/* Kids Math — styles. Light and dark, iPad-first. */

:root {
  --bg: #f6f3ee;
  --card: #ffffff;
  --ink: #1d1f24;
  --muted: #6b7079;
  --line: #e3ded6;
  --accent: #2f6fed;
  --accent-ink: #ffffff;
  --orange: #f08a24;
  --blue: #2f6fed;
  --good: #22a06b;
  --good-bg: #e3f6ec;
  --bad: #d9453b;
  --bad-bg: #fde8e6;
  --key: #ffffff;
  --key-press: #ebe7e0;
  --shadow: 0 1px 2px rgba(0,0,0,.06), 0 6px 20px rgba(0,0,0,.06);
  --radius: 18px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #15171c;
    --card: #1f2229;
    --ink: #eef0f4;
    --muted: #9aa1ad;
    --line: #2c3038;
    --accent: #5b8def;
    --orange: #f59e3f;
    --blue: #5b8def;
    --good: #3cc585;
    --good-bg: #1b3a2c;
    --bad: #f0665c;
    --bad-bg: #44231f;
    --key: #262a33;
    --key-press: #343946;
    --shadow: 0 1px 2px rgba(0,0,0,.4), 0 6px 20px rgba(0,0,0,.3);
  }
}

* { box-sizing: border-box; -webkit-tap-highlight-color: transparent; }
html, body { height: 100%; margin: 0; }
body {
  background: var(--bg);
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, system-ui, sans-serif;
  font-size: 18px;
  line-height: 1.4;
  touch-action: manipulation;
  padding: env(safe-area-inset-top) env(safe-area-inset-right) env(safe-area-inset-bottom) env(safe-area-inset-left);
}

#app { max-width: 760px; margin: 0 auto; padding: 16px; min-height: 100%; display: flex; flex-direction: column; }
.screen { display: flex; flex-direction: column; gap: 16px; flex: 1; }
.screen.center { align-items: center; justify-content: center; text-align: center; }

h1 { font-size: 34px; margin: 8px 0 0; letter-spacing: -0.01em; }
h2 { font-size: 24px; margin: 0; }
p { margin: 0; }
.muted { color: var(--muted); }
.small { font-size: 15px; }

/* Top bar */
.topbar { display: flex; align-items: center; justify-content: space-between; gap: 12px; min-height: 44px; }
.topbar .title { font-weight: 700; font-size: 20px; flex: 1; text-align: center; }
.topbar .spacer { width: 88px; }

button {
  font: inherit;
  color: inherit;
  border: 0;
  cursor: pointer;
  user-select: none;
  -webkit-user-select: none;
}
button:active { transform: translateY(1px); }

.btn {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 12px 18px;
  font-size: 18px;
  font-weight: 600;
  min-height: 48px;
  box-shadow: var(--shadow);
}
.btn.primary { background: var(--accent); color: var(--accent-ink); border-color: transparent; }
.btn.ghost { background: transparent; border-color: transparent; box-shadow: none; color: var(--accent); font-weight: 600; min-width: 88px; }
.btn.danger { color: var(--bad); }
.btn.wide { width: 100%; }
.btn:disabled { opacity: .45; cursor: default; }
.row { display: flex; gap: 12px; flex-wrap: wrap; }
.row > .btn { flex: 1; }

/* Cards */
.cards { display: grid; gap: 14px; grid-template-columns: 1fr; }
@media (min-width: 560px) { .cards.two { grid-template-columns: 1fr 1fr; } }

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 18px 20px;
  box-shadow: var(--shadow);
  text-align: left;
  display: flex;
  align-items: center;
  gap: 16px;
  width: 100%;
}
.card .icon {
  width: 56px; height: 56px; flex: none;
  border-radius: 16px;
  display: grid; place-items: center;
  font-size: 30px; font-weight: 800; color: #fff;
  font-family: Georgia, "Times New Roman", serif;
}
.card .icon.orange { background: var(--orange); }
.card .icon.blue { background: var(--blue); }
.card .body { flex: 1; min-width: 0; }
.card .name { font-size: 20px; font-weight: 700; }
.card .desc { color: var(--muted); font-size: 15px; margin-top: 2px; }
.card .meta { font-size: 15px; color: var(--muted); text-align: right; flex: none; }
.card .meta b { color: var(--ink); font-size: 18px; display: block; }
.card.subject { padding: 26px 22px; }
.card.subject .name { font-size: 26px; }

/* Quiz */
.quiz { gap: 12px; }
.status { display: flex; justify-content: space-between; align-items: center; color: var(--muted); font-size: 16px; font-weight: 600; }
.status .streak { color: var(--orange); }
.progressbar { height: 6px; background: var(--line); border-radius: 3px; overflow: hidden; }
.progressbar > div { height: 100%; background: var(--accent); transition: width .25s; }

.question {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 28px 20px;
  text-align: center;
  font-size: 44px;
  font-weight: 700;
  letter-spacing: 0.01em;
  min-height: 120px;
  display: grid;
  place-items: center;
  white-space: pre-wrap;
  font-variant-numeric: tabular-nums;
}
.question.long { font-size: 26px; font-weight: 600; line-height: 1.35; }
.question .qt { display: flex; flex-direction: column; gap: 6px; align-items: center; }
.question .lead { font-size: 18px; font-weight: 600; color: var(--muted); }
.question.long .line:not(:first-child), .question.long .lead + .line { font-size: 40px; font-weight: 700; }
.question .var { font-family: Georgia, "Times New Roman", serif; font-style: italic; font-weight: 600; }

.answer {
  display: flex; align-items: center; justify-content: center; gap: 12px;
  background: var(--card);
  border: 2px solid var(--line);
  border-radius: 14px;
  min-height: 68px;
  font-size: 36px;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  transition: border-color .15s, background .15s;
}
.answer .label { color: var(--muted); font-size: 20px; font-weight: 600; }
.answer .caret { display: inline-block; width: 2px; height: 36px; background: var(--accent); animation: blink 1s steps(1) infinite; }
@keyframes blink { 50% { opacity: 0; } }
.answer.good { border-color: var(--good); background: var(--good-bg); }
.answer.bad { border-color: var(--bad); background: var(--bad-bg); }

.feedback { min-height: 52px; text-align: center; font-size: 18px; font-weight: 600; display: grid; place-items: center; }
.feedback.good { color: var(--good); }
.feedback.bad { color: var(--bad); }
.feedback .explain { color: var(--muted); font-weight: 500; font-size: 16px; display: block; margin-top: 2px; }

.keypad {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
  margin-top: auto;
}
.key {
  background: var(--key);
  border: 1px solid var(--line);
  border-radius: 14px;
  font-size: 28px;
  font-weight: 600;
  min-height: 62px;
  box-shadow: var(--shadow);
  font-variant-numeric: tabular-nums;
}
.key:active { background: var(--key-press); }
.key.fn { font-size: 22px; color: var(--muted); }
.key.check { background: var(--accent); color: var(--accent-ink); border-color: transparent; font-size: 22px; }
.key.check.next { background: var(--good); }
.key:disabled { opacity: .35; }
@media (min-height: 900px) { .key { min-height: 76px; } }

/* Results */
.score { text-align: center; padding: 24px 0 8px; }
.score .big { font-size: 64px; font-weight: 800; line-height: 1; letter-spacing: -0.02em; }
.score .sub { color: var(--muted); margin-top: 8px; font-size: 17px; }
.list { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); overflow: hidden; }
.list .item { display: flex; justify-content: space-between; align-items: center; gap: 12px; padding: 12px 18px; border-top: 1px solid var(--line); }
.list .item:first-child { border-top: 0; }
.list .item .q { font-weight: 600; white-space: pre-wrap; }
.list .item .a { color: var(--muted); font-size: 16px; text-align: right; flex: none; }
.list .item .a b { color: var(--good); }
.list .item .a s { color: var(--bad); }
.list .head { padding: 12px 18px; font-weight: 700; background: var(--bg); }

/* Progress grid */
.grid-wrap { overflow-x: auto; }
.grid { display: grid; grid-template-columns: 34px repeat(12, 1fr); gap: 3px; min-width: 420px; }
.grid .h { font-size: 13px; color: var(--muted); font-weight: 700; display: grid; place-items: center; height: 30px; }
.grid .c { height: 30px; border-radius: 6px; background: var(--line); display: grid; place-items: center; font-size: 12px; font-weight: 600; color: transparent; }
.grid .c.good { background: var(--good); color: #fff; }
.grid .c.ok { background: var(--orange); color: #fff; }
.grid .c.bad { background: var(--bad); color: #fff; }
.legend { display: flex; gap: 14px; font-size: 14px; color: var(--muted); flex-wrap: wrap; }
.legend i { display: inline-block; width: 14px; height: 14px; border-radius: 4px; vertical-align: -2px; margin-right: 5px; }

table { width: 100%; border-collapse: collapse; font-size: 16px; }
th, td { text-align: left; padding: 10px 14px; border-top: 1px solid var(--line); }
th { color: var(--muted); font-size: 14px; font-weight: 700; border-top: 0; }
td.num, th.num { text-align: right; font-variant-numeric: tabular-nums; }

.footer { margin-top: auto; text-align: center; color: var(--muted); font-size: 14px; padding-top: 8px; }
.error { background: var(--bad-bg); color: var(--bad); border-radius: 14px; padding: 16px; text-align: left; white-space: pre-wrap; font-size: 15px; }