/* ---------------------------------------------------------------
   Shuō Ba — design tokens

   Mobile-first, built against iPhone 16 (393 x 852pt) and 16 Pro Max
   (440 x 956pt). Light palette on :root; dark overrides in one guarded
   media block plus an explicit [data-theme] block, so the OS setting and
   the in-app toggle both work in both directions.
   --------------------------------------------------------------- */
:root {
  --bg:        #fbfaf8;
  --surface:   #ffffff;
  --surface-2: #f2efea;
  --line:      #e2ddd4;
  --text:      #1a1a1a;
  --muted:     #6b6559;
  --accent:    #c1272d;   /* Chinese red, used sparingly as the action colour */
  --accent-ink:#ffffff;
  --good:      #1f7a4d;
  --warn:      #a8620a;
  --bad:       #b3261e;
  --tone1:     #d4322c;
  --tone2:     #d18700;
  --tone3:     #1f7a4d;
  --tone4:     #2a5db0;
  --tone5:     #7c7c7c;

  --radius:    16px;
  --shadow:    0 1px 2px rgba(0,0,0,.05), 0 8px 24px rgba(0,0,0,.06);
  --font:      -apple-system, BlinkMacSystemFont, system-ui, "Segoe UI", Roboto, sans-serif;
  --font-zh:   "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  --maxw:      860px;

  /* Safe areas: 0 everywhere except notched iPhones, where the OS fills them. */
  --sat: env(safe-area-inset-top, 0px);
  --sar: env(safe-area-inset-right, 0px);
  --sab: env(safe-area-inset-bottom, 0px);
  --sal: env(safe-area-inset-left, 0px);
  --tabbar-h: 58px;
  --tap: 44px;            /* Apple HIG minimum touch target */
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg:#0f1115; --surface:#171a21; --surface-2:#1f232c; --line:#2b303b;
    --text:#e9e6e1; --muted:#9aa0ad; --accent:#e3574f; --accent-ink:#14161a;
    --good:#4ec98a; --warn:#e2a13c; --bad:#f07167;
    --tone1:#f2645e; --tone2:#e5a93a; --tone3:#4ec98a; --tone4:#6fa8ff; --tone5:#9aa0ad;
    --shadow: 0 1px 2px rgba(0,0,0,.4), 0 8px 24px rgba(0,0,0,.3);
  }
}
:root[data-theme="dark"] {
  --bg:#0f1115; --surface:#171a21; --surface-2:#1f232c; --line:#2b303b;
  --text:#e9e6e1; --muted:#9aa0ad; --accent:#e3574f; --accent-ink:#14161a;
  --good:#4ec98a; --warn:#e2a13c; --bad:#f07167;
  --tone1:#f2645e; --tone2:#e5a93a; --tone3:#4ec98a; --tone4:#6fa8ff; --tone5:#9aa0ad;
  --shadow: 0 1px 2px rgba(0,0,0,.4), 0 8px 24px rgba(0,0,0,.3);
}

* { box-sizing: border-box; }
/* Any `display` rule of ours outranks the UA's `[hidden] { display: none }`.
   Without this, hiding a nav item with el.hidden silently does nothing — which
   is exactly how the progressive nav shipped broken once. */
[hidden] { display: none !important; }
html {
  -webkit-text-size-adjust: 100%;   /* stop iOS inflating text in landscape */
  height: 100%;
}
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.55;
  min-height: 100dvh;               /* dvh, not vh: iOS Safari's URL bar moves */
  display: flex;
  flex-direction: column;
  /* Kill the grey flash on tap; we draw our own press states instead. */
  -webkit-tap-highlight-color: transparent;
  overscroll-behavior-y: none;      /* no rubber-band bounce past the app */
  text-rendering: optimizeLegibility;
}
a { color: inherit; }
h1,h2,h3 { line-height: 1.2; margin: 0 0 .4em; letter-spacing: -0.01em; }
h1 { font-size: clamp(1.5rem, 5vw, 2rem); }
h2 { font-size: 1.15rem; }
p { margin: 0 0 1em; }
kbd {
  font: inherit; font-size: .78em; padding: .05em .35em;
  border: 1px solid var(--line); border-radius: 4px; background: var(--surface-2);
}

.skip { position: absolute; left: -9999px; top: 0; z-index: 100;
  background: var(--accent); color: var(--accent-ink); padding: .6rem 1rem; }
.skip:focus { left: 0; }

/* ---------- top bar ---------- */
.topbar {
  position: sticky; top: 0; z-index: 20;
  display: flex; align-items: center; justify-content: space-between; gap: .5rem;
  background: color-mix(in srgb, var(--bg) 85%, transparent);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--line);
  padding: calc(var(--sat) + .45rem) calc(var(--sar) + 1rem) .45rem calc(var(--sal) + 1rem);
}
.brand { display: inline-flex; align-items: center; gap: .5rem; text-decoration: none; min-height: var(--tap); }
.brand-zh { font-family: var(--font-zh); font-size: 1.4rem; font-weight: 700; color: var(--accent); }
.brand-en { font-weight: 650; font-size: .9rem; display: flex; flex-direction: column; line-height: 1.1; }
.brand-en small { font-weight: 400; font-size: .68rem; color: var(--muted); }

.topbar-actions { display: flex; align-items: center; gap: .3rem; }
.icon-btn {
  display: grid; place-items: center;
  width: var(--tap); height: var(--tap); border-radius: 12px;
  color: var(--muted); text-decoration: none;
}
.icon-btn svg { width: 21px; height: 21px; fill: none; stroke: currentColor; stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round; }
.icon-btn[aria-current="page"] { color: var(--accent); background: var(--surface-2); }
.install-btn {
  font: inherit; font-size: .85rem; font-weight: 650; cursor: pointer;
  padding: .45rem .8rem; min-height: 36px; border-radius: 999px;
  background: var(--accent); color: var(--accent-ink); border: 0;
}

/* ---------- main + footer spacing ---------- */
.main {
  flex: 1; width: 100%; max-width: var(--maxw); margin: 0 auto;
  padding: 1.1rem calc(var(--sal) + 1rem) calc(var(--tabbar-h) + var(--sab) + 1.5rem) calc(var(--sar) + 1rem);
}
.main:focus { outline: none; }
.loading { color: var(--muted); padding: 2rem 0; }

/* ---------- bottom tab bar (phones) ---------- */
.tabbar {
  position: fixed; left: 0; right: 0; bottom: 0; z-index: 30;
  display: flex; align-items: stretch;
  background: color-mix(in srgb, var(--bg) 92%, transparent);
  -webkit-backdrop-filter: blur(16px);
  backdrop-filter: blur(16px);
  border-top: 1px solid var(--line);
  padding-bottom: var(--sab);        /* clears the home indicator */
  padding-left: var(--sal); padding-right: var(--sar);
}
.tabbar a {
  position: relative;
  flex: 1 1 0; min-width: 0;
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  gap: 2px; padding: .4rem .15rem;
  min-height: var(--tabbar-h);
  text-decoration: none; color: var(--muted);
  font-size: .63rem; font-weight: 600; letter-spacing: .01em;
  transition: color .15s ease, transform .1s ease;
}
.tabbar a svg { width: 23px; height: 23px; fill: none; stroke: currentColor; stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round; }
.tabbar a span { white-space: nowrap; overflow: hidden; text-overflow: ellipsis; max-width: 100%; }
.tabbar a[aria-current="page"] { color: var(--accent); }
.tabbar a:active { transform: scale(.92); }
.tabbar .wide-only { display: none; }

.badge {
  position: absolute; top: .3rem; left: 56%;
  min-width: 17px; height: 17px; padding: 0 4px;
  display: grid; place-items: center;
  background: var(--accent); color: var(--accent-ink);
  border-radius: 999px; font-size: .62rem; font-weight: 800; font-style: normal;
}

/* Tablet and up: move navigation to the top, drop the fixed bottom bar.

   The tab bar comes AFTER <main> in the DOM so that phone users — and screen
   readers — reach the content first. `position: sticky` does not reorder
   anything, so on wide screens the bar has to be pulled above the content with
   flex `order`; without this it lands at the bottom of the document. */
@media (min-width: 720px) {
  :root { --tabbar-h: 0px; }
  .topbar { order: 1; }
  .tabbar { order: 2; }
  .main   { order: 3; }
  .tabbar {
    position: sticky; top: calc(var(--sat) + 56px); bottom: auto;
    border-top: 0; border-bottom: 1px solid var(--line);
    max-width: var(--maxw); margin: 0 auto; padding: .3rem .5rem;
    gap: .15rem;
  }
  .tabbar a {
    flex: 0 0 auto; flex-direction: row; gap: .4rem;
    min-height: 40px; padding: .4rem .75rem; border-radius: 999px; font-size: .85rem;
  }
  .tabbar a svg { width: 18px; height: 18px; }
  .tabbar a[aria-current="page"] { background: var(--accent); color: var(--accent-ink); }
  .tabbar .wide-only { display: flex; }
  .tabbar a:active { transform: none; }
  .badge { position: static; margin-left: .1rem; }
  .topbar-actions .icon-btn { display: none; }
  .main { padding-bottom: 3rem; }
}

/* ---------- building blocks ---------- */
.card {
  background: var(--surface); border: 1px solid var(--line);
  border-radius: var(--radius); padding: 1.1rem; box-shadow: var(--shadow);
}
.stack > * + * { margin-top: .9rem; }
.grid { display: grid; gap: 1rem; grid-template-columns: repeat(auto-fit, minmax(230px, 1fr)); }
.row { display: flex; gap: .5rem; flex-wrap: wrap; align-items: center; }
.muted { color: var(--muted); }
.small { font-size: .85rem; }
.center { text-align: center; }

.btn {
  font: inherit; font-weight: 600; cursor: pointer;
  min-height: var(--tap);
  padding: .65rem 1.05rem; border-radius: 12px;
  border: 1px solid var(--line); background: var(--surface); color: var(--text);
  transition: transform .09s ease, background .15s ease, border-color .15s ease;
  touch-action: manipulation;        /* removes the 300ms double-tap delay */
}
.btn:hover { background: var(--surface-2); }
.btn:active { transform: scale(.96); background: var(--surface-2); }
.btn:disabled { opacity: .45; cursor: not-allowed; transform: none; }
.btn-primary { background: var(--accent); border-color: var(--accent); color: var(--accent-ink); }
.btn-primary:hover { filter: brightness(1.07); background: var(--accent); }
.btn-lg { padding: .85rem 1.4rem; font-size: 1.02rem; min-height: 50px; }
.btn-ghost { background: transparent; }
.tappable { touch-action: manipulation; -webkit-user-select: none; user-select: none; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

/* ---------- Chinese typography ---------- */
.zh { font-family: var(--font-zh); line-height: 1.35; }
.zh-xl { font-size: clamp(2.1rem, 11vw, 3.4rem); font-weight: 600; }
.zh-lg { font-size: clamp(1.55rem, 7.5vw, 2.2rem); font-weight: 600; }
.pinyin { font-size: 1.05rem; color: var(--muted); letter-spacing: .02em; }
.en { font-size: 1.02rem; }

.t1 { color: var(--tone1); } .t2 { color: var(--tone2); }
.t3 { color: var(--tone3); } .t4 { color: var(--tone4); } .t5 { color: var(--tone5); }

.tone-key { display: flex; gap: .7rem; flex-wrap: wrap; font-size: .8rem; }
.tone-key span { display: inline-flex; align-items: center; gap: .3rem; font-weight: 600; }

/* ---------- dashboard ---------- */
.hero { padding: 1.3rem; background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); }
.stat { text-align: center; padding: .8rem .4rem; background: var(--surface-2); border-radius: 12px; }
.stat b { display: block; font-size: 1.6rem; line-height: 1.1; font-variant-numeric: tabular-nums; }
.stat span { font-size: .72rem; color: var(--muted); }
.stats { display: grid; grid-template-columns: repeat(4, 1fr); gap: .45rem; }
@media (max-width: 460px) { .stats { grid-template-columns: repeat(2, 1fr); } }

.step { display: flex; gap: .75rem; align-items: flex-start; }
.step-n {
  flex: none; width: 1.7rem; height: 1.7rem; border-radius: 999px;
  background: var(--accent); color: var(--accent-ink);
  display: grid; place-items: center; font-weight: 700; font-size: .85rem;
}
.step-n.done { background: var(--good); }
.step-n.todo { background: var(--surface-2); color: var(--muted); }

.bar { height: 8px; background: var(--surface-2); border-radius: 999px; overflow: hidden; }
.bar > i { display: block; height: 100%; background: var(--good); border-radius: 999px;
  transition: width .45s cubic-bezier(.2,.8,.2,1); }

/* ---------- study surfaces ---------- */
.study {
  min-height: 300px; display: flex; flex-direction: column; justify-content: center;
  text-align: center; gap: .55rem; padding: 1.5rem 1rem;
  animation: rise .22s cubic-bezier(.2,.8,.2,1);
}
@keyframes rise { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: none; } }

.grades { display: grid; grid-template-columns: repeat(4, 1fr); gap: .4rem; }
.grade { padding: .6rem .2rem; }
.grade b { display: block; font-size: .92rem; }
.grade small { font-weight: 500; opacity: .75; font-size: .72rem; }
.grade[data-g="1"]:active { border-color: var(--bad); }
.grade[data-g="3"]:active { border-color: var(--good); }

.words { display: flex; flex-wrap: wrap; gap: .4rem; justify-content: center; }
.word { background: var(--surface-2); border-radius: 10px; padding: .35rem .55rem; text-align: center; min-width: 3.2rem; }
.word b { display: block; font-family: var(--font-zh); font-size: 1.1rem; font-weight: 600; }
.word i { display: block; font-style: normal; font-size: .7rem; color: var(--muted); }
.word u { display: block; text-decoration: none; font-size: .7rem; }

.choices { display: grid; gap: .5rem; grid-template-columns: 1fr; }
@media (min-width: 560px) { .choices { grid-template-columns: repeat(2, 1fr); } }
.choice { padding: .85rem .7rem; font-family: var(--font-zh); font-size: 1.2rem; min-height: var(--tap); }
.choice.correct { background: color-mix(in srgb, var(--good) 20%, var(--surface)); border-color: var(--good); }
.choice.wrong   { background: color-mix(in srgb, var(--bad) 18%, var(--surface));  border-color: var(--bad); animation: shake .32s; }
@keyframes shake { 0%,100%{transform:translateX(0)} 25%{transform:translateX(-5px)} 75%{transform:translateX(5px)} }

.mic {
  width: 88px; height: 88px; border-radius: 999px; font-size: 1.9rem;
  border: 2px solid var(--line); background: var(--surface); color: var(--text);
  cursor: pointer; display: grid; place-items: center; margin: 0 auto;
  touch-action: manipulation; transition: transform .1s ease, border-color .2s ease;
}
.mic:active { transform: scale(.93); }
.mic.live { border-color: var(--accent); color: var(--accent); animation: pulse 1.25s infinite; }
@keyframes pulse {
  0%   { box-shadow: 0 0 0 0 color-mix(in srgb, var(--accent) 50%, transparent); }
  100% { box-shadow: 0 0 0 20px transparent; }
}

.marks { display: flex; gap: .25rem; justify-content: center; flex-wrap: wrap; }
.mark { font-family: var(--font-zh); font-size: 1.85rem; padding: .05rem .25rem; border-radius: 8px; border-bottom: 4px solid transparent; }
.mark.ok  { color: var(--good); border-bottom-color: var(--good); }
.mark.bad { color: var(--bad);  border-bottom-color: var(--bad); }
.score { font-size: 2.5rem; font-weight: 700; line-height: 1; font-variant-numeric: tabular-nums;
  animation: pop .3s cubic-bezier(.2,1.4,.4,1); }
@keyframes pop { from { transform: scale(.7); opacity: 0; } to { transform: scale(1); opacity: 1; } }

/* ---------- dialogue ---------- */
.transcript { display: flex; flex-direction: column; gap: .4rem; margin-bottom: .2rem; }
.bubble {
  max-width: 85%; padding: .5rem .75rem; border-radius: 16px;
  background: var(--surface-2); text-align: left;
  animation: rise .2s cubic-bezier(.2,.8,.2,1);
}
.bubble.partner { align-self: flex-start; border-bottom-left-radius: 5px; }
.bubble.you {
  align-self: flex-end; border-bottom-right-radius: 5px;
  background: color-mix(in srgb, var(--accent) 14%, var(--surface));
}

/* ---------- lists ---------- */
.list { list-style: none; margin: 0; padding: 0; }
.list li { display: flex; gap: .7rem; align-items: center; padding: .6rem .1rem; border-bottom: 1px solid var(--line); }
.list li:last-child { border-bottom: 0; }
.list .zh { font-size: 1.2rem; min-width: 6rem; }
.pill { font-size: .68rem; font-weight: 700; padding: .12rem .5rem; border-radius: 999px; background: var(--surface-2); color: var(--muted); white-space: nowrap; }
.pill.new { background: color-mix(in srgb, var(--tone4) 22%, var(--surface)); color: var(--tone4); }
.pill.learning { background: color-mix(in srgb, var(--warn) 22%, var(--surface)); color: var(--warn); }
.pill.review { background: color-mix(in srgb, var(--good) 20%, var(--surface)); color: var(--good); }

.notice { padding: .75rem .9rem; border-radius: 12px; border: 1px solid var(--line); background: var(--surface-2); font-size: .88rem; text-align: left; }
.notice.warn { border-color: var(--warn); background: color-mix(in srgb, var(--warn) 12%, var(--surface)); }

/* ---------- toasts ---------- */
.toast-host {
  position: fixed; left: 50%; transform: translateX(-50%);
  bottom: calc(var(--tabbar-h) + var(--sab) + 12px);
  z-index: 60; display: flex; flex-direction: column; gap: .4rem;
  pointer-events: none; width: min(92vw, 420px);
}
@media (min-width: 720px) { .toast-host { bottom: 20px; } }
.toast {
  padding: .6rem .95rem; border-radius: 999px;
  background: var(--text); color: var(--bg);
  font-size: .88rem; font-weight: 600; text-align: center;
  box-shadow: 0 6px 24px rgba(0,0,0,.25);
  opacity: 0; transform: translateY(10px) scale(.96);
  transition: opacity .22s ease, transform .22s cubic-bezier(.2,.8,.2,1);
}
.toast.in { opacity: 1; transform: none; }
.toast-correct { background: var(--good); color: #fff; }
.toast-wrong   { background: var(--bad);  color: #fff; }
.toast-partial { background: var(--warn); color: #fff; }

/* ---------- forms ---------- */
label.field { display: block; margin-bottom: 1rem; font-weight: 600; font-size: .92rem; }
label.field small { display: block; font-weight: 400; color: var(--muted); margin-top: .1rem; }
select, input[type="range"], input[type="search"], textarea {
  font: inherit; width: 100%; margin-top: .35rem;
  /* 16px minimum stops iOS Safari zooming the page on focus. */
  font-size: 16px;
}
select, textarea, input[type="search"] {
  padding: .6rem; border-radius: 10px; border: 1px solid var(--line);
  background: var(--surface); color: var(--text); min-height: var(--tap);
  -webkit-appearance: none; appearance: none;
}
select { background-image: none; }
textarea { min-height: 120px; font-family: ui-monospace, monospace; font-size: 14px; }
input[type="range"] { height: var(--tap); accent-color: var(--accent); }

/* ---------- motion & display preferences ---------- */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: .001ms !important; animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
  }
}
@media (display-mode: standalone) {
  /* Installed: there is no browser chrome to scroll away, so lock the bounce. */
  body { overscroll-behavior: none; }
}

/* ---------- script track: pinyin + characters ---------- */
.sound-row {
  display: flex; align-items: center; gap: .6rem; width: 100%;
  text-align: left; padding: .5rem .4rem; min-height: var(--tap);
  border: 0; border-bottom: 1px solid var(--line); border-radius: 0;
}
.sound-row:last-child { border-bottom: 0; }

.trap-row {
  display: flex; flex-wrap: wrap; gap: .4rem; align-items: center;
  padding: .45rem 0; border-bottom: 1px solid var(--line); font-size: .88rem;
}
.trap-row:last-child { border-bottom: 0; }
.trap-wrong { color: var(--bad); text-decoration: line-through; }
.trap-right { color: var(--good); font-weight: 600; }

/* Components and characters are scanned, not read — a grid beats a list. */
.comp-grid {
  display: grid; gap: .5rem;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
}
.comp {
  background: var(--surface-2); border-radius: 10px; padding: .5rem .6rem;
  display: flex; flex-direction: column; gap: .1rem; font-size: .78rem;
}
.comp > b { font-size: 1.6rem; font-family: var(--font-zh); line-height: 1.1; }
.comp > span:nth-of-type(1) { font-weight: 650; font-size: .82rem; }
.comp-in { color: var(--muted); font-size: 1rem; letter-spacing: .1em; }

.char-grid {
  display: grid; gap: .4rem;
  grid-template-columns: repeat(auto-fill, minmax(78px, 1fr));
}
.char-cell {
  padding: .45rem .2rem; min-height: 76px; border-radius: 12px;
  display: flex; flex-direction: column; align-items: center; gap: 0;
}
.char-cell b { font-family: var(--font-zh); font-size: 1.75rem; font-weight: 600; line-height: 1.1; }
.char-cell i { font-style: normal; font-size: .72rem; color: var(--muted); }
.char-cell u { text-decoration: none; font-size: .64rem; color: var(--muted);
  max-width: 100%; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.char-cell.known { border-color: var(--good); background: color-mix(in srgb, var(--good) 12%, var(--surface)); }
.char-cell.known u { color: var(--good); }

/* ---------- the guided path ---------- */
.lesson-row {
  display: flex; align-items: center; gap: .6rem; width: 100%;
  text-align: left; font-weight: 550; font-size: .92rem;
  padding: .5rem .6rem; min-height: var(--tap);
}
.lesson-row:disabled { opacity: .38; }
.lesson-dot {
  flex: none; width: 1.7rem; height: 1.7rem; border-radius: 999px;
  display: grid; place-items: center;
  background: var(--surface-2); color: var(--muted);
  font-size: .78rem; font-weight: 700;
}
.lesson-dot.done { background: var(--good); color: #fff; }
.lesson-dot.now  { background: var(--accent-ink); color: var(--accent); }

/* Tone contours: the picture and the audio come from the same numbers, so a
   learner with no Mandarin voice installed can still learn tones exactly. */
.contour {
  display: grid; place-items: center; color: var(--accent);
  padding: .3rem; cursor: pointer;
}
.contour-row {
  display: grid; gap: .5rem;
  grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
}
.contour-btn {
  display: flex; flex-direction: column; align-items: center; gap: .15rem;
  color: var(--accent); padding: .6rem .4rem; min-height: 96px;
}
.contour-btn b { color: var(--text); font-size: .9rem; }
.contour-btn span { font-family: var(--font); }
.choice .contour, .choice svg { color: currentColor; }
.choice { display: flex; flex-direction: column; align-items: center; gap: .2rem; }

/* No-voice help: numbered fix steps, readable at phone width. */
.voice-steps { margin: 0; padding-left: 1.3rem; display: grid; gap: .45rem; font-size: .9rem; text-align: left; }
.voice-steps li { line-height: 1.45; }

/* Under every new word: what each character means and what it is built from. */
.char-breakdown { display: grid; gap: .35rem; text-align: left; padding: .6rem .8rem; border-radius: 12px; background: var(--surface-2); }
.char-line { display: flex; gap: .7rem; align-items: baseline; }
.char-line > .zh { font-size: 1.5rem; min-width: 1.8rem; font-weight: 600; }

/* Visually hidden but read by screen readers (answer announcements). */
.sr-only {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; border: 0;
}

/* Tone written as a number as well as a colour, for colour-blind learners. */
.tnum { font-size: .62em; margin-left: .05em; opacity: .85; }

/* "Said as ní hǎo" — the pronunciation when tone sandhi changes the spelling. */
.said-as { display: flex; gap: .45rem; justify-content: center; align-items: baseline; flex-wrap: wrap; }
.pinyin.said { font-size: .95rem; }

/* Spelling-trap reminders under a word. */
.trap-notes { display: grid; gap: .35rem; }
.trap-chip {
  font-size: .85rem; text-align: left; padding: .45rem .7rem; border-radius: 10px;
  border: 1px solid color-mix(in srgb, var(--warn) 45%, var(--line));
  background: color-mix(in srgb, var(--warn) 9%, var(--surface));
}