/* Kaikou 開口 — mobile-first learner interface.
   Designed portrait at 360–430px, then widened at 720px.
   Single stylesheet, no build step, no framework. */

/* ------------------------------------------------------------------ tokens */
:root {
  color-scheme: dark;

  --bg: #0b1120;
  --bg-raised: #111a2e;
  --bg-card: #16223a;
  --bg-inset: #0e1729;
  --line: #24334f;
  --line-strong: #33456a;

  --text: #eef2ff;
  --text-muted: #a3b0cc;
  --text-faint: #6f7f9e;

  --accent: #fb923c;
  --accent-press: #f97316;
  --accent-ink: #1a0f04;

  --ok: #34d399;
  --ok-ink: #052e21;
  --warn: #fbbf24;
  --warn-ink: #2a1c02;
  --bad: #f87171;
  --bad-ink: #2b0b0b;

  --radius: 14px;
  --radius-sm: 10px;
  --radius-pill: 999px;

  --shadow: 0 1px 2px rgb(0 0 0 / .3), 0 8px 24px rgb(0 0 0 / .22);
  --shadow-raise: 0 2px 4px rgb(0 0 0 / .35), 0 14px 34px rgb(0 0 0 / .3);

  --tap: 48px;
  --gutter: 1.15rem;
  --maxw: 42rem;

  --sans: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue",
          "PingFang TC", "Noto Sans TC", "Noto Sans", sans-serif;
  --cjk: "PingFang TC", "Hiragino Sans CNS", "Microsoft JhengHei",
         "Noto Sans TC", "Source Han Sans TC", var(--sans);
}

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

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
}

body {
  margin: 0;
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
  background: var(--bg);
  color: var(--text);
  font-family: var(--sans);
  font-size: 1.0625rem;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow-wrap: break-word;
}

h1, h2, h3 { line-height: 1.25; margin: 0 0 .5rem; font-weight: 650; letter-spacing: -.012em; }
h1 { font-size: clamp(1.75rem, 6.5vw, 2.35rem); }
h2 { font-size: clamp(1.25rem, 4.5vw, 1.55rem); }
h3 { font-size: clamp(1.1rem, 4vw, 1.3rem); }
p { margin: 0 0 .9rem; }
p:last-child { margin-bottom: 0; }

a { color: var(--accent); text-underline-offset: .18em; }
a:hover { color: var(--accent-press); }

code, .kbd {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: .88em;
}
.kbd {
  background: var(--bg-inset);
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: .05em .45em;
}

:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 3px;
  border-radius: 6px;
}

.muted { color: var(--text-muted); }
.small { font-size: .875rem; }
.lede { color: var(--text-muted); font-size: 1.075rem; max-width: 38ch; }
.eyebrow {
  color: var(--accent);
  font-size: .78rem;
  font-weight: 700;
  letter-spacing: .11em;
  text-transform: uppercase;
  margin: 0 0 .35rem;
}

.skip-link {
  position: absolute; left: -9999px; top: 0;
  background: var(--accent); color: var(--accent-ink);
  padding: .75rem 1.15rem; z-index: 100; border-radius: 0 0 var(--radius-sm) 0;
}
.skip-link:focus { left: 0; }

/* ----------------------------------------------------------------- header */
.site-header {
  position: sticky; top: 0; z-index: 20;
  display: flex; align-items: center; justify-content: space-between;
  gap: .75rem;
  padding: .7rem var(--gutter);
  padding-top: calc(.7rem + env(safe-area-inset-top));
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(14px) saturate(150%);
  -webkit-backdrop-filter: blur(14px) saturate(150%);
  border-bottom: 1px solid var(--line);
}

.wordmark {
  display: flex; align-items: baseline; gap: .55rem;
  text-decoration: none; color: var(--text);
  min-height: var(--tap); align-content: center; flex-wrap: wrap;
}
.wordmark-cjk {
  font-family: var(--cjk);
  font-size: 1.55rem; font-weight: 700; letter-spacing: .06em;
}
.wordmark-latin {
  font-size: .82rem; font-weight: 600; letter-spacing: .16em;
  text-transform: uppercase; color: var(--text-faint);
}

.site-nav { display: flex; gap: .25rem; }
.site-nav a {
  display: inline-flex; align-items: center;
  min-height: var(--tap); padding: 0 .85rem;
  border-radius: var(--radius-pill);
  color: var(--text-muted); text-decoration: none;
  font-size: .95rem; font-weight: 550;
}
.site-nav a[aria-current="page"] {
  background: var(--bg-card); color: var(--text);
}

/* ------------------------------------------------------------------ main */
.site-main {
  flex: 1 0 auto;
  width: 100%; max-width: var(--maxw);
  margin: 0 auto;
  padding: 1.4rem var(--gutter) 3rem;
  padding-bottom: calc(3rem + env(safe-area-inset-bottom));
}

.page-head { margin-bottom: 1.5rem; }
.crumbs {
  display: flex; gap: .5rem; align-items: center; flex-wrap: wrap;
  font-size: .9rem; color: var(--text-faint);
  margin-bottom: 1.15rem;
}
.crumbs a { color: var(--text-muted); text-decoration: none; }

.section-title { margin-top: 0; }

/* ---------------------------------------------------------------- banner */
.banner {
  margin: 0;
  padding: .85rem var(--gutter);
  padding-top: calc(.85rem + env(safe-area-inset-top));
  background: var(--warn); color: var(--warn-ink);
  font-size: .95rem; font-weight: 550;
}
.banner:empty, .banner[hidden] { display: none; }
.banner a { color: inherit; }

/* ------------------------------------------------------------------- hero */
.hero {
  text-align: left;
  padding: 1.25rem 0 2.15rem;
}
.hero-wordmark {
  font-family: var(--cjk);
  font-size: clamp(3.25rem, 17vw, 5.25rem);
  font-weight: 700; letter-spacing: .08em;
  line-height: 1; margin: 0 0 .65rem;
  background: linear-gradient(180deg, var(--accent), var(--accent-press));
  -webkit-background-clip: text; background-clip: text;
  color: transparent;
}
.hero-tagline {
  font-size: clamp(1.15rem, 4.8vw, 1.45rem);
  font-weight: 600; margin-bottom: .65rem; max-width: 22ch;
}
.hero-lede { color: var(--text-muted); max-width: 40ch; }

/* ------------------------------------------------------------------ cards */
.card {
  background: var(--bg-card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.15rem;
  margin-bottom: 1.15rem;
  box-shadow: var(--shadow);
}
.card-danger { border-color: color-mix(in srgb, var(--bad) 42%, var(--line)); }

/* ---------------------------------------------------------------- buttons */
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  gap: .45rem;
  min-height: var(--tap); padding: 0 1.25rem;
  border-radius: var(--radius-pill);
  border: 1px solid transparent;
  font: inherit; font-size: 1.02rem; font-weight: 620;
  text-decoration: none; cursor: pointer;
  touch-action: manipulation;
  transition: transform .07s ease, background-color .15s ease, border-color .15s ease;
  user-select: none;
  -webkit-user-select: none;
}
.btn:active { transform: translateY(1px) scale(.985); }

.btn-primary { background: var(--accent); color: var(--accent-ink); }
.btn-primary:hover { background: var(--accent-press); color: var(--accent-ink); }

.btn-ghost {
  background: var(--bg-inset); color: var(--text);
  border-color: var(--line-strong);
}
.btn-ghost:hover { background: var(--bg-raised); color: var(--text); }

.btn-danger { background: var(--bad); color: var(--bad-ink); }
.btn-danger:hover { background: #ef4444; color: var(--bad-ink); }

.btn-danger-ghost {
  background: transparent; color: var(--bad);
  border-color: color-mix(in srgb, var(--bad) 45%, transparent);
}
.btn-danger-ghost:hover { background: color-mix(in srgb, var(--bad) 14%, transparent); color: var(--bad); }

.btn-lg { min-height: 56px; font-size: 1.12rem; padding: 0 1.75rem; }
.btn-block { width: 100%; }

.btn-icon {
  min-width: var(--tap); min-height: var(--tap);
  padding: 0; border-radius: var(--radius-pill);
  background: var(--bg-inset); color: var(--text);
  border: 1px solid var(--line-strong);
  font-size: .95rem;
}
.btn-icon:hover { background: var(--bg-raised); }

.btn[disabled], .btn[aria-disabled="true"] {
  opacity: .5; pointer-events: none;
}

.cta-row, .action-row {
  display: flex; flex-wrap: wrap; gap: .6rem;
  margin: 1.15rem 0;
}
.action-row .btn, .cta-row .btn { flex: 1 1 auto; }

/* ------------------------------------------------------------- level list */
.level-list { list-style: none; margin: 0; padding: 0; display: grid; gap: .95rem; }

.level-card {
  background: var(--bg-card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.05rem;
  box-shadow: var(--shadow);
  transition: border-color .2s ease, box-shadow .2s ease;
}
.level-card[data-state="locked"] { opacity: .52; }
.level-card[data-state="passed"] { border-color: color-mix(in srgb, var(--ok) 55%, var(--line)); }
.level-card[data-state="current"] {
  border-color: color-mix(in srgb, var(--accent) 60%, var(--line));
  box-shadow: var(--shadow-raise);
}

.level-card-head { display: flex; gap: .85rem; align-items: flex-start; }
.level-num {
  flex: 0 0 auto;
  width: 2.35rem; height: 2.35rem;
  display: grid; place-items: center;
  border-radius: var(--radius-pill);
  background: var(--bg-inset); border: 1px solid var(--line-strong);
  font-weight: 700; font-size: 1.02rem;
}
.level-card[data-state="passed"] .level-num {
  background: var(--ok); color: var(--ok-ink); border-color: transparent;
}
.level-card[data-state="current"] .level-num {
  background: var(--accent); color: var(--accent-ink); border-color: transparent;
}
.level-title { margin-bottom: .25rem; }
.level-title a { color: var(--text); text-decoration: none; }
.level-title a:hover { color: var(--accent); }
.level-outcome { color: var(--text-muted); margin-bottom: .55rem; font-size: .98rem; }

.level-meta {
  display: flex; flex-wrap: wrap; gap: .45rem .85rem;
  color: var(--text-faint); font-size: .88rem;
  margin-bottom: .85rem;
}
.level-actions { display: flex; flex-wrap: wrap; gap: .55rem; margin: 0; }
.level-actions .btn { flex: 1 1 8.5rem; }

.tag {
  display: inline-flex; align-items: center;
  padding: .12rem .6rem; border-radius: var(--radius-pill);
  font-size: .8rem; font-weight: 650; letter-spacing: .01em;
}
.tag-ok { background: var(--ok); color: var(--ok-ink); }
.tag-warn { background: var(--warn); color: var(--warn-ink); }
.tag-muted { background: var(--bg-inset); color: var(--text-muted); border: 1px solid var(--line); }

/* ------------------------------------------------------------------ items */
.item-list { list-style: none; margin: 0; padding: 0; display: grid; gap: .8rem; }

.item {
  background: var(--bg-inset);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  padding: .95rem 1rem;
}
.item-top {
  display: flex; align-items: center; justify-content: space-between; gap: .75rem;
}
.item-hanzi {
  font-family: var(--cjk);
  font-size: 1.72rem; line-height: 1.35;
  letter-spacing: .04em; margin: 0;
}
.item-pinyin {
  color: var(--accent); font-size: 1.02rem; font-weight: 600;
  margin: .15rem 0 .25rem; letter-spacing: .012em;
}
.item-english { margin: 0 0 .45rem; }
.item-hint { color: var(--text-muted); font-size: .93rem; margin-bottom: .35rem; }
.item-hint em { color: var(--text); font-style: normal; font-weight: 600; }
.item-notes { color: var(--text-faint); font-size: .9rem; margin: 0; }

/* --------------------------------------------------------------- practice */
.stage { margin-bottom: 1.25rem; }

.stage-shell {
  background: var(--bg-card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.35rem 1.15rem 1.15rem;
  box-shadow: var(--shadow);
  display: grid; gap: 1.15rem;
  justify-items: center; text-align: center;
}

.progress-track {
  width: 100%; height: .55rem;
  background: var(--bg-inset);
  border-radius: var(--radius-pill);
  overflow: hidden;
}
.progress-fill {
  height: 100%; width: 0;
  background: linear-gradient(90deg, var(--accent), var(--accent-press));
  border-radius: inherit;
  transition: width .3s ease;
}

.stage-kicker {
  color: var(--text-faint); font-size: .86rem;
  letter-spacing: .11em; text-transform: uppercase; font-weight: 700;
  margin: 0;
}

.prompt-en {
  font-size: clamp(1.45rem, 6vw, 1.95rem);
  font-weight: 650; line-height: 1.3; margin: 0;
  max-width: 18ch;
}
.prompt-hanzi {
  font-family: var(--cjk);
  font-size: clamp(2.35rem, 11vw, 3.5rem);
  line-height: 1.25; letter-spacing: .06em; margin: 0;
}
.prompt-hanzi[hidden] { display: none; }
.prompt-pinyin {
  color: var(--accent); font-size: clamp(1.15rem, 5vw, 1.45rem);
  font-weight: 620; margin: 0;
}
.prompt-hint { color: var(--text-faint); margin: 0; }

.stage-actions {
  display: flex; flex-wrap: wrap; gap: .7rem;
  width: 100%; justify-content: center;
}

/* the mic is the single dominant affordance */
.mic {
  --mic-size: 128px;
  width: var(--mic-size); height: var(--mic-size);
  border-radius: 50%;
  border: none;
  background: var(--accent); color: var(--accent-ink);
  font-size: 1.05rem; font-weight: 700;
  display: grid; place-items: center;
  cursor: pointer; touch-action: manipulation;
  box-shadow: 0 10px 30px rgb(249 115 22 / .32);
  transition: transform .12s ease, background-color .18s ease, box-shadow .18s ease;
}
.mic:hover { background: var(--accent-press); }
.mic:active { transform: scale(.95); }
.mic[data-state="listening"] {
  background: var(--bad);
  box-shadow: 0 0 0 0 rgb(248 113 113 / .55);
  animation: pulse 1.35s ease-out infinite;
}
.mic[data-state="listening"]::after {
  content: "";
  position: absolute;
  inset: 6px;
  border: 2px solid currentColor;
  border-radius: 50%;
  opacity: .38;
}
.mic { position: relative; user-select: none; -webkit-user-select: none; -webkit-touch-callout: none; }
.mic[data-state="busy"] { opacity: .65; pointer-events: none; }
.mic[disabled] { opacity: .45; pointer-events: none; }
.mic:disabled { cursor: not-allowed; box-shadow: none; }
.self-check-actions { margin-top: .8rem; }

@keyframes pulse {
  0%   { box-shadow: 0 0 0 0 rgb(248 113 113 / .5); }
  70%  { box-shadow: 0 0 0 26px rgb(248 113 113 / 0); }
  100% { box-shadow: 0 0 0 0 rgb(248 113 113 / 0); }
}

.mic-label { color: var(--text-muted); font-size: .95rem; margin: 0; }
.mic-label.mic-status-visible {
  position: fixed;
  top: calc(env(safe-area-inset-top) + 4.75rem);
  left: 50%;
  transform: translateX(-50%);
  z-index: 30;
  width: min(100%, 34rem);
  padding: .75rem 1rem;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-pill);
  background: var(--bg);
  color: var(--text);
  box-shadow: var(--shadow-raise);
  font-weight: 650;
  pointer-events: none;
}

.feedback {
  width: 100%;
  border-radius: var(--radius-sm);
  padding: .95rem 1.05rem;
  text-align: left;
  border: 1px solid var(--line);
  background: var(--bg-inset);
}
.feedback[hidden] { display: none; }
.feedback[data-verdict="correct"] {
  background: color-mix(in srgb, var(--ok) 16%, var(--bg-inset));
  border-color: color-mix(in srgb, var(--ok) 55%, var(--line));
}
.feedback[data-verdict="close"] {
  background: color-mix(in srgb, var(--warn) 16%, var(--bg-inset));
  border-color: color-mix(in srgb, var(--warn) 55%, var(--line));
}
.feedback[data-verdict="wrong"], .feedback[data-verdict="no_speech"] {
  background: color-mix(in srgb, var(--bad) 14%, var(--bg-inset));
  border-color: color-mix(in srgb, var(--bad) 50%, var(--line));
}
.feedback-head {
  display: flex; align-items: center; gap: .55rem;
  font-weight: 700; margin: 0 0 .35rem;
}
.feedback-body { color: var(--text-muted); margin: 0; font-size: .97rem; }

/* fixed thumb-zone bar for the primary action */
.action-bar {
  position: sticky; bottom: 0; z-index: 15;
  display: flex; gap: .65rem;
  margin: 1.15rem calc(var(--gutter) * -1) 0;
  padding: .85rem var(--gutter);
  padding-bottom: calc(.85rem + env(safe-area-inset-bottom));
  background: color-mix(in srgb, var(--bg) 92%, transparent);
  backdrop-filter: blur(14px) saturate(150%);
  -webkit-backdrop-filter: blur(14px) saturate(150%);
  border-top: 1px solid var(--line);
}
.action-bar .btn { flex: 1 1 auto; }

/* --------------------------------------------------------------- settings */
.field { margin-bottom: 1.15rem; }
.field > label {
  display: block; font-weight: 620; margin-bottom: .38rem; font-size: .98rem;
}
.field .help {
  color: var(--text-faint); font-size: .88rem; margin: .38rem 0 0;
}
.field-row {
  display: grid; gap: .85rem;
  grid-template-columns: repeat(auto-fit, minmax(8.5rem, 1fr));
}

input[type="text"], input[type="number"], input:not([type]),
input[type="search"], textarea, select {
  width: 100%;
  min-height: var(--tap);
  padding: .62rem .85rem;
  background: var(--bg-inset);
  color: var(--text);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-sm);
  font: inherit;
  touch-action: manipulation;
}
textarea { min-height: 5.5rem; resize: vertical; line-height: 1.55; }
select { appearance: none; padding-right: 2.25rem; }
input:focus-visible, textarea:focus-visible, select:focus-visible {
  border-color: var(--accent); outline-offset: 1px;
}
input[readonly] { color: var(--text-muted); background: var(--bg-raised); }

input[type="range"] {
  width: 100%; height: var(--tap);
  accent-color: var(--accent);
}
input[type="checkbox"] {
  width: 1.35rem; height: 1.35rem;
  accent-color: var(--accent);
  flex: 0 0 auto;
}

.field-check {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: .25rem .75rem;
  align-items: center;
}
.field-check label { margin: 0; }
.field-check .help { grid-column: 2; }

.capability { margin: 0; display: grid; gap: .1rem; }
.capability > div {
  display: flex; justify-content: space-between; gap: 1rem;
  padding: .62rem 0;
  border-bottom: 1px solid var(--line);
}
.capability > div:last-child { border-bottom: 0; }
.capability dt { color: var(--text-muted); }
.capability dd { margin: 0; font-weight: 620; text-align: right; }
.capability dd[data-ok="1"] { color: var(--ok); }
.capability dd[data-ok="0"] { color: var(--warn); }

/* ------------------------------------------------------------------ admin */
.admin-list { list-style: none; margin: 0; padding: 0; display: grid; gap: .75rem; }
.admin-row {
  display: flex; flex-wrap: wrap; gap: .75rem;
  justify-content: space-between; align-items: center;
  padding: .95rem 1rem;
  background: var(--bg-inset);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
}
.admin-row-title { font-weight: 640; margin-bottom: .2rem; }
.admin-row-title a { color: var(--text); text-decoration: none; }
.admin-row-actions { display: flex; gap: .5rem; margin: 0; flex-wrap: wrap; }

.form .btn[type="submit"] { margin-top: .35rem; }

.flash {
  border-radius: var(--radius-sm);
  padding: .85rem 1.05rem;
  margin-bottom: 1.15rem;
  font-weight: 560;
}
.flash-ok { background: color-mix(in srgb, var(--ok) 18%, var(--bg-card)); border: 1px solid color-mix(in srgb, var(--ok) 55%, var(--line)); }
.flash-err { background: color-mix(in srgb, var(--bad) 16%, var(--bg-card)); border: 1px solid color-mix(in srgb, var(--bad) 50%, var(--line)); }

/* ----------------------------------------------------------------- footer */
.site-footer {
  border-top: 1px solid var(--line);
  padding: 1.35rem var(--gutter);
  padding-bottom: calc(1.35rem + env(safe-area-inset-bottom));
  color: var(--text-faint); font-size: .88rem;
}
.site-footer p { max-width: var(--maxw); margin: 0 auto .45rem; }
.site-footer p:last-child { margin-bottom: 0; }

/* ---------------------------------------------------------------- learn */
.learn-card {
  background: var(--bg-card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.55rem 1.25rem;
  box-shadow: var(--shadow);
  display: grid; gap: 1.05rem; justify-items: center; text-align: center;
}
.learn-fallback { margin-top: 1.15rem; }

/* ------------------------------------------------------------ wide screens */
@media (min-width: 720px) {
  :root { --gutter: 1.75rem; }
  .site-main { padding-top: 2.15rem; }
  .hero { padding-top: 2.15rem; }
  .action-row .btn, .cta-row .btn { flex: 0 0 auto; }
  .mic { --mic-size: 148px; }
  .item-list { grid-template-columns: 1fr 1fr; }
  .learn-fallback .item-list { grid-template-columns: 1fr 1fr; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
    scroll-behavior: auto !important;
  }
}