@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500&display=swap');

/* ==========================================================================
   Priyam Srivastava — personal site
   Type:  IBM Plex Mono for display, labels, and data. IBM Plex Sans for prose.
   Color: teal = sensing and metrology, plum = networks and control.
   ========================================================================== */

:root {
  --mono: 'IBM Plex Mono', ui-monospace, SFMono-Regular, Menlo, monospace;
  --sans: 'Inter', 'IBM Plex Sans', system-ui, -apple-system, 'Segoe UI', sans-serif;
  --wrap: 1080px;
  --gutter: 2rem;
}

html[data-theme='dark'] {
  --bg: #0F1216;
  --bg-2: #181C23;
  --line: #2A313D;
  --line-soft: #1F242D;
  --fg: #F3F5F8;
  --prose: #DDE3EB;
  --fg-2: #C2C9D4;
  --fg-3: #8B94A2;
  --metro-fg: #3FDCC7;
  --net-fg: #F096C2;
}

html[data-theme='light'] {
  --bg: #FCFCFD;
  --bg-2: #F1F3F6;
  --line: #D8DCE3;
  --line-soft: #E6E9EE;
  --fg: #0F1319;
  --prose: #262C35;
  --fg-2: #3F4753;
  --fg-3: #6B7481;
  --metro-fg: #0C7266;
  --net-fg: #98356C;
}

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

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--fg);
  font-family: var(--sans);
  font-size: 18px;
  line-height: 1.78;
  -webkit-font-smoothing: antialiased;
}

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

a { color: inherit; }

:focus-visible { outline: 2px solid var(--metro-fg); outline-offset: 3px; }

.skip { position: absolute; left: -9999px; }
.skip:focus {
  left: 1rem; top: 1rem; z-index: 50;
  background: var(--bg-2); padding: 0.6rem 1rem;
  font-family: var(--mono); font-size: 0.8rem;
}

/* ---------------------------------------------------------------- top bar */
.topbar {
  position: sticky; top: 0; z-index: 30;
  background: var(--bg);
  border-bottom: 1px solid var(--line-soft);
}

.bar { display: flex; align-items: center; gap: 1.5rem; height: 64px; }

.mark {
  display: flex; align-items: center; gap: 0.6rem;
  font-family: var(--mono); font-size: 0.88rem; font-weight: 500;
  text-decoration: none; letter-spacing: -0.01em;
}

.mark-glyph {
  width: 10px; height: 10px; flex: none;
  border: 1.5px solid var(--metro-fg); border-radius: 50%;
}

.mark-name { white-space: nowrap; }

.navlinks {
  display: flex; gap: 1.4rem; margin-left: auto;
  font-family: var(--mono); font-size: 0.84rem;
}

.navlinks a {
  color: var(--fg-3); text-decoration: none;
  padding-bottom: 3px; border-bottom: 1px solid transparent;
  transition: color 0.15s ease, border-color 0.15s ease;
}
.navlinks a:hover { color: var(--fg); }
.navlinks a.on { color: var(--fg); border-bottom-color: var(--metro-fg); }

.theme-btn {
  font-family: var(--mono); font-size: 0.75rem;
  color: var(--fg-3); background: transparent;
  border: 1px solid var(--line); border-radius: 4px;
  padding: 0.3rem 0.6rem; cursor: pointer;
}
.theme-btn:hover { color: var(--fg); border-color: var(--fg-3); }

/* ---------------------------------------------------------------- page intro */
main { padding-bottom: 4rem; }

.page-intro {
  padding: 4.5rem 0 3.5rem;
  max-width: 34em;
  animation: rise 0.5s ease-out both;
}

.eyebrow {
  font-family: var(--mono); font-size: 0.74rem;
  letter-spacing: 0.16em; text-transform: uppercase;
  color: var(--fg-3); margin-bottom: 1.1rem;
}

.page-intro h1 {
  font-family: var(--mono);
  font-size: clamp(1.6rem, 3.2vw, 2.35rem);
  font-weight: 500; line-height: 1.25; letter-spacing: -0.035em;
  margin-bottom: 1.2rem;
}

.lede { color: var(--prose); font-size: 1.1rem; max-width: 34em; }

/* pages with no sidebar element beside the intro run it full width */
.page-intro.intro-wide, .page-intro.intro-wide .lede { max-width: none; }

.lede, .prose p, .thrust p, ul.news .what {
  text-align: left;
  -webkit-hyphens: none; hyphens: none;
}

/* ---------------------------------------------------------------- sections */
section, article { margin-bottom: 4.75rem; }
section:last-child, article:last-child { margin-bottom: 0; }

h2.sechead {
  font-family: var(--mono); font-size: 0.88rem; font-weight: 500;
  letter-spacing: 0.1em; text-transform: uppercase;
  color: var(--fg); margin-bottom: 1.3rem;
  padding-bottom: 0.7rem; border-bottom: 1px solid var(--line);
}

.prose h2.sechead { margin-top: 3rem; }
.prose h2.sechead:first-child { margin-top: 0; }

.sechint { font-family: var(--mono); font-size: 0.83rem; color: var(--fg-3); }

.cols { display: grid; grid-template-columns: 1.55fr 1fr; gap: 3.5rem; }
.cols > * { min-width: 0; }

.prose { max-width: 34em; }
.prose p { color: var(--prose); margin-bottom: 1.2rem; }
.prose p:last-child { margin-bottom: 0; }
.prose.small { font-size: 0.9rem; }
.prose a, .lede a { text-decoration-color: var(--metro-fg); }

.sublabel {
  font-family: var(--mono); font-size: 0.72rem;
  letter-spacing: 0.12em; text-transform: uppercase;
  color: var(--fg-3); margin: 2rem 0 0.7rem;
}
.side .sublabel:first-child { margin-top: 0; }

.intro-row {
  display: grid; grid-template-columns: 1.55fr 1fr;
  gap: 3.5rem; align-items: start;
  padding: 4.5rem 0 3.5rem;
}
.intro-row .page-intro { padding: 0; min-width: 0; }

.portrait {
  display: block; margin: 0;
  width: 200px; max-width: 100%; aspect-ratio: 200 / 270; height: auto;
  object-fit: cover; object-position: 50% 34%;
  border-radius: 50%;
  border: 1px solid var(--line);
  animation: rise 0.5s ease-out 0.1s both;
}

/* ---------------------------------------------------------------- data lists */
.facts { font-family: var(--mono); font-size: 0.86rem; border-top: 1px solid var(--line-soft); }
.facts dt { color: var(--fg-3); padding-top: 0.7rem; }
.facts dd { color: var(--fg); padding-bottom: 0.7rem; border-bottom: 1px solid var(--line-soft); }

ul.plain, ul.linklist, ul.news { list-style: none; }

ul.plain .what { min-width: 0; }

ul.plain li {
  display: grid; grid-template-columns: 78px 1fr; gap: 1.1rem;
  padding: 0.8rem 0; border-bottom: 1px solid var(--line-soft);
  font-size: 1rem; color: var(--prose); align-items: baseline;
}

.when {
  font-family: var(--mono); font-size: 0.82rem; color: var(--fg-3);
  font-variant-numeric: tabular-nums;
}

ul.linklist li {
  padding: 0.6rem 0; border-bottom: 1px solid var(--line-soft);
  font-family: var(--mono); font-size: 0.88rem;
}
ul.linklist a { color: var(--fg); text-decoration-color: var(--metro-fg); }

ul.news { border-top: 1px solid var(--line-soft); }
ul.news li {
  display: grid; grid-template-columns: 100px 1fr; gap: 1.5rem;
  padding: 0.95rem 0; border-bottom: 1px solid var(--line-soft);
  align-items: baseline;
}
ul.news .what { font-size: 1rem; color: var(--prose); min-width: 0; }

/* ---------------------------------------------------------------- thrusts */
.thrust > * { min-width: 0; }
.thrust-body { max-width: none; }

/* prose flows across two columns so it fills the width without the lines
   getting too long to read comfortably */
.thrust-text {
  columns: 18em 2;
  -webkit-column-gap: 3.5rem; column-gap: 3.5rem;
  orphans: 2; widows: 2;
  margin-bottom: 0.4rem;
}
.thrust-text p { margin-bottom: 1rem; }
.thrust-text p:last-child { margin-bottom: 0; }

.explorer .prose { max-width: none; }

/* Figure plate: the diagrams are drawn on white, so give them a deliberate
   white card rather than letting them glow against the dark page. */
.plate { margin-top: 2rem; }

.plate a {
  display: block; background: #ffffff;
  border: 1px solid var(--line); border-radius: 4px;
  padding: 1rem; transition: border-color 0.15s ease;
}
.plate a:hover { border-color: var(--metro-fg); }
.t-net .plate a:hover { border-color: var(--net-fg); }

.plate img { width: 100%; height: auto; display: block; }

.plate figcaption {
  font-family: var(--mono); font-size: 0.8rem; line-height: 1.7;
  color: var(--fg-2); margin-top: 0.9rem; max-width: none;
}

.figslot {
  aspect-ratio: 4 / 3; min-height: 150px;
  display: flex; align-items: center; justify-content: center;
  text-align: center; padding: 0.5rem;
  border: 1px dashed var(--line); border-radius: 3px; background: var(--bg-2);
  font-family: var(--mono); font-size: 0.7rem; color: var(--fg-3);
}

.tag {
  font-family: var(--mono); font-size: 0.72rem;
  letter-spacing: 0.1em; text-transform: uppercase; margin-bottom: 0.5rem;
}
.t-metro .tag { color: var(--metro-fg); }
.t-net .tag { color: var(--net-fg); }

.thrust h2 {
  font-family: var(--mono); font-size: 1.15rem; font-weight: 500;
  letter-spacing: -0.02em; margin-bottom: 0.9rem;
}

.thrust p { color: var(--prose); font-size: 1.02rem; margin-bottom: 1rem; }

.refs { display: flex; flex-wrap: wrap; gap: 1rem; }
.refs a, .plinks a {
  font-family: var(--mono); font-size: 0.78rem; color: var(--fg-3);
  text-decoration: none; border-bottom: 1px solid var(--line);
}
.refs a:hover, .plinks a:hover { color: var(--fg); border-bottom-color: var(--fg-3); }

/* ---------------------------------------------------------------- explorer */
.explorer { border: 1px solid var(--line); border-radius: 4px; padding: 1.75rem; }

.ctrls {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1.5rem; margin: 1.5rem 0 1.25rem;
}

.ctrl { display: flex; align-items: center; gap: 0.75rem; }
.ctrl label { font-family: var(--mono); font-size: 0.76rem; color: var(--fg-3); white-space: nowrap; }
.ctrl input[type='range'] { flex: 1; accent-color: var(--metro-fg); min-width: 0; }
.ctrl output {
  font-family: var(--mono); font-size: 0.78rem; color: var(--fg);
  min-width: 2.6em; text-align: right; font-variant-numeric: tabular-nums;
}

.readout { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 1px; background: var(--line-soft); }
.stat { background: var(--bg); padding: 0.8rem 1rem; }
.skey { font-family: var(--mono); font-size: 0.7rem; letter-spacing: 0.08em; text-transform: uppercase; color: var(--fg-3); }
.sval { font-family: var(--mono); font-size: 1.25rem; font-variant-numeric: tabular-nums; }

#plot { width: 100%; height: auto; margin-top: 1.5rem; }
#plot .cv-prod { fill: none; stroke: var(--fg-3); stroke-width: 2; stroke-dasharray: 5 4; }
#plot .cv-ghz { fill: none; stroke: var(--metro-fg); stroke-width: 2.4; }
#plot .pt-prod { fill: var(--fg-3); }
#plot .pt-ghz { fill: var(--metro-fg); }
#plot .lbl { font-family: var(--mono); font-size: 11px; fill: var(--fg-3); }
#plot .lbl.hlt { fill: var(--metro-fg); }
#plot .gl { stroke: var(--line-soft); stroke-width: 1; }

.fignote { font-family: var(--mono); font-size: 0.79rem; line-height: 1.7; color: var(--fg-3); margin-top: 1.1rem; max-width: none; }

/* ---------------------------------------------------------------- filters */
.filters { display: flex; flex-wrap: wrap; gap: 0.5rem; margin-bottom: 1rem; }

.chip {
  font-family: var(--mono); font-size: 0.8rem; color: var(--fg-3);
  background: transparent; border: 1px solid var(--line); border-radius: 4px;
  padding: 0.35rem 0.75rem; cursor: pointer;
  transition: color 0.15s ease, border-color 0.15s ease;
}
.chip:hover { color: var(--fg); border-color: var(--fg-3); }
.chip.on { color: var(--bg); background: var(--metro-fg); border-color: var(--metro-fg); }

/* ---------------------------------------------------------------- pubs */
.pubs { list-style: none; counter-reset: pub; border-top: 1px solid var(--line); margin-bottom: 1.5rem; }

.pubs li {
  counter-increment: pub; position: relative;
  padding: 1.6rem 0 1.6rem 3.4rem;
  border-bottom: 1px solid var(--line-soft);
}
.pubs li[hidden] { display: none; }

.pubs li::before {
  content: counter(pub, decimal-leading-zero);
  position: absolute; left: 0; top: 1.75rem;
  font-family: var(--mono); font-size: 0.78rem; color: var(--fg-3);
  font-variant-numeric: tabular-nums;
}

.ptitle {
  font-family: var(--mono); font-size: 1.05rem; font-weight: 500;
  line-height: 1.45; letter-spacing: -0.015em; margin-bottom: 0.35rem;
}

.pauth { font-size: 0.98rem; color: var(--prose); margin-bottom: 0.4rem; }
.pauth .me { color: var(--fg); font-weight: 500; box-shadow: inset 0 -2px 0 var(--metro-fg); }

.pmeta {
  font-family: var(--mono); font-size: 0.82rem; color: var(--fg-3);
  display: flex; flex-wrap: wrap; align-items: center; gap: 0.6rem;
  margin-bottom: 0.5rem;
}

.badge {
  font-size: 0.68rem; letter-spacing: 0.06em; text-transform: uppercase;
  padding: 0.12rem 0.45rem; border-radius: 3px;
  border: 1px solid var(--line); color: var(--fg-2); background: var(--bg-2);
}
.badge.ok { color: var(--metro-fg); border-color: var(--metro-fg); background: transparent; }
.badge.wip { color: var(--net-fg); border-color: var(--net-fg); background: transparent; }

/* ---------------------------------------------------------------- skills */
.skillgrid {
  display: grid; grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px; background: var(--line-soft); border: 1px solid var(--line-soft);
}
.skillcard { background: var(--bg); padding: 1.5rem 1.6rem; }
.sklabel {
  font-family: var(--mono); font-size: 0.72rem;
  letter-spacing: 0.12em; text-transform: uppercase;
  color: var(--net-fg); margin-bottom: 0.6rem;
}
.skitems { font-size: 1.02rem; line-height: 1.85; color: var(--prose); }

/* ---------------------------------------------------------------- buttons */
.btn {
  display: inline-block; font-family: var(--mono); font-size: 0.8rem;
  text-decoration: none; color: var(--fg-2);
  border: 1px solid var(--line); border-radius: 4px; padding: 0.5rem 0.9rem;
  transition: all 0.15s ease;
}
.btn:hover { color: var(--fg); border-color: var(--fg-3); background: var(--bg-2); }
.btn.primary { color: var(--bg); background: var(--metro-fg); border-color: var(--metro-fg); font-weight: 500; }
.btn.primary:hover { color: var(--bg); filter: brightness(1.08); }

.cta { border-top: 1px solid var(--line); padding-top: 1.75rem; }
.cta p { margin-bottom: 1rem; }

/* ---------------------------------------------------------------- footer */
.sitefoot {
  border-top: 1px solid var(--line); padding: 1.6rem 0 3rem;
  font-family: var(--mono); font-size: 0.78rem; color: var(--fg-3);
}
.footrow { display: flex; justify-content: space-between; gap: 1rem; flex-wrap: wrap; }
.footrow a { color: var(--fg-3); }

/* ---------------------------------------------------------------- motion */
@keyframes rise { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { animation: none !important; transition: none !important; }
}

/* ---------------------------------------------------------------- responsive */
@media (max-width: 860px) {
  :root { --gutter: 1.25rem; }
  body { font-size: 16px; }
  .bar { height: auto; padding: 0.9rem 0; flex-wrap: wrap; gap: 0.75rem; }
  .navlinks { margin-left: 0; width: 100%; order: 3; gap: 1.1rem; flex-wrap: wrap; }
  .theme-btn { margin-left: auto; }
  .page-intro { padding: 2.5rem 0 2.5rem; }
  .cols { grid-template-columns: 1fr; gap: 2.5rem; }
  .intro-row {
    grid-template-columns: 1fr !important;
    gap: 1.5rem !important;
    padding: 2.5rem 0 !important;
  }
  .portrait { width: 132px !important; }
  .plate a { padding: 0.5rem; }
  .thrust-text { columns: 1 !important; }
  .skillgrid { grid-template-columns: 1fr; }
  .readout { grid-template-columns: 1fr; }
  .explorer { padding: 1.25rem; }
  ul.news li { grid-template-columns: 1fr; gap: 0.2rem; }
  ul.plain li { grid-template-columns: 66px 1fr; gap: 0.75rem; }
  section, article { margin-bottom: 3rem; }
}