/* ==========================================================================
   sdatoken.org — site.css
   Shared shell + components. Requires tokens.css loaded first.
   Sections: 1 reset · 2 base type · 3 layout · 4 shell (header/footer/nav)
             5 buttons · 6 cards & tiles · 7 badges/pills · 8 forms
             9 tables · 10 stats/gauges · 11 overlays (drawer/modal/toast)
             12 game & learn primitives · 13 utilities
   ========================================================================== */

/* 1 ─ Reset ------------------------------------------------------------- */
*,
*::before,
*::after {
  box-sizing: border-box;
}
html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}
body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: var(--text-md);
  font-weight: var(--weight-regular);
  line-height: var(--leading-body);
  color: var(--color-ink);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
img,
svg,
canvas,
video {
  display: block;
  max-width: 100%;
  height: auto;
}
button,
input,
select,
textarea {
  font: inherit;
  color: inherit;
}
button {
  cursor: pointer;
  background: none;
  border: 0;
  padding: 0;
}
a {
  color: var(--color-link);
  text-decoration: none;
}
a:hover {
  text-decoration: underline;
  text-underline-offset: 3px;
}
/* A link inside running text cannot be distinguished by colour alone: --color-sky
   is only 1.5:1 against the body ink (WCAG 1.4.1, QA part 19). Nav, tiles, chips
   and buttons are not running text and keep their clean look. */
p a:not(.btn):not(.chip),
dd a:not(.btn),
figcaption a {
  text-decoration: underline;
  text-underline-offset: 3px;
}
:focus-visible {
  outline: 3px solid var(--color-sky);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}
::selection {
  background: var(--color-spark-soft);
}
[hidden] {
  display: none !important;
}

/* 2 ─ Base type --------------------------------------------------------- */
h1,
h2,
h3,
h4 {
  margin: 0 0 var(--space-3);
  font-weight: var(--weight-black);
  line-height: var(--leading-tight);
  letter-spacing: -0.01em;
  color: var(--color-ink);
}
h1 {
  font-size: var(--text-3xl);
}
h2 {
  font-size: var(--text-2xl);
}
h3 {
  font-size: var(--text-xl);
}
h4 {
  font-size: var(--text-lg);
}
p {
  margin: 0 0 var(--space-4);
}
p:last-child {
  margin-bottom: 0;
}
small,
.text-sm {
  font-size: var(--text-sm);
}
.text-xs {
  font-size: var(--text-xs);
}
.muted {
  color: var(--color-ink-muted);
}
.faint {
  color: var(--color-ink-faint);
}
.eyebrow {
  display: inline-block;
  font-size: var(--text-xs);
  font-weight: var(--weight-black);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-ink-faint);
  margin-bottom: var(--space-2);
}
.num {
  font-variant-numeric: tabular-nums lining-nums;
  font-feature-settings: 'tnum' 1;
}
.lead {
  font-size: var(--text-lg);
  color: var(--color-ink-muted);
}
code,
kbd {
  font-family: var(--font-mono);
  font-size: 0.9em;
  background: var(--color-surface-2);
  padding: 0.1em 0.4em;
  border-radius: 6px;
}
hr {
  border: 0;
  border-top: var(--border-w) solid var(--color-border);
  margin: var(--space-8) 0;
}
dfn[data-term] {
  font-style: normal;
  border-bottom: 2px dotted var(--color-sky);
  cursor: help;
}

/* 3 ─ Layout ------------------------------------------------------------ */
.container {
  /* 95 % of the viewport on mobile, 80 % on desktop (user rule), capped for ultrawide */
  width: min(95%, var(--container-max));
  margin-inline: auto;
}
@media (min-width: 900px) {
  .container {
    width: min(80%, var(--container-max));
  }
}
.container--wide {
  width: min(95%, var(--container-max));
}
@media (min-width: 900px) {
  .container--wide {
    width: min(88%, var(--container-max));
  }
}
.container--narrow {
  width: min(95%, 760px);
}
.section {
  padding-block: var(--space-10);
}
.section--tight {
  padding-block: var(--space-6);
}
.stack > * + * {
  margin-top: var(--space-4);
}
.stack--sm > * + * {
  margin-top: var(--space-2);
}
.stack--lg > * + * {
  margin-top: var(--space-8);
}
.cluster {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  align-items: center;
}
.cluster--between {
  justify-content: space-between;
}
.grid {
  display: grid;
  gap: var(--space-4);
}
.grid--2 {
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 320px), 1fr));
}
.grid--3 {
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 260px), 1fr));
}
.grid--4 {
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 220px), 1fr));
}
.split {
  display: grid;
  gap: var(--space-6);
  grid-template-columns: 1fr;
}
@media (min-width: 900px) {
  .split {
    grid-template-columns: 3fr 2fr;
    align-items: start;
  }
  .split--even {
    grid-template-columns: 1fr 1fr;
  }
}
main {
  min-height: 60vh;
}
/* grid/flex children must be allowed to shrink below content width */
.grid > *,
.split > *,
.cluster > * {
  min-width: 0;
}

/* 4 ─ Shell -------------------------------------------------------------- */
/* All sizes: top bar with a labelled "☰ Menu" button at the far left; the dark
   rail is CLOSED until opened and slides in from the left as an overlay (with a
   backdrop). Mobile (<1024) additionally gets a fixed bottom tab bar. The
   <site-header> component emits all of it. */
body {
  padding-bottom: 0;
}
@media (max-width: 1023.98px) {
  body {
    padding-bottom: calc(var(--tabbar-h) + env(safe-area-inset-bottom, 0px));
  }
}

/* --- rail (off-canvas menu, all sizes) --- */
.rail {
  display: flex;
  position: fixed;
  inset: 0 auto 0 0;
  width: min(var(--rail-w), 86vw);
  background: var(--rail-bg);
  color: var(--rail-ink);
  z-index: 220;
  flex-direction: column;
  padding: var(--space-4) var(--space-3);
  gap: var(--space-2);
  overflow-y: auto;
  transform: translateX(-100%);
  transition: transform var(--dur-slow) var(--ease-out);
  box-shadow: none;
}
.rail[data-open='true'] {
  transform: none;
  box-shadow: 12px 0 40px rgba(0, 0, 0, 0.35);
}
.rail__close {
  position: absolute;
  top: 12px;
  right: 10px;
  width: 36px;
  height: 36px;
  border-radius: 10px;
  color: var(--rail-ink-muted);
  display: grid;
  place-items: center;
  font-size: 18px;
}
.rail__close:hover {
  background: var(--rail-bg-2);
  color: #fff;
}
.rail-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(15, 19, 26, 0.45);
  z-index: 219;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--dur-base);
}
.rail-backdrop[data-open='true'] {
  opacity: 1;
  pointer-events: auto;
}
/* the opener: labelled, far left, exactly where the panel appears */
.menu-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  height: 40px;
  padding: 0 14px 0 12px;
  border-radius: var(--radius-md);
  background: var(--rail-bg);
  color: #fff;
  font-weight: var(--weight-black);
  font-size: var(--text-sm);
  box-shadow: 0 3px 0 #0b0e13;
  flex-shrink: 0;
}
.menu-btn:hover {
  background: var(--rail-bg-2);
}
.menu-btn:active {
  transform: translateY(2px);
  box-shadow: 0 1px 0 #0b0e13;
}
.menu-btn .ico {
  font-size: 18px;
  line-height: 1;
}
.rail__brand {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 6px 10px 14px;
  color: var(--rail-ink);
  text-decoration: none;
  font-weight: var(--weight-black);
  font-size: var(--text-lg);
  letter-spacing: -0.01em;
}
.rail__brand:hover {
  text-decoration: none;
}
.rail__brand .brand__mark {
  background: var(--rail-accent);
  box-shadow: 0 3px 0 #178f48;
  color: #0b1a10;
}
.rail__brand small {
  display: block;
  font-size: var(--text-xs);
  font-weight: var(--weight-bold);
  color: var(--rail-ink-muted);
  letter-spacing: 0.06em;
  text-transform: uppercase;
}
.rail__nav {
  display: flex;
  flex-direction: column;
  gap: 2px;
}
.rail__link {
  display: flex;
  align-items: center;
  gap: 12px;
  height: 46px;
  padding: 0 12px;
  border-radius: var(--radius-md);
  color: var(--rail-ink-muted);
  font-weight: var(--weight-bold);
  font-size: var(--text-md);
  text-decoration: none;
  transition:
    background var(--dur-fast),
    color var(--dur-fast);
}
.rail__link:hover {
  background: var(--rail-bg-2);
  color: var(--rail-ink);
  text-decoration: none;
}
.rail__link[aria-current='page'] {
  background: var(--rail-bg-2);
  color: #fff;
  box-shadow: inset 3px 0 0 var(--rail-accent);
}
.rail__link .ico {
  width: 26px;
  font-size: 20px;
  text-align: center;
  line-height: 1;
}
.rail__link--featured {
  margin: 6px 0;
  background: var(--grad-hero);
  color: #fff;
  height: 52px;
  box-shadow: 0 4px 0 #0c5629;
}
.rail__link--featured:hover {
  filter: brightness(1.06);
  color: #fff;
}
.rail__link--featured[aria-current='page'] {
  box-shadow:
    0 4px 0 #0c5629,
    inset 0 0 0 2px rgba(255, 255, 255, 0.35);
}
.rail__section {
  margin: 12px 12px 4px;
  font-size: var(--text-xs);
  font-weight: var(--weight-black);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--rail-ink-muted);
}
.rail__foot {
  margin-top: auto;
  padding: 12px 8px 4px;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  display: flex;
  flex-direction: column;
  gap: 8px;
  font-size: var(--text-sm);
  color: var(--rail-ink-muted);
}
.rail__foot .streak-chip {
  background: rgba(255, 197, 61, 0.16);
  color: #ffd76a;
}
.rail__foot .btn {
  --btn-bg: var(--rail-bg-2);
  --btn-edge: #0b0e13;
  --btn-ink: var(--rail-ink);
}

/* --- top bar (all sizes) --- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--header-h);
  background: var(--color-surface);
  border-bottom: var(--border-w) solid var(--color-border);
}
.site-header__inner {
  height: 100%;
  display: grid;
  grid-template-columns: 1fr auto 1fr; /* left | centred quick links | right */
  align-items: center;
  gap: var(--space-3);
  width: auto;
  margin: 0;
  padding: 0 var(--space-4);
}
.site-header__left {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  min-width: 0;
}
/* quick links, centred in the bar and in the SAME place on every page (the
   grid's 1fr side columns absorb the varying brand/context width) */
.topnav {
  display: none;
  gap: 4px;
  justify-self: center;
}
@media (min-width: 900px) {
  .topnav {
    display: flex;
  }
}
.topnav .nav__link {
  display: inline-flex;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-weight: var(--weight-black);
  font-size: var(--text-lg);
  color: var(--color-ink);
  text-decoration: none;
  white-space: nowrap;
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
}
.brand:hover {
  text-decoration: none;
}
.brand__mark {
  flex-shrink: 0;
  width: 32px;
  height: 32px;
  border-radius: 10px;
  background: var(--color-primary);
  color: #fff;
  display: grid;
  place-items: center;
  font-size: 18px;
  box-shadow: 0 3px 0 var(--color-primary-strong);
}
.brand__ctx {
  color: var(--color-ink-faint);
  font-weight: var(--weight-bold);
}
.header-actions {
  justify-self: end;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  gap: var(--space-2);
}
.header-actions .ext-link {
  display: none;
  align-items: center;
  gap: 6px;
  height: 36px;
  padding: 0 12px;
  border-radius: var(--radius-pill);
  border: var(--border-w) solid var(--color-border);
  color: var(--color-ink-muted);
  font-weight: var(--weight-black);
  font-size: var(--text-sm);
  white-space: nowrap;
  text-decoration: none;
}
.header-actions .ext-link:hover {
  border-color: var(--color-primary);
  color: var(--color-primary-ink);
  text-decoration: none;
}
@media (min-width: 720px) {
  .header-actions .ext-link {
    display: inline-flex;
  }
}
.icon-btn {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  display: inline-grid;
  place-items: center;
  font-size: 20px;
  color: var(--color-ink-muted);
  transition: background var(--dur-fast);
}
.icon-btn:hover {
  background: var(--color-surface-2);
  color: var(--color-ink);
}
.streak-chip {
  display: inline-flex;
  white-space: nowrap;
  align-items: center;
  gap: 6px;
  height: 36px;
  padding: 0 var(--space-3);
  border-radius: var(--radius-pill);
  background: var(--color-spark-soft);
  color: var(--color-ink);
  font-weight: var(--weight-black);
  font-size: var(--text-sm);
}
/* legacy desktop nav kept for pages that still hand-write it (styleguide) */
.nav {
  display: none;
  gap: var(--space-1);
  margin-left: auto;
}
.nav__link {
  display: inline-flex;
  align-items: center;
  height: 40px;
  padding: 0 var(--space-4);
  border-radius: var(--radius-md);
  font-weight: var(--weight-bold);
  color: var(--color-ink-muted);
  text-decoration: none;
}
.nav__link[aria-current='page'] {
  background: var(--color-primary-soft);
  color: var(--color-primary-ink);
}

/* --- bottom tab bar (mobile / tablet) --- */
.tabbar {
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  height: calc(var(--tabbar-h) + env(safe-area-inset-bottom, 0px));
  padding-bottom: env(safe-area-inset-bottom, 0px);
  background: var(--color-surface);
  border-top: var(--border-w) solid var(--color-border);
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  z-index: 110;
}
@media (min-width: 1024px) {
  .tabbar {
    display: none;
  }
}
.tabbar__item {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 2px;
  color: var(--color-ink-muted);
  font-size: 11px;
  font-weight: var(--weight-black);
  text-decoration: none;
  letter-spacing: 0.02em;
}
.tabbar__item .ico {
  font-size: 22px;
  line-height: 1;
}
.tabbar__item[aria-current='page'] {
  color: var(--color-primary-ink);
}
.tabbar__item[aria-current='page'] .ico {
  transform: translateY(-1px);
}
.tabbar__item--featured .ico {
  display: grid;
  place-items: center;
  width: 40px;
  height: 40px;
  margin-top: -14px;
  border-radius: 14px;
  background: var(--grad-hero);
  color: #fff;
  box-shadow: 0 3px 0 #0c5629;
}
.tabbar__item:hover {
  text-decoration: none;
}

/* "More" sheet (mobile) */
.nav-sheet {
  position: fixed;
  inset: var(--header-h) 0 calc(var(--tabbar-h) + env(safe-area-inset-bottom, 0px)) 0;
  background: var(--color-surface);
  z-index: 99;
  padding: var(--space-6) var(--space-4);
  display: none;
  flex-direction: column;
  gap: var(--space-2);
  overflow-y: auto;
}
.nav-sheet[data-open='true'] {
  display: flex;
}
.nav-sheet .nav__link {
  display: flex;
  height: 52px;
  font-size: var(--text-lg);
  gap: 12px;
}

/* --- footer --- */
.site-footer {
  margin-top: var(--space-16);
  padding: var(--space-10) 0 var(--space-8);
  border-top: var(--border-w) solid var(--color-border);
  color: var(--color-ink-muted);
  font-size: var(--text-sm);
}
.site-footer h4 {
  font-size: var(--text-sm);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-ink-faint);
  margin-bottom: var(--space-3);
}
.site-footer ul {
  list-style: none;
  padding: 0;
  margin: 0;
}
.site-footer li + li {
  margin-top: var(--space-2);
}
.site-footer a {
  color: var(--color-ink-muted);
}
.site-footer a:hover {
  color: var(--color-ink);
}
.site-footer__legal {
  margin-top: var(--space-8);
  padding-top: var(--space-6);
  border-top: 1px solid var(--color-border);
  font-size: var(--text-xs);
  color: var(--color-ink-faint);
}

/* "More to play" strip at the bottom of games */
.more-strip {
  display: flex;
  gap: var(--space-3);
  overflow-x: auto;
  padding-bottom: var(--space-2);
  scrollbar-width: thin;
}
.more-strip .tile {
  min-width: 220px;
}

/* --- section headings with colour (chess.com-style bold labels) --- */
.section-head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  margin-bottom: var(--space-4);
}
.section-head h2 {
  margin: 0;
  display: flex;
  align-items: center;
  gap: 10px;
}
.section-head__ico {
  width: 36px;
  height: 36px;
  border-radius: 10px;
  display: grid;
  place-items: center;
  font-size: 20px;
  background: var(--color-primary-soft);
}
.section-head__ico--spark {
  background: var(--color-spark-soft);
}
.section-head__ico--sky {
  background: var(--color-sky-soft);
}
.section-head__ico--violet {
  background: #efe9ff;
}

/* 5 ─ Buttons ------------------------------------------------------------ */
.btn {
  --btn-bg: var(--color-surface-2);
  --btn-edge: var(--color-border-strong);
  --btn-ink: var(--color-ink);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  min-height: 48px;
  padding: 0 var(--space-6);
  border-radius: var(--radius-lg);
  background: var(--btn-bg);
  color: var(--btn-ink);
  font-weight: var(--weight-black);
  font-size: var(--text-md);
  letter-spacing: 0.01em;
  text-decoration: none;
  border: 0;
  box-shadow: 0 4px 0 var(--btn-edge);
  transform: translateY(0);
  transition:
    transform var(--dur-fast) var(--ease-out),
    box-shadow var(--dur-fast),
    filter var(--dur-fast);
  user-select: none;
  white-space: nowrap;
}
.btn:hover {
  filter: brightness(1.04);
  text-decoration: none;
}
.btn:active {
  transform: translateY(4px);
  box-shadow: 0 0 0 var(--btn-edge);
}
.btn:disabled,
.btn[aria-disabled='true'] {
  opacity: 0.5;
  pointer-events: none;
}
.btn--primary {
  --btn-bg: var(--color-primary-btn);
  --btn-edge: var(--color-primary-btn-edge);
  --btn-ink: #fff;
}
.btn--spark {
  --btn-bg: var(--color-spark);
  --btn-edge: var(--color-spark-strong);
  --btn-ink: #3b2a00;
}
.btn--sky {
  --btn-bg: var(--color-sky-btn);
  --btn-edge: var(--color-sky-btn-edge);
  --btn-ink: #fff;
}
.btn--danger {
  --btn-bg: var(--color-danger-btn);
  --btn-edge: var(--color-danger-btn-edge);
  --btn-ink: #fff;
}
.btn--ghost {
  --btn-bg: transparent;
  --btn-edge: transparent;
  --btn-ink: var(--color-ink-muted);
  box-shadow: inset 0 0 0 var(--border-w) var(--color-border);
}
.btn--ghost:active {
  transform: none;
}
.btn--sm {
  min-height: 36px;
  padding: 0 var(--space-4);
  font-size: var(--text-sm);
  border-radius: var(--radius-md);
  box-shadow: 0 3px 0 var(--btn-edge);
}
.btn--sm:active {
  transform: translateY(3px);
}
.btn--lg {
  min-height: 56px;
  padding: 0 var(--space-8);
  font-size: var(--text-lg);
}
.btn--block {
  width: 100%;
}
.btn__icon {
  font-size: 1.2em;
  line-height: 1;
}

/* segmented control (lenses, tabs) */
.seg {
  display: inline-flex;
  padding: 4px;
  gap: 4px;
  background: var(--color-surface-2);
  border-radius: var(--radius-md);
}
.seg__btn {
  min-height: 36px;
  padding: 0 var(--space-4);
  border-radius: 9px;
  font-weight: var(--weight-bold);
  color: var(--color-ink-muted);
  transition:
    background var(--dur-fast),
    color var(--dur-fast);
}
.seg__btn[aria-pressed='true'],
.seg__btn.is-active {
  background: var(--color-surface);
  color: var(--color-ink);
  box-shadow: var(--shadow-edge);
}

/* 6 ─ Cards & tiles ------------------------------------------------------ */
.card {
  background: var(--color-surface);
  border: var(--border-w) solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
}
a.card {
  display: block;
  color: inherit;
}
a.card:hover {
  text-decoration: none;
  border-color: var(--color-primary);
}
.card--pad-lg {
  padding: var(--space-8);
}
.card--flat {
  border-color: transparent;
  background: var(--color-surface-2);
}
.card--accent {
  border-color: var(--color-primary);
  background: var(--color-primary-soft);
}
.card__title {
  font-size: var(--text-lg);
  margin-bottom: var(--space-2);
}
.card__meta {
  font-size: var(--text-sm);
  color: var(--color-ink-muted);
}

/* Tile = clickable card (games, tools). Whole thing is a link. */
.tile {
  --tile-accent: var(--color-primary);
  position: relative;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  min-height: 160px;
  padding: var(--space-5);
  background: var(--color-surface);
  border: var(--border-w) solid var(--color-border);
  border-radius: var(--radius-xl);
  color: var(--color-ink);
  text-decoration: none;
  box-shadow: 0 4px 0 var(--color-border);
  transition:
    transform var(--dur-base) var(--ease-out),
    box-shadow var(--dur-base),
    border-color var(--dur-base);
}
.tile:hover {
  transform: translateY(-3px);
  border-color: var(--tile-accent);
  box-shadow: 0 7px 0 var(--tile-accent);
  text-decoration: none;
}
.tile:active {
  transform: translateY(2px);
  box-shadow: 0 2px 0 var(--tile-accent);
}
.tile__icon {
  width: 52px;
  height: 52px;
  border-radius: 14px;
  display: grid;
  place-items: center;
  font-size: 28px;
  background: color-mix(in srgb, var(--tile-accent) 14%, var(--color-surface));
}
.tile__title {
  font-size: var(--text-lg);
  font-weight: var(--weight-black);
  margin: 0;
}
.tile__desc {
  color: var(--color-ink-muted);
  font-size: var(--text-sm);
  margin: 0;
}
.tile__foot {
  margin-top: auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2);
  font-size: var(--text-sm);
  font-weight: var(--weight-bold);
  color: var(--color-ink-muted);
}
/* --tile-accent paints borders and shadows (non-text, 3:1 is enough); the live
   stat is small text, so it uses the darker text-safe shade (WCAG AA 4.5:1). */
.tile__live {
  color: var(--tile-accent-ink, var(--color-primary-btn));
}
.tile--spark {
  --tile-accent: var(--color-spark-strong);
  --tile-accent-ink: var(--color-spark-ink);
}
.tile--sky {
  --tile-accent: var(--color-sky);
  --tile-accent-ink: var(--color-sky-btn);
}
.tile--danger {
  --tile-accent: var(--color-danger);
  --tile-accent-ink: var(--color-danger-btn);
}
.tile--purple {
  --tile-accent: var(--src-nuclear);
  --tile-accent-ink: var(--color-purple-ink);
}
.tile--hero {
  min-height: 220px;
  grid-column: 1 / -1;
}

/* 7 ─ Badges & pills ----------------------------------------------------- */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  height: 24px;
  padding: 0 10px;
  border-radius: var(--radius-pill);
  font-size: var(--text-xs);
  font-weight: var(--weight-black);
  letter-spacing: 0.02em;
  background: var(--color-surface-2);
  color: var(--color-ink-muted);
  white-space: nowrap;
}
.badge--primary {
  background: var(--color-primary-soft);
  color: var(--color-primary-ink);
}
.badge--spark {
  background: var(--color-spark-soft);
  color: #6b4b00;
}
.badge--sky {
  background: var(--color-sky-soft);
  color: var(--color-sky-strong);
}
.badge--danger {
  background: var(--color-danger-soft);
  color: var(--color-danger-strong);
}
.badge--warn {
  background: var(--color-warn-soft);
  color: #8a5a00;
}
.badge--live::before {
  content: '';
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--color-primary);
  box-shadow: 0 0 0 0 rgba(31, 178, 90, 0.5);
  animation: pulse 1.8s infinite;
}
@keyframes pulse {
  0% {
    box-shadow: 0 0 0 0 rgba(31, 178, 90, 0.5);
  }
  70% {
    box-shadow: 0 0 0 8px rgba(31, 178, 90, 0);
  }
  100% {
    box-shadow: 0 0 0 0 rgba(31, 178, 90, 0);
  }
}
.chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-height: 34px;
  padding: 0 var(--space-3);
  border-radius: var(--radius-pill);
  border: var(--border-w) solid var(--color-border);
  background: var(--color-surface);
  font-weight: var(--weight-bold);
  font-size: var(--text-sm);
  color: var(--color-ink-muted);
  cursor: pointer;
}
.chip[aria-pressed='true'],
.chip.is-active {
  border-color: var(--color-primary);
  background: var(--color-primary-soft);
  color: var(--color-primary-ink);
}
.flag {
  font-size: 1.25em;
  line-height: 1;
}

/* 8 ─ Forms -------------------------------------------------------------- */
.field {
  display: flex;
  flex-direction: column;
  gap: 6px;
}
.field__label {
  font-size: var(--text-sm);
  font-weight: var(--weight-black);
  color: var(--color-ink-muted);
}
.field__hint {
  font-size: var(--text-xs);
  color: var(--color-ink-faint);
}
.input,
.select,
.textarea {
  width: 100%;
  min-height: 48px;
  padding: 0 var(--space-4);
  border-radius: var(--radius-md);
  border: var(--border-w) solid var(--color-border);
  background: var(--color-surface);
  color: var(--color-ink);
  font-weight: var(--weight-bold);
  transition:
    border-color var(--dur-fast),
    box-shadow var(--dur-fast);
}
.textarea {
  min-height: 120px;
  padding-block: var(--space-3);
}
.input:focus,
.select:focus,
.textarea:focus {
  outline: none;
  border-color: var(--color-sky);
  box-shadow: 0 0 0 4px var(--color-sky-soft);
}
.select {
  appearance: none;
  padding-right: 40px;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' fill='none' stroke='%235b6472' stroke-width='2.5' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M4 6l4 4 4-4'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 14px center;
}
.input-group {
  display: flex;
}
.input-group .input {
  border-radius: var(--radius-md) 0 0 var(--radius-md);
}
.input-group__addon {
  display: inline-flex;
  align-items: center;
  padding: 0 var(--space-3);
  border: var(--border-w) solid var(--color-border);
  border-left: 0;
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  background: var(--color-surface-2);
  color: var(--color-ink-muted);
  font-weight: var(--weight-bold);
  font-size: var(--text-sm);
}
/* range slider (used by Race to Zero, Solar Studio) */
.range {
  --range-fill: var(--color-primary);
  --range-pct: 50%;
  appearance: none;
  width: 100%;
  height: 32px;
  background: transparent;
  cursor: pointer;
}
.range::-webkit-slider-runnable-track {
  height: 12px;
  border-radius: 6px;
  background: linear-gradient(
    to right,
    var(--range-fill) 0 var(--range-pct),
    var(--color-surface-2) var(--range-pct) 100%
  );
  border: 1px solid var(--color-border);
}
.range::-moz-range-track {
  height: 12px;
  border-radius: 6px;
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
}
.range::-moz-range-progress {
  height: 12px;
  border-radius: 6px;
  background: var(--range-fill);
}
.range::-webkit-slider-thumb {
  appearance: none;
  width: 28px;
  height: 28px;
  margin-top: -9px;
  border-radius: 50%;
  background: var(--color-surface);
  border: 3px solid var(--range-fill);
  box-shadow: 0 3px 0 var(--color-border-strong);
}
.range::-moz-range-thumb {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--color-surface);
  border: 3px solid var(--range-fill);
  box-shadow: 0 3px 0 var(--color-border-strong);
}
.range:disabled {
  opacity: 0.4;
}

/* 9 ─ Tables ------------------------------------------------------------- */
.table-wrap {
  overflow-x: auto;
  border: var(--border-w) solid var(--color-border);
  border-radius: var(--radius-lg);
  background: var(--color-surface);
}
.table {
  width: 100%;
  border-collapse: collapse;
  font-size: var(--text-sm);
}
.table th,
.table td {
  padding: var(--space-3) var(--space-4);
  text-align: left;
  vertical-align: middle;
}
.table th {
  font-size: var(--text-xs);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-ink-faint);
  border-bottom: var(--border-w) solid var(--color-border);
}
.table tbody tr + tr td {
  border-top: 1px solid var(--color-border);
}
.table tbody tr:hover td {
  background: var(--color-surface-2);
}
.table td.num,
.table th.num {
  text-align: right;
}
.table--rank td:first-child {
  width: 3ch;
  font-weight: var(--weight-black);
  color: var(--color-ink-faint);
}

/* 10 ─ Stats & gauges ---------------------------------------------------- */
.stat {
  display: flex;
  flex-direction: column;
  gap: 2px;
}
.stat__label {
  font-size: var(--text-xs);
  font-weight: var(--weight-black);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-ink-faint);
}
.stat__value {
  font-size: var(--text-2xl);
  font-weight: var(--weight-black);
  line-height: 1.05;
  font-variant-numeric: tabular-nums;
}
.stat__value--xl {
  font-size: var(--text-4xl);
}
.stat__unit {
  font-size: 0.5em;
  font-weight: var(--weight-bold);
  color: var(--color-ink-muted);
  margin-left: 2px;
}
.stat__delta {
  font-size: var(--text-sm);
  font-weight: var(--weight-black);
}
.delta--good {
  color: var(--color-primary-strong);
}
.delta--bad {
  color: var(--color-danger);
}
.delta--flat {
  color: var(--color-ink-faint);
}
.stat-row {
  display: grid;
  gap: var(--space-4);
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
}

/* linear gauge with target marker */
.gauge {
  --gauge-pct: 0%;
  --gauge-target: 100%;
  --gauge-color: var(--color-primary);
  position: relative;
  height: 14px;
  border-radius: 7px;
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  overflow: visible;
}
.gauge__fill {
  height: 100%;
  width: var(--gauge-pct);
  border-radius: inherit;
  background: var(--gauge-color);
  transition:
    width var(--dur-slow) var(--ease-out),
    background var(--dur-base);
}
.gauge__target {
  position: absolute;
  top: -5px;
  bottom: -5px;
  left: var(--gauge-target);
  width: 3px;
  background: var(--color-ink);
  border-radius: 2px;
}
.gauge__target::after {
  content: '🎯';
  position: absolute;
  top: -20px;
  left: 50%;
  transform: translateX(-50%);
  font-size: 12px;
}
.gauge--ok {
  --gauge-color: var(--color-primary);
}
.gauge--warn {
  --gauge-color: var(--color-warn);
}
.gauge--bad {
  --gauge-color: var(--color-danger);
}
.gauge-row {
  display: grid;
  grid-template-columns: 110px 1fr auto;
  gap: var(--space-3);
  align-items: center;
  font-size: var(--text-sm);
}
.gauge-row__label {
  font-weight: var(--weight-black);
  color: var(--color-ink-muted);
}
.gauge-row__value {
  font-weight: var(--weight-black);
  font-variant-numeric: tabular-nums;
  min-width: 6ch;
  text-align: right;
}

/* progress bar (XP, lessons) */
.progress {
  height: 16px;
  border-radius: 8px;
  background: var(--color-surface-2);
  overflow: hidden;
  border: 1px solid var(--color-border);
}
.progress__bar {
  height: 100%;
  background: var(--color-primary);
  border-radius: inherit;
  transition: width var(--dur-slow) var(--ease-out);
}
.progress--spark .progress__bar {
  background: var(--color-spark);
}

/* 11 ─ Overlays ---------------------------------------------------------- */
.backdrop {
  position: fixed;
  inset: 0;
  background: rgba(15, 19, 26, 0.45);
  z-index: 200;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--dur-base);
}
.backdrop[data-open='true'] {
  opacity: 1;
  pointer-events: auto;
}
.drawer {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  width: min(440px, 100%);
  background: var(--color-surface);
  border-left: var(--border-w) solid var(--color-border);
  z-index: 201;
  transform: translateX(100%);
  transition: transform var(--dur-slow) var(--ease-out);
  display: flex;
  flex-direction: column;
}
.drawer[data-open='true'] {
  transform: translateX(0);
}
.drawer__head {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-4);
  border-bottom: var(--border-w) solid var(--color-border);
}
.drawer__body {
  padding: var(--space-4);
  overflow-y: auto;
  flex: 1;
}
.modal {
  position: fixed;
  inset: 0;
  z-index: 202;
  display: grid;
  place-items: center;
  padding: var(--space-4);
  pointer-events: none;
}
.modal__panel {
  width: min(520px, 100%);
  max-height: 90vh;
  overflow-y: auto;
  background: var(--color-surface);
  border: var(--border-w) solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--space-8);
  box-shadow: var(--shadow-pop);
  transform: translateY(16px) scale(0.98);
  opacity: 0;
  transition:
    transform var(--dur-slow) var(--ease-bounce),
    opacity var(--dur-base);
}
.modal[data-open='true'] {
  pointer-events: auto;
}
.modal[data-open='true'] .modal__panel {
  transform: none;
  opacity: 1;
}
.toast-stack {
  position: fixed;
  left: 50%;
  bottom: var(--space-6);
  transform: translateX(-50%);
  z-index: 300;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  width: min(480px, calc(100% - 2 * var(--space-4)));
  pointer-events: none;
}
.toast {
  pointer-events: auto;
  display: flex;
  gap: var(--space-3);
  align-items: flex-start;
  padding: var(--space-3) var(--space-4);
  background: var(--color-ink);
  color: var(--color-inverse);
  border-radius: var(--radius-lg);
  font-weight: var(--weight-bold);
  font-size: var(--text-sm);
  box-shadow: var(--shadow-pop);
  animation: toast-in var(--dur-slow) var(--ease-bounce);
}
.toast--good {
  background: var(--color-primary-strong);
  color: #fff;
}
.toast--bad {
  background: var(--color-danger-strong);
  color: #fff;
}
@keyframes toast-in {
  from {
    transform: translateY(16px);
    opacity: 0;
  }
}
.popover {
  position: absolute;
  z-index: 150;
  width: min(320px, 90vw);
  padding: var(--space-4);
  background: var(--color-surface);
  border: var(--border-w) solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-float);
  font-size: var(--text-sm);
}

/* 12 ─ Game & learn primitives ------------------------------------------ */
/* objective card: what to reach, three gauges */
.objective {
  border: var(--border-w) solid var(--color-spark);
  background: var(--color-spark-soft);
  border-radius: var(--radius-lg);
  padding: var(--space-4) var(--space-5);
}
.objective__title {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-weight: var(--weight-black);
  margin-bottom: var(--space-3);
}
.objective__stars {
  margin-left: auto;
  letter-spacing: 2px;
  font-size: var(--text-lg);
}

/* coach line */
.coach {
  display: flex;
  gap: var(--space-3);
  align-items: flex-start;
  padding: var(--space-3) var(--space-4);
  border-radius: var(--radius-lg);
  background: var(--color-surface-2);
  font-size: var(--text-sm);
}
.coach__avatar {
  font-size: 22px;
  line-height: 1;
}
.coach--good {
  background: var(--color-primary-soft);
  color: var(--color-primary-ink);
}
.coach--bad {
  background: var(--color-danger-soft);
  color: var(--color-danger-strong);
}
.coach--warn {
  background: var(--color-warn-soft);
}

/* contextual learn card */
.learn-card {
  display: grid;
  grid-template-columns: 44px 1fr auto;
  gap: var(--space-3);
  align-items: center;
  padding: var(--space-3) var(--space-4);
  border: var(--border-w) dashed var(--color-sky);
  border-radius: var(--radius-lg);
  background: var(--color-sky-soft);
}
.learn-card__icon {
  font-size: 26px;
  text-align: center;
}
.learn-card__title {
  font-weight: var(--weight-black);
  margin: 0;
}
.learn-card__meta {
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
}
.learn-card__actions {
  display: flex;
  gap: var(--space-2);
}
@media (max-width: 480px) {
  .learn-card {
    grid-template-columns: 44px 1fr;
  }
  .learn-card__actions {
    grid-column: 1 / -1;
  }
}

/* banner (regulatory / warning) */
.banner {
  display: flex;
  gap: var(--space-3);
  align-items: flex-start;
  padding: var(--space-3) var(--space-4);
  border-radius: var(--radius-lg);
  border: var(--border-w) solid var(--color-warn);
  background: var(--color-warn-soft);
  font-size: var(--text-sm);
}
.banner--danger {
  border-color: var(--color-danger);
  background: var(--color-danger-soft);
}
.banner--info {
  border-color: var(--color-sky);
  background: var(--color-sky-soft);
}
.banner__icon {
  font-size: 20px;
  line-height: 1.2;
}

/* guess grid (Griddle) */
.guess-row {
  display: grid;
  grid-template-columns: 1.6fr repeat(4, 1fr);
  gap: 6px;
}
.guess-cell {
  min-height: 48px;
  border-radius: var(--radius-md);
  display: grid;
  place-items: center;
  font-weight: var(--weight-black);
  font-size: var(--text-sm);
  background: var(--color-surface-2);
  border: var(--border-w) solid var(--color-border);
  text-align: center;
  padding: 0 4px;
}
.guess-cell--hit {
  background: var(--color-primary);
  border-color: var(--color-primary-strong);
  color: #fff;
}
.guess-cell--near {
  background: var(--color-spark);
  border-color: var(--color-spark-strong);
  color: #3b2a00;
}
.guess-cell--miss {
  background: var(--color-surface-2);
  color: var(--color-ink-muted);
}
.guess-cell--empty {
  border-style: dashed;
}

/* result modal contents */
.result-hero {
  text-align: center;
}
.result-hero__emoji {
  font-size: 56px;
  line-height: 1;
  margin-bottom: var(--space-3);
}
.result-hero .stat__value {
  font-size: var(--text-3xl);
}
.xp-pop {
  display: inline-block;
  font-weight: var(--weight-black);
  color: var(--color-spark-strong);
  animation: xp-pop var(--dur-slow) var(--ease-bounce);
}
@keyframes xp-pop {
  from {
    transform: scale(0.6);
    opacity: 0;
  }
}

/* streak / level chips */
.level-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 12px;
  border-radius: var(--radius-pill);
  background: var(--color-ink);
  color: var(--color-inverse);
  font-size: var(--text-xs);
  font-weight: var(--weight-black);
}

/* 13 ─ Utilities --------------------------------------------------------- */
.visually-hidden {
  position: absolute !important;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}
.text-center {
  text-align: center;
}
.text-right {
  text-align: right;
}
.mt-0 {
  margin-top: 0 !important;
}
.mt-2 {
  margin-top: var(--space-2);
}
.mt-4 {
  margin-top: var(--space-4);
}
.mt-6 {
  margin-top: var(--space-6);
}
.mt-8 {
  margin-top: var(--space-8);
}
.mb-2 {
  margin-bottom: var(--space-2);
}
.mb-4 {
  margin-bottom: var(--space-4);
}
.mb-6 {
  margin-bottom: var(--space-6);
}
.w-full {
  width: 100%;
}
.flex-1 {
  flex: 1;
}
.nowrap {
  white-space: nowrap;
}
.sr-live {
  position: absolute;
  left: -9999px;
}
.hide-mobile {
  display: none;
}
@media (min-width: 720px) {
  .hide-mobile {
    display: initial;
  }
  .hide-desktop {
    display: none;
  }
}
.skeleton {
  background: linear-gradient(
    90deg,
    var(--color-surface-2) 25%,
    var(--color-border) 50%,
    var(--color-surface-2) 75%
  );
  background-size: 200% 100%;
  animation: shimmer 1.4s infinite;
  border-radius: var(--radius-sm);
  color: transparent !important;
}
@keyframes shimmer {
  to {
    background-position: -200% 0;
  }
}

/* 14 ─ Glossary (drawer, <dfn> popover, /glossary page) ------------------ */
glossary-drawer {
  display: contents;
}
glossary-drawer .drawer[data-open='false'] {
  visibility: hidden;
  transition:
    transform var(--dur-slow) var(--ease-out),
    visibility var(--dur-slow);
}
.gloss-rows {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}
.gloss-row {
  padding: var(--space-3);
  border: var(--border-w) solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-surface);
}
.gloss-row__name {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex-wrap: wrap;
  font-weight: var(--weight-black);
}
.gloss-row__def {
  margin: var(--space-2) 0 0;
  font-size: var(--text-sm);
  color: var(--color-ink-muted);
}
.gloss-row__see {
  margin: var(--space-2) 0 0;
}
.gloss-link {
  color: var(--color-sky);
  font: inherit;
  font-weight: var(--weight-bold);
  text-decoration: underline;
  text-underline-offset: 3px;
}
.gloss-row.is-target,
.gterm.is-target {
  border-color: var(--color-primary);
  background: var(--color-primary-soft);
}
.gloss-list {
  display: grid;
  gap: var(--space-4);
  grid-template-columns: repeat(auto-fill, minmax(min(100%, 300px), 1fr));
}
.gterm {
  scroll-margin-top: calc(var(--header-h) + var(--space-4));
}
.gterm__name {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex-wrap: wrap;
  margin: 0 0 var(--space-2);
  font-size: var(--text-lg);
  line-height: var(--leading-snug);
}
.gterm__def {
  color: var(--color-ink-muted);
  font-size: var(--text-sm);
}
.gterm__see {
  margin: var(--space-3) 0 0;
}
.gloss-pop__term {
  display: block;
  font-size: var(--text-sm);
}
.gloss-pop__def {
  margin: var(--space-2) 0 var(--space-3);
  color: var(--color-ink-muted);
}

/* 15 ─ Lessons (/learn/<slug>, rendered by scripts/build-lessons.mjs) ------ */
.lesson {
  font-size: var(--text-md);
}
.lesson > * + * {
  margin-top: var(--space-4);
}
.lesson h3 {
  margin: var(--space-10) 0 var(--space-3);
  font-size: var(--text-xl);
}
.lesson h4 {
  margin: var(--space-6) 0 var(--space-2);
  font-size: var(--text-lg);
  color: var(--color-ink-muted);
}
.lesson > h3:first-child,
.lesson > h4:first-child {
  margin-top: 0;
}
.lesson ul,
.lesson ol {
  margin: 0 0 var(--space-4);
  padding-left: var(--space-6);
}
.lesson li + li {
  margin-top: var(--space-2);
}
.lesson sup a {
  font-size: var(--text-xs);
  font-weight: var(--weight-bold);
  text-decoration: none;
}
/* reference lists quote bare URLs — never let one push the page sideways */
.lesson a {
  overflow-wrap: anywhere;
}
/* some stat cards hold a phrase, not a number — let it wrap on a phone */
.lesson .stat__value {
  font-size: var(--text-xl);
  overflow-wrap: break-word;
  hyphens: auto;
}
@media (max-width: 460px) {
  .lesson .stat__value {
    font-size: var(--text-lg);
  }
}
/* lesson titles are long: the CTA and prev/next must wrap, not overflow */
.lesson-cta .btn,
.lesson-nav .btn {
  white-space: normal;
  text-align: center;
  max-width: 100%;
}
.lesson .table-wrap,
.lesson .stat-row,
.lesson .callout,
.lesson .formula {
  margin-block: var(--space-6);
}
.lesson .stat.card {
  text-align: center;
}

/* callout — a boxed aside inside lesson prose */
.callout {
  padding: var(--space-5);
  border-radius: var(--radius-lg);
  border-left: 4px solid var(--color-primary);
  background: var(--color-primary-soft);
  color: var(--color-ink);
}
.callout h4 {
  margin: 0 0 var(--space-2);
  color: var(--color-ink);
}
.callout > *:last-child {
  margin-bottom: 0;
}
.callout--sky {
  border-left-color: var(--color-sky);
  background: var(--color-sky-soft);
}
.callout--spark {
  border-left-color: var(--color-spark-strong);
  background: var(--color-spark-soft);
}
.callout--warn {
  border-left-color: var(--color-warn);
  background: var(--color-warn-soft);
}

/* formula — a worked calculation lifted from the source material */
.formula {
  padding: var(--space-5);
  border-radius: var(--radius-md);
  background: var(--color-surface-2);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  line-height: 1.8;
  overflow-x: auto;
}

/* quiz options (/learn/quiz-energy) */
.quiz-option {
  display: flex;
  gap: var(--space-3);
  align-items: flex-start;
  padding: var(--space-3) var(--space-4);
  border: var(--border-w) solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-surface);
  cursor: pointer;
}
.quiz-option:hover {
  border-color: var(--color-border-strong);
}
.quiz-option input {
  margin-top: 4px;
  accent-color: var(--color-primary);
}
.quiz-option.is-correct {
  border-color: var(--color-primary);
  background: var(--color-primary-soft);
}
.quiz-option.is-wrong {
  border-color: var(--color-danger);
  background: var(--color-danger-soft);
}