/* Jiajia — public/styles.css (full file, no truncation) */
:root {
  /* Dark is default; we'll override in light mode below */
  color-scheme: dark light;
  --bg: #0b0d10;
  --fg: #e8eef4;
  --muted: #9fb0c3;
  --accent: #7aa2ff;
  --bonus: #6ee7b7;
  --danger: #ffa94d;
  /* high-contrast stroke for display text in dark theme */
  --stroke: rgba(255,255,255,0.92);
}
@media (prefers-color-scheme: light) {
  :root {
    --bg: #ffffff;
    --fg: #0b0d10;
    --muted: #666666;
    --accent: #2f6fed;
    --bonus: #12b886;
    --danger: #e8590c;
    /* high-contrast stroke for display text in light theme */
    --stroke: rgba(0,0,0,0.92);
  }
}
* { box-sizing: border-box; }
html, body { height: 100%; margin: 0; }
body { background: var(--bg); color: var(--fg); font: 400 18px/1.4 ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, "Helvetica Neue", Arial; }

/* Optional: kid-friendly rounded font (drop KidsRounded.woff2 into /public/fonts/) */
@font-face {
  font-family: 'KidsRounded';
  src: url('/public/fonts/KidsRounded.woff2') format('woff2');
  font-weight: 400 900;
  font-style: normal;
  font-display: swap;
}

.app { min-height: 100%; display: grid; grid-template-rows: auto 1fr auto; }

/* Top bar */
.topbar { position: fixed; top: 0; left: 0; right: 0; display: flex; justify-content: space-between; align-items: center; gap: 8px; padding: 6px 12px; z-index: 10; }

.burger { position: static; font-size: 22px; background: transparent; color: var(--fg); border: 1px solid color-mix(in oklab, var(--fg), transparent 80%); border-radius: 12px; padding: 6px 10px; cursor: pointer; }

.center { height: 100vh; display: grid; place-content: center; gap: 16px; text-align: center; padding-inline: 16px; }
.brand #brand-logo { height: 24px; width: auto; display: block; margin-bottom: 4px; }
.brand #brand-text { line-height: 1; }
.problem {
  /* Bigger, friendly display with outline and glow */
  font-size: clamp(56px, 10vw, 112px);
  font-weight: 900;
  letter-spacing: 0.5px;
  line-height: 1.02;
  font-family: 'KidsRounded', ui-rounded, ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  /* Stronger outline for contrast */
  /* Stronger, higher-contrast outline */
  -webkit-text-stroke: 3px var(--stroke);
  text-shadow:
    0 2px 0 rgba(0,0,0,0.20),
    0 6px 18px rgba(0,0,0,0.50),
    0 12px 36px rgba(0,0,0,0.60),
    0 0 24px rgba(255,255,255,0.25);
}
.problem .problem__text { display: inline-block; will-change: transform, opacity; font-size: 1em; }

/* + cyan core */
.problem.op-add .problem__text{
  background: linear-gradient(180deg,#CFFFFF 0%,#4DE3FF 55%,#00B8FF 100%);
  -webkit-background-clip:text;background-clip:text;-webkit-text-fill-color:transparent;color:transparent;
  text-shadow: 0 0 2px #00B8FF, 0 0 10px #00B8FF, 0 0 24px #00B8FF, 0 0 44px rgba(0,184,255,.9);
}
/* − magenta core */
.problem.op-sub .problem__text{
  background: linear-gradient(180deg,#FFD6F2 0%,#FF5CCF 55%,#FF00A8 100%);
  -webkit-background-clip:text;background-clip:text;-webkit-text-fill-color:transparent;color:transparent;
  text-shadow: 0 0 2px #FF00A8, 0 0 10px #FF00A8, 0 0 24px #FF00A8, 0 0 44px rgba(255,0,168,.9);
}
/* × amber laser */
.problem.op-mul .problem__text{
  background: linear-gradient(180deg,#FFF3D6 0%,#FFC94D 55%,#FF9900 100%);
  -webkit-background-clip:text;background-clip:text;-webkit-text-fill-color:transparent;color:transparent;
  text-shadow: 0 0 2px #FF9900, 0 0 10px #FF9900, 0 0 24px #FF9900, 0 0 44px rgba(255,153,0,.9);
}
/* ÷ toxic green */
.problem.op-div .problem__text{
  background: linear-gradient(180deg,#E7FFDF 0%,#8CFF66 55%,#39FF14 100%);
  -webkit-background-clip:text;background-clip:text;-webkit-text-fill-color:transparent;color:transparent;
  text-shadow: 0 0 2px #39FF14, 0 0 10px #39FF14, 0 0 24px #39FF14, 0 0 44px rgba(57,255,20,.9);
}

#answer {
  /* Match the big problem font look & feel */
  font-family: 'KidsRounded', ui-rounded, ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  font-weight: 900;
  font-size: clamp(44px, 8vw, 88px);
  letter-spacing: 0.5px;
  line-height: 1.05;
  text-align: center;

  /* Visual style */
  background: transparent;
  color: var(--fg);
  /* text-outline support is spotty on inputs, but keep it for Safari/WebKit that honor it */
  -webkit-text-stroke: 2px var(--stroke);
  text-shadow:
    0 2px 0 rgba(0,0,0,0.20),
    0 6px 18px rgba(0,0,0,0.40),
    0 0 22px color-mix(in oklab, var(--accent), transparent 30%);

  /* Box */
  width: min(60vw, 340px);
  padding: 10px 14px;
  margin-inline: auto;
  border: 2px solid color-mix(in oklab, var(--fg), transparent 60%);
  border-radius: 14px;
  outline: none;
  caret-color: currentColor;
}
/* Remove number spinners */
#answer::-webkit-outer-spin-button,
#answer::-webkit-inner-spin-button { -webkit-appearance: none; margin: 0; }
#answer[type=number] { -moz-appearance: textfield; }
#answer:focus { border-color: var(--accent); box-shadow: 0 0 0 4px color-mix(in oklab, var(--accent), transparent 75%); }

.bonus-bar { position: fixed; left: 0; right: 0; bottom: 0; height: 12px; background: color-mix(in oklab, var(--fg), transparent 93%); }
.bonus-fill { height: 100%; width: 100%; background: linear-gradient(90deg, var(--bonus), color-mix(in oklab, var(--bonus), #000 10%)); transition: width 80ms linear; }

/* Floating points */
#points-float-container { position: fixed; inset: 0; pointer-events: none; }
.points-float { position: absolute; left: 50%; top: calc(50% - 5vh); transform: translate(-50%, -50%);
  font-weight: 800; opacity: 0; animation: floatUp 900ms ease-out forwards; }
.points-bonus { font-size: 42px; color: var(--bonus); text-shadow: 0 0 10px color-mix(in oklab, var(--bonus), #000 40%); }
.points-base { font-size: 28px; color: var(--accent); text-shadow: 0 0 8px color-mix(in oklab, var(--accent), #000 50%); }
.points-wrong { font-size: 72px; /* ~300% for strong feedback */ color: var(--danger); text-shadow: 0 0 12px color-mix(in oklab, var(--danger), #000 45%); line-height: 1; }
@keyframes floatUp { from { transform: translate(-50%, -50%) translateY(10px); opacity: 0; } to { transform: translate(-50%, -50%) translateY(-40px); opacity: 1; } }

/* Next-level progress indicator */
.advance-indicator {
  position: fixed;
  left: 12px;
  bottom: 20px; /* sits just above the 12px bonus bar */
  z-index: 9;   /* under the topbar (10), above page */
  font-size: 14px;
  color: var(--muted);
  background: color-mix(in oklab, var(--fg), transparent 92%);
  padding: 6px 10px;
  border-radius: 10px;
  backdrop-filter: blur(2px);
  pointer-events: none;
}

/* Get Ready popover */
.getready[hidden] { display: none; }
.getready {
  position: fixed;
  inset: 0;
  z-index: 20; /* above topbar (10) and indicator (9) */
  display: grid;
  place-items: center;
  /* Opaque panel only; let clicks pass through outside the panel */
  pointer-events: none;
  background: transparent;
}
.getready__panel {
  width: min(92vw, 520px);
  background: var(--bg); /* opaque */
  color: var(--fg);
  border: 1px solid color-mix(in oklab, var(--fg), transparent 85%);
  border-radius: 16px;
  box-shadow: 0 10px 30px color-mix(in oklab, #000, transparent 60%);
  padding: 18px 20px 16px;
  pointer-events: auto; /* make panel clickable */
}
.getready__panel h2 { margin: 0 0 8px; font-size: 20px; }
.getready__panel p { margin: 0 0 14px; font-size: 15px; line-height: 1.4; color: var(--muted); }

.go-btn {
  display: inline-block;
  font-size: 16px;
  font-weight: 700;
  padding: 10px 16px;
  border-radius: 12px;
  border: 1px solid color-mix(in oklab, var(--accent), transparent 60%);
  background: color-mix(in oklab, var(--accent), #000 10%);
  color: white;
  cursor: pointer;
}
.go-btn:focus { outline: none; box-shadow: 0 0 0 4px color-mix(in oklab, var(--accent), transparent 70%); }
.go-btn:hover { filter: brightness(1.05); }

/* Explicit theme override via data-theme attribute */
html[data-theme="light"] :root, html[data-theme="light"] {
  --bg: #ffffff;
  --fg: #0b0d10;
  --muted: #666666;
  --accent: #2f6fed;
  --bonus: #12b886;
  --danger: #e8590c;
}
html[data-theme="dark"] :root, html[data-theme="dark"] {
  --bg: #0b0d10;
  --fg: #e8eef4;
  --muted: #9fb0c3;
  --accent: #7aa2ff;
  --bonus: #6ee7b7;
  --danger: #ffa94d;
}

/* Burger menu panel */
.menu {
  position: fixed;          /* fixed to viewport */
  right: 12px;
  top: 44px;                /* tighter to topbar */
  bottom: 0;                /* extend to bottom of screen */
  width: min(92vw, 320px);  /* compact panel */
  overflow: auto;           /* panel scrolls only if taller than viewport */
  background: var(--bg);    /* opaque background */
  color: var(--fg);
  border: 1px solid color-mix(in oklab, var(--fg), transparent 85%);
  border-radius: 12px;
  box-shadow: 0 10px 30px color-mix(in oklab, #000, transparent 60%);
  z-index: 100;             /* above page; below modals */
}
.menu[hidden] { display: none; }
.menu__section { padding: 6px 8px; }
.menu__label { opacity: .8; font-size: 12px; margin: 4px 8px 6px; }
.menu__item { width: 100%; text-align: left; padding: 9px 12px; border-radius: 10px; border: 1px solid color-mix(in oklab, var(--fg), transparent 88%); background: transparent; color: var(--fg); cursor: pointer; }
.menu__item + .menu__item { margin-top: 6px; }
.menu__item:hover { background: color-mix(in oklab, var(--fg), transparent 95%); }

/* Language selector (dropdown-style) */
.lang-select { position: relative; padding: 6px 8px; }
.lang-select__button {
  width: 100%; display: inline-flex; align-items: center; justify-content: space-between; gap: 10px;
  padding: 8px 10px; border-radius: 10px; cursor: pointer;
  background: color-mix(in oklab, var(--bg), #000 4%); color: var(--fg);
  border: 1px solid color-mix(in oklab, var(--fg), transparent 90%);
}
.lang-select__button:hover { background: color-mix(in oklab, var(--fg), transparent 95%); }
.lang-select__button::after { content: '▾'; opacity: 0.7; font-size: 12px; margin-left: 6px; }
.lang-select__popup {
  position: absolute; left: 8px; right: 8px; top: calc(100% + 6px);
  background: color-mix(in oklab, var(--bg), #000 6%);
  color: var(--fg);
  border: 1px solid color-mix(in oklab, var(--fg), transparent 85%);
  border-radius: 12px; box-shadow: 0 10px 30px color-mix(in oklab, #000, transparent 60%);
  max-height: 45vh; overflow: auto; z-index: 200; /* scroll inside popup only */
}
.lang-select__list { list-style: none; margin: 0; padding: 6px; }
.lang-select__item { margin: 2px 0; }
.lang-select__option {
  width: 100%; text-align: left; padding: 8px 10px; border-radius: 10px; cursor: pointer;
  background: transparent; color: var(--fg);
  border: 1px solid color-mix(in oklab, var(--fg), transparent 92%);
}
.lang-select__option:hover { background: color-mix(in oklab, var(--fg), transparent 95%); }
.lang-select__option.is-selected { border-color: color-mix(in oklab, var(--accent), transparent 40%); box-shadow: 0 0 0 3px color-mix(in oklab, var(--accent), transparent 80%); }

/* Language selector (dropdown-style) */
.lang-select { position: relative; padding: 6px 8px; }
.lang-select__button {
  width: 100%; display: inline-flex; align-items: center; justify-content: space-between; gap: 10px;
  padding: 8px 10px; border-radius: 10px; cursor: pointer;
  background: transparent; color: var(--fg);
  border: 1px solid color-mix(in oklab, var(--fg), transparent 90%);
}
.lang-select__button:hover { background: color-mix(in oklab, var(--fg), transparent 95%); }
.lang-select__button::after {
  content: '▾'; opacity: 0.7; font-size: 12px; margin-left: 6px;
}
.lang-select__popup {
  position: absolute; left: 8px; right: 8px; top: calc(100% + 6px);
  background: color-mix(in oklab, var(--bg), #000 6%);
  color: var(--fg);
  border: 1px solid color-mix(in oklab, var(--fg), transparent 85%);
  border-radius: 12px; box-shadow: 0 10px 30px color-mix(in oklab, #000, transparent 60%);
  max-height: 45vh; overflow: auto; z-index: 20;
}
.lang-select__list { list-style: none; margin: 0; padding: 6px; }
.lang-select__item { margin: 2px 0; }
.lang-select__option {
  width: 100%; text-align: left; padding: 8px 10px; border-radius: 10px; cursor: pointer;
  background: transparent; color: var(--fg);
  border: 1px solid color-mix(in oklab, var(--fg), transparent 92%);
}
.lang-select__option:hover { background: color-mix(in oklab, var(--fg), transparent 95%); }
.lang-select__option.is-selected {
  border-color: color-mix(in oklab, var(--accent), transparent 40%);
  box-shadow: 0 0 0 3px color-mix(in oklab, var(--accent), transparent 80%);
}

/* History Browser popover */
.history-browser[hidden] { display: none; }
.history-browser {
  position: fixed; inset: 0; z-index: 25;
  background: color-mix(in oklab, var(--bg), #000 35%);
  display: grid; place-items: center;
}
.history-browser__panel {
  width: min(96vw, 880px);
  max-height: 80vh;
  display: flex;
  flex-direction: column;
  overflow: hidden; /* keep header pinned; scroll inner content */
  background: var(--bg);
  color: var(--fg);
  border: 1px solid color-mix(in oklab, var(--fg), transparent 85%);
  border-radius: 16px; box-shadow: 0 10px 30px color-mix(in oklab, #000, transparent 55%);
  padding: 16px;
}
.history-browser__header { display: flex; justify-content: space-between; align-items: center; gap: 12px; margin-bottom: 10px; flex: 0 0 auto; }
.history-browser__title { font-size: 18px; font-weight: 700; }
.history-browser__close { background: transparent; color: var(--fg); border: 1px solid color-mix(in oklab, var(--fg), transparent 80%); border-radius: 10px; padding: 6px 10px; cursor: pointer; }

/* Tables inside History Browser */
.table { width: 100%; border-collapse: collapse; font-size: 14px; table-layout: auto; }
.table thead th { position: sticky; top: 0; background: color-mix(in oklab, var(--bg), #000 10%); }
.table th, .table td { padding: 8px 10px; border-bottom: 1px solid color-mix(in oklab, var(--fg), transparent 88%); text-align: left; }
.table tr:hover { background: color-mix(in oklab, var(--fg), transparent 96%); }

/* History Browser content areas scroll inside the panel */
#hb-summaries-view,
#hb-day-view {
  flex: 1 1 auto;
  min-height: 0;   /* enables child to shrink in flex column */
  overflow: auto;
}

/* Keep the Day Details sub-header pinned at the top of its scroll area */
#hb-day-view .history-browser__header {
  position: sticky;
  top: 0;
  z-index: 2;
  background: var(--bg);
  margin-top: 0;          /* override inline margin if present */
  padding-top: 6px;       /* small breathing room under the main header */
}

/* Problem animations (respect reduced motion) */
@media (prefers-reduced-motion: no-preference) {
  .problem .problem__text.anim-in { animation: probIn 260ms cubic-bezier(.22,.95,.2,1) both; }
  .problem .problem__text.is-correct { animation: probOutRight 300ms cubic-bezier(.2,.9,.2,1) both; }
  .problem .problem__text.is-wrong { animation: probShake 220ms linear both; }
}
@supports not ((-webkit-background-clip: text) or (background-clip: text)) {
  /* Fallback: show solid text color when gradient-clip isn't supported */
  .problem .problem__text { color: var(--fg) !important; background: none !important; }
}

@keyframes probIn {
  from { opacity: 0; transform: translateX(-22vw) rotate(-2deg) scale(.98); filter: blur(0.3px); }
  60%  { opacity: 1; transform: translateX(6px) rotate(0.2deg) scale(1.01); filter: blur(0); }
  to   { opacity: 1; transform: translateX(0) rotate(0) scale(1); filter: blur(0); }
}

@keyframes probOutRight {
  from { opacity: 1; transform: translateX(0) scale(1); }
  to   { opacity: 0; transform: translateX(140px) scale(.96); }
}
@keyframes probShake {
  0%   { transform: translateX(0); }
  20%  { transform: translateX(-10px); }
  40%  { transform: translateX(10px); }
  60%  { transform: translateX(-6px); }
  80%  { transform: translateX(6px); }
  100% { transform: translateX(0); }
}
/* ==========================
   Ghost Input + Mirrored Answer (Option B)
   --------------------------
   Enable by adding `ghost-mode` to <body> and rendering a mirror element
   (e.g., <span id="answer-mirror" class="answer-mirror"></span>) near the problem text.
   JS should keep the real #answer focused (for mobile keyboard) but hidden
   and copy its value into #answer-mirror.
   ========================== */

/* Hide but keep #answer focusable in ghost mode (DON'T use display:none) */
body.ghost-mode #answer {
  position: fixed !important;
  top: -9999px !important; left: -9999px !important;
  width: 1px !important; height: 1px !important;
  opacity: 0 !important; padding: 0 !important; margin: 0 !important;
  border: 0 !important; box-shadow: none !important;
}

/* Mirrored answer display — matches problem typography */
.answer-mirror {
  display: inline-block;
  min-width: 1ch;
  text-align: center;
  /* Inherit the exact typography (size, family, weight, line-height) from .problem */
  font: inherit;
  letter-spacing: inherit;
  line-height: inherit;
  -webkit-text-stroke: 3px var(--stroke);
  text-shadow:
    0 2px 0 rgba(0,0,0,0.20),
    0 6px 18px rgba(0,0,0,0.50),
    0 12px 36px rgba(0,0,0,0.60),
    0 0 24px rgba(255,255,255,0.25);
  /* Default solid fallback (will be overridden by op-specific gradient rules) */
  color: var(--fg);
}

/* Apply the same neon gradients per operation to the mirrored answer */
.problem.op-add .answer-mirror {
  background: linear-gradient(180deg,#CFFFFF 0%,#4DE3FF 55%,#00B8FF 100%);
  -webkit-background-clip:text; background-clip:text; -webkit-text-fill-color:transparent; color:transparent;
  text-shadow: 0 0 2px #00B8FF, 0 0 10px #00B8FF, 0 0 24px #00B8FF, 0 0 44px rgba(0,184,255,.9);
}
.problem.op-sub .answer-mirror {
  background: linear-gradient(180deg,#FFD6F2 0%,#FF5CCF 55%,#FF00A8 100%);
  -webkit-background-clip:text; background-clip:text; -webkit-text-fill-color:transparent; color:transparent;
  text-shadow: 0 0 2px #FF00A8, 0 0 10px #FF00A8, 0 0 24px #FF00A8, 0 0 44px rgba(255,0,168,.9);
}
.problem.op-mul .answer-mirror {
  background: linear-gradient(180deg,#FFF3D6 0%,#FFC94D 55%,#FF9900 100%);
  -webkit-background-clip:text; background-clip:text; -webkit-text-fill-color:transparent; color:transparent;
  text-shadow: 0 0 2px #FF9900, 0 0 10px #FF9900, 0 0 24px #FF9900, 0 0 44px rgba(255,153,0,.9);
}
.problem.op-div .answer-mirror {
  background: linear-gradient(180deg,#E7FFDF 0%,#8CFF66 55%,#39FF14 100%);
  -webkit-background-clip:text; background-clip:text; -webkit-text-fill-color:transparent; color:transparent;
  text-shadow: 0 0 2px #39FF14, 0 0 10px #39FF14, 0 0 24px #39FF14, 0 0 44px rgba(57,255,20,.9);
}

/* When reduced motion is allowed, animate the mirrored answer similarly */
@media (prefers-reduced-motion: no-preference) {
  .answer-mirror.anim-in    { animation: probIn 260ms cubic-bezier(.22,.95,.2,1) both; }
  .answer-mirror.is-correct { animation: probOutRight 300ms cubic-bezier(.2,.9,.2,1) both; }
  .answer-mirror.is-wrong   { animation: probShake 220ms linear both; }
}


/* --- Pill toggles & segmented control (Theme Mode & options) --- */
.toggle-row { display:flex; align-items:center; justify-content:space-between; gap:12px; padding:8px 10px; border:1px solid color-mix(in oklab, var(--fg), transparent 88%); border-radius:10px; }
.toggle-row + .toggle-row { margin-top:6px; }

.switch {
  --h: 26px; --w: 48px;
  position: relative; width: var(--w); height: var(--h);
  background: color-mix(in oklab, var(--fg), transparent 90%);
  border: 1px solid color-mix(in oklab, var(--fg), transparent 85%);
  border-radius: var(--h); cursor: pointer; flex: 0 0 auto;
  transition: background .2s ease, border-color .2s ease;
}
.switch::after{
  content:''; position:absolute; top:2px; left:2px; width: calc(var(--h) - 4px); height: calc(var(--h) - 4px);
  background: var(--bg); border-radius: 999px; box-shadow: 0 1px 2px rgba(0,0,0,0.25);
  transition: transform .2s ease;
}
.switch.is-on{
  background: color-mix(in oklab, var(--accent), #000 12%);
  border-color: color-mix(in oklab, var(--accent), transparent 40%);
}
.switch.is-on::after{ transform: translateX(calc(var(--w) - var(--h))); }

.segmented {
  display: inline-flex; border: 1px solid color-mix(in oklab, var(--fg), transparent 85%);
  border-radius: 999px; overflow: hidden; background: transparent;
}
.segmented__btn {
  padding: 6px 10px; font-size: 13px; cursor: pointer; border: 0; background: transparent; color: var(--fg);
}
.segmented__btn + .segmented__btn { border-left: 1px solid color-mix(in oklab, var(--fg), transparent 90%); }
.segmented__btn.is-active { background: color-mix(in oklab, var(--fg), transparent 92%); }