/* Bhanu Prakash Putta — portfolio
   Direction: an engineer's field notebook. Warm paper, ink, hairline rules,
   one signal colour. Serif for voice, grotesk for reading, mono for numbers. */

:root {
  --paper: #f5f2eb;
  --paper-2: #ece7dc;
  --card: #fbf9f4;
  --ink: #17160f;
  --ink-2: #4a463c;
  --ink-3: #6b665a;
  --rule: #d9d2c3;
  --rule-strong: #17160f;
  --signal: #c8431a;
  --signal-ink: #a5360f;
  --signal-wash: #f4dccf;
  --figure-bg: #fdfcf8;

  --serif: "Instrument Serif", "Iowan Old Style", Georgia, serif;
  --sans: "Geist", ui-sans-serif, system-ui, -apple-system, "Segoe UI", sans-serif;
  --mono: "Geist Mono", ui-monospace, SFMono-Regular, Menlo, monospace;

  --measure: 680px;
  --wide: 1120px;
  --gutter: clamp(16px, 4vw, 40px);
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --paper: #12110d;
    --paper-2: #1b1a15;
    --card: #181712;
    --ink: #ede7da;
    --ink-2: #bdb6a6;
    --ink-3: #8b8576;
    --rule: #2f2d25;
    --rule-strong: #ede7da;
    --signal: #ff7a4a;
    --signal-ink: #ff9a72;
    --signal-wash: #3a1f14;
    --figure-bg: var(--card);
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --paper: #12110d; --paper-2: #1b1a15; --card: #181712; --ink: #ede7da; --ink-2: #bdb6a6;
  --ink-3: #8b8576; --rule: #2f2d25; --rule-strong: #ede7da; --signal: #ff7a4a;
  --signal-ink: #ff9a72; --signal-wash: #3a1f14; --figure-bg: #181712; color-scheme: dark;
}

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; scroll-padding-top: 72px; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 400 16.5px/1.6 var(--sans);
  font-feature-settings: "ss01", "cv11";
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
::selection { background: var(--signal); color: var(--paper); }

a { color: inherit; text-decoration-line: underline; text-decoration-color: var(--rule); text-decoration-thickness: 1px; text-underline-offset: 3px; transition: text-decoration-color .15s, color .15s; }
a:hover { text-decoration-color: var(--signal); color: var(--signal-ink); }
:focus-visible { outline: 2px solid var(--signal); outline-offset: 3px; border-radius: 2px; }

.wrap { max-width: var(--wide); margin: 0 auto; padding: 0 var(--gutter); }

/* ---------- type ---------- */
.mono, .label { font-family: var(--mono); font-feature-settings: "zero"; }
.label { font-size: 12px; letter-spacing: 0.06em; text-transform: uppercase; color: var(--ink-3); }
.display {
  font-family: var(--serif); font-weight: 400;
  font-size: clamp(44px, 7.4vw, 104px); line-height: 0.98; letter-spacing: -0.015em; margin: 0;
}
.display em, h2 em, .h-serif em { font-style: italic; }
.hero .display em { color: var(--signal); }
h1, h2, h3 { margin: 0; font-weight: 400; }
h2 { font-family: var(--serif); font-size: clamp(32px, 4.2vw, 52px); line-height: 1.04; letter-spacing: -0.01em; }
h3 { font-family: var(--sans); font-size: 18px; font-weight: 600; letter-spacing: -0.01em; }
.h-serif { font-family: var(--serif); font-size: clamp(28px, 3.4vw, 40px); line-height: 1.08; }
p { margin: 0 0 1em; }
.muted { color: var(--ink-2); }
.small { font-size: 14px; }

/* ---------- top bar ---------- */
.topbar { position: sticky; top: 0; z-index: 20; background: color-mix(in srgb, var(--paper) 88%, transparent); backdrop-filter: saturate(1.2) blur(10px); -webkit-backdrop-filter: saturate(1.2) blur(10px); border-bottom: 1px solid var(--rule); }
.topbar .wrap { display: flex; align-items: center; justify-content: space-between; height: 56px; gap: 16px; }
.brand { font-family: var(--mono); font-size: 13px; letter-spacing: 0.02em; text-decoration: none; white-space: nowrap; }
.brand b { font-weight: 600; }
.topbar nav { display: flex; align-items: center; gap: 22px; font-size: 14px; }
.topbar nav a { text-decoration: none; color: var(--ink-2); }
.topbar nav a:hover { color: var(--ink); }
.status { display: inline-flex; align-items: center; gap: 8px; font-family: var(--mono); font-size: 12px; color: var(--ink-2); }
.status::before { content: ""; width: 7px; height: 7px; border-radius: 50%; background: var(--signal); box-shadow: 0 0 0 3px color-mix(in srgb, var(--signal) 22%, transparent); }

/* ---------- hero ---------- */
.hero { padding-top: clamp(40px, 6vw, 72px); padding-bottom: clamp(40px, 6vw, 72px); }
.hero .label { margin-bottom: 28px; display: block; }
.hero-grid { display: grid; grid-template-columns: minmax(0, 1fr) 300px; gap: 48px; align-items: end; margin-top: 40px; }
.hero-lede { font-size: 19px; line-height: 1.55; color: var(--ink-2); max-width: 560px; margin: 0; }
.hero-lede a { color: var(--ink); }
.hero-meta { border-top: 1px solid var(--rule-strong); }
.hero-meta div { display: flex; justify-content: space-between; gap: 16px; padding: 10px 0; border-bottom: 1px solid var(--rule); font-size: 14px; }
.hero-meta dt { color: var(--ink-3); font-family: var(--mono); font-size: 12px; text-transform: uppercase; letter-spacing: 0.06em; padding-top: 2px; }
.hero-meta dd { margin: 0; text-align: right; }

.links { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 32px; }
.btn { display: inline-flex; align-items: center; gap: 10px; height: 44px; padding: 0 18px; border: 1px solid var(--rule-strong); border-radius: 999px; font-size: 15px; font-weight: 500; text-decoration: none; color: var(--ink); background: transparent; transition: background .15s, color .15s; }
.btn:hover { background: var(--ink); color: var(--paper); text-decoration: none; }
.btn.solid { background: var(--ink); color: var(--paper); }
.btn.solid:hover { background: var(--signal); border-color: var(--signal); color: #fff; }
.btn .arr { font-family: var(--mono); transition: transform .15s; }
.btn:hover .arr { transform: translateX(3px); }

/* ---------- proof strip ---------- */
.proof { display: grid; grid-template-columns: repeat(4, 1fr); border-top: 1px solid var(--rule-strong); border-bottom: 1px solid var(--rule); }
.proof > div { padding: 22px 20px 20px 0; }
.proof > div + div { padding-left: 20px; border-left: 1px solid var(--rule); }
.proof b, .numbers b { font-variant-numeric: tabular-nums; }
.proof b .to, .numbers b .to, .to { display: inline; font-family: var(--mono); font-size: .42em; line-height: 1; vertical-align: .55em; color: var(--ink-3); margin: 0 .2em; }
.proof b { display: block; font-family: var(--serif); font-weight: 400; font-size: clamp(36px, 4vw, 52px); line-height: 1; letter-spacing: -0.01em; }
.proof span { display: block; margin-top: 10px; font-size: 13.5px; color: var(--ink-2); line-height: 1.4; }

/* ---------- sections ---------- */
.section { padding: clamp(64px, 9vw, 112px) 0; }
.section-head { display: grid; grid-template-columns: 200px minmax(0, 1fr); gap: 32px; margin-bottom: 48px; align-items: baseline; }
.section-head .label { padding-top: 10px; }
.section-head p { color: var(--ink-2); max-width: 560px; margin: 14px 0 0; }

/* ---------- work index ---------- */
.work { border-top: 1px solid var(--rule-strong); }
.work-item { display: grid; grid-template-columns: 200px minmax(0, 1fr) minmax(0, 1.05fr); gap: 32px; padding: 40px 0; border-bottom: 1px solid var(--rule); text-decoration: none; color: inherit; }
.work-item:hover { text-decoration: none; color: inherit; }
.work-item .idx { font-family: var(--mono); font-size: 13px; color: var(--ink-3); }
.work-item .idx span { display: block; margin-top: 6px; }
.work-item h3 { font-family: var(--serif); font-weight: 400; font-size: clamp(34px, 4vw, 48px); line-height: 1; letter-spacing: -0.01em; margin-bottom: 14px; transition: color .15s; }
.work-item:hover h3 { color: var(--signal); }
.work-item p { color: var(--ink-2); }
.facts { list-style: none; margin: 18px 0 0; padding: 0; border-top: 1px solid var(--rule); }
.facts li { display: flex; justify-content: space-between; gap: 16px; padding: 8px 0; border-bottom: 1px solid var(--rule); font-size: 14px; color: var(--ink-2); }
.facts li b { font-family: var(--mono); font-weight: 500; color: var(--ink); font-size: 14px; white-space: nowrap; }
.more { display: inline-flex; gap: 8px; margin-top: 18px; font-weight: 500; font-size: 15px; text-decoration: underline; text-decoration-color: transparent; text-underline-offset: 4px; transition: text-decoration-color .15s; }
.work-item:hover .more { text-decoration-color: var(--signal); }
.more .arr { font-family: var(--mono); transition: transform .15s; }
.work-item:hover .more .arr { transform: translateX(4px); }
.thumb { background: var(--figure-bg); border: 1px solid var(--rule); border-radius: 6px; aspect-ratio: 16 / 10; overflow: hidden; display: grid; place-items: center; }
.thumb img { width: 100%; height: 100%; object-fit: cover; object-position: top left; display: block; }
.thumb.contain img { object-fit: contain; padding: 12px; }
.work-minor { display: grid; grid-template-columns: 200px repeat(2, minmax(0, 1fr)); gap: 32px; padding: 32px 0; border-bottom: 1px solid var(--rule); }
.work-minor article h3 { font-family: var(--serif); font-weight: 400; font-size: 28px; margin: 0 0 8px; }
.work-minor article p { color: var(--ink-2); font-size: 15px; margin-bottom: 10px; }

/* ---------- principles / services ---------- */
.principles, .offer { margin-left: 232px; }
.principles { display: grid; grid-template-columns: repeat(3, 1fr); gap: 0; border-top: 1px solid var(--rule-strong); }
.principles > div { padding: 24px 28px 8px 0; }
.principles > div + div { padding-left: 28px; border-left: 1px solid var(--rule); }
.principles .n { font-family: var(--mono); font-size: 12px; color: var(--signal-ink); }
.principles h3 { font-family: var(--serif); font-weight: 400; font-size: 28px; line-height: 1.1; margin: 10px 0 12px; }
.principles p { color: var(--ink-2); font-size: 15.5px; }

.offer { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 0 48px; }
.offer-head { display: grid; grid-template-columns: 200px minmax(0,1fr); gap: 32px; margin-top: 64px; }
.offer-head + .offer { margin-top: 0; }
.offer div { padding: 18px 0; border-top: 1px solid var(--rule); }
.offer h3 { margin-bottom: 6px; }
.offer p { color: var(--ink-2); font-size: 15px; margin: 0; }

/* ---------- experience ---------- */
.timeline { border-top: 1px solid var(--rule-strong); }
.timeline .row { display: grid; grid-template-columns: 200px minmax(0, 1fr) minmax(0, 1.4fr); gap: 32px; padding: 22px 0; border-bottom: 1px solid var(--rule); }
.timeline .yr { font-family: var(--mono); font-size: 13px; color: var(--ink-3); padding-top: 3px; }
.timeline .role b { display: block; font-weight: 600; }
.timeline .role span { color: var(--ink-2); font-size: 15px; }
.timeline p { margin: 0; color: var(--ink-2); font-size: 15.5px; }
.footnote { margin-top: 18px; font-size: 14px; color: var(--ink-3); }

/* ---------- contact ---------- */
.contact { padding: 0 0 clamp(72px, 10vw, 128px); }
.contact .wrap > .inner { border-top: 1px solid var(--rule-strong); padding-top: clamp(56px, 8vw, 96px); }
.contact .display { font-size: clamp(40px, 6.4vw, 88px); max-width: 15ch; }

footer.site { border-top: 1px solid var(--rule); padding: 24px 0 40px; font-family: var(--mono); font-size: 12px; color: var(--ink-3); }
footer.site .wrap { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 12px; }
footer.site a { color: var(--ink-2); }

/* ---------- case study ---------- */
.case-head { padding: clamp(40px, 7vw, 88px) 0 40px; }
.crumb { font-family: var(--mono); font-size: 12px; color: var(--ink-3); text-transform: uppercase; letter-spacing: 0.06em; }
.crumb a { text-decoration: none; color: var(--ink-2); }
.case-head .display { font-size: clamp(44px, 6.6vw, 92px); margin: 22px 0 28px; max-width: 16ch; }
.case-head .dek { font-size: 20px; line-height: 1.5; color: var(--ink-2); max-width: 640px; margin: 0; }

.case { display: grid; grid-template-columns: 200px minmax(0, var(--measure)) minmax(0, 1fr); gap: 32px; }
.case aside.meta { grid-column: 1; grid-row: 1 / span 40; position: sticky; top: 84px; align-self: start; font-size: 14px; }
.case aside.meta dl { margin: 0; padding-bottom: 18px; border-bottom: 1px solid var(--rule); }
.case aside.meta dt { font-family: var(--mono); font-size: 11.5px; text-transform: uppercase; letter-spacing: 0.06em; color: var(--ink-3); margin-top: 18px; }
.case aside.meta dt:first-child { margin-top: 0; }
.case aside.meta dd { margin: 4px 0 0; color: var(--ink-2); }
.case > .body { grid-column: 2; min-width: 0; }
section.body { padding: 44px 0 8px; border-top: 1px solid var(--rule); }
section.body.first { border-top: 0; padding-top: 0; }
.body h2 { font-size: clamp(30px, 3.4vw, 40px); margin-bottom: 18px; }
.body h3 { margin: 28px 0 8px; }
.body p, .body li { font-size: 17px; line-height: 1.65; }
.body ul { padding-left: 20px; margin: 0 0 1em; }
.body li { margin: 6px 0; }
.body li::marker { color: var(--ink-3); }
.body b, .body strong { font-weight: 600; }
.sn { font-family: var(--mono); font-size: 12px; color: var(--signal-ink); vertical-align: super; }

.figure-wide { grid-column: 2 / 4; margin: 8px 0 28px; min-width: 0; }
.figure-wide .frame, figure .frame { display: block; background: var(--figure-bg); border: 1px solid var(--rule); border-radius: 6px; padding: clamp(12px, 2vw, 24px); overflow-x: auto; cursor: zoom-in; text-decoration: none; }
figure { margin: 28px 0; }
figure img { display: block; width: 100%; height: auto; max-height: 640px; object-fit: contain; margin: 0 auto; }
figcaption { font-size: 13.5px; color: var(--ink-3); margin-top: 10px; max-width: var(--measure); }
figcaption .label { color: var(--signal-ink); margin-right: 10px; }

.numbers { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); border-top: 1px solid var(--rule-strong); border-bottom: 1px solid var(--rule); margin: 0 0 48px; }
.numbers > div { padding: 18px 16px 16px 0; }
.numbers > div + div { padding-left: 16px; border-left: 1px solid var(--rule); }
.numbers b { display: block; font-family: var(--serif); font-weight: 400; font-size: clamp(30px, 3.4vw, 42px); line-height: 1; }
.numbers span { display: block; margin-top: 8px; font-size: 13px; color: var(--ink-2); line-height: 1.35; }

.callout { border-left: 2px solid var(--signal); padding: 4px 0 4px 18px; margin: 24px 0; color: var(--ink-2); font-size: 16px; }
.callout .label { display: block; margin-bottom: 6px; color: var(--signal-ink); }

.pull, .body p.pull { font-family: var(--serif); font-size: clamp(26px, 3vw, 34px); line-height: 1.2; margin: 32px 0; padding: 0; color: var(--ink); }

table { width: 100%; border-collapse: collapse; font-size: 15px; margin: 18px 0 24px; }
thead th { font-family: var(--mono); font-size: 11.5px; font-weight: 500; text-transform: uppercase; letter-spacing: 0.06em; color: var(--ink-3); text-align: left; padding: 0 12px 10px 0; border-bottom: 1px solid var(--rule-strong); }
td { padding: 11px 12px 11px 0; border-bottom: 1px solid var(--rule); vertical-align: top; }
td.num, th.num { text-align: right; font-family: var(--mono); font-size: 14px; padding-right: 0; padding-left: 12px; }
thead th.num { font-size: 11.5px; }
tr.win td { color: var(--ink); font-weight: 600; }
.bar { display: inline-block; height: 6px; border-radius: 3px; background: var(--ink); vertical-align: middle; margin-right: 8px; }
tr.win .bar { background: var(--signal); }
.table-scroll { overflow-x: auto; -webkit-overflow-scrolling: touch; }

code { font-family: var(--mono); font-size: 0.86em; background: var(--paper-2); padding: 1px 5px; border-radius: 3px; }
pre { font-family: var(--mono); font-size: 13.5px; line-height: 1.6; background: #1b1a15; color: #ede7da; border: 1px solid var(--rule); padding: 18px 20px; border-radius: 6px; overflow-x: auto; margin: 18px 0 24px; }
pre code { background: none; padding: 0; font-size: inherit; color: inherit; }
pre .c { color: #8b8576; }
pre .hi { color: #ff7a4a; }

.tags { list-style: none; margin: 0; padding: 0; display: flex; flex-wrap: wrap; gap: 6px; }
.body ul.tags { padding-left: 0; }
.body .tags li { margin: 0; line-height: 1.5; font-size: 12px; }
.tags li { font-family: var(--mono); font-size: 12px; padding: 3px 8px; border: 1px solid var(--rule); border-radius: 3px; color: var(--ink-2); }

.next { border-top: 1px solid var(--rule-strong); margin-top: 72px; padding: 40px 0 72px; display: grid; grid-template-columns: 200px minmax(0, 1fr) auto; gap: 32px; align-items: end; }
.next a.big { font-family: var(--serif); font-size: clamp(32px, 4vw, 52px); line-height: 1; text-decoration: none; }
.next a.big:hover { color: var(--signal); }

/* ---------- house diagrams (inline SVG) ---------- */
.dg-hint { display: none; }
.dg-frame { background: var(--card); border: 1px solid var(--rule); border-radius: 6px; padding: clamp(14px, 2.4vw, 28px); overflow-x: auto; -webkit-overflow-scrolling: touch; }
.dg { display: block; width: 100%; height: auto; min-width: 720px; }
.dg .box { fill: var(--paper); stroke: var(--ink); stroke-width: 1.25; }
.dg .box.soft { fill: none; stroke: var(--rule); stroke-dasharray: 3 4; }
.dg .box.hot { fill: var(--signal-wash); stroke: var(--signal); }
.dg .box.ext { fill: var(--paper-2); stroke: var(--ink-3); }
.dg .t { fill: var(--ink); font: 600 14px var(--sans); }
.dg .s { fill: var(--ink-3); font: 400 12px var(--mono); }
.dg .g { fill: var(--ink-3); font: 500 11px var(--mono); letter-spacing: .08em; text-transform: uppercase; }
.dg .e { fill: none; stroke: var(--ink-2); stroke-width: 1.25; }
.dg .e.dash { stroke-dasharray: 4 4; stroke: var(--ink-3); }
.dg .e.hot { stroke: var(--signal); }
.dg .el { fill: var(--ink-2); font: 400 11px var(--mono); }
.dg .ah { fill: var(--ink-2); }
.dg .ah.hot { fill: var(--signal); }
.dg .n { fill: var(--signal-ink); font: 500 11px var(--mono); }

/* ---------- reveal ---------- */
@media (prefers-reduced-motion: no-preference) {
  .rise { animation: rise .7s cubic-bezier(.2,.7,.2,1) both; }
  .rise.d1 { animation-delay: .06s; } .rise.d2 { animation-delay: .12s; } .rise.d3 { animation-delay: .18s; }
  @keyframes rise { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: none; } }
}

/* ---------- responsive ---------- */
@media (max-width: 960px) {
  .hero-grid { grid-template-columns: 1fr; gap: 32px; }
  .section-head, .work-item, .work-minor, .timeline .row, .next { grid-template-columns: 1fr; gap: 14px; }
  .work-item .thumb { order: -1; }
  .work-item { gap: 18px; }
  .case { grid-template-columns: 1fr; }
  .case aside.meta { position: static; grid-column: 1; display: none; }
  .case > .body, .figure-wide { grid-column: 1; }
  .principles { grid-template-columns: 1fr; }
  .principles, .offer { margin-left: 0; }
  .offer-head { grid-template-columns: 1fr; gap: 10px; }
  .principles > div, .principles > div + div { padding: 22px 0 6px; border-left: 0; border-top: 1px solid var(--rule); }
  .principles > div:first-child { border-top: 0; }
}
@media (max-width: 640px) {
  body { font-size: 16px; }
  .topbar nav { gap: 14px; }
  .topbar .hide-sm, .topbar .status { display: none; }
  .proof { grid-template-columns: 1fr 1fr; }
  .proof > div:nth-child(3) { padding-left: 0; border-left: 0; }
  .proof > div:nth-child(n+3) { border-top: 1px solid var(--rule); }
  .offer { grid-template-columns: 1fr; }
  .links .hide-sm { display: none; }
  .work-item .idx span { display: inline; margin-left: 8px; }
  .dg-frame { margin: 0 calc(-1 * var(--gutter)); border-radius: 0; border-left: 0; border-right: 0; }
  .dg { min-width: 640px; }
  .dg-hint { display: inline; font-family: var(--mono); color: var(--ink-3); margin-left: 6px; }
  .body table.metrics-t th:nth-child(n+3), .body table.metrics-t td:nth-child(n+3) { display: none; }
  .bar { display: block; margin: 0 0 6px; }
  .hero-lede, .case-head .dek { font-size: 17.5px; }
  .body p, .body li { font-size: 16.5px; }
  .numbers { grid-template-columns: 1fr 1fr; }
  .numbers > div:nth-child(odd) { padding-left: 0; border-left: 0; }
  .numbers > div:nth-child(n+3) { border-top: 1px solid var(--rule); }
}