/* =====================================================================
   Inertia-1 project page
   Light, energetic "sport science" theme.
   Palette: orange (primary) / grass-green / sky-blue on a light base.
   ===================================================================== */

:root {
  --orange: #df8a52;
  --orange-dark: #c4713a;
  --green: #5fa074;
  --green-bright: #74b389;
  --blue: #5c9cbd;
  --blue-bright: #79b1cd;
  --violet: #8f86b3;

  --ink: #2b3744;
  --ink-soft: #54616f;
  --muted: #84919e;
  --line: #e7e9ee;

  --bg: #f4f5f7;
  --bg-alt: #ecedf1;
  --surface: #fbfbfc;
  --dark: #34414f;

  --grad-o: linear-gradient(120deg, #e7a87a 0%, #c4713a 100%);
  --grad-g: linear-gradient(120deg, #8cc09e 0%, #4f8a63 100%);
  --grad-b: linear-gradient(120deg, #8bbad2 0%, #4a7e9c 100%);
  --grad: var(--grad-o);
  --grad-soft: linear-gradient(120deg, rgba(223,138,82,.10), rgba(196,113,58,.08));

  --shadow-sm: 0 2px 8px rgba(43, 55, 68, .05);
  --shadow: 0 10px 28px rgba(43, 55, 68, .07);
  --shadow-lg: 0 20px 50px rgba(43, 55, 68, .10);

  --radius: 18px;
  --radius-sm: 12px;
  --maxw: 1080px;
}

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

html { scroll-behavior: smooth; scroll-padding-top: 84px; font-size: 17px; }

body {
  font-family: "Inter", system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

h1, h2, h3, h4, .display {
  font-family: "Space Grotesk", "Inter", system-ui, sans-serif;
  letter-spacing: -0.01em;
  line-height: 1.15;
}

a { color: var(--orange-dark); text-decoration: none; }
a:hover { text-decoration: underline; }
img, svg, video { max-width: 100%; display: block; }

::selection { background: rgba(223, 138, 82, .20); }
::-webkit-scrollbar { width: 10px; height: 10px; }
::-webkit-scrollbar-thumb { background: #c8d2df; border-radius: 6px; }
::-webkit-scrollbar-thumb:hover { background: #aab8c8; }

.wrap { width: min(var(--maxw), 92vw); margin: 0 auto; }

.grad-text {
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
}

/* ===================== Navbar ===================== */
.nav {
  position: fixed; inset: 0 0 auto 0; z-index: 1000;
  height: 64px;
  background: rgba(246, 248, 251, .82);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--line);
}
.nav-inner {
  width: min(var(--maxw), 92vw); margin: 0 auto; height: 100%;
  display: flex; align-items: center; justify-content: space-between;
}
.brand { display: flex; align-items: center; gap: .55rem; font-family: "Space Grotesk", sans-serif; font-weight: 700; font-size: 1.15rem; color: var(--ink); }
.brand:hover { text-decoration: none; }
.brand .mark {
  width: 26px; height: 26px; border-radius: 8px; background: var(--grad);
  box-shadow: 0 3px 10px rgba(223,138,82,.25);
}
.brand .v { font-weight: 500; color: var(--muted); font-size: .8rem; padding: 2px 7px; border: 1px solid var(--line); border-radius: 999px; }

.nav-links { display: flex; align-items: center; gap: .25rem; list-style: none; }
.nav-links a {
  color: var(--ink-soft); font-weight: 500; font-size: .92rem;
  padding: .45rem .8rem; border-radius: 9px; transition: color .18s, background .18s;
}
.nav-links a:hover { color: var(--ink); background: rgba(43,55,68,.05); text-decoration: none; }
.nav-links a.active { color: var(--orange-dark); background: rgba(223,138,82,.14); }
.nav-links .ghub { display: inline-flex; align-items: center; gap: .35rem; }
.nav-links .ghub i { font-size: 1.05rem; }

.nav-toggle { display: none; background: none; border: none; font-size: 1.3rem; color: var(--ink); cursor: pointer; }

@media (max-width: 820px) {
  .nav-toggle { display: block; }
  .nav-links {
    position: absolute; top: 64px; left: 0; right: 0;
    flex-direction: column; align-items: stretch; gap: 0;
    background: rgba(246,248,251,.98); border-bottom: 1px solid var(--line);
    padding: .5rem .8rem 1rem; display: none;
  }
  .nav-links.open { display: flex; }
  .nav-links a { padding: .7rem .6rem; border-radius: 8px; }
}

/* ===================== Hero ===================== */
.hero {
  position: relative; padding: 116px 0 56px; overflow: hidden;
  background:
    radial-gradient(60% 80% at 85% -10%, rgba(92,156,189,.10), transparent 60%),
    radial-gradient(55% 70% at 8% 0%, rgba(223,138,82,.10), transparent 60%),
    linear-gradient(180deg, #fff 0%, var(--bg) 100%);
}
.hero::after {
  content: ""; position: absolute; left: 0; right: 0; bottom: -1px; height: 6px; background: var(--grad);
}
.hero-lines { position: absolute; inset: 0; opacity: .5; pointer-events: none; }
.eyebrow {
  display: inline-flex; align-items: center; gap: .5rem;
  font-family: "Space Grotesk", sans-serif; font-weight: 500; font-size: .8rem;
  text-transform: uppercase; letter-spacing: .14em;
  color: var(--ink-soft); background: var(--surface);
  border: 1px solid var(--line); border-radius: 999px; padding: .4rem .85rem;
  box-shadow: var(--shadow-sm);
}
.eyebrow .dot { width: 8px; height: 8px; border-radius: 50%; background: var(--grad); }
.hero h1 {
  font-size: clamp(2.1rem, 5.4vw, 3.5rem);
  font-weight: 700; margin: 1.1rem 0 .4rem; max-width: 16ch;
}
.hero .tagline { font-size: clamp(1.02rem, 2.2vw, 1.25rem); color: var(--ink-soft); max-width: 60ch; }

.authors { margin: 1.5rem 0 .35rem; line-height: 1.9; font-size: 1.02rem; }
.authors a, .authors span { color: var(--ink); font-weight: 600; }
.authors a:hover { color: var(--orange-dark); }
.authors sup { color: var(--orange-dark); font-weight: 700; }
.affil { color: var(--muted); font-size: .92rem; }
.affil .corr { color: var(--ink-soft); }

.btns { display: flex; flex-wrap: wrap; gap: .65rem; margin-top: 1.6rem; }
.btn {
  display: inline-flex; align-items: center; gap: .5rem;
  font-weight: 600; font-size: .92rem; padding: .62rem 1.15rem; border-radius: 999px;
  border: 1px solid var(--dark); color: #fff; background: var(--dark);
  transition: transform .15s, box-shadow .15s, opacity .15s;
}
.btn:hover { transform: translateY(-2px); box-shadow: var(--shadow); text-decoration: none; }
.btn.primary { background: var(--orange); border-color: var(--orange); box-shadow: 0 8px 20px rgba(223,138,82,.22); }
.btn.outline { background: var(--surface); color: var(--ink); border-color: var(--line); }
.btn.disabled { opacity: .5; pointer-events: none; }
.btn .tag { font-size: .68rem; font-weight: 700; padding: .05rem .4rem; border-radius: 6px; background: rgba(255,255,255,.22); }
.btn.outline .tag { background: var(--bg-alt); color: var(--muted); }

/* ===================== Stat band ===================== */
.stats {
  background: var(--dark); color: #fff; padding: 2.1rem 0;
}
.stats-grid {
  display: grid; grid-template-columns: repeat(6, 1fr); gap: 1rem; text-align: center;
}
.stat .num { font-family: "Space Grotesk", sans-serif; font-weight: 700; font-size: clamp(1.4rem, 3.4vw, 2.1rem); }
.stat .num.o { color: var(--orange); }
.stat .num.g { color: var(--green-bright); }
.stat .num.b { color: var(--blue-bright); }
.stat .lab { font-size: .76rem; color: #b9c4d2; text-transform: uppercase; letter-spacing: .08em; margin-top: .25rem; }
@media (max-width: 720px) { .stats-grid { grid-template-columns: repeat(3, 1fr); row-gap: 1.5rem; } }

/* ===================== Sections ===================== */
.section { padding: 76px 0; }
.section.alt { background: var(--bg-alt); }
.section-head { max-width: 760px; margin-bottom: 2rem; }
.kicker {
  font-family: "Space Grotesk", sans-serif; font-weight: 600; font-size: .82rem;
  letter-spacing: .12em; text-transform: uppercase; color: var(--orange-dark);
  display: inline-flex; align-items: center; gap: .5rem;
}
.kicker::before { content: ""; width: 26px; height: 3px; border-radius: 2px; background: var(--grad); display: inline-block; }
.section-head h2 { font-size: clamp(1.7rem, 3.6vw, 2.4rem); font-weight: 700; margin: .6rem 0 .5rem; }
.section-head p { color: var(--ink-soft); font-size: 1.05rem; }

.lead { color: var(--ink-soft); font-size: 1.08rem; max-width: 72ch; }
.lead + .lead { margin-top: 1rem; }
.lead strong, p strong { color: var(--ink); }

/* Card primitives */
.card {
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 1.5rem 1.6rem; box-shadow: var(--shadow-sm);
}
.prose { color: var(--ink-soft); }
.prose p + p { margin-top: .9rem; }

/* News */
.news { display: flex; flex-direction: column; gap: 0; margin-top: 1.6rem; }
.news .row { display: flex; gap: 1rem; align-items: baseline; padding: .7rem 0; border-bottom: 1px dashed var(--line); }
.news .row:last-child { border-bottom: none; }
.news .date {
  font-family: "Space Grotesk", sans-serif; font-weight: 600; font-size: .82rem; color: #fff;
  background: var(--dark); border-radius: 999px; padding: .15rem .6rem; white-space: nowrap;
}
.news .what { color: var(--ink-soft); }

/* ===================== Pillars ===================== */
.pillars { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1rem; margin-top: 1.6rem; }
@media (max-width: 860px) { .pillars { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 520px) { .pillars { grid-template-columns: 1fr; } }
.pillar {
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 1.4rem; box-shadow: var(--shadow-sm); position: relative; overflow: hidden;
  transition: transform .18s, box-shadow .18s;
}
.pillar:hover { transform: translateY(-3px); box-shadow: var(--shadow); }
.pillar::before { content: ""; position: absolute; top: 0; left: 0; right: 0; height: 4px; background: var(--accent, var(--grad)); }
.pillar .idx { font-family: "Space Grotesk", sans-serif; font-weight: 700; font-size: 1.1rem; color: #fff; width: 34px; height: 34px; border-radius: 10px; display: grid; place-items: center; background: var(--accent, var(--orange)); }
.pillar h3 { font-size: 1.08rem; margin: .8rem 0 .35rem; }
.pillar p { color: var(--ink-soft); font-size: .95rem; }
.pillar.o { --accent: var(--grad-o); }
.pillar.g { --accent: var(--grad-g); }
.pillar.b { --accent: var(--grad-b); }
.pillar.mix { --accent: var(--grad-o); }

/* ===================== Method groups ===================== */
.subhead { font-size: 1.18rem; font-weight: 700; margin: 2.4rem 0 1rem; display: flex; align-items: center; gap: .6rem; }
.subhead .bar { width: 6px; height: 22px; border-radius: 3px; background: var(--grad); }

.methods { display: grid; grid-template-columns: repeat(2, 1fr); gap: 1rem; }
@media (max-width: 760px) { .methods { grid-template-columns: 1fr; } }
.method {
  border: 1px solid var(--line); border-left: 4px solid var(--accent, var(--orange));
  border-radius: var(--radius-sm); padding: 1.05rem 1.2rem; background: var(--surface);
}
.method.o { --accent: var(--orange); }
.method.g { --accent: var(--green); }
.method.b { --accent: var(--blue); }
.method.k { --accent: var(--violet); }
.method.n { --accent: var(--ink-soft); }
.method h4 { font-size: 1rem; margin-bottom: .15rem; }
.method .ms { color: var(--muted); font-size: .9rem; margin-bottom: .55rem; }
.method p { color: var(--ink-soft); font-size: .92rem; margin-bottom: .6rem; }
.pills { display: flex; flex-wrap: wrap; gap: .4rem; }
.pill {
  font-family: "Space Grotesk", sans-serif; font-weight: 500; font-size: .8rem;
  padding: .2rem .65rem; border-radius: 999px; background: var(--bg-alt); color: var(--ink-soft);
  border: 1px solid var(--line);
}
.pill.o { background: rgba(223,138,82,.12); color: var(--orange-dark); border-color: rgba(223,138,82,.28); }
.pill.g { background: rgba(116,179,137,.16); color: var(--green); border-color: rgba(116,179,137,.32); }
.pill.b { background: rgba(92,156,189,.16); color: #4a7e9c; border-color: rgba(92,156,189,.32); }

/* ===================== Task / dataset cards ===================== */
.tasks { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1rem; }
@media (max-width: 760px) { .tasks { grid-template-columns: 1fr; } }
.task { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 1.3rem 1.4rem; box-shadow: var(--shadow-sm); }
.task .top { display: flex; align-items: center; justify-content: space-between; }
.task .ic { width: 40px; height: 40px; border-radius: 11px; display: grid; place-items: center; color: #fff; font-size: 1.1rem; background: var(--accent, var(--orange)); }
.task.o { --accent: var(--orange); } .task.g { --accent: var(--green); } .task.b { --accent: var(--blue); }
.task .count { font-family: "Space Grotesk", sans-serif; font-weight: 700; font-size: 1.7rem; color: var(--ink); }
.task h4 { margin: .7rem 0 .3rem; font-size: 1.08rem; }
.task p { color: var(--ink-soft); font-size: .93rem; }
.task .sets { margin-top: .7rem; }

/* ===================== Coverage axes ===================== */
.axes { display: grid; grid-template-columns: repeat(4, 1fr); gap: .8rem; margin-top: 1.4rem; }
@media (max-width: 860px) { .axes { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 480px) { .axes { grid-template-columns: 1fr; } }
.axis { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius-sm); padding: 1rem 1.1rem; }
.axis .name { font-family: "Space Grotesk", sans-serif; font-weight: 600; font-size: .82rem; text-transform: uppercase; letter-spacing: .07em; color: var(--muted); margin-bottom: .55rem; }
.axis .vals { display: flex; flex-wrap: wrap; gap: .35rem; }
.axes-layout { display: grid; grid-template-columns: 1.5fr 1fr; gap: 1.6rem; align-items: start; margin-top: 1.4rem; }
.axes-layout .axes { grid-template-columns: repeat(2, 1fr); margin-top: 0; }
.axes-layout .figure { margin-top: 0; }
@media (max-width: 860px) {
  .axes-layout { grid-template-columns: 1fr; }
  .axes-layout .figure { max-width: 460px; }
}
@media (max-width: 480px) { .axes-layout .axes { grid-template-columns: 1fr; } }

/* ===================== Callout ===================== */
.callout {
  margin-top: 1.8rem; border-radius: var(--radius);
  background: var(--dark); color: #eaf0f7; padding: 1.5rem 1.7rem;
  display: grid; grid-template-columns: auto 1fr; gap: 1.2rem; align-items: center;
}
.callout .badge { font-family: "Space Grotesk", sans-serif; font-weight: 700; font-size: .8rem; letter-spacing: .1em; text-transform: uppercase; color: var(--ink); background: var(--grad); padding: .5rem .8rem; border-radius: 10px; }
.callout .chips { display: flex; flex-wrap: wrap; gap: .5rem; }
.callout .chip { font-family: "Space Grotesk", sans-serif; font-weight: 500; font-size: .85rem; padding: .3rem .7rem; border-radius: 999px; border: 1px solid rgba(255,255,255,.18); color: #fff; }
.callout .chip b { color: var(--orange); }
@media (max-width: 620px) { .callout { grid-template-columns: 1fr; } }

/* ===================== Findings ===================== */
.takeaways { display: grid; grid-template-columns: repeat(2, 1fr); gap: 1rem; margin-top: 1.6rem; }
@media (max-width: 760px) { .takeaways { grid-template-columns: 1fr; } }
.takeaway { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 1.3rem 1.4rem; box-shadow: var(--shadow-sm); display: grid; grid-template-columns: auto 1fr; gap: 1rem; }
.takeaway:last-child { grid-column: 1 / -1; }
.takeaway .n { font-family: "Space Grotesk", sans-serif; font-weight: 700; font-size: 1.3rem; color: var(--accent, var(--orange)); line-height: 1; }
.takeaway h4 { font-size: 1.04rem; margin-bottom: .3rem; }
.takeaway p { color: var(--ink-soft); font-size: .94rem; }
.takeaway:nth-child(1) { --accent: var(--orange); }
.takeaway:nth-child(2) { --accent: var(--green); }
.takeaway:nth-child(3) { --accent: var(--blue); }
.takeaway:nth-child(4) { --accent: var(--orange-dark); }
.takeaway:nth-child(5) { --accent: var(--violet); }

/* Finding block (text + figure) */
.finding { margin-top: 2.6rem; }
.finding .tagrow { display: flex; align-items: center; gap: .7rem; margin-bottom: .6rem; }
.finding .secnum { font-family: "Space Grotesk", sans-serif; font-weight: 700; font-size: .85rem; color: #fff; background: var(--dark); border-radius: 8px; padding: .2rem .55rem; }
.finding h3 { font-size: 1.3rem; }
.finding .prose { max-width: 74ch; }

.metrics { display: flex; flex-wrap: wrap; gap: .8rem; margin: 1rem 0 .2rem; }
.metric { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius-sm); padding: .7rem 1rem; box-shadow: var(--shadow-sm); }
.metric .mv { font-family: "Space Grotesk", sans-serif; font-weight: 700; font-size: 1.15rem; }
.metric .ml { font-size: .78rem; color: var(--muted); text-transform: uppercase; letter-spacing: .06em; }
.metric.o .mv { color: var(--orange-dark); } .metric.g .mv { color: var(--green); } .metric.b .mv { color: var(--blue); }

/* ===================== Figures ===================== */
.figure { margin: 1.4rem 0 0; }
.figure .frame {
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
  padding: .6rem; box-shadow: var(--shadow-sm); overflow: hidden;
}
.figure .frame img, .figure .frame video { width: 100%; border-radius: 12px; display: block; }
.figure figcaption { color: var(--muted); font-size: .9rem; margin-top: .7rem; }
.figure figcaption b { color: var(--ink-soft); }
.figure.shrink { max-width: 75%; margin-left: auto; margin-right: auto; }
@media (max-width: 760px) { .figure.shrink { max-width: 100%; } }
.figs-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 1.2rem; align-items: start; }
.figs-row { display: flex; flex-wrap: wrap; align-items: flex-start; justify-content: center; gap: 1.2rem; margin-top: 1.4rem; }
.figs-row .figure { margin: 0; display: table; }
.figs-row .figure .frame img { height: 300px; width: auto; max-width: 100%; }
.figs-row .figure figcaption { display: table-caption; caption-side: bottom; }
@media (max-width: 760px) {
  .figs-2 { grid-template-columns: 1fr; }
  .figs-row { flex-direction: column; align-items: center; }
  .figs-row .figure { display: block; width: 100%; }
  .figs-row .figure .frame img { height: auto; width: 100%; }
}

/* Teaser */
.teaser { margin-top: 2.2rem; }

/* ===================== Paper / BibTeX ===================== */
.bibtex {
  background: var(--dark); color: #e7edf5; border-radius: var(--radius);
  padding: 1.3rem 1.5rem; overflow-x: auto; font-size: .86rem; line-height: 1.65;
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  box-shadow: var(--shadow);
}
.bibtex .k { color: var(--orange); }
.ack { color: var(--muted); font-size: .92rem; margin-top: 1.2rem; }

/* ===================== Footer ===================== */
.footer { background: var(--dark); color: #aeb9c7; padding: 2.2rem 0; }
.footer .row { display: flex; align-items: center; justify-content: space-between; gap: 1rem; flex-wrap: wrap; }
.footer .brand2 { display: flex; align-items: center; gap: .5rem; color: #fff; font-family: "Space Grotesk", sans-serif; font-weight: 700; }
.footer .brand2 .mark { width: 22px; height: 22px; border-radius: 7px; background: var(--grad); }
.footer a { color: #cdd6e2; }
.footer .icons { display: flex; gap: .9rem; font-size: 1.15rem; }
.footer .fine { font-size: .82rem; margin-top: .8rem; color: #8190a1; }

/* reveal on scroll */
.reveal { opacity: 0; transform: translateY(16px); transition: opacity .5s ease, transform .5s ease; }
.reveal.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) { .reveal { opacity: 1; transform: none; transition: none; } html { scroll-behavior: auto; } }