:root {
  --bg: #f6f8fc;
  --surface: #ffffff;
  --surface-2: #eef2f9;
  --text: #1d2433;
  --muted: #5f6b80;
  --border: #d9e0ec;
  --primary: #2f6fde;
  --primary-ink: #ffffff;
  --ok: #1f9d55;
  --ok-bg: #e3f6eb;
  --bad: #d64545;
  --bad-bg: #fde8e8;
  --c-initial: #2f6fde;
  --c-initial-bg: #e6eefc;
  --c-medial: #1f9d55;
  --c-medial-bg: #e3f6eb;
  --c-final: #d9781a;
  --c-final-bg: #fdf0e1;
  --c-tone: #8a4fd8;
  --c-tone-bg: #f1e9fc;
  --shadow: 0 2px 8px rgba(29, 36, 51, .08);
  --radius: 14px;
  --font: "Microsoft JhengHei", "PingFang TC", "Noto Sans TC", "Heiti TC", system-ui, sans-serif;
  --font-kai: "DFKai-SB", "BiauKai", "TW-Kai", "Kaiti TC", "標楷體", var(--font);
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #12161f;
    --surface: #1b212d;
    --surface-2: #242c3a;
    --text: #e8edf6;
    --muted: #9aa6bb;
    --border: #313b4d;
    --primary: #5b8ff0;
    --ok: #4cc386;
    --ok-bg: #173628;
    --bad: #f07272;
    --bad-bg: #3c1c1f;
    --c-initial: #7aa6f5;
    --c-initial-bg: #1f2d4a;
    --c-medial: #5fd193;
    --c-medial-bg: #173628;
    --c-final: #f2a65a;
    --c-final-bg: #3a2a17;
    --c-tone: #b88bf2;
    --c-tone-bg: #2d2242;
    --shadow: 0 2px 8px rgba(0, 0, 0, .35);
    color-scheme: dark;
  }
}

* { box-sizing: border-box; }
html, body { margin: 0; }
body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  -webkit-tap-highlight-color: transparent;
  min-height: 100dvh;
}
button { font: inherit; color: inherit; cursor: pointer; }

.topbar {
  position: sticky; top: 0; z-index: 10;
  display: flex; align-items: center; gap: 8px;
  padding: calc(env(safe-area-inset-top) + 8px) 12px 8px;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
}
.topbar h1 { flex: 1; margin: 0; font-size: 1.2rem; text-align: center; }
.icon-btn {
  width: 40px; height: 40px; border: 0; border-radius: 10px;
  background: transparent; font-size: 1.4rem; line-height: 1;
}
.icon-btn:hover { background: var(--surface-2); }
.icon-btn[hidden] { visibility: hidden; display: block; }

main { max-width: 760px; margin: 0 auto; padding: 16px 16px calc(env(safe-area-inset-bottom) + 24px); outline: none; }

/* 首頁 */
.hero { text-align: center; margin: 8px 0 20px; }
.hero .big { font-family: var(--font-kai); font-size: 2.6rem; letter-spacing: .2em; color: var(--primary); }
.hero p { color: var(--muted); margin: 6px 0 0; }
.menu { display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); gap: 12px; }
.menu-card {
  display: flex; gap: 12px; align-items: center; text-align: left;
  padding: 16px; border: 1px solid var(--border); border-radius: var(--radius);
  background: var(--surface); box-shadow: var(--shadow);
  transition: transform .1s;
}
.menu-card:active { transform: scale(.98); }
.menu-card .ico { font-size: 2rem; }
.menu-card h2 { margin: 0; font-size: 1.1rem; }
.menu-card p { margin: 2px 0 0; color: var(--muted); font-size: .85rem; }
.menu-card .stars { margin-top: 4px; font-size: .85rem; color: #e0a800; min-height: 1.1em; }
.stats { margin-top: 20px; text-align: center; color: var(--muted); font-size: .9rem; }
.install { margin: 16px auto 0; display: block; }

/* 共用按鈕 */
.btn {
  padding: 10px 18px; border-radius: 12px; border: 1px solid var(--border);
  background: var(--surface); font-size: 1rem;
}
.btn.primary { background: var(--primary); color: var(--primary-ink); border-color: var(--primary); }
.btn:disabled { opacity: .5; cursor: default; }
.row { display: flex; gap: 10px; justify-content: center; flex-wrap: wrap; margin-top: 16px; }

/* 認識符號 */
.section-title { margin: 20px 0 8px; font-size: 1rem; color: var(--muted); }
.sym-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(64px, 1fr)); gap: 8px; }
.sym {
  aspect-ratio: 1; border-radius: 12px; border: 2px solid transparent;
  font-family: var(--font-kai); font-size: 2rem; position: relative;
}
.sym.initial { background: var(--c-initial-bg); color: var(--c-initial); }
.sym.medial { background: var(--c-medial-bg); color: var(--c-medial); }
.sym.final { background: var(--c-final-bg); color: var(--c-final); }
.sym.tone { background: var(--c-tone-bg); color: var(--c-tone); font-family: var(--font); }
.sym.learned::after { content: "✓"; position: absolute; top: 2px; right: 6px; font-size: .75rem; font-family: var(--font); }
.sym:focus-visible, .sym.active { border-color: currentColor; }

.detail {
  margin-top: 16px; padding: 16px; border-radius: var(--radius);
  background: var(--surface); border: 1px solid var(--border); box-shadow: var(--shadow);
  display: flex; gap: 16px; align-items: center; flex-wrap: wrap;
}
.detail .bigsym { font-family: var(--font-kai); font-size: 4.5rem; width: 96px; text-align: center; }
.detail .info { flex: 1; min-width: 180px; }
.detail .emoji { font-size: 2.6rem; }
.tag { display: inline-block; padding: 2px 8px; border-radius: 99px; font-size: .8rem; }
.tag.initial { background: var(--c-initial-bg); color: var(--c-initial); }
.tag.medial { background: var(--c-medial-bg); color: var(--c-medial); }
.tag.final { background: var(--c-final-bg); color: var(--c-final); }
.tag.tone { background: var(--c-tone-bg); color: var(--c-tone); }

/* 直式注音（國字右側） */
.word { display: inline-flex; gap: 2px; font-family: var(--font-kai); }
.zc { display: inline-flex; align-items: center; }
.zc .han { font-size: 1em; line-height: 1; }
.zc .zy { display: inline-flex; align-items: center; font-size: .36em; line-height: 1.05; margin-left: .1em; }
.zc .zy-col { display: inline-flex; flex-direction: column; align-items: center; }
.zc .zy-tone { width: .7em; text-align: left; }
.zc .zy-neutral { line-height: .6; }
.zc .zy-hide { visibility: hidden; }
.word-lg { font-size: 3.4rem; }
.word-md { font-size: 2.2rem; }

/* 測驗 */
.quiz-head { display: flex; justify-content: space-between; align-items: center; color: var(--muted); font-size: .9rem; }
.progress { height: 8px; background: var(--surface-2); border-radius: 99px; overflow: hidden; margin: 8px 0 16px; }
.progress > div { height: 100%; background: var(--primary); transition: width .3s; }
.prompt {
  text-align: center; padding: 20px 12px; border-radius: var(--radius);
  background: var(--surface); border: 1px solid var(--border); box-shadow: var(--shadow);
}
.prompt .emoji { font-size: 3.4rem; line-height: 1.2; }
.prompt .hint { color: var(--muted); margin-top: 6px; }
.play {
  width: 96px; height: 96px; border-radius: 50%; border: 0;
  background: var(--primary); color: var(--primary-ink); font-size: 2.4rem;
  box-shadow: var(--shadow);
}
.play:active { transform: scale(.95); }
.options { display: grid; grid-template-columns: repeat(2, 1fr); gap: 10px; margin-top: 16px; }
.opt {
  padding: 16px 8px; border-radius: 12px; border: 2px solid var(--border);
  background: var(--surface); font-size: 1.6rem; font-family: var(--font-kai); min-height: 72px;
}
.opt.small { font-size: 1.25rem; }
.opt.ok { border-color: var(--ok); background: var(--ok-bg); color: var(--ok); }
.opt.bad { border-color: var(--bad); background: var(--bad-bg); color: var(--bad); }
.feedback { min-height: 1.6em; text-align: center; margin-top: 12px; font-weight: bold; }
.feedback.ok { color: var(--ok); }
.feedback.bad { color: var(--bad); }

.result { text-align: center; padding: 24px 12px; }
.result .stars { font-size: 3rem; color: #e0a800; letter-spacing: .1em; }
.result .score { font-size: 1.4rem; margin: 8px 0; }

/* 拼音打字 */
.slots { display: flex; justify-content: center; gap: 10px; flex-wrap: wrap; margin-top: 14px; }
.slot {
  min-width: 72px; padding: 8px 10px; border-radius: 10px; border: 2px dashed var(--border);
  font-family: var(--font-kai); font-size: 1.5rem; text-align: center; min-height: 52px;
}
.slot.current { border-color: var(--primary); border-style: solid; }
.slot.done { border-color: var(--ok); border-style: solid; color: var(--ok); background: var(--ok-bg); }
.slot .caret { display: inline-block; width: 2px; height: 1em; background: var(--primary); vertical-align: middle; animation: blink 1s steps(1) infinite; }
@keyframes blink { 50% { opacity: 0; } }
.shake { animation: shake .35s; }
@keyframes shake { 20%, 60% { transform: translateX(-6px); } 40%, 80% { transform: translateX(6px); } }

.kb { margin-top: 16px; user-select: none; }
.kb-row { display: flex; justify-content: center; gap: 4px; margin-bottom: 4px; }
.kb-row:nth-child(2) { padding-left: 2%; }
.kb-row:nth-child(3) { padding-left: 4%; }
.kb-row:nth-child(4) { padding-left: 6%; }
.key {
  flex: 1 1 0; max-width: 58px; min-width: 0; height: 54px; border-radius: 8px;
  border: 1px solid var(--border); background: var(--surface); position: relative;
  font-family: var(--font-kai); font-size: 1.35rem; padding: 0;
  box-shadow: 0 1px 0 var(--border);
}
.key .k { position: absolute; top: 2px; left: 4px; font-size: .6rem; color: var(--muted); font-family: var(--font); }
.key.initial { color: var(--c-initial); }
.key.medial { color: var(--c-medial); }
.key.final { color: var(--c-final); }
.key.tone { color: var(--c-tone); background: var(--c-tone-bg); }
.key.next { outline: 3px solid #e0a800; outline-offset: -2px; }
.key.pressed { transform: translateY(1px); background: var(--surface-2); }
.kb-row.fn .key { max-width: none; font-family: var(--font); font-size: .95rem; }
.kb-row.fn .key.space { flex: 4 1 0; }
.toggle { display: inline-flex; gap: 6px; align-items: center; color: var(--muted); font-size: .9rem; }

.toast {
  position: fixed; left: 50%; bottom: calc(env(safe-area-inset-bottom) + 20px); transform: translateX(-50%) translateY(20px);
  background: var(--text); color: var(--bg); padding: 10px 16px; border-radius: 10px;
  opacity: 0; pointer-events: none; transition: .25s; max-width: calc(100% - 32px); font-size: .9rem;
}
.toast.show { opacity: 1; transform: translateX(-50%); }

@media (max-width: 480px) {
  .key { height: 48px; font-size: 1.15rem; }
  .kb-row { gap: 3px; }
  .word-lg { font-size: 2.8rem; }
  .opt { font-size: 1.35rem; }
  .opt.small { font-size: 1.05rem; }
}

/* 英文學習者輔助 */
.lang-btn { font-size: 1rem; font-weight: bold; width: auto; min-width: 40px; padding: 0 8px; }
.py { color: var(--muted); font-family: var(--font); font-size: .95rem; letter-spacing: .02em; }
.meaning { color: var(--muted); font-size: 1rem; margin-top: 4px; }
.tip { margin-top: 6px; font-size: .95rem; line-height: 1.4; }
.tip b { font-family: var(--font); color: var(--primary); }
.settings { display: flex; justify-content: center; margin-top: 16px; }
.sym { display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 0; line-height: 1.1; }
.sym .sym-py { font-family: var(--font); font-size: .8rem; opacity: .85; }
.group-head { display: flex; align-items: center; justify-content: space-between; gap: 8px; }
.small-btn { padding: 4px 12px; font-size: .85rem; margin-top: 12px; }
html[lang="en"] { --font: "Segoe UI", -apple-system, BlinkMacSystemFont, Roboto, "Microsoft JhengHei", "PingFang TC", "Noto Sans TC", sans-serif; }
.detail { position: sticky; bottom: calc(env(safe-area-inset-bottom) + 8px); z-index: 5; }