/* TaoLab V0.1 — foundation stylesheet
   Mobile-first, dependency-free, no animation. */

:root {
  --paper: #f7f5f0;
  --ink: #1d1b16;
  --muted: #6f6a5e;
  --line: #e2ddd0;
  --accent: #3e5c4b;
  --serif: Georgia, "Times New Roman", "Songti SC", "SimSun", serif;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

img,
svg {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: var(--ink);
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

a:hover {
  color: var(--accent);
}

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

::selection {
  background: var(--accent);
  color: var(--paper);
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  z-index: 10;
  background: var(--ink);
  color: var(--paper);
  padding: 0.6rem 1rem;
  text-decoration: none;
}

.skip-link:focus {
  left: 0;
  color: var(--paper);
}

/* Header */

.site-header {
  position: sticky;
  top: 0;
  z-index: 5;
  background: var(--paper);
  border-bottom: 1px solid var(--line);
}

.header-inner {
  max-width: 72rem;
  margin: 0 auto;
  padding: 0.85rem 1.25rem;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem 1rem;
}

.brand {
  font-family: var(--serif);
  font-weight: 700;
  font-size: 1.3rem;
  line-height: 1.1;
  text-decoration: none;
}

.brand .since {
  display: block;
  font-family: var(--sans);
  font-weight: 400;
  font-size: 0.62rem;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--muted);
  margin-top: 0.15rem;
}

.nav-toggle {
  font: inherit;
  min-height: 44px;
  font-size: 0.78rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink);
  background: none;
  border: 1px solid var(--muted);
  padding: 0.45rem 0.8rem;
  cursor: pointer;
}

.nav-toggle:hover {
  border-color: var(--ink);
}

.site-nav {
  display: none;
  width: 100%;
}

.site-nav.is-open {
  display: block;
}

.nav-list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.nav-list a {
  display: block;
  padding: 0.72rem 0;
  text-decoration: none;
  border-bottom: 1px solid var(--line);
  font-size: 0.82rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.nav-list a:hover {
  color: var(--accent);
}

.nav-list a[aria-current="page"] {
  color: var(--accent);
  font-weight: 600;
}

/* Main */

main {
  max-width: 72rem;
  margin: 0 auto;
  padding: 0 1.25rem 5rem;
}

main:focus {
  outline: none;
}

.hero {
  padding: 3.25rem 0 2.5rem;
}

.kicker {
  margin: 0 0 1rem;
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--muted);
}

h1 {
  margin: 0;
  font-family: var(--serif);
  font-weight: 700;
  font-size: clamp(3rem, 13vw, 6.25rem);
  line-height: 1.02;
  letter-spacing: -0.01em;
}

.hero-tagline {
  margin: 1.25rem 0 0;
  font-family: var(--serif);
  font-style: italic;
  font-size: clamp(1.15rem, 4.5vw, 1.55rem);
}

.lede {
  margin: 1.75rem 0 0;
  max-width: 44rem;
  font-size: clamp(1.05rem, 2.5vw, 1.22rem);
  line-height: 1.7;
}

.page-head {
  padding: 2.5rem 0 1.75rem;
  max-width: 50rem;
}

.page-head h1 {
  font-size: clamp(2.25rem, 7vw, 3.25rem);
  line-height: 1.08;
}

/* Sections */

.section {
  border-top: 1px solid var(--line);
  padding: 2.25rem 0;
}

.section-label {
  display: block;
  margin: 0 0 0.65rem;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--muted);
}

h2 {
  margin: 0 0 1.1rem;
  font-family: var(--serif);
  font-weight: 700;
  font-size: clamp(1.5rem, 3.5vw, 1.95rem);
  line-height: 1.2;
}

.grid {
  display: grid;
  gap: 1.9rem 2.75rem;
}

.item {
  border-top: 1px solid var(--line);
  padding-top: 1rem;
}

.item h3 {
  margin: 0 0 0.5rem;
  font-family: var(--sans);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent);
}

.item p {
  margin: 0;
  max-width: 34rem;
}

ol.principles {
  list-style: none;
  margin: 0;
  padding: 0;
  counter-reset: principle;
}

ol.principles li {
  position: relative;
  counter-increment: principle;
  padding: 0 0 1.25rem 2.4rem;
  max-width: 42rem;
}

ol.principles li::before {
  content: counter(principle);
  position: absolute;
  left: 0;
  top: 0.05rem;
  font-family: var(--serif);
  font-style: italic;
  font-size: 1.05rem;
  color: var(--accent);
}

ol.principles strong {
  font-weight: 600;
}

.note {
  border-left: 2px solid var(--accent);
  padding: 0.15rem 0 0.15rem 1.1rem;
  color: var(--muted);
  max-width: 44rem;
}

.note p {
  margin: 0;
}

.prose {
  max-width: 46rem;
}

.prose p {
  margin: 0 0 1.1rem;
}

.prose p:last-child {
  margin-bottom: 0;
}

.prose ul {
  margin: 0 0 1.1rem;
  padding-left: 1.1rem;
}

.prose li {
  margin-bottom: 0.5rem;
}

/* Footer */

.site-footer {
  border-top: 1px solid var(--line);
}

.footer-inner {
  max-width: 72rem;
  margin: 0 auto;
  padding: 2.25rem 1.25rem 3rem;
  display: flex;
  flex-direction: column;
  gap: 0.9rem;
}

.footer-brand {
  margin: 0;
  font-family: var(--serif);
  font-weight: 700;
  font-size: 1.05rem;
}

.footer-brand span {
  display: block;
  font-family: var(--sans);
  font-weight: 400;
  font-size: 0.62rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--muted);
  margin-top: 0.1rem;
}

.footer-tagline {
  margin: 0;
  font-family: var(--serif);
  font-style: italic;
  color: var(--muted);
}

.footer-nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.3rem 1.25rem;
}

.footer-nav a {
  font-size: 0.8rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  text-decoration: none;
}

.footer-nav a:hover {
  color: var(--accent);
}

.footer-copy {
  margin: 0;
  font-size: 0.78rem;
  color: var(--muted);
}

/* Tablet and up */

@media (min-width: 760px) {
  .nav-toggle {
    display: none;
  }

  .site-nav {
    display: block;
    width: auto;
  }

  .nav-list {
    display: flex;
    gap: 1.75rem;
    border-top: 0;
  }

  .nav-list a {
    padding: 0.3rem 0;
    border-bottom: 0;
    font-size: 0.78rem;
  }

  .grid.cols-3 {
    grid-template-columns: repeat(3, 1fr);
  }

  .grid.cols-2 {
    grid-template-columns: repeat(2, 1fr);
  }

  .footer-inner {
    flex-direction: row;
    flex-wrap: wrap;
    align-items: baseline;
    justify-content: space-between;
  }
}