/* Phase 1 visual customization: palette tokens, nav/ToC treatment, footer rhythm. */

:root {
  --pollux-radius: 0.5rem;
  --pollux-border-width: 1px;
  --pollux-layout-max: 61rem;
  --pollux-sidebar-width: 12.1rem;
  --pollux-content-offset: 1.2rem;
  --pollux-page-left: 1rem;
  --pollux-header-offset: 2.4rem;
  --pollux-sidebar-bottom-space: 1.25rem;
  --pollux-nav-gutter: 0.25rem;
  --pollux-nav-indent: 0.45rem;
  --pollux-nav-link-margin-top: 0.5em;
  --pollux-toc-link-size: 0.72rem;
  --pollux-toc-link-line-height: 1.45;
  --pollux-toc-link-padding-y: 0.18rem;
  --pollux-toc-active-bar-offset: -0.85rem;

  /* Content text inset: the horizontal padding from the content container
     edge to where text actually begins.  Used by BOTH .md-content__inner
     (as margin-inline) and .md-footer (as padding-inline) so they align
     mechanically.  Adjust this single value to change the breathing room
     between sidebar and text on both content and footer simultaneously. */
  --pollux-content-inset: 2.4rem;

  /* Code font */
  --md-code-font: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo,
    Monaco, Consolas, monospace;

  /* Brand palette */
  --pollux-blue-900: hsl(220, 55%, 12%);
  --pollux-blue-800: hsl(220, 50%, 18%);
  --pollux-blue-700: hsl(222, 47%, 25%);
  --pollux-blue-500: hsl(222, 50%, 42%);
  --pollux-blue-400: hsl(222, 55%, 55%);
  --pollux-blue-100: hsl(220, 40%, 92%);
  --pollux-gold-600: hsl(36, 65%, 42%);
  --pollux-gold-500: hsl(38, 60%, 52%);
  --pollux-gold-400: hsl(38, 55%, 62%);
  --pollux-gold-300: hsl(40, 45%, 75%);
  --pollux-gold-100: hsl(40, 35%, 92%);
}

body[data-md-color-scheme="default"] {
  /* Override Material's generated accent with brand blue.
     --md-primary-fg-color = header bar background (Material's naming is
     inverted); we override it to brand dark-blue so the header matches
     the homepage hero. --md-primary-bg-color = header text color. */
  --md-accent-fg-color: var(--pollux-blue-500);
  --md-accent-fg-color--transparent: hsla(222, 50%, 42%, 0.1);
  --md-primary-fg-color: var(--pollux-blue-700);
  --md-primary-fg-color--light: var(--pollux-blue-500);
  --md-primary-bg-color: hsl(220, 20%, 98%);
  --md-primary-bg-color--light: hsla(220, 20%, 98%, 0.7);
  --pollux-nav-hover-bg: rgba(15, 23, 42, 0.04);
  --pollux-nav-active-bg: hsla(222, 50%, 42%, 0.1);
  --pollux-nav-active-color: hsl(222, 50%, 30%);
  --pollux-nav-border: rgba(15, 23, 42, 0.1);
  --pollux-toc-border: rgba(15, 23, 42, 0.16);
  --pollux-accent: var(--pollux-blue-500);
  --pollux-footer-border: rgba(15, 23, 42, 0.08);
  --pollux-pill-bg: rgba(15, 23, 42, 0.06);
  --pollux-pill-hover-bg: rgba(15, 23, 42, 0.1);
  --pollux-pill-color: rgb(15, 23, 42);
  --pollux-meta-color: rgba(15, 23, 42, 0.55);
  --pollux-title-color: rgb(15, 23, 42);
  --pollux-title-hover-color: rgba(15, 23, 42, 0.65);
}

body[data-md-color-scheme="slate"] {
  /* Override Material's generated accent with brand blue.
     In dark mode the header bar should also be dark. */
  --md-accent-fg-color: var(--pollux-blue-400);
  --md-accent-fg-color--transparent: hsla(222, 55%, 55%, 0.12);
  --md-primary-fg-color: var(--pollux-blue-900);
  --md-primary-fg-color--light: var(--pollux-blue-700);
  --md-primary-bg-color: hsl(220, 15%, 90%);
  --md-primary-bg-color--light: hsla(220, 15%, 90%, 0.7);
  --pollux-nav-hover-bg: rgba(255, 255, 255, 0.06);
  --pollux-nav-active-bg: hsla(222, 55%, 55%, 0.18);
  --pollux-nav-active-color: hsl(220, 40%, 82%);
  --pollux-nav-border: rgba(255, 255, 255, 0.12);
  --pollux-toc-border: rgba(255, 255, 255, 0.22);
  --pollux-accent: var(--pollux-blue-400);
  --pollux-footer-border: rgba(255, 255, 255, 0.1);
  --pollux-pill-bg: rgba(255, 255, 255, 0.08);
  --pollux-pill-hover-bg: rgba(255, 255, 255, 0.14);
  --pollux-pill-color: rgba(255, 255, 255, 0.85);
  --pollux-meta-color: rgba(255, 255, 255, 0.45);
  --pollux-title-color: rgba(255, 255, 255, 0.92);
  --pollux-title-hover-color: rgba(255, 255, 255, 0.6);
}

/* ── Sidebar ─────────────────────────────────────────────────── */

.md-sidebar--primary {
  border-inline-end: var(--pollux-border-width) solid var(--pollux-nav-border);
}

html,
body {
  overscroll-behavior-y: none;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ── Code blocks & inline code ──────────────────────────────── */

.md-typeset code {
  border-radius: 4px;
  font-size: 0.78em;
  padding: 0.15em 0.35em;
}

.md-typeset pre > code {
  border-radius: var(--pollux-radius);
  font-size: 0.82em;
  padding: 1em 1.2em;
}

/* ── Navigation links ────────────────────────────────────────── */

.md-nav__item--section > .md-nav__link {
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.md-nav__link {
  border-radius: var(--pollux-radius);
  transition: background-color 180ms ease, color 180ms ease;
}

.md-nav__item > .md-nav__link:hover {
  background: var(--pollux-nav-hover-bg);
}

.md-nav__item--active > .md-nav__link,
.md-nav__item--active > .md-nav__link:hover {
  background: var(--pollux-nav-active-bg);
  color: var(--pollux-nav-active-color);
  font-weight: 600;
}

/* ── Integrated ToC (all viewports) ──────────────────────────── */
/* Color + weight overrides only; layout is defined by breakpoint. */

.md-nav--secondary .md-nav__link:hover {
  background: transparent;
  color: var(--pollux-accent);
}

.md-nav--secondary .md-nav__link--active {
  color: var(--pollux-accent);
  font-weight: 600;
}

/* ── Footer: base ────────────────────────────────────────────── */

.md-footer {
  margin-top: 2.5rem;
  background: none;
  color: inherit;
}

/* ── Footer: prev/next pill navigation ───────────────────────── */

.pollux-footer-nav {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 1.5rem;
}

.pollux-footer-nav__item {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 0.35rem;
}

.pollux-footer-nav__item--next {
  margin-inline-start: auto;
  align-items: flex-end;
}

.pollux-footer-nav__pill {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  padding: 0.28rem 0.8rem;
  border-radius: 999px;
  background: var(--pollux-pill-bg);
  color: var(--pollux-pill-color);
  font-size: 0.8rem;
  font-weight: 500;
  text-decoration: none;
  transition: background-color 180ms ease, color 180ms ease;
}

.pollux-footer-nav__pill:hover {
  background: var(--pollux-pill-hover-bg);
  color: var(--pollux-pill-color);
}

.pollux-footer-nav__icon {
  width: 0.85rem;
  height: 0.85rem;
  flex-shrink: 0;
}

.pollux-footer-nav__title {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--pollux-title-color);
  text-decoration: none;
  transition: color 180ms ease;
}

.pollux-footer-nav__title:hover {
  color: var(--pollux-title-hover-color);
}

/* ── Footer: copyright + social meta row ─────────────────────── */

.pollux-footer-meta {
  margin-top: 2rem;
}

.pollux-footer-meta__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  border-top: 1px solid var(--pollux-footer-border);
  padding-top: 1.25rem;
  padding-bottom: 1.5rem;
}

.pollux-footer-meta__copyright {
  margin: 0;
  font-size: 0.72rem;
  color: var(--pollux-meta-color);
}

.pollux-footer-meta__social {
  display: flex;
  gap: 0.75rem;
}

.pollux-footer-meta__social-link {
  color: var(--pollux-meta-color);
  transition: color 180ms ease;
}

.pollux-footer-meta__social-link:hover {
  color: var(--pollux-accent);
}

.pollux-footer-meta__social-link svg {
  width: 1.1rem;
  height: 1.1rem;
  fill: currentcolor;
}

/* ── Breakpoint strategy ─────────────────────────────────────────
   Material defines three layout modes (mobile / tablet / desktop) with
   breakpoints at ~60 em and ~76.25 em.  The hooks/patch_material_css.py
   hook rewrites these to 51.2 em at build time, collapsing the model to
   two states: mobile (< 51.2 em) and desktop (≥ 51.2 em).  This means
   extra.css only needs to handle these two cases.

   Block order:
   1. min-width: 51.2em   – all non-mobile layout + visuals
   2. max-width: 51.199em – mobile/drawer-only rules
   3. min-width: 100em    – ultra-wide font-size bump
   ────────────────────────────────────────────────────────────── */

/* ── Non-mobile layout + visuals (≥ 51.2 em) ─────────────────── */
/* 51.2em ~= 1024px at Material's default 125% root font-size (20px). */
@media screen and (min-width: 51.2em) {
  /* ── a. Nav visual treatment ─── */

  .md-nav--primary .md-nav__item {
    border-top: 0;
  }

  .md-nav--primary .md-nav__link {
    margin-top: var(--pollux-nav-link-margin-top);
    padding: 0;
  }

  /* Boosted-specificity active link: .md-nav--primary prefix matches
     Material's selector weight (0,3,0) so the custom color wins. */
  .md-nav--primary .md-nav__item--active > .md-nav__link,
  .md-nav--primary .md-nav__item--active > .md-nav__link:hover {
    background: var(--pollux-nav-active-bg);
    color: var(--pollux-nav-active-color);
    font-weight: 600;
  }

  .md-nav--integrated .md-nav__link[for="__toc"] {
    display: none;
  }

  .md-nav--integrated .md-nav__link[for="__toc"] + .md-nav__link {
    display: flex;
  }

  /* Keep integrated ToC inline in desktop mode. */
  .md-nav--integrated .md-nav__link[for="__toc"] ~ .md-nav {
    display: block;
  }

  .md-nav--integrated .md-nav--secondary > .md-nav__title {
    display: none;
  }

  .md-nav__item--section > .md-nav > .md-nav__list {
    border-inline-start: 1px solid var(--pollux-nav-border);
    margin-inline-start: 0.2rem;
    padding-inline-start: var(--pollux-nav-indent);
  }

  .md-nav--secondary {
    margin: 0.25rem 0 0.5rem 0.2rem;
    padding-inline-start: var(--pollux-nav-indent);
    border-inline-start: 1px solid var(--pollux-toc-border);
  }

  .md-nav--secondary > .md-nav__title {
    letter-spacing: 0.04em;
    text-transform: uppercase;
  }

  .md-nav--secondary .md-nav__item {
    position: relative;
  }

  .md-nav--secondary .md-nav__link {
    font-size: var(--pollux-toc-link-size);
    line-height: var(--pollux-toc-link-line-height);
    margin-top: 0;
    padding-block: var(--pollux-toc-link-padding-y);
    position: relative;
  }

  .md-nav--secondary .md-nav__link--active::before {
    background: var(--pollux-accent);
    border-radius: 999px;
    bottom: 0.22rem;
    content: "";
    inset-inline-start: var(--pollux-toc-active-bar-offset);
    position: absolute;
    top: 0.22rem;
    width: 2px;
  }

  /* ── b. Layout ─── */

  /* Left anchor stays constant; free width opens to the right. */
  .md-grid {
    margin-left: var(--pollux-page-left);
    margin-right: 0;
    max-width: var(--pollux-layout-max);
  }

  /* Force desktop header controls from the desktop threshold upward:
     removes the "in-between" drawer behavior. */
  .md-header__button[for="__drawer"] {
    display: none;
  }

  .md-header__button.md-logo {
    display: inline-flex;
  }

  /* Material's mid-width rules treat primary nav as an off-canvas drawer.
     Reset to desktop nav behavior from the desktop threshold upward. */
  [dir="ltr"] .md-sidebar--primary {
    left: auto;
  }

  [dir="rtl"] .md-sidebar--primary {
    right: auto;
  }

  .md-sidebar--primary {
    background: none;
    box-shadow: none;
    height: 0;
    position: sticky;
    top: var(--pollux-header-offset) !important;
    transform: none !important;
    z-index: 2;
  }

  /* Remove built-in desktop sidebar padding so nav starts directly below
     the fixed header, instead of aligning with content heading offset. */
  .md-sidebar {
    padding: 0;
  }

  /* Decouple top spacing: keep breathing room for content without pushing
     the sidebar down to align with the page title. */
  .md-main__inner {
    margin-top: 0;
  }

  [data-md-toggle="drawer"]:checked ~ .md-container .md-sidebar--primary {
    box-shadow: none;
    transform: none;
  }

  .md-sidebar--primary .md-sidebar__scrollwrap {
    bottom: auto;
    left: auto;
    margin: 0 0.2rem;
    overflow-y: auto;
    position: static;
    right: auto;
    scroll-snap-type: none;
    top: auto;
  }

  .md-nav--primary {
    background-color: initial;
    display: block;
    flex-direction: initial;
    height: auto;
    left: auto;
    position: static;
    right: auto;
    top: auto;
    z-index: auto;
  }

  /* Reset nested nav containers out of drawer-panel mode. */
  .md-nav--primary .md-nav {
    background-color: initial;
    display: block;
    flex-direction: initial;
    height: auto;
    left: auto;
    opacity: 1;
    position: static;
    right: auto;
    top: auto;
    transform: none;
  }

  /* Desktop/tablet section expansion should be inline, not slide-over. */
  .md-nav--primary .md-nav__toggle ~ .md-nav {
    display: none;
    opacity: 1;
    transform: none;
    transition: none;
    visibility: visible;
  }

  .md-nav--primary .md-nav__toggle:checked ~ .md-nav,
  .md-nav--primary .md-nav__toggle.md-toggle--indeterminate ~ .md-nav {
    display: block;
  }

  .md-nav--primary .md-nav__toggle ~ .md-nav > .md-nav__list {
    overflow: visible;
  }

  .md-nav--primary .md-nav__item--nested > .md-nav > .md-nav__title {
    display: none;
  }

  /* Remove duplicate site title row inside desktop sidebar. */
  .md-nav--primary > .md-nav__title {
    display: none;
  }

  .md-nav--primary > .md-nav__list {
    background-color: transparent;
    box-shadow: none;
    overflow-y: visible;
    scroll-snap-type: none;
    touch-action: auto;
  }

  .md-overlay {
    display: none;
  }

  .md-container {
    position: relative;
  }

  /* Full-height sidebar border: extends through the footer area so the
     sidebar column doesn't end abruptly when scrolled to the bottom. */
  [dir="ltr"] .md-container::after {
    content: "";
    position: absolute;
    top: 0;
    bottom: 0;
    left: calc(var(--pollux-page-left) + var(--pollux-sidebar-width));
    width: 0;
    border-inline-end: var(--pollux-border-width) solid var(--pollux-nav-border);
    pointer-events: none;
    z-index: 1;
  }

  [dir="rtl"] .md-container::after {
    content: "";
    position: absolute;
    top: 0;
    bottom: 0;
    right: calc(var(--pollux-page-left) + var(--pollux-sidebar-width));
    width: 0;
    border-inline-start: var(--pollux-border-width) solid var(--pollux-nav-border);
    pointer-events: none;
    z-index: 1;
  }

  /* Sidebar's own border is replaced by the full-height pseudo-element. */
  .md-sidebar--primary {
    border-inline-end: none;
  }

  /* Material sets inline heights on scrollwrap via JS.
     Pin the desktop nav scroll area to viewport height to prevent collapse
     near the footer boundary. */
  .md-sidebar .md-sidebar__scrollwrap {
    height: calc(100vh - var(--pollux-header-offset)) !important;
    overscroll-behavior: none;
  }

  .md-header--lifted ~ .md-container .md-sidebar .md-sidebar__scrollwrap {
    height: calc(100vh - var(--pollux-header-offset)) !important;
  }

  /* Keep desktop sidebar anchored; don't follow header height transitions. */
  .md-sidebar {
    top: var(--pollux-header-offset) !important;
  }

  .md-header--lifted ~ .md-container .md-sidebar {
    top: var(--pollux-header-offset) !important;
  }

  /* Sidebar content fills the JS-controlled scroll area. */
  .md-sidebar--primary .md-sidebar__inner {
    min-height: 100%;
  }

  [dir="ltr"] .md-sidebar--primary .md-nav__list {
    padding-left: var(--pollux-nav-gutter);
  }

  [dir="rtl"] .md-sidebar--primary .md-nav__list {
    padding-right: var(--pollux-nav-gutter);
  }

  .md-sidebar--primary .md-nav__list {
    padding-bottom: var(--pollux-sidebar-bottom-space);
    scroll-padding-bottom: var(--pollux-sidebar-bottom-space);
  }

  /* Material sets directional margins on .md-content__inner at high
     specificity (e.g. [dir=ltr] .md-sidebar--primary:not([hidden]) ~
     .md-content > .md-content__inner { margin-left: 1.2rem }).
     We match that specificity so --pollux-content-inset actually wins. */
  .md-content > .md-content__inner {
    margin-top: 1.5rem;
  }

  [dir="ltr"] .md-sidebar--primary:not([hidden]) ~ .md-content > .md-content__inner {
    margin-left: var(--pollux-content-inset);
    margin-right: var(--pollux-content-inset);
  }

  [dir="rtl"] .md-sidebar--primary:not([hidden]) ~ .md-content > .md-content__inner {
    margin-right: var(--pollux-content-inset);
    margin-left: var(--pollux-content-inset);
  }

  /* ── c. Footer offset ───
     The footer sits outside .md-grid, so it needs explicit constraints
     to align with the content area.  The footer's outer left edge is
     placed at the content container's left edge (page-left + sidebar).
     padding-inline: content-inset then matches .md-content__inner's
     margin-inline, so footer text and page text share the same edges.
     max-width prevents overshoot on wide viewports. */

  [dir="ltr"] .md-footer {
    margin-left: calc(
      var(--pollux-page-left) + var(--pollux-sidebar-width)
    );
    margin-right: 0;
    max-width: calc(
      var(--pollux-layout-max) - var(--pollux-sidebar-width)
    );
    padding-inline: var(--pollux-content-inset);
    width: auto;
    box-sizing: border-box;
  }

  [dir="rtl"] .md-footer {
    margin-right: calc(
      var(--pollux-page-left) + var(--pollux-sidebar-width)
    );
    margin-left: 0;
    max-width: calc(
      var(--pollux-layout-max) - var(--pollux-sidebar-width)
    );
    padding-inline: var(--pollux-content-inset);
    width: auto;
    box-sizing: border-box;
  }
}

/* ── Narrow viewport (< 51.2 em): drawer + footer ───────────────
   This covers all non-desktop widths; there is no separate tablet mode. */
@media screen and (max-width: 51.199em) {
  .md-nav--primary .md-nav--secondary {
    display: flex;
    flex-direction: column;
    height: 100%;
  }

  /* Keep the back-arrow icon visible on the ToC drawer title
     so users have a clear way to dismiss the ToC panel. */
  .md-nav--primary .md-nav--secondary .md-nav__title .md-nav__icon {
    display: block;
  }

  /* Compact the title bar (Material default: 5.6rem / 3rem top padding).
     Keep enough left padding for the absolutely-positioned back icon. */
  .md-nav--primary .md-nav--secondary .md-nav__title {
    align-items: center;
    display: flex;
    height: 3rem;
    line-height: 1.2;
    padding: 0.6rem 0.8rem 0.6rem 2.2rem;
  }

  /* Nudge the back icon to vertically align with the compacted title. */
  .md-nav--primary .md-nav--secondary .md-nav__title .md-nav__icon {
    top: 50%;
    transform: translateY(-50%);
  }

  /* Ensure the ToC item list gets remaining height and can scroll. */
  .md-nav--primary .md-nav--secondary > .md-nav__list {
    flex: 1;
    min-height: 0;
    overflow-y: auto;
    overscroll-behavior: contain;
    scroll-snap-type: none;
    -webkit-overflow-scrolling: auto;
  }

  /* Keep footer nav in one horizontal row on mobile,
     with content-aligned gutters on both sides. */
  .md-footer {
    padding-inline: clamp(1rem, 4vw, 1.25rem);
  }

  .pollux-footer-nav {
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    column-gap: 0.9rem;
    row-gap: 0.5rem;
    align-items: start;
  }

  .pollux-footer-nav__item {
    min-width: 0;
    gap: 0.45rem;
  }

  .pollux-footer-nav__item--prev {
    grid-column: 1;
    align-items: flex-start;
    justify-self: start;
  }

  .pollux-footer-nav__item--next {
    grid-column: 2;
    margin-inline-start: 0;
    align-items: flex-end;
    justify-self: end;
  }

  .pollux-footer-nav__title {
    max-width: 14rem;
  }

  .pollux-footer-nav__item--next .pollux-footer-nav__title {
    text-align: right;
  }

  .pollux-footer-meta__inner {
    flex-direction: column;
    align-items: center;
    text-align: center;
  }
}

/* ── Ultra-wide (≥ 100 em) ──────────────────────────────────── */
/* Keep base text sizing stable across ultra-wide viewports. */
@media screen and (min-width: 100em) {
  html {
    font-size: 125%;
  }
}