/* ============================================================
   Raokhanthi — base + layout (MOBILE FIRST)
   Tactile, studio-crafted layout with Outfit display headings,
   DM Sans prose, and live header/sidebar mastery chrome.
   ============================================================ */

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

html {
  font-size: calc(16px * var(--text-scale, 1));
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + var(--sp-4));
  scroll-padding-bottom: calc(var(--mobilenav-h) + 32px);
  -webkit-text-size-adjust: 100%;
  overflow-x: hidden;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font);
  font-size: var(--fs-base);
  line-height: var(--lh-base);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  font-variant-numeric: tabular-nums;
  zoom: var(--zoom, 1);
  overflow-x: hidden;
  padding-bottom: calc(var(--mobilenav-h) + 52px + env(safe-area-inset-bottom, 0px));
}
@media (min-width: 768px) { body { padding-bottom: 0; } }

/* warmth / tint overlay */
body::after {
  content: "";
  position: fixed; inset: 0; pointer-events: none; z-index: 70;
  background: var(--warm-color, transparent);
  opacity: var(--warm-opacity, 0);
  transition: opacity 0.18s ease;
}

img, svg, video { max-width: 100%; height: auto; }
a { color: var(--brand); text-decoration: none; font-weight: 500; }
a:hover { text-decoration: underline; text-underline-offset: 3px; }
hr { border: 0; border-top: 1px solid var(--line); margin: var(--sp-5) 0; }

:focus-visible {
  outline: 2.5px solid var(--brand);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

.skip-link {
  position: absolute; left: -9999px; top: 0; z-index: 200;
  background: var(--brand); color: #fff; padding: 10px 16px;
  border-radius: 0 0 var(--radius) 0; font-weight: 700;
}
.skip-link:focus { left: 0; }

/* ---------- crafted display & prose typography ---------- */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  color: var(--ink);
  letter-spacing: var(--tracking-tight);
  line-height: var(--lh-tight);
  margin: var(--sp-5) 0 var(--sp-3);
  font-weight: 700;
  text-wrap: balance;
  overflow-wrap: anywhere;
}
h1 { font-size: var(--fs-3xl); margin-top: 0; }
h2 { font-size: var(--fs-2xl); padding-bottom: var(--sp-2); border-bottom: 1.5px solid var(--line); }
h3 { font-size: var(--fs-xl); }
h4 { font-size: var(--fs-lg); font-family: var(--font); }
@media (min-width: 768px) {
  h1 { font-size: var(--fs-4xl); }
  h2 { font-size: var(--fs-2xl); }
  h3 { font-size: var(--fs-xl); }
}
p { margin: 0 0 var(--sp-4); }
small { font-size: var(--fs-xs); color: var(--muted); }
code, kbd, samp {
  font-family: var(--font-mono); font-size: 0.88em;
  background: var(--surface-2); border: 1px solid var(--line);
  border-radius: 6px; padding: 0.12em 0.4em;
  overflow-wrap: anywhere;
}
blockquote {
  margin: var(--sp-5) 0; padding: var(--sp-3) 0 var(--sp-3) var(--sp-4);
  border-left: 3px solid var(--accent); color: var(--ink-soft);
  font-size: var(--fs-lg);
}
mark { background: var(--warn-soft); color: var(--ink); padding: 0 0.2em; border-radius: 4px; }

/* ---------- responsive PWA header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 60;
  background: color-mix(in srgb, var(--surface) 92%, transparent);
  backdrop-filter: blur(14px) saturate(140%);
  -webkit-backdrop-filter: blur(14px) saturate(140%);
  border-bottom: 1.5px solid var(--line);
}
.site-header .bar {
  display: flex; align-items: center; justify-content: space-between;
  gap: 8px;
  height: var(--header-h);
  max-width: var(--content-max); margin: 0 auto;
  padding: 0 var(--sp-3);
  min-width: 0;
}
@media (min-width: 480px) { .site-header .bar { gap: var(--sp-3); padding: 0 var(--sp-4); } }
@media (min-width: 768px) { .site-header .bar { padding: 0 var(--sp-5); } }

.brand {
  display: inline-flex; align-items: center; gap: 9px;
  color: var(--ink);
  min-width: 0;
  flex: 0 1 auto;
  max-width: 100%;
  overflow: hidden;
}
.brand:hover { text-decoration: none; }
.brand .mark {
  width: 32px; height: 32px; flex: 0 0 32px; display: block;
  aspect-ratio: 1 / 1;
  border-radius: 9px;
  box-shadow: var(--shadow-xs);
}
@media (min-width: 768px) { .brand .mark { width: 36px; height: 36px; flex-basis: 36px; border-radius: 10px; } }
.brand-wordmark {
  font-family: var(--font-display);
  font-size: clamp(1rem, 2.6vw, 1.2rem);
  font-weight: 700;
  letter-spacing: -0.025em;
  line-height: 1.15;
  color: var(--ink);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  min-width: 0;
}

.header-nav {
  display: none;
  align-items: center;
  gap: var(--sp-3);
  flex: 0 0 auto;
}
@media (min-width: 1024px) {
  .header-nav { display: flex; }
}
@media (min-width: 1200px) {
  .header-nav { gap: var(--sp-4); }
}
.header-nav a {
  position: relative;
  font-family: var(--font-display);
  font-size: var(--fs-sm);
  font-weight: 600;
  color: var(--muted);
  padding: 6px 4px;
  white-space: nowrap;
  text-decoration: none;
  transition: color var(--dur-fast) var(--ease);
}
.header-nav a:hover { color: var(--ink); text-decoration: none; }
.header-nav a[aria-current="page"] { color: var(--brand); }
.header-nav a[aria-current="page"]::after {
  content: "";
  position: absolute;
  left: 0; right: 0; bottom: -2px;
  height: 2.5px;
  background: var(--brand);
  border-radius: 2px;
}

.header-tools {
  display: flex;
  align-items: center;
  gap: 6px;
  flex: 0 0 auto;
}
@media (min-width: 640px) {
  .header-tools { gap: 8px; }
}
@media (max-width: 639px) {
  .header-tools .icon-btn {
    width: 36px;
    height: 36px;
  }
}

/* Header HUD Pill (shown on >= 560px; under 768px the bottom nav has a dedicated Progress tab) */
.hud-pill {
  display: none;
  align-items: center;
  gap: 6px;
  padding: 5px 10px;
  border-radius: var(--radius-pill);
  background: var(--surface-2);
  border: 1.5px solid var(--outline);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 700;
  text-decoration: none;
  color: var(--ink);
  white-space: nowrap;
  cursor: pointer;
  box-shadow: 0 2px 0 var(--outline);
  transition: transform var(--dur-fast) var(--ease), border-color var(--dur-fast) var(--ease);
}
@media (min-width: 560px) {
  .hud-pill { display: inline-flex; }
}
.hud-pill:hover, .hud-pill[aria-expanded="true"] {
  text-decoration: none;
  border-color: var(--brand);
  transform: translateY(-1px);
}
.hud-lvl {
  color: var(--brand);
  background: var(--brand-soft);
  padding: 1px 6px;
  border-radius: var(--radius-pill);
}
.hud-xp {
  display: inline-flex; align-items: center; gap: 3px;
  color: var(--xp);
}
.hud-xp .icon { width: 0.95em; height: 0.95em; fill: currentColor; }

.header-search { display: none; align-items: center; position: relative; }
@media (min-width: 768px) { .header-search { display: flex; } }
.header-search .icon {
  position: absolute; left: 11px; color: var(--faint);
  pointer-events: none; width: 0.95rem; height: 0.95rem;
}
.header-search input {
  width: clamp(148px, 15vw, 210px);
  height: 38px;
  padding: 6px 28px 6px 32px;
  border: 1.5px solid var(--outline); border-radius: var(--radius);
  background: var(--bg); color: var(--ink);
  font: inherit; font-size: var(--fs-xs); font-weight: 500;
}
.header-search input:focus {
  background: var(--surface);
  border-color: var(--brand); outline: none;
  box-shadow: 0 0 0 3px var(--brand-soft);
}
.search-kbd {
  position: absolute; right: 8px;
  font-family: var(--font-mono); font-size: 0.68rem;
  line-height: 1; padding: 3px 5px;
  color: var(--faint); background: var(--surface);
  border: 1px solid var(--line); border-radius: 4px;
  pointer-events: none;
}

/* Professional Hamburger Trigger (.nav-toggle) */
.nav-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  height: 36px;
  padding: 0 10px;
  border: 1.5px solid var(--outline);
  border-radius: 10px;
  background: var(--surface);
  color: var(--ink);
  font-family: var(--font-display);
  font-size: 0.76rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  cursor: pointer;
  box-shadow: 0 2px 0 var(--outline);
  transition: transform var(--dur-fast) var(--ease),
              border-color var(--dur-fast) var(--ease),
              background-color var(--dur-fast) var(--ease),
              color var(--dur-fast) var(--ease);
}
@media (min-width: 640px) {
  .nav-toggle { height: 38px; padding: 0 12px; font-size: 0.78rem; }
}
.nav-toggle:hover {
  border-color: var(--outline-hover);
  background: var(--surface-2);
}
.nav-toggle:active {
  transform: translateY(1px);
}
.nav-toggle[aria-expanded="true"] {
  border-color: var(--brand);
  background: var(--brand-soft);
  color: var(--brand);
  box-shadow: 0 2px 0 var(--brand);
}
.burger {
  position: relative;
  width: 16px;
  height: 12px;
  display: inline-flex;
  flex-direction: column;
  justify-content: space-between;
  flex: none;
}
.burger i {
  display: block;
  width: 100%;
  height: 2px;
  background: currentColor;
  border-radius: 2px;
  transform-origin: center;
  transition: transform 180ms var(--ease), opacity 140ms var(--ease), width 180ms var(--ease);
}
.burger i:nth-child(2) {
  width: 72%;
  margin-left: auto;
}
.nav-toggle:hover .burger i:nth-child(2) {
  width: 100%;
}
.nav-toggle[aria-expanded="true"] .burger i:nth-child(1) {
  transform: translateY(5px) rotate(45deg);
}
.nav-toggle[aria-expanded="true"] .burger i:nth-child(2) {
  opacity: 0;
  transform: scaleX(0);
}
.nav-toggle[aria-expanded="true"] .burger i:nth-child(3) {
  transform: translateY(-5px) rotate(-45deg);
}
@media (max-width: 440px) {
  .nav-toggle { width: 36px; padding: 0; }
  .nav-toggle-lbl { display: none; }
}
@media (min-width: 1024px) {
  body:not([data-page="home"]) .nav-toggle { display: none; }
}

/* ---------- shell ---------- */
.shell {
  max-width: var(--content-max);
  margin: 0 auto;
  padding: var(--sp-5) var(--sp-4) var(--sp-7);
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--sp-5);
  align-items: start;
}
@media (min-width: 768px) { .shell { padding: var(--sp-6) var(--sp-5) var(--sp-8); } }
@media (min-width: 1024px) {
  body:not([data-page="home"]) .shell { grid-template-columns: var(--sidebar-w) minmax(0, 1fr); gap: var(--sp-6); }
  .shell.no-sidebar { grid-template-columns: minmax(0, 1fr); }
}
@media (min-width: 1360px) {
  body:not([data-page="home"]):not([data-page="progress"]) .shell.has-toc { grid-template-columns: var(--sidebar-w) minmax(0, 1fr) var(--toc-w); }
}
body[data-page="home"] .shell {
  max-width: 1200px;
  padding-top: var(--sp-2);
}
body[data-page="home"] .toc,
body[data-page="progress"] .toc {
  display: none !important;
}

/* ---------- slide-over drawer & desktop sidebar ---------- */
body.drawer-open {
  overflow: hidden;
}
@media (min-width: 1024px) {
  body:not([data-page="home"]).drawer-open { overflow: visible; }
}

.drawer-backdrop {
  position: fixed;
  inset: 0;
  z-index: 88;
  background: rgba(12, 15, 22, 0.52);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  opacity: 0;
  pointer-events: none;
  transition: opacity 220ms var(--ease);
}
.drawer-backdrop.open {
  opacity: 1;
  pointer-events: auto;
}

.sidebar {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  z-index: 92;
  width: min(360px, 90vw);
  background: var(--surface);
  border-left: 1.5px solid var(--outline);
  box-shadow: var(--shadow-lg);
  display: flex;
  flex-direction: column;
  font-size: var(--fs-sm);
  transform: translateX(102%);
  visibility: hidden;
  transition: transform 240ms var(--ease), visibility 240ms;
  overflow: hidden;
}
.sidebar.open {
  transform: translateX(0);
  visibility: visible;
}

.drawer-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 14px 16px;
  border-bottom: 1.5px solid var(--line);
  background: var(--surface);
  flex: none;
}
.drawer-brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  text-decoration: none;
  min-width: 0;
}
.drawer-brand:hover { text-decoration: none; }
.drawer-brand img {
  width: 32px;
  height: 32px;
  border-radius: 8px;
  flex: none;
}
.drawer-brand strong {
  display: block;
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 700;
  line-height: 1.15;
  color: var(--ink);
}
.drawer-brand span {
  display: block;
  font-size: 0.7rem;
  color: var(--muted);
  font-weight: 500;
}

.drawer-search {
  position: relative;
  display: flex;
  align-items: center;
  margin: 12px 16px 4px;
  flex: none;
}
.drawer-search .icon {
  position: absolute;
  left: 12px;
  color: var(--faint);
  width: 0.95rem;
  height: 0.95rem;
  pointer-events: none;
}
.drawer-search input {
  width: 100%;
  height: 40px;
  padding: 6px 12px 6px 34px;
  border: 1.5px solid var(--outline);
  border-radius: var(--radius);
  background: var(--bg);
  color: var(--ink);
  font: inherit;
  font-size: var(--fs-xs);
  font-weight: 500;
}
.drawer-search input:focus {
  background: var(--surface);
  border-color: var(--brand);
  outline: none;
  box-shadow: 0 0 0 3px var(--brand-soft);
}

.sidebar-scroll {
  flex: 1;
  overflow-y: auto;
  overscroll-behavior: contain;
  padding: 14px 16px calc(var(--mobilenav-h) + 28px);
}

@media (min-width: 1024px) {
  body:not([data-page="home"]) .drawer-head,
  body:not([data-page="home"]) .drawer-search,
  body:not([data-page="home"]) .drawer-backdrop {
    display: none !important;
  }
  body:not([data-page="home"]) .sidebar,
  body:not([data-page="home"]) .sidebar.open {
    display: block;
    position: sticky;
    top: calc(var(--header-h) + var(--sp-5));
    inset: auto;
    width: auto;
    background: transparent;
    border-left: 0;
    box-shadow: none;
    transform: none;
    visibility: visible;
    max-height: calc(100vh - var(--header-h) - var(--sp-6));
    overflow-y: auto;
    padding: 0 var(--sp-2) 0 0;
  }
  body:not([data-page="home"]) .sidebar-scroll {
    padding: 0;
    overflow: visible;
  }
}
.sidebar-group { margin-bottom: var(--sp-4); }
.sidebar-group > h2 {
  font-family: var(--font-display); font-size: 0.7rem; font-weight: 700;
  text-transform: uppercase; letter-spacing: var(--tracking-wide);
  color: var(--faint); border: 0; padding: 0 10px; margin: 0 0 6px;
}
.sidebar nav ul { list-style: none; margin: 0; padding: 0; }
.sidebar nav li { margin: 2px 0; }
.sidebar nav a {
  display: flex; align-items: center; gap: 10px;
  padding: 8px 11px; border-radius: var(--radius-sm);
  color: var(--ink-soft); font-weight: 500;
  border-left: 3px solid transparent;
  transition: background 0.14s, color 0.14s, border-color 0.14s;
}
.sidebar nav a:hover { background: var(--surface-2); color: var(--ink); text-decoration: none; }
.sidebar nav a[aria-current="page"] {
  background: var(--brand-soft); color: var(--brand);
  font-weight: 700; border-left-color: var(--brand);
}
.nav-count {
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 0.68rem; font-weight: 700;
  padding: 1px 6px; border-radius: var(--radius-pill);
  background: var(--surface); border: 1px solid var(--line);
  color: var(--muted);
}

/* Sidebar Mastery Card */
.sidebar .progress-card {
  margin-top: var(--sp-4); padding: var(--sp-4);
  background: var(--surface);
  border: 1.5px solid var(--outline);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
}
.pc-top {
  display: flex; justify-content: space-between; align-items: flex-start;
  gap: 8px; margin-bottom: 10px;
}
.pc-lvl {
  display: block; font-family: var(--font-mono);
  font-size: 0.66rem; font-weight: 700;
  letter-spacing: 0.05em; color: var(--brand);
}
.pc-bo { font-size: var(--fs-sm); color: var(--ink); }
.pc-xp {
  display: inline-flex; align-items: center; gap: 3px;
  font-family: var(--font-mono); font-size: 0.72rem; font-weight: 700;
  color: var(--xp); background: var(--xp-soft);
  padding: 2px 8px; border-radius: var(--radius-pill);
}
.pc-xp .icon { width: 0.9em; height: 0.9em; fill: currentColor; }
.pc-meta {
  display: flex; justify-content: space-between;
  font-size: 0.7rem; color: var(--muted); font-weight: 500;
  margin: 8px 0 12px;
}
.pc-cta { width: 100%; }

/* ---------- main column ---------- */
.main { min-width: 0; }
.page-head { margin-bottom: var(--sp-5); }
.page-head .eyebrow {
  display: inline-flex; align-items: center; gap: 8px;
  font-family: var(--font-display);
  font-size: var(--fs-xs); font-weight: 700;
  letter-spacing: var(--tracking-wide); text-transform: uppercase;
  color: var(--brand); margin-bottom: var(--sp-2);
}
.page-head .eyebrow::before {
  content: ""; width: 18px; height: 2.5px; border-radius: 2px;
  background: linear-gradient(90deg, var(--brand), var(--accent));
}
.page-head h1 {
  font-size: clamp(1.8rem, 5vw, var(--fs-4xl));
  margin-bottom: var(--sp-2);
}
.page-head .lede {
  font-size: var(--fs-base); color: var(--muted);
  line-height: var(--lh-base);
  max-width: var(--prose-max);
  margin-bottom: 0;
}
@media (min-width: 768px) { .page-head .lede { font-size: var(--fs-lg); } }
.prose { max-width: var(--prose-max); }
.prose p, .prose li { color: var(--ink-soft); }

/* ---------- on-this-page (desktop only) ---------- */
.toc { display: none; position: sticky; top: calc(var(--header-h) + var(--sp-5)); font-size: var(--fs-xs); }
@media (min-width: 1360px) { .toc { display: block; } }
.toc h2 {
  font-family: var(--font-display); font-size: 0.7rem; font-weight: 700;
  text-transform: uppercase; letter-spacing: var(--tracking-wide);
  color: var(--faint); border: 0; padding: 0; margin: 0 0 var(--sp-2);
}
.toc ul { list-style: none; margin: 0; padding: 0; border-left: 1.5px solid var(--line); }
.toc a {
  display: block; padding: 5px 0 5px var(--sp-3); margin-left: -1.5px;
  border-left: 2px solid transparent; color: var(--muted); line-height: 1.4;
  transition: color 0.14s, border-color 0.14s;
}
.toc a:hover { color: var(--ink); text-decoration: none; border-left-color: var(--line-strong); }
.toc a.active { color: var(--brand); border-left-color: var(--brand); font-weight: 700; }

/* ---------- mobile bottom navigation & learner progress sheet ---------- */
.mobile-nav {
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 65;
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  align-items: stretch;
  gap: 2px;
  height: calc(var(--mobilenav-h) + env(safe-area-inset-bottom, 0px));
  padding: 4px 6px calc(4px + env(safe-area-inset-bottom, 0px));
  background: color-mix(in srgb, var(--surface) 95%, transparent);
  backdrop-filter: blur(16px) saturate(150%);
  -webkit-backdrop-filter: blur(16px) saturate(150%);
  border-top: 1.5px solid var(--line);
}
@media (min-width: 768px) {
  .mobile-nav { display: none; }
}

.mnav-item {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 3px;
  border: 0;
  border-radius: 10px;
  background: transparent;
  cursor: pointer;
  font-family: var(--font-display);
  font-size: 0.68rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--muted);
  text-decoration: none;
  padding: 4px 2px;
  min-height: 48px;
  min-width: 0;
  user-select: none;
  -webkit-tap-highlight-color: transparent;
  transition: color var(--dur-fast) var(--ease), background-color var(--dur-fast) var(--ease);
}
.mnav-item:hover {
  color: var(--ink);
  text-decoration: none;
}
.mnav-icon {
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 34px;
  height: 24px;
  border-radius: var(--radius-pill);
  transition: background-color var(--dur-fast) var(--ease), transform var(--dur-fast) var(--ease);
}
.mnav-icon .icon {
  width: 1.25rem;
  height: 1.25rem;
}
.mnav-label {
  max-width: 100%;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  line-height: 1.1;
}
.mnav-badge {
  position: absolute;
  top: -3px;
  right: -5px;
  font-family: var(--font-mono);
  font-size: 0.56rem;
  font-weight: 700;
  line-height: 1;
  padding: 2px 4px;
  border-radius: var(--radius-pill);
  background: var(--brand);
  color: #ffffff;
  border: 1.5px solid var(--surface);
}
html[data-theme="dark"] .mnav-badge {
  color: #0c0f16;
}
.mnav-item[aria-current="page"],
.mnav-item[aria-expanded="true"] {
  color: var(--brand);
  font-weight: 700;
}
.mnav-item[aria-current="page"] .mnav-icon,
.mnav-item[aria-expanded="true"] .mnav-icon {
  background: var(--brand-soft);
}

/* ---------- footer ---------- */
.site-footer {
  margin-top: var(--sp-7); padding: var(--sp-6) 0 var(--sp-7);
  border-top: 1.5px solid var(--line); background: var(--bg-soft);
  font-size: var(--fs-sm); color: var(--muted);
}
.site-footer .inner {
  max-width: var(--content-max); margin: 0 auto; padding: 0 var(--sp-4);
  display: grid; gap: var(--sp-5); grid-template-columns: minmax(0, 1fr);
}
@media (min-width: 640px) { .site-footer .inner { grid-template-columns: 1fr 1fr; padding: 0 var(--sp-5); } }
@media (min-width: 900px) { .site-footer .inner { grid-template-columns: 2fr 1fr 1fr; } }
.site-footer h3 {
  font-family: var(--font-display); font-size: var(--fs-xs);
  text-transform: uppercase; letter-spacing: var(--tracking-wide);
  color: var(--faint); margin: 0 0 var(--sp-3);
}
.site-footer ul { list-style: none; margin: 0; padding: 0; }
.site-footer li { margin: 6px 0; }
.site-footer a { color: var(--muted); }
.site-footer a:hover { color: var(--brand); }
.site-footer .fine { margin-top: var(--sp-5); max-width: 80ch; font-size: var(--fs-xs); line-height: var(--lh-base); }

/* ---------- utility ---------- */
.container { max-width: var(--content-max); margin: 0 auto; padding: 0 var(--sp-4); }
@media (min-width: 768px) { .container { padding: 0 var(--sp-5); } }
.stack > * + * { margin-top: var(--sp-4); }
.grid { display: grid; gap: var(--sp-4); grid-template-columns: minmax(0, 1fr); }
@media (min-width: 560px) { .grid { grid-template-columns: repeat(2, minmax(0, 1fr)); } }
@media (min-width: 980px) { .grid { grid-template-columns: repeat(3, minmax(0, 1fr)); } }
.grid-2 { display: grid; gap: var(--sp-4); grid-template-columns: minmax(0, 1fr); }
@media (min-width: 768px) { .grid-2 { grid-template-columns: repeat(2, minmax(0, 1fr)); } }
.visually-hidden {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; border: 0;
}
.section { padding: var(--sp-5) 0; }
.section + .section { border-top: 1.5px solid var(--line); }

.table-wrap, pre, .glyph-grid, .num-grid { max-width: 100%; }

/* ---------- header brand ----------
   The brand is the wordmark image itself. Its artwork is 1478x440, so the
   width is left to follow the height — the logo is never squashed to fit a box.
   The wordmark is dark blue on transparency, so in dark theme it sits on a
   soft light plate rather than disappearing into the header. */
.brand-logo {
  display: block;
  height: 34px; width: auto;
  flex: 0 0 auto;
}
@media (min-width: 768px) { .brand-logo { height: 38px; } }
html[data-theme="dark"] .brand-logo {
  /* content-box so the plate wraps the logo instead of shrinking it */
  box-sizing: content-box;
  background: #f7f9fc;
  padding: 4px 8px;
  border-radius: 10px;
  box-shadow: var(--shadow-xs);
}
@media print { .brand-logo { height: 32px; } }

/* ---------- launch splash (installed app only) ----------
   Static markup on every page, so it paints on the first frame — never
   injected by script. It is shown only when the page is running as an
   installed app, and only on the first page of a session: the media query
   covers Android/desktop, and html[data-display="standalone"] covers iOS,
   which has no display-mode media query. */
.splash {
  position: fixed; inset: 0; z-index: 200;
  display: none;
  place-items: center;
  background:
    radial-gradient(680px 420px at 50% 38%, color-mix(in srgb, var(--brand) 9%, transparent), transparent 70%),
    var(--bg);
  transition: opacity 400ms var(--ease-out);
}
@media (display-mode: standalone) { html:not(.splash-done) .splash { display: grid; } }
html[data-display="standalone"]:not(.splash-done) .splash { display: grid; }
.splash.is-done { opacity: 0; }

.splash-inner {
  display: grid; justify-items: center; gap: var(--sp-3);
  padding: var(--sp-6); text-align: center;
  padding-top: max(var(--sp-6), env(safe-area-inset-top, 0px));
}
.splash-mark { position: relative; display: grid; place-items: center; width: 120px; height: 120px; }
.splash-logo { width: 120px; height: 120px; display: block; border-radius: 28px; box-shadow: var(--shadow-sm); }
.splash-ring {
  position: absolute; inset: -12px;
  border-radius: 50%;
  border: 3px solid color-mix(in srgb, var(--brand) 20%, transparent);
  border-top-color: var(--brand);
  border-right-color: color-mix(in srgb, var(--brand) 55%, transparent);
  animation: splash-spin 900ms linear infinite;
}
@keyframes splash-spin { to { transform: rotate(360deg); } }

.splash-title {
  margin: var(--sp-3) 0 0;
  font-family: var(--font-display);
  font-size: var(--fs-2xl); font-weight: 800;
  letter-spacing: -0.022em; line-height: 1.1;
  color: var(--ink);
}
.splash-sub { margin: 0; font-size: var(--fs-sm); color: var(--muted); letter-spacing: 0.015em; }
.splash-bar {
  margin-top: var(--sp-4);
  width: 184px; height: 5px; border-radius: 999px;
  background: color-mix(in srgb, var(--brand) 30%, transparent);
  overflow: hidden;
}
.splash-bar span {
  display: block; width: 55%; height: 100%; border-radius: 999px;
  background: linear-gradient(90deg, var(--brand), var(--accent));
  box-shadow: 0 0 10px color-mix(in srgb, var(--brand) 55%, transparent);
  animation: splash-bar 1.15s var(--ease) infinite;
}
/* the sweep is bounded so a piece of the fill is on screen at every moment */
@keyframes splash-bar { 0% { transform: translateX(-55%); } 100% { transform: translateX(160%); } }

@media (prefers-reduced-motion: reduce) {
  .splash-ring { animation: none; opacity: 0.55; }
  .splash-bar span { animation: none; width: 100%; }
}