template-columns: minmax(0, 1fr); } }
.insp-view { position: relative; aspect-ratio: 4 / 3; max-width: 100%; background: var(--surface); border-radius: 8px; overflow: hidden; }
.viewer, .dispimg { position: absolute; inset: 0; }
.viewer canvas { display: block; touch-action: none; cursor: grab; }
.viewer canvas:active { cursor: grabbing; }
.vmsg { position: absolute; inset: auto 12px 36px 12px; text-align: center; font-family: var(--f-ui); font-size: 12.5px; color: var(--ink-3); margin: 0; }
.vtabs { position: absolute; left: 10px; top: 10px; display: flex; flex-wrap: wrap; gap: 6px; }
.vtabs .chip { background: var(--bg); }
.vhint { position: absolute; right: 12px; bottom: 8px; margin: 0; font-family: var(--f-ui); font-size: 11.5px; color: var(--ink-3); }
.insp-meta { font-family: var(--f-ui); font-size: 13.5px; }
.insp-meta h5 { font-size: 16px; font-weight: 600; margin: 0 0 8px; }
.insp-meta dl { display: grid; grid-template-columns: auto minmax(0, 1fr); gap: 6px 16px; margin: 0 0 12px; font-variant-numeric: tabular-nums; }
.insp-meta dt { color: var(--ink-3); }
.insp-meta dd { margin: 0; color: var(--ink); overflow-wrap: anywhere; }
.insp-meta .links { margin: 0; line-height: 1.8; }
.insp-stack .insp-meta { display: grid; grid-template-columns: minmax(0, 1fr); }
.gal-layout { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: 28px; align-items: start; margin-top: 4px; }
@media (max-width: 900px) { .gal-layout { grid-template-columns: minmax(0, 1fr); } }
.gal-grid { position: relative; display: grid; grid-template-columns: repeat(auto-fill, minmax(84px, 1fr)); gap: 4px; max-height: 620px; overflow-y: auto; padding: 2px; align-content: start; border: 1px solid var(--rule); border-radius: 8px; }
@media (max-width: 900px) { .gal-grid { max-height: 380px; grid-template-columns: repeat(auto-fill, minmax(72px, 1fr)); } }
.tile { appearance: none; border: 1px solid transparent; background: var(--bg); border-radius: 6px; padding: 2px 2px 5px; cursor: pointer; display: flex; flex-direction: column; align-items: stretch; gap: 0; font-family: var(--f-ui); font-size: 11px; color: var(--ink-3); font-variant-numeric: tabular-nums; min-width: 0; }
.tile .thumb { width: 100%; aspect-ratio: 1; }
.tile .cap { white-space: nowrap; overflow: hidden; text-overflow: ellipsis; text-align: center; }
.tile:hover { border-color: var(--rule); }
.tile[aria-selected="true"] { border-color: var(--accent); background: var(--accent-soft); color: var(--ink); }
.tile .ok { color: var(--pass); font-weight: 600; }
.chip .n { color: var(--ink-3); font-variant-numeric: tabular-nums; }
#gal-insp .insp-table { margin-top: 14px; }

.plot3d { width: 100%; height: 520px; }
@media (max-width: 600px) { .plot3d { height: 420px; } body { font-size: 18px; } .dek { font-size: 19px; } }
@media (prefers-reduced-motion: reduce) { * { transition: none !important; animation: none !important; } }