:root {
  /* ---- Core five ---------------------------------------- */
  --ruco-yellow: #E8B923;
  --ruco-blue:   #2F80ED;
  --white:       #FFFFFF;
  --mist:        #9AA1AC;
  --graphite:    #1E2228;

  /* ---- Yellow ramp -------------------------------------- */
  --yellow-50:  #FBF4D6;  --yellow-100: #F4E08C;  --yellow-200: #EECB4E;
  --yellow-400: #E8B923;  --yellow-500: #C99D12;  --yellow-600: #9C7A0C;  --yellow-700: #6B5407;

  /* ---- Blue ramp ---------------------------------------- */
  --blue-50:  #EAF1FE;  --blue-100: #C2D9FB;  --blue-200: #86B2F6;
  --blue-400: #2F80ED;  --blue-500: #1C63C9;  --blue-600: #15499A;  --blue-700: #0E3068;

  /* ---- Neutral ramp (white → graphite) ------------------ */
  --grey-0:   #FFFFFF;  --grey-50:  #F2F3F5;  --grey-100: #E2E4E8;  --grey-300: #9AA1AC;
  --grey-500: #6A7280;  --grey-700: #3A4049;  --grey-900: #1E2228;

  /* ---- Semantic aliases --------------------------------- */
  --color-bg:           var(--grey-50);
  --color-surface:      var(--white);
  --color-border:       var(--grey-100);
  --color-text:         var(--graphite);
  --color-text-muted:   var(--grey-500);
  --color-text-subtle:  var(--mist);

  --color-link:         var(--ruco-blue);
  --color-link-hover:   var(--blue-500);

  --color-accent:       var(--ruco-yellow);
  --color-accent-hover: #F4D24E;
  --color-on-accent:    var(--graphite);

  --color-ink:          var(--graphite);
  --color-on-ink:       var(--white);

  /* ---- Radii, shadow, type ------------------------------ */
  --radius-sm: 8px;  --radius-md: 12px;  --radius-lg: 16px;
  --shadow-card: 0 1px 3px rgba(16,24,40,.08);
  --shadow-lift: 0 10px 28px rgba(16,24,40,.16);
  --font-sans: 'Segoe UI', system-ui, -apple-system, Arial, sans-serif;
  --font-mono: ui-monospace, 'SF Mono', Menlo, monospace;
}

*,*::before,*::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 16px; line-height: 1.6;
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
}

h1,h2,h3,h4,h5,h6 {
  margin: 0 0 .5em;
  color: var(--color-text);
  font-weight: 800; letter-spacing: -.02em; line-height: 1.12;
  text-wrap: balance;
}
h1 { font-size: clamp(2rem, 4vw, 2.75rem); }
h2 { font-size: 1.5rem; }
h3 { font-size: 1.25rem; }
p  { margin: 0 0 1em; }
small, .text-muted { color: var(--color-text-muted); }

.eyebrow {
  font-size: .75rem; font-weight: 700;
  letter-spacing: .14em; text-transform: uppercase;
  color: var(--color-link);
}
code, pre, .mono { font-family: var(--font-mono); }

a { color: var(--color-link); text-decoration: none; transition: color .15s; }
a:hover { color: var(--color-link-hover); text-decoration: underline; }
a:focus-visible { outline: 2px solid var(--color-link); outline-offset: 2px; border-radius: 3px; }

/* Surfaces */
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
  padding: 1.75rem;
}
.surface-ink { background: var(--color-ink); color: var(--color-on-ink); }
.surface-ink h1, .surface-ink h2, .surface-ink h3 { color: var(--color-on-ink); }
.surface-ink p { color: var(--mist); }

/* Buttons */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: .5em;
  padding: .875rem 1.625rem;
  border: 1px solid transparent; border-radius: var(--radius-sm);
  font-family: inherit; font-size: .9375rem; font-weight: 700; line-height: 1;
  cursor: pointer; transition: background .15s, border-color .15s, color .15s;
  text-decoration: none;
}
.btn:hover { text-decoration: none; }
.btn-primary   { background: var(--color-accent); color: var(--color-on-accent); }
.btn-primary:hover   { background: var(--color-accent-hover); color: var(--color-on-accent); }
.btn-secondary { background: var(--ruco-blue); color: var(--white); }
.btn-secondary:hover { background: var(--blue-500); color: var(--white); }
.btn-ghost     { background: transparent; border-color: var(--color-border); color: var(--color-text); }
.btn-ghost:hover     { border-color: var(--mist); background: var(--grey-50); }
.btn-ghost-light { background: transparent; border-color: var(--grey-700); color: var(--color-on-ink); }
.btn-ghost-light:hover { background: var(--grey-700); border-color: var(--grey-700); color: var(--color-on-ink); }

/* Forms */
.label {
  display: block; margin-bottom: .375rem;
  font-size: .75rem; font-weight: 600; letter-spacing: .06em;
  text-transform: uppercase; color: var(--grey-500);
}
.input {
  width: 100%; padding: .875rem 1rem; font: inherit;
  color: var(--color-text); background: var(--white);
  border: 1.5px solid var(--color-border); border-radius: var(--radius-sm);
  transition: border-color .2s;
}
.input::placeholder { color: var(--mist); }
.input:focus { outline: none; border-color: var(--ruco-blue); }

/* ---- Layout ------------------------------------------- */
.container {
  width: 100%;
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* Nav */
.site-nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
}
.nav-inner {
  display: flex;
  align-items: center;
  height: 60px;
  gap: 1.5rem;
  position: relative;
}
.nav-brand {
  display: inline-flex;
  align-items: center;
  gap: .5rem;
  font-weight: 700;
  font-size: 1rem;
  color: var(--color-text);
  text-decoration: none;
  flex-shrink: 0;
}
.nav-brand:hover { color: var(--color-link); text-decoration: none; }
.nav-brand img { display: block; }
.nav-links {
  display: flex;
  align-items: center;
  gap: 1.25rem;
  list-style: none;
  margin: 0 0 0 auto;
  padding: 0;
}
.nav-links a { font-size: .9375rem; color: var(--color-text-muted); }
.nav-links a:hover { color: var(--color-link); text-decoration: none; }
.nav-toggle {
  display: none;
  margin-left: auto;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: .5rem;
  width: 36px; height: 36px;
}
.nav-toggle span {
  display: block;
  width: 20px; height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: transform .2s, opacity .2s;
}

/* Hero */
.hero {
  padding: 5rem 0 4.5rem;
  text-align: center;
}
.hero .eyebrow { margin-bottom: 1rem; color: var(--ruco-yellow); }
.hero h1 {
  color: var(--color-on-ink);
  font-size: clamp(2.25rem, 5vw, 3.5rem);
  margin-bottom: 1.25rem;
}
.hero-desc {
  font-size: 1.125rem;
  color: var(--mist);
  max-width: 600px;
  margin: 0 auto 2rem;
}
.hero-ctas {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}

/* Features */
.features-section { padding: 5rem 0; }
.features-section > .container > h2 { text-align: center; margin-bottom: 2.5rem; }
.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.5rem;
}
.feature-card {
  padding: 1.75rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
  transition: box-shadow .2s, transform .2s;
}
.feature-card:hover {
  box-shadow: var(--shadow-lift);
  transform: translateY(-2px);
}
.feature-icon { font-size: 1.375rem; margin-bottom: .75rem; line-height: 1; }
.feature-card h3 { margin-bottom: .375rem; font-size: 1rem; }
.feature-card p { margin: 0; color: var(--color-text-muted); font-size: .9375rem; }

/* Install strip */
.install-section {
  background: var(--grey-50);
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
  padding: 3rem 0;
  text-align: center;
}
.install-section h2 { margin-bottom: 1rem; }
.install-section p { color: var(--color-text-muted); margin-bottom: 1.5rem; }
.install-block {
  display: inline-flex;
  align-items: center;
  gap: 1rem;
  background: var(--grey-900);
  color: var(--color-on-ink);
  padding: .875rem 1.5rem;
  border-radius: var(--radius-md);
  font-family: var(--font-mono);
  font-size: .9375rem;
}
.install-block code { color: var(--ruco-yellow); }

/* Project grid (ruco.dev home) */
.projects-section { padding: 5rem 0; }
.projects-section > .container > h2 { margin-bottom: 2.5rem; }
.project-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.5rem;
}
.project-card {
  display: block;
  padding: 1.75rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
  color: var(--color-text);
  text-decoration: none;
  transition: box-shadow .2s, transform .2s, border-color .2s;
}
.project-card:hover {
  box-shadow: var(--shadow-lift);
  transform: translateY(-2px);
  border-color: var(--ruco-blue);
  text-decoration: none;
  color: var(--color-text);
}
.project-card .eyebrow { margin-bottom: .5rem; }
.project-card h3 { margin-bottom: .375rem; }
.project-card p { margin: 0; color: var(--color-text-muted); font-size: .9375rem; }

/* Footer */
.site-footer { padding: 2.5rem 0; }
.footer-inner {
  display: flex;
  align-items: center;
  gap: 2rem;
  flex-wrap: wrap;
}
.site-footer .nav-brand { color: var(--mist); font-size: .9375rem; }
.site-footer .nav-brand:hover { color: var(--white); }
.footer-links {
  display: flex;
  gap: 1.5rem;
  margin-left: auto;
}
.footer-links a { color: var(--mist); font-size: .9375rem; }
.footer-links a:hover { color: var(--white); text-decoration: none; }

/* Docs layout */
.docs-hero {
  padding: 3rem 0 2rem;
  border-bottom: 1px solid var(--color-border);
  background: var(--color-surface);
}
.docs-hero h1 { font-size: 1.75rem; margin-bottom: .25rem; }
.docs-layout {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 3rem;
  padding: 3rem 0 5rem;
}
.docs-sidebar {
  position: sticky;
  top: 76px;
  align-self: start;
}
.docs-sidebar-label {
  font-size: .6875rem; font-weight: 700; letter-spacing: .1em; text-transform: uppercase;
  color: var(--color-text-subtle); padding: .5rem .75rem .25rem; display: block;
}
.docs-sidebar nav { display: flex; flex-direction: column; gap: 2px; }
.docs-sidebar a {
  padding: .375rem .75rem;
  border-radius: var(--radius-sm);
  font-size: .9375rem;
  color: var(--color-text-muted);
  display: block;
}
.docs-sidebar a:hover, .docs-sidebar a.active {
  background: var(--grey-100);
  color: var(--color-text);
  text-decoration: none;
}
.docs-content h2 {
  font-size: 1.25rem;
  margin-top: 2.5rem;
  padding-top: 2.5rem;
  border-top: 1px solid var(--color-border);
}
.docs-content h2:first-child { margin-top: 0; padding-top: 0; border-top: none; }
.docs-content h3 { font-size: 1rem; margin-top: 1.5rem; }
.docs-content pre {
  background: var(--grey-900);
  color: var(--color-on-ink);
  padding: 1.25rem 1.5rem;
  border-radius: var(--radius-md);
  overflow-x: auto;
  font-size: .875rem;
  margin: .75rem 0 1.5rem;
  line-height: 1.55;
}
.docs-content code:not(pre code) {
  background: var(--grey-100);
  padding: .125em .375em;
  border-radius: 4px;
  font-size: .875em;
}
.docs-content ul, .docs-content ol { padding-left: 1.5rem; margin-bottom: 1em; }
.docs-content li { margin-bottom: .25em; }

/* Responsive */
@media (max-width: 768px) {
  .nav-toggle { display: flex; }
  .nav-links {
    display: none;
    position: absolute;
    top: 60px; left: 0; right: 0;
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    flex-direction: column;
    gap: 0;
    padding: .5rem 0;
    margin: 0;
  }
  .nav-links.open { display: flex; }
  .nav-links li { width: 100%; }
  .nav-links li a { display: block; padding: .75rem 1.5rem; }
  .docs-layout { grid-template-columns: 1fr; }
  .docs-sidebar { display: none; }
  .footer-inner { flex-direction: column; align-items: flex-start; }
  .footer-links { margin-left: 0; }
}