/* =====================================================================
   RoboJacks 4674 course theme
   ---------------------------------------------------------------------
   To match robojacks4674.org exactly, change only the values in this
   first block. Everything else on the site reads from these variables.
   ===================================================================== */
:root {
  /* Colors taken from the RoboJacks logo */
  --brand: #33499b;          /* logo blue: links, accents, headings rule */
  --brand-dark: #24357a;     /* hover / pressed */
  --silver: #c7c7c6;         /* logo silver: axe head and lettering */
  --wood: #944e10;           /* logo axe handle, used sparingly */
  --plaid-dark: #1e2026;     /* header and footer background */
  --plaid-light: #b3202a;    /* red squares in the buffalo-plaid band */
  --header-text: #ffffff;

  --font-body: "Open Sans", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --font-heading: "Montserrat", var(--font-body);
  --font-code: ui-monospace, "Cascadia Code", Consolas, monospace;

  --bg: #ffffff;
  --surface: #f4f5f8;
  --border: #dcdee5;
  --text: #1e1e1e;
  --text-muted: #5b5b5b;

  --note: #33499b;
  --tip: #2e8b57;
  --warning: #b86e00;
  --danger: #c0262d;
  --question: #6d4fb8;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --brand: #8fa2ec;
    --brand-dark: #b4c1f5;
    --note: #8fa2ec;
    --bg: #131417;
    --surface: #1d1f24;
    --border: #33363d;
    --text: #ececec;
    --text-muted: #a8a8a8;
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
    --brand: #8fa2ec;
    --brand-dark: #b4c1f5;
    --note: #8fa2ec;
    --bg: #131417;
    --surface: #1d1f24;
    --border: #33363d;
    --text: #ececec;
    --text-muted: #a8a8a8;
  color-scheme: dark;
}

/* ---------- Base ---------- */
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.65 var(--font-body);
}
a { color: var(--brand); }
a:hover { color: var(--brand-dark); }
img { max-width: 100%; }

.skip-link {
  position: absolute; left: -999px; top: 0;
  background: var(--brand); color: #fff; padding: 8px 12px; z-index: 10;
}
.skip-link:focus { left: 8px; }

/* ---------- Plaid band (lumberjack buffalo check) ---------- */
.plaid {
  height: 28px;
  background-color: var(--plaid-light);
  background-image:
    linear-gradient(90deg, rgba(0,0,0,.55) 50%, transparent 50%),
    linear-gradient(rgba(0,0,0,.55) 50%, transparent 50%);
  background-size: 28px 28px;
}
.plaid-thin { height: 12px; background-size: 12px 12px; }

/* ---------- Header ---------- */
.site-header { background: var(--plaid-dark); color: var(--header-text); }
.header-inner {
  max-width: 1200px; margin: 0 auto; padding: 18px 20px;
  display: flex; align-items: center; justify-content: space-between; gap: 16px;
}
.brand { color: var(--header-text); text-decoration: none; display: flex; align-items: center; gap: 14px; }
.brand-logo { height: 76px; width: auto; flex: none; }
.brand-text { display: flex; flex-direction: column; }
.brand:hover { color: var(--header-text); }
.brand-title {
  font: 800 1.9rem/1.1 var(--font-heading);
  letter-spacing: .02em; text-transform: uppercase; color: var(--silver);
}
.brand-subtitle { font-size: .95rem; opacity: .85; }
.header-link {
  color: var(--header-text); text-decoration: none; font-weight: 600;
  border: 2px solid var(--header-text); border-radius: 4px; padding: 6px 14px;
  white-space: nowrap;
}
.header-link:hover { background: var(--header-text); color: var(--plaid-dark); }
.header-actions { display: flex; align-items: center; gap: 14px; flex: none; }

/* ---------- Light/dark switch (top right of the header) ---------- */
.theme-toggle {
  display: inline-flex; align-items: center; gap: 6px;
  background: none; border: 0; padding: 4px; margin: 0; cursor: pointer;
  color: var(--header-text); border-radius: 999px;
}
.theme-toggle:focus-visible { outline: 3px solid var(--silver); outline-offset: 2px; }
.theme-icon { width: 18px; height: 18px; fill: none; stroke: currentColor; stroke-width: 2; stroke-linecap: round; opacity: .55; transition: opacity .2s; }
.theme-icon-sun circle { fill: currentColor; stroke: none; }
.theme-icon-moon { fill: currentColor; stroke: none; }
.theme-track {
  position: relative; width: 48px; height: 26px; border-radius: 999px;
  background: #5c616e; border: 2px solid var(--header-text); transition: background .2s;
}
.theme-knob {
  position: absolute; top: 2px; left: 2px; width: 18px; height: 18px; border-radius: 50%;
  background: var(--header-text); transition: transform .2s;
}
.theme-toggle[aria-checked="true"] .theme-track { background: var(--plaid-light); }
.theme-toggle[aria-checked="true"] .theme-knob { transform: translateX(22px); }
.theme-toggle[aria-checked="false"] .theme-icon-sun,
.theme-toggle[aria-checked="true"] .theme-icon-moon { opacity: 1; }
@media (prefers-reduced-motion: reduce) {
  .theme-track, .theme-knob, .theme-icon { transition: none; }
}

/* ---------- Search (button in the header, panel over the page) ---------- */
.search-open {
  display: inline-flex; align-items: center; gap: 8px; cursor: pointer;
  background: rgba(255,255,255,.08); color: var(--header-text);
  border: 2px solid var(--header-text); border-radius: 4px; padding: 6px 12px;
  font: 600 1rem var(--font-body);
}
.search-open:hover { background: var(--header-text); color: var(--plaid-dark); }
.search-open:focus-visible { outline: 3px solid var(--silver); outline-offset: 2px; }
.search-open svg, .search-row svg { width: 18px; height: 18px; fill: none; stroke: currentColor; stroke-width: 2.4; stroke-linecap: round; flex: none; }
.search-panel {
  position: fixed; inset: 0; z-index: 50; background: rgba(10,11,14,.55);
  display: flex; justify-content: center; align-items: flex-start; padding: 8vh 16px 16px;
}
.search-panel[hidden] { display: none; }
.search-is-open, .search-is-open body { overflow: hidden; }
.search-box {
  width: 100%; max-width: 680px; max-height: 80vh; display: flex; flex-direction: column;
  background: var(--bg); color: var(--text); border: 1px solid var(--border);
  border-top: 5px solid var(--plaid-light); border-radius: 8px; box-shadow: 0 18px 50px rgba(0,0,0,.35);
}
.search-row { display: flex; align-items: center; gap: 10px; padding: 12px 14px; border-bottom: 1px solid var(--border); color: var(--text-muted); }
.search-input {
  flex: 1; min-width: 0; border: 0; outline: 0; background: transparent; color: var(--text);
  font: 400 1.1rem var(--font-body); padding: 6px 0;
}
.search-close {
  background: var(--surface); color: var(--text-muted); border: 1px solid var(--border);
  border-radius: 4px; padding: 3px 8px; font: 600 .8rem var(--font-body); cursor: pointer;
}
.search-status { margin: 0; padding: 8px 16px; font-size: .88rem; color: var(--text-muted); }
.search-status:empty { display: none; }
.search-results { list-style: none; margin: 0; padding: 0 8px 8px; overflow-y: auto; }
.search-results a {
  display: block; padding: 10px 10px; border-radius: 6px; text-decoration: none; color: var(--text);
}
.search-results a:hover, .search-results a.is-active, .search-results a:focus-visible { background: var(--surface); outline: 0; }
.search-results a.is-active { box-shadow: inset 3px 0 0 var(--brand); }
.search-page { display: block; font-size: .8rem; font-weight: 700; color: var(--brand); text-transform: uppercase; letter-spacing: .03em; }
.search-heading { display: block; font-weight: 700; margin-top: 2px; }
.search-snippet { display: block; font-size: .9rem; color: var(--text-muted); margin-top: 3px; overflow-wrap: anywhere; }
.search-results mark { background: rgba(179,32,42,.18); color: inherit; border-radius: 2px; padding: 0 1px; }

/* ---------- Tabs (Lessons / Labs) ---------- */
.tabs { background: var(--plaid-dark); border-top: 1px solid rgba(255,255,255,.12); }
.tabs-inner {
  max-width: 1200px; margin: 0 auto;
  padding-block: 10px;
  padding-left: max(16px, env(safe-area-inset-left, 0px));
  padding-right: max(16px, env(safe-area-inset-right, 0px));
  display: flex; gap: 10px;
}
.tab {
  flex: 0 1 180px; text-align: center;
  color: var(--header-text); text-decoration: none; padding: 10px 18px;
  font: 800 1rem var(--font-heading); letter-spacing: .06em; text-transform: uppercase;
  border: 2px solid rgba(255,255,255,.55); border-radius: 6px;
}
.tab:hover { background: rgba(255,255,255,.12); color: var(--header-text); }
.tab.current { background: var(--plaid-light); border-color: var(--plaid-light); color: #fff; }
.tab:focus-visible { outline: 3px solid var(--header-text); outline-offset: 2px; }
@media (max-width: 860px) { .tab { flex: 1 1 0; } }

/* Big call-to-action button used on the home page */
.cta {
  display: inline-block; margin: .4em 0 1em; padding: 14px 22px;
  background: var(--plaid-light); color: #fff; text-decoration: none; border-radius: 6px;
  font: 800 1.05rem var(--font-heading); letter-spacing: .04em; text-transform: uppercase;
}
.cta:hover { background: var(--plaid-dark); color: #fff; }

/* ---------- Layout ---------- */
.layout {
  max-width: 1200px; margin: 0 auto; padding: 24px 20px 48px;
  display: grid; grid-template-columns: 270px minmax(0, 1fr); gap: 40px;
}
.sidebar { position: sticky; top: 16px; align-self: start; max-height: calc(100vh - 32px); overflow-y: auto; }
.sidebar-toggle > summary { display: none; }
.nav-section { margin-bottom: 6px; }
.nav-section > summary {
  cursor: pointer; font: 700 .8rem var(--font-heading);
  text-transform: uppercase; letter-spacing: .06em; color: var(--text-muted);
  padding: 6px 0;
}
.nav-section ul { list-style: none; margin: 0 0 8px; padding: 0; }
.nav-section a {
  display: block; padding: 5px 10px; border-left: 3px solid transparent;
  color: var(--text); text-decoration: none; font-size: .95rem;
}
.nav-section a:hover { color: var(--brand); border-left-color: var(--border); }
.nav-section a.current { color: var(--brand); border-left-color: var(--brand); font-weight: 600; background: var(--surface); }

/* ---------- Content ---------- */
.content { min-width: 0; }
.content h1, .content h2, .content h3, .content h4 { font-family: var(--font-heading); line-height: 1.25; }
.content h1 { font-size: 2.2rem; margin: 0 0 .6em; padding-bottom: .3em; border-bottom: 4px solid var(--brand); }
.content h2 { font-size: 1.5rem; margin-top: 2em; }
.content h3 { font-size: 1.2rem; margin-top: 1.6em; }
.headerlink { margin-left: .4em; color: var(--border); text-decoration: none; opacity: 0; }
h1:hover .headerlink, h2:hover .headerlink, h3:hover .headerlink, h4:hover .headerlink { opacity: 1; }

code { font-family: var(--font-code); font-size: .9em; background: var(--surface); padding: .1em .35em; border-radius: 3px; }
.highlight { border-radius: 6px; margin: 1em 0; border: 1px solid var(--border); overflow-x: auto; }
.highlight pre { margin: 0; padding: 14px 16px; line-height: 1.5; }
.highlight code { background: none; padding: 0; font-size: .88rem; }
:not(pre) > code { overflow-wrap: break-word; }
p > code, li > code { word-break: break-word; }

table { border-collapse: collapse; width: 100%; margin: 1em 0; display: block; overflow-x: auto; }
th, td { border: 1px solid var(--border); padding: 8px 12px; text-align: left; vertical-align: top; }
th { background: var(--surface); font-family: var(--font-heading); }

kbd {
  font-family: var(--font-code); font-size: .85em; padding: .1em .45em;
  border: 1px solid var(--border); border-bottom-width: 2px; border-radius: 4px; background: var(--surface);
}

/* Task lists */
.task-list { list-style: none; padding-left: 0; }
.task-list-item input { margin-right: .5em; accent-color: var(--brand); }
.task-list-control { display: inline-flex; align-items: center; }
.task-list-indicator { display: none; }

/* Mermaid diagrams */
div.mermaid { margin: 1.4em 0; text-align: center; overflow-x: auto; }

/* ---------- Callouts (admonitions + collapsible questions) ---------- */
.admonition, details.question, details.note, details.tip, details.warning {
  border-left: 4px solid var(--c, var(--note)); background: var(--surface);
  border-radius: 0 6px 6px 0; padding: 4px 16px 10px; margin: 1.2em 0;
}
.admonition-title, details > summary { font-weight: 700; color: var(--c, var(--note)); margin: 8px 0 4px; }
details:not(.nav-section):not(.sidebar-toggle) > summary { cursor: pointer; }
.admonition > :last-child, details > :last-child { margin-bottom: 4px; }
.tip, .success { --c: var(--tip); }
.warning, .caution { --c: var(--warning); }
.danger, .error { --c: var(--danger); }
.question { --c: var(--question); }
.info, .note { --c: var(--note); }
.example { --c: var(--brand); }

/* ---------- Figures (mostly from the WPILib docs) ---------- */
.content p > img {
  display: block; margin: 1.2em auto .3em; max-width: 100%; height: auto;
  background: #fff; padding: 8px; border: 1px solid var(--border); border-radius: 6px;
}
.content .credit { text-align: center; font-size: .82rem; color: var(--text-muted); margin-top: 0; }
.wpilib { --c: var(--brand); }

/* WPILib PID simulators */
.viz-div { border-color: var(--border) !important; border-radius: 6px; background: #fff; color: #1e1e1e; color-scheme: light; overflow-x: auto; margin: 1em 0 !important; }
.viz-div table { display: table; width: auto; }
.viz-div td { border: none; padding: 2px 6px; }

/* ---------- Prev / next ---------- */
.pager { display: flex; justify-content: space-between; gap: 16px; margin-top: 48px; padding-top: 20px; border-top: 1px solid var(--border); }
.pager a {
  flex: 1; max-width: 48%; text-decoration: none; padding: 12px 16px;
  border: 1px solid var(--border); border-radius: 6px; color: var(--text); font-weight: 600;
}
.pager a:hover { border-color: var(--brand); color: var(--brand); }
.pager span { display: block; font-size: .8rem; font-weight: 400; color: var(--text-muted); }
.pager-next { text-align: right; margin-left: auto; }

/* ---------- Footer ---------- */
.site-footer { background: var(--plaid-dark); color: #ddd; }
.footer-inner {
  max-width: 1200px; margin: 0 auto; padding: 16px 20px;
  display: flex; flex-wrap: wrap; gap: 12px 24px; justify-content: space-between; font-size: .9rem;
}
.footer-inner span:first-child { font-family: var(--font-heading); font-weight: 800; text-transform: uppercase; color: #fff; }
.site-footer a { color: #fff; }

/* ---------- Phones ---------- */
@media (max-width: 860px) {
  .layout { grid-template-columns: 1fr; gap: 16px; padding-top: 12px; }
  .sidebar { position: static; max-height: none; }
  .sidebar-toggle { border: 1px solid var(--border); border-radius: 6px; padding: 4px 12px; }
  .sidebar-toggle > summary { display: block; cursor: pointer; font-weight: 700; padding: 6px 0; }
  .brand-title { font-size: 1.3rem; }
  .brand-logo { height: 56px; }
  .header-inner { padding: 12px 16px; }
  .header-link { display: none; }
  .search-open { padding: 6px 9px; }
  .search-open-label { display: none; }
  .header-actions { gap: 8px; }
  .content h1 { font-size: 1.7rem; }
}