/* ==== Design tokens ==== */
:root {
  --color-primary: #2563EB;
  --color-primary-dark: #1D4ED8;
  --color-on-primary: #FFFFFF;
  --color-secondary: #F59E0B;
  --color-secondary-dark: #D97706;
  --color-on-secondary: #0F172A;
  --color-accent: #EC4899;
  --color-accent-dark: #DB2777;
  --color-on-accent: #000000;
  --color-background: #131B45;
  --color-foreground: #0F172A;
  --color-on-bg: #FFFFFF;
  --color-on-bg-muted: #C7D2FE;
  --color-card: #FFFFFF;
  --color-card-foreground: #0F172A;
  --color-muted: #F1F5FD;
  --color-muted-foreground: #475569;
  --color-border: #E4ECFC;
  --color-success: #16A34A;
  --color-success-dark: #15803D;
  --color-destructive: #DC2626;
  --color-on-destructive: #FFFFFF;
  --color-ring: #2563EB;

  --radius-sm: 12px;
  --radius-md: 18px;
  --radius-lg: 24px;
  --radius-xl: 32px;

  --shadow-clay: 0 8px 0 rgba(15, 23, 42, 0.12), 0 14px 24px rgba(37, 99, 235, 0.12), inset 0 2px 0 rgba(255,255,255,0.6);
  --shadow-clay-sm: 0 5px 0 rgba(15, 23, 42, 0.12), 0 8px 16px rgba(37, 99, 235, 0.10), inset 0 2px 0 rgba(255,255,255,0.6);
  --shadow-card: 0 10px 30px rgba(37, 99, 235, 0.10), 0 2px 0 rgba(255,255,255,0.8) inset;

  /* Glossy gem-button treatment: top specular shine layer, stacked in front of a 3-stop gem gradient */
  --gloss-shine: linear-gradient(180deg, rgba(255,255,255,0.65) 0%, rgba(255,255,255,0.15) 30%, rgba(255,255,255,0) 48%);
  --gloss-shine-strong: radial-gradient(ellipse 70% 55% at 32% 20%, rgba(255,255,255,0.85), rgba(255,255,255,0) 60%);
  --gloss-shadow: 0 5px 0 rgba(15,23,42,0.30), 0 10px 22px rgba(15,23,42,0.28), inset 0 2px 2px rgba(255,255,255,0.75), inset 0 -6px 10px rgba(15,23,42,0.18);
  --gloss-shadow-sm: 0 3px 0 rgba(15,23,42,0.28), 0 6px 14px rgba(15,23,42,0.22), inset 0 2px 2px rgba(255,255,255,0.7), inset 0 -4px 7px rgba(15,23,42,0.16);

  --font-heading: 'Segoe UI', Tahoma, Calibri, Arial, sans-serif;
  --font-body: 'Segoe UI', Tahoma, Calibri, Arial, sans-serif;

  --glow-1: rgba(139, 92, 246, 0.35);
  --glow-2: rgba(56, 189, 248, 0.3);
  --glow-3: rgba(99, 102, 241, 0.28);
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }

html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  overflow: hidden;
}

.inapp-escape-banner {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 300;
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
  padding: 10px 16px;
  padding-top: calc(10px + env(safe-area-inset-top, 0px));
  background: linear-gradient(180deg, #FFF3DC 0%, #FCE3B0 100%);
  border-bottom: 3px solid #6B3A02;
  color: #5A3200;
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 0.85rem;
  line-height: 1.4;
  box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}
.inapp-escape-banner span { flex: 1 1 220px; }
.inapp-escape-banner button {
  flex-shrink: 0;
  background: var(--gloss-shine-strong), linear-gradient(180deg, #FFD98F 0%, #F59E0B 100%);
  border: 2px solid #B45309;
  border-radius: var(--radius-md);
  color: #5A3200;
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 0.8rem;
  padding: 8px 14px;
  white-space: nowrap;
}

body {
  font-family: var(--font-body);
  background:
    radial-gradient(1.5px 1.5px at 15% 22%, #fff, transparent),
    radial-gradient(1px 1px at 42% 12%, #fff, transparent),
    radial-gradient(2px 2px at 68% 28%, #fff, transparent),
    radial-gradient(1px 1px at 85% 15%, #fff, transparent),
    radial-gradient(1.5px 1.5px at 92% 55%, #fff, transparent),
    radial-gradient(1px 1px at 25% 60%, #fff, transparent),
    radial-gradient(2px 2px at 10% 78%, #fff, transparent),
    radial-gradient(1px 1px at 55% 82%, #fff, transparent),
    radial-gradient(1.5px 1.5px at 78% 90%, #fff, transparent),
    radial-gradient(1px 1px at 5% 45%, #fff, transparent),
    radial-gradient(circle at 20% 15%, var(--glow-1), transparent 40%),
    radial-gradient(circle at 85% 25%, var(--glow-2), transparent 40%),
    radial-gradient(circle at 45% 90%, var(--glow-3), transparent 45%),
    linear-gradient(180deg, #0B1230 0%, #131B45 45%, #1B2A5E 100%);
  transition: background 600ms ease-out;
  color: var(--color-on-bg);
  user-select: none;
  cursor: default;
}

/* Real background photo from thầy, home screen only — other screens keep
   the CSS starfield since he scoped this image to "trang chủ". */
#screen-home {
  background: url('assets/ui/bg-home.jpg') center center / cover no-repeat;
}

button {
  font-family: inherit;
  cursor: pointer;
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
}
button:focus-visible,
.icon-btn:focus-visible {
  outline: 3px solid var(--color-ring);
  outline-offset: 3px;
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }
}

/* ==== Screens ==== */
.screen {
  position: fixed;
  inset: 0;
  display: none;
  flex-direction: column;
  align-items: center;
  overflow-y: auto;
  opacity: 0;
}
.screen.active {
  display: flex;
  opacity: 1;
  animation: screen-fade-in 220ms ease-out;
}
@keyframes screen-fade-in {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ==== Sound toggle ==== */
.top-fixed { position: fixed; top: calc(18px + env(safe-area-inset-top, 0px)); right: calc(18px + env(safe-area-inset-right, 0px)); z-index: 50; }
.settings-btn { right: calc(78px + env(safe-area-inset-right, 0px)); }

.icon-btn {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  border: 3px solid #B9C6E0;
  background: var(--gloss-shine-strong), linear-gradient(180deg, #FFFFFF 0%, #E4EBFA 55%, #C6D4F0 100%);
  color: var(--color-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--gloss-shadow-sm);
  transition: transform 150ms ease-out, box-shadow 150ms ease-out;
}
.icon-btn.is-muted {
  color: #7C8698;
  background: radial-gradient(ellipse 70% 55% at 32% 20%, rgba(255,255,255,0.35), rgba(255,255,255,0) 60%), linear-gradient(180deg, #C3CAD6 0%, #9AA4B4 55%, #7C8698 100%);
  border-color: #5B6474;
}
.icon-btn:hover { transform: translateY(-2px); }
.icon-btn:active {
  transform: translateY(2px) scale(0.96);
  box-shadow: 0 2px 0 rgba(15,23,42,0.12), inset 0 2px 0 rgba(255,255,255,0.5);
}

/* ==== Buttons ==== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  border: 3px solid transparent;
  border-radius: 999px;
  font-family: var(--font-heading);
  font-weight: 800;
  letter-spacing: 0.3px;
  padding: 16px 28px;
  font-size: 1.1rem;
  box-shadow: var(--gloss-shadow);
  text-shadow: 0 1px 2px rgba(0,0,0,0.25);
  transition: transform 150ms ease-out, box-shadow 150ms ease-out, filter 150ms ease-out;
}
.btn:hover { transform: translateY(-3px); filter: brightness(1.06); }
.btn:active {
  transform: translateY(4px) scale(0.98);
  box-shadow: 0 2px 0 rgba(15,23,42,0.3), inset 0 2px 2px rgba(255,255,255,0.5), inset 0 -3px 6px rgba(15,23,42,0.2);
}
.btn:disabled {
  opacity: 0.45;
  cursor: not-allowed;
  transform: none;
  box-shadow: var(--gloss-shadow-sm);
}

.btn-primary {
  background: var(--gloss-shine-strong), linear-gradient(180deg, #A0F0E8 0%, #2B8FA3 45%, #0E4A5C 100%);
  color: var(--color-on-primary);
  border-color: #0A2E38;
}
.btn-secondary {
  background: var(--gloss-shine-strong), linear-gradient(180deg, #D8A6FF 0%, #7C2D8F 45%, #3D0F4A 100%);
  color: #FFFFFF;
  border-color: #2A0A33;
}
.btn-xl { padding: 20px 40px; font-size: 1.25rem; }
.btn-lg { padding: 16px 28px; font-size: 1.05rem; }

/* ==== HOME ==== */
.home-wrap {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 100%;
  /* Extra bottom padding so centered content never lands underneath the
     fixed-height footer bar on shorter screens (it's opaque and would
     just hide whatever sits behind it, like the homework button). */
  padding: 40px 20px 150px;
  gap: 6px;
  text-align: center;
}

.title-hero-img {
  width: min(92vw, 480px);
  height: auto;
  margin: 10px 0 0;
}

.subtitle-img {
  width: min(70vw, 300px);
  height: auto;
  margin: 12px 0 22px;
}

.update-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 0.85rem;
  color: var(--color-on-secondary);
  background: var(--gloss-shine-strong), linear-gradient(180deg, #FFD98F 0%, #F59E0B 55%, #B45F06 100%);
  border: 2px solid #6B3A02;
  border-radius: 999px;
  padding: 5px 16px;
  margin: -14px 0 22px;
  box-shadow: var(--gloss-shadow-sm);
}

.app-version {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 0.75rem;
  color: var(--color-on-bg-muted);
  opacity: 0.7;
  margin: 14px 0 0;
}

.home-actions {
  display: flex;
  gap: 18px;
  flex-wrap: wrap;
  justify-content: center;
}
/* Real cropped gem-button artwork — button element kept for click/keyboard
   behavior, just stripped of its own chrome. */
.btn-gem-img {
  background: none;
  border: none;
  padding: 0;
  box-shadow: none;
  cursor: pointer;
  transition: transform 150ms ease-out;
}
.btn-gem-img:hover { transform: translateY(-3px); filter: brightness(1.06); }
.btn-gem-img:active { transform: translateY(3px) scale(0.98); }
.btn-gem-img img { display: block; height: 88px; width: auto; }

/* "Ôn học sinh giỏi" button: real gem-artwork background (thầy's PNG, gold
   frame + purple glass), with the icon/label drawn as a real CSS overlay
   on top since the image's own baked-in text came out unreadable. */
.btn-gifted-img { position: relative; }
.btn-gifted-icon {
  position: absolute;
  left: 17%;
  top: 50%;
  transform: translate(-50%, -50%);
  font-size: 26px;
  line-height: 1;
  pointer-events: none;
}
.btn-gifted-label {
  position: absolute;
  left: 34%;
  top: 50%;
  transform: translateY(-50%);
  width: 58%;
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 14px;
  line-height: 1.15;
  color: #fff;
  text-shadow: 0 1px 3px rgba(0,0,0,0.55);
  text-align: left;
  pointer-events: none;
}

/* Icon-only homework button (real photo/AI-teach icon comes later from
   thầy — placeholder SVG for now). */
.btn-homework-icon {
  width: 68px;
  height: 68px;
  border-radius: 50%;
  border: none;
  background: none;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-top: 6px;
  transition: transform 150ms ease-out;
  filter: drop-shadow(0 4px 8px rgba(0,0,0,0.4));
}
.btn-homework-icon img { width: 100%; height: 100%; object-fit: contain; }
.btn-homework-icon:hover { transform: translateY(-2px) scale(1.04); }
.btn-homework-icon:active { transform: translateY(2px) scale(0.96); }

/* ==== License screen ==== */
.license-title {
  font-family: 'Corbel', 'Calibri', var(--font-heading);
  font-weight: 800;
  -webkit-text-stroke: 1.2px var(--color-accent);
  font-size: clamp(1.8rem, 4.5vw, 2.6rem);
  color: var(--color-accent);
  text-shadow: 0 3px 10px rgba(0,0,0,0.35), 0 0 22px rgba(236,72,153,0.45);
  margin: 10px 0 6px;
}
.license-desc {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--color-on-bg-muted);
  max-width: 460px;
  margin: 0 0 24px;
  line-height: 1.5;
}
.license-form {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
}
.license-input {
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 1.15rem;
  letter-spacing: 2px;
  text-align: center;
  text-transform: uppercase;
  color: var(--color-primary);
  background: var(--gloss-shine), linear-gradient(180deg, #FFFFFF 0%, #EDF2FC 55%, #D7E1F5 100%);
  border: 3px solid #B9C6E0;
  border-radius: var(--radius-lg);
  padding: 16px 20px;
  min-width: 260px;
  box-shadow: var(--gloss-shadow-sm);
}
.license-input:focus {
  outline: none;
  border-color: var(--color-primary);
}
.license-error {
  margin: 18px 0 0;
  font-weight: 800;
  color: #FCA5A5;
  max-width: 460px;
}
.license-contact-input {
  text-transform: none;
  letter-spacing: normal;
  font-weight: 600;
  font-size: 0.95rem;
  min-width: 320px;
  flex-basis: 100%;
}
.license-contact-hint {
  margin: 10px 0 0;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--color-on-bg-muted);
  max-width: 460px;
  line-height: 1.4;
}

/* ==== Teacher settings modal ==== */
.settings-desc {
  color: var(--color-muted-foreground);
  font-weight: 700;
  margin: 0 0 18px;
}
.settings-avatar-row {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 20px;
}
.settings-avatar-preview {
  width: 84px;
  height: 84px;
  border-radius: 50%;
  object-fit: cover;
  border: 4px solid #B9C6E0;
  box-shadow: var(--gloss-shadow-sm);
  flex-shrink: 0;
}
.settings-avatar-actions {
  display: flex;
  flex-direction: column;
  gap: 8px;
  align-items: flex-start;
}
.settings-reset-link {
  background: none;
  border: none;
  padding: 0;
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 0.85rem;
  color: var(--color-primary);
  text-decoration: underline;
}
.settings-label {
  display: block;
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 0.95rem;
  color: var(--color-foreground);
  margin: 0 0 8px;
}
.settings-name-input {
  width: 100%;
  min-width: 0;
  text-transform: none;
  letter-spacing: normal;
  margin-bottom: 20px;
}
.settings-notif-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  margin-bottom: 20px;
  padding: 12px 14px;
  background: var(--color-muted);
  border-radius: var(--radius-md);
}
.settings-notif-row .settings-desc { margin: 2px 0 0; font-size: 0.82rem; }
.settings-notif-row .btn { flex-shrink: 0; padding: 10px 16px; font-size: 0.9rem; }
#btnSaveSettings { width: 100%; }
.settings-saved-msg {
  margin: 14px 0 0;
  text-align: center;
  font-weight: 800;
  color: var(--color-success-dark);
}

.contact-footer {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  padding: 14px 20px calc(14px + env(safe-area-inset-bottom, 0px));
  background: linear-gradient(180deg, #8A5A2E 0%, #5C3417 100%);
  border-top: 3px solid #3E2410;
  box-shadow: 0 -4px 14px rgba(0,0,0,0.35);
}
.contact-line {
  font-family: var(--font-heading);
  font-size: 0.85rem;
  font-weight: 700;
  color: #F3D48A;
  margin: 0;
}
.contact-line strong { color: #FFE9BE; }
.contact-actions {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
  justify-content: center;
}
.contact-phone-img img,
.contact-img-btn img {
  display: block;
  height: 34px;
  width: auto;
}
.contact-img-btn {
  background: none;
  border: none;
  padding: 0;
  cursor: pointer;
  transition: transform 150ms ease-out;
}
.contact-img-btn:hover { transform: translateY(-2px); }
.contact-img-btn:active { transform: translateY(1px) scale(0.97); }
.contact-web-btn:hover { transform: translateY(-2px); }
.contact-web-btn:active { transform: translateY(1px) scale(0.97); }

.mascot-game, .mascot-result {
  position: relative;
  padding: 6px;
}
.mascot-game::before, .mascot-result::before {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: 50%;
  background:
    radial-gradient(circle 5px at 50% 3%, #34D399, transparent 62%),
    radial-gradient(circle 5px at 97% 50%, #38BDF8, transparent 62%),
    radial-gradient(circle 5px at 50% 97%, #34D399, transparent 62%),
    radial-gradient(circle 5px at 3% 50%, #38BDF8, transparent 62%),
    conic-gradient(from -20deg, #C9963A, #F3D48A, #C9963A, #8B5E1F, #C9963A, #F3D48A, #C9963A, #8B5E1F, #C9963A);
  box-shadow: 0 3px 8px rgba(0,0,0,0.35), inset 0 0 0 2px #6B4413;
  z-index: -1;
}
.mascot-game { width: 80px; height: 80px; margin: 0 auto 6px; transition: transform 200ms ease-out; }
.mascot-result { width: 100px; height: 100px; margin: 0 auto; }

/* Home/license/homework mascot: real cropped gear-frame artwork (with a
   transparent hole) layered over the live photo, instead of a CSS ring.
   Grid stacking (both layers in the same 1x1 cell) instead of
   absolute+percentage+transform centering — that combination rendered
   correctly in Chromium but put the photo well below/right of the hole
   on iOS Safari; grid layering doesn't have that cross-browser edge case. */
.mascot-hero-wrap {
  display: grid;
  width: 164px;
  height: 110px;
  margin: 0 auto;
  animation: floaty 3.2s ease-in-out infinite;
}
.mascot-hero-wrap > * { grid-area: 1 / 1; }
.mascot-hero {
  width: 74px;
  height: 74px;
  align-self: center;
  justify-self: center;
  /* Nudge from dead-center to the hole's actual center (very slightly
     below and right of the frame's midpoint). */
  transform: translate(1px, 3px);
}
.mascot-frame-overlay {
  width: 100%;
  height: 100%;
  align-self: center;
  justify-self: center;
  z-index: 2;
  pointer-events: none;
}
.mascot-hero .mascot-photo {
  width: 100%;
  height: 100%;
  border: none;
  box-shadow: none;
}

@keyframes floaty {
  0%, 100% { transform: translateY(0) rotate(-2deg); }
  50% { transform: translateY(-14px) rotate(2deg); }
}

.mascot-photo {
  width: 100%;
  height: 100%;
  object-fit: cover;
  border-radius: 50%;
  display: block;
  border: 5px solid #fff;
  box-shadow: var(--gloss-shadow-sm);
  transition: border-color 200ms ease-out;
}
.mascot-photo.mood-idle { border-color: #B9C6E0; animation: breathe 2.6s ease-in-out infinite; }
.mascot-photo.mood-happy { border-color: var(--color-success); animation: pop-in 300ms ease-out; }
.mascot-photo.mood-sad { border-color: var(--color-destructive); animation: shake 420ms ease-in-out; }
.mascot-photo.mood-think { border-color: var(--color-secondary); animation: mascot-think 1s ease-in-out infinite; }
@keyframes mascot-think {
  0%, 100% { transform: rotate(-5deg); }
  50% { transform: rotate(5deg); }
}
@keyframes breathe {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.045); }
}

/* ==== Ambient "app is alive" activity strip ==== */
.activity-strip {
  display: flex;
  gap: 9px;
  align-items: center;
  justify-content: center;
  padding: 2px 0;
}
.activity-strip span {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--color-primary);
  opacity: 0.3;
  animation: activity-wave 1.5s ease-in-out infinite;
}
.activity-strip span:nth-child(1) { animation-delay: 0s; }
.activity-strip span:nth-child(2) { animation-delay: 0.12s; }
.activity-strip span:nth-child(3) { animation-delay: 0.24s; }
.activity-strip span:nth-child(4) { animation-delay: 0.36s; }
.activity-strip span:nth-child(5) { animation-delay: 0.48s; }
@keyframes activity-wave {
  0%, 100% { opacity: 0.25; transform: translateY(0) scale(0.8); }
  50% { opacity: 1; transform: translateY(-5px) scale(1.15); }
}

/* ==== Gentle ambient pulse on HUD icons ==== */
@keyframes icon-breathe {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.55; }
}
.hud-score svg { animation: icon-breathe 2.4s ease-in-out infinite; }
.heart:not(.lost) { animation: icon-breathe 2.8s ease-in-out infinite; }

.mascot-name {
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 0.95rem;
  color: #F3D48A;
  background: linear-gradient(180deg, #1B2A5E 0%, #0F1838 100%);
  border: 2px solid #C9963A;
  border-radius: 999px;
  padding: 3px 14px;
  margin: 8px 0 0;
  text-align: center;
  text-shadow: 0 1px 2px rgba(0,0,0,0.5);
  box-shadow: var(--gloss-shadow-sm);
}
.mascot-name-game { margin: 6px 0 4px; }
.mascot-name-break { margin: 4px 0 8px; font-size: 0.85rem; }

/* ==== Topbar (setup) ==== */
.topbar {
  width: 100%;
  max-width: 900px;
  display: flex;
  align-items: center;
  justify-content: flex-start;
  gap: 14px;
  /* space-between used to shove the title to the far right edge, straight
     under the fixed settings/sound buttons pinned there — keep it next to
     the back button instead, with enough right padding to clear those. */
  padding: calc(20px + env(safe-area-inset-top, 0px)) calc(140px + env(safe-area-inset-right, 0px)) 6px calc(20px + env(safe-area-inset-left, 0px));
}
.topbar-title {
  font-family: var(--font-heading);
  font-weight: 900;
  font-size: 1.6rem;
  margin: 0;
  min-width: 0;
  background: linear-gradient(90deg, #6EE7F5 0%, #A78BFA 55%, #F472B6 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

/* ==== Setup screen ==== */
.setup-wrap {
  width: 100%;
  max-width: 900px;
  padding: 10px 20px 50px;
  display: flex;
  flex-direction: column;
  gap: 28px;
}
.setup-label {
  display: inline-flex;
  align-items: center;
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 0.95rem;
  color: #fff;
  background: rgba(255,255,255,0.08);
  border: 1px solid rgba(255,255,255,0.18);
  border-radius: 999px;
  padding: 6px 16px;
  margin: 0 0 12px;
}

.grade-row {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 8px;
}
.grade-card {
  border: none;
  border-radius: 14px;
  padding: 14px 4px 10px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  font-family: var(--font-heading);
  font-weight: 800;
  color: #fff;
  text-shadow: 0 1px 2px rgba(0,0,0,0.35);
  box-shadow: 0 4px 0 rgba(0,0,0,0.25), 0 6px 12px rgba(0,0,0,0.25), inset 0 2px 0 rgba(255,255,255,0.35);
  transition: transform 150ms ease-out, box-shadow 150ms ease-out;
}
.grade-num {
  width: auto; height: auto;
  background: none;
  box-shadow: none;
  font-size: 1.6rem;
  font-weight: 900;
}
.grade-card span:last-child { font-size: 0.7rem; opacity: 0.95; }
.grade-card:hover { transform: translateY(-2px); }
.grade-card[data-grade="1"] { background: var(--gloss-shine-strong), linear-gradient(180deg, #6EE7A8 0%, #16A34A 60%, #0D7A38 100%); }
.grade-card[data-grade="2"] { background: var(--gloss-shine-strong), linear-gradient(180deg, #7EC8FF 0%, #2563EB 60%, #1741A6 100%); }
.grade-card[data-grade="3"] { background: var(--gloss-shine-strong), linear-gradient(180deg, #D7A8FF 0%, #9333EA 60%, #6B0FA8 100%); }
.grade-card[data-grade="4"] { background: var(--gloss-shine-strong), linear-gradient(180deg, #FF9E9E 0%, #DC2626 60%, #971B1B 100%); }
.grade-card[data-grade="5"] { background: var(--gloss-shine-strong), linear-gradient(180deg, #FFDD8F 0%, #D97706 60%, #B45F06 100%); }
.grade-card.selected {
  transform: translateY(2px);
  box-shadow: 0 0 0 3px #fff, 0 0 0 6px rgba(255,255,255,0.5), 0 4px 12px rgba(0,0,0,0.3);
}

.op-row {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
}
.op-sym svg { display: block; }
.op-card {
  border: 2px solid rgba(255,255,255,0.5);
  border-radius: 14px;
  padding: 14px 4px 12px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 0.85rem;
  color: #3B2410;
  box-shadow: 0 3px 0 rgba(0,0,0,0.15), 0 5px 10px rgba(0,0,0,0.18);
  transition: transform 150ms ease-out, box-shadow 150ms ease-out;
}
.op-sym {
  width: 34px; height: 34px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 9px;
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 1.2rem;
  color: #fff;
  background: rgba(0,0,0,0.18);
}
.op-card:hover { transform: translateY(-2px); }
.op-card[data-op="add"] { background: var(--gloss-shine), linear-gradient(180deg, #FFE0EC, #FFC0D9); }
.op-card[data-op="sub"] { background: var(--gloss-shine), linear-gradient(180deg, #FFE0EC, #FFC0D9); }
.op-card[data-op="mul"] { background: var(--gloss-shine), linear-gradient(180deg, #FFCFCF, #FF9E9E); }
.op-card[data-op="div"] { background: var(--gloss-shine), linear-gradient(180deg, #D7ECFF, #AEDBFF); }
.op-card[data-op="mix"] { background: var(--gloss-shine), linear-gradient(180deg, #E7D6FF, #CBB0FF); }
.op-card[data-op="word"] { background: var(--gloss-shine), linear-gradient(180deg, #FFF3D6, #FFE3A8); }
.op-card.selected {
  box-shadow: 0 0 0 3px #fff, 0 0 0 6px rgba(255,255,255,0.5), 0 4px 12px rgba(0,0,0,0.3);
  transform: translateY(2px);
}

.mode-row {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
}
.mode-card {
  position: relative;
  background: linear-gradient(180deg, rgba(30,41,82,0.9), rgba(15,21,50,0.9));
  border: 2px solid rgba(255,255,255,0.15);
  border-radius: var(--radius-md);
  padding: 16px 12px;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 4px;
  text-align: left;
  color: #fff;
  box-shadow: 0 4px 10px rgba(0,0,0,0.3);
  transition: transform 150ms ease-out, box-shadow 150ms ease-out, border-color 150ms;
}
.mode-icon { color: #FFD98F; margin-bottom: 2px; }
.mode-title { font-family: var(--font-heading); font-size: 1.05rem; font-weight: 800; }
.mode-desc { color: rgba(255,255,255,0.65); font-size: 0.76rem; font-weight: 600; }
.mode-card:hover { transform: translateY(-2px); }
.mode-card.selected {
  background: var(--gloss-shine-strong), linear-gradient(180deg, #FFD98F 0%, #F59E0B 55%, #B45F06 100%);
  border-color: #FFE9A8;
  box-shadow: 0 0 0 3px rgba(255,217,143,0.5), 0 6px 16px rgba(0,0,0,0.35);
  color: #fff;
  text-shadow: 0 1px 2px rgba(0,0,0,0.3);
}
.mode-card.selected .mode-icon,
.mode-card.selected .mode-desc { color: rgba(255,255,255,0.9); }
.mode-card-soon {
  opacity: 0.55;
  cursor: not-allowed;
}
.mode-card-soon:hover { transform: none; }
.soon-badge {
  position: absolute;
  top: 8px;
  right: 8px;
  font-size: 0.58rem;
  font-weight: 800;
  color: #5A3200;
  background: linear-gradient(180deg, #FFE9A8, #F5C242);
  padding: 2px 8px;
  border-radius: 999px;
}

.best-score-box {
  align-self: center;
  background: linear-gradient(180deg, rgba(30,41,82,0.85), rgba(15,21,50,0.85));
  border: 2px dashed rgba(255,255,255,0.25);
  border-radius: var(--radius-md);
  padding: 10px 20px;
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 1.05rem;
  color: rgba(255,255,255,0.85);
  box-shadow: var(--gloss-shadow-sm);
}
.best-score-box strong { color: #FFD98F; font-size: 1.25rem; }
.best-stars { display: inline-flex; gap: 2px; font-size: 1.3rem; line-height: 1; }
.best-stars .star { color: rgba(255,255,255,0.25); }
.best-stars .star.on { color: var(--color-secondary); }

.btn-gold {
  background: var(--gloss-shine-strong), linear-gradient(180deg, #FFE9A8 0%, #F5C242 45%, #C88A12 100%);
  color: #5A3200;
  border-color: #8A5A0A;
}
.btn-start { align-self: center; min-width: 260px; }

/* ==== Ôn học sinh giỏi ==== */
.gifted-wrap {
  width: 100%;
  max-width: 700px;
  padding: 10px 20px 50px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}
.gifted-grade-picker { display: flex; flex-direction: column; gap: 10px; }
.gifted-problem-list { display: flex; flex-direction: column; gap: 16px; }
.gifted-card {
  background: linear-gradient(180deg, rgba(30,41,82,0.9), rgba(15,21,50,0.9));
  border: 2px solid rgba(255,255,255,0.15);
  border-radius: var(--radius-md);
  padding: 16px 18px;
  color: #fff;
  box-shadow: 0 4px 10px rgba(0,0,0,0.3);
}
.gifted-card-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 10px;
}
.gifted-level {
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 0.7rem;
  padding: 3px 12px;
  border-radius: 999px;
}
.gifted-level-basic { background: linear-gradient(180deg, #6EE7A8, #16A34A); color: #06280F; }
.gifted-level-advanced { background: linear-gradient(180deg, #FFB199, #F97316); color: #3A1300; }
.gifted-num { font-family: var(--font-heading); font-weight: 700; font-size: 0.78rem; color: rgba(255,255,255,0.5); }
.gifted-question { font-weight: 700; line-height: 1.55; margin: 0 0 12px; }
.gifted-reveal-btn {
  background: var(--gloss-shine-strong), linear-gradient(180deg, #FFD98F 0%, #F59E0B 55%, #B45F06 100%);
  border: 2px solid #6B3A02;
  border-radius: 999px;
  color: #fff;
  text-shadow: 0 1px 2px rgba(0,0,0,0.3);
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 0.85rem;
  padding: 8px 18px;
  box-shadow: var(--gloss-shadow-sm);
  transition: transform 150ms ease-out;
}
.gifted-reveal-btn:hover { transform: translateY(-2px); }
.gifted-reveal-btn:active { transform: translateY(2px) scale(0.97); }
.gifted-solution {
  margin: 12px 0 0;
  padding: 10px 14px;
  background: rgba(255,255,255,0.08);
  border-left: 3px solid #34D399;
  border-radius: 8px;
  font-size: 0.9rem;
  line-height: 1.6;
  color: rgba(255,255,255,0.9);
}

/* ==== Phần dạy trước khi mở lời giải ==== */
.gifted-learn-btn {
  background: var(--gloss-shine-strong), linear-gradient(180deg, #A5B4FC 0%, #6366F1 55%, #3730A3 100%);
  border: 2px solid #29216B;
  border-radius: 999px;
  color: #fff;
  text-shadow: 0 1px 2px rgba(0,0,0,0.35);
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 0.85rem;
  padding: 8px 18px;
  box-shadow: var(--gloss-shadow-sm);
  transition: transform 150ms ease-out;
}
.gifted-learn-btn:hover { transform: translateY(-2px); }
.gifted-learn-btn:active { transform: translateY(2px) scale(0.97); }

.gifted-teach {
  margin-top: 12px;
  padding: 14px 16px 16px;
  background: rgba(99,102,241,0.12);
  border: 2px solid rgba(165,180,252,0.45);
  border-radius: 12px;
}
.gifted-teach-dots { display: flex; gap: 6px; margin-bottom: 10px; }
.gifted-teach-dots i {
  flex: 1;
  height: 5px;
  border-radius: 999px;
  background: rgba(255,255,255,0.18);
  transition: background 200ms ease-out;
}
.gifted-teach-dots i.on { background: #A5B4FC; }
.gifted-step-count {
  margin: 0 0 4px;
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: #C7D2FE;
}
.gifted-step-title {
  margin: 0 0 8px;
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 1.02rem;
  color: #fff;
}
.gifted-step-body {
  font-size: 0.92rem;
  line-height: 1.7;
  color: rgba(255,255,255,0.92);
}
.gifted-step-body strong { color: #FDE68A; font-weight: 800; }
.gifted-step-body em { font-style: italic; color: rgba(255,255,255,0.75); }
.gifted-step-next {
  margin-top: 14px;
  width: 100%;
  min-height: 46px;
  background: var(--gloss-shine-strong), linear-gradient(180deg, #7DD3FC 0%, #0EA5E9 55%, #075985 100%);
  border: 2px solid #05364F;
  border-radius: 999px;
  color: #fff;
  text-shadow: 0 1px 2px rgba(0,0,0,0.35);
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 0.9rem;
  box-shadow: var(--gloss-shadow-sm);
  transition: transform 150ms ease-out;
}
.gifted-step-next:hover { transform: translateY(-2px); }
.gifted-step-next:active { transform: translateY(2px) scale(0.98); }

.gifted-locked-note {
  margin: 8px 0 0;
  font-size: 0.76rem;
  line-height: 1.5;
  color: rgba(255,255,255,0.5);
}

/* ==== Game HUD ==== */
.game-hud {
  width: 100%;
  max-width: 900px;
  display: flex;
  align-items: center;
  gap: 16px;
  /* Extra right padding keeps the score from sliding under the fixed
     settings/sound buttons pinned to the top-right corner (settings sits
     78-126px from the edge, sound sits 18-66px — 140px clears both). */
  padding: calc(18px + env(safe-area-inset-top, 0px)) calc(140px + env(safe-area-inset-right, 0px)) 4px calc(20px + env(safe-area-inset-left, 0px));
}
.hud-mid { flex: 1; display: flex; flex-direction: column; gap: 6px; align-items: center; }
.hud-lives { display: flex; gap: 4px; }
.heart { width: 22px; height: 22px; color: var(--color-accent); }
.heart.lost { color: var(--color-border); }

.hud-timerbar {
  width: 100%;
  max-width: 420px;
  height: 14px;
  background: var(--color-muted);
  border: 2px solid var(--color-border);
  border-radius: 999px;
  overflow: hidden;
}
.hud-timerfill {
  height: 100%;
  width: 100%;
  background: linear-gradient(90deg, var(--color-success), #86EFAC);
  transition: width 1s linear, background-color 300ms;
}
.hud-timerfill.warn { background: linear-gradient(90deg, var(--color-secondary), #FCD34D); }
.hud-timerfill.danger { background: linear-gradient(90deg, var(--color-destructive), #F87171); }

.hud-progress {
  font-family: var(--font-heading);
  font-size: 0.9rem;
  font-weight: 800;
  color: var(--color-on-bg-muted);
}

.hud-score {
  display: flex;
  align-items: center;
  gap: 6px;
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 1.25rem;
  color: var(--color-secondary-dark);
  background: var(--gloss-shine), linear-gradient(180deg, #FFFFFF 0%, #FFF3DC 55%, #FCE3B0 100%);
  border: 3px solid #B9C6E0;
  border-radius: 999px;
  padding: 8px 16px;
  box-shadow: var(--gloss-shadow-sm);
}

/* ==== Game stage ==== */
.game-stage {
  width: 100%;
  max-width: 640px;
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 10px 20px 40px;
  gap: 14px;
}

.streak-badge {
  background: var(--gloss-shine-strong), linear-gradient(180deg, #FFD98F 0%, #F59E0B 55%, #B45F06 100%);
  color: var(--color-on-secondary);
  font-family: var(--font-heading);
  font-weight: 800;
  padding: 8px 18px;
  border-radius: 999px;
  border: 2px solid #6B3A02;
  box-shadow: var(--gloss-shadow-sm);
  animation: pop-in 250ms ease-out;
}

.question-card {
  background: var(--gloss-shine), linear-gradient(180deg, #FFFFFF 0%, #EDF2FC 55%, #D7E1F5 100%);
  border: 4px solid #B9C6E0;
  border-radius: var(--radius-xl);
  width: 100%;
  min-height: 140px;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--gloss-shadow);
  padding: 20px;
}
.question-card.shake { animation: shake 420ms ease-in-out; border-color: var(--color-destructive); }
.question-card.correct-flash { border-color: var(--color-success); }

.question-text {
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: clamp(2.4rem, 7vw, 3.4rem);
  color: var(--color-foreground);
  letter-spacing: 2px;
  text-align: center;
}
.question-text.word-text {
  font-size: 1.3rem;
  letter-spacing: normal;
  line-height: 1.6;
  text-align: left;
}

.answers-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
  width: 100%;
}

.answer-btn {
  background: var(--gloss-shine), linear-gradient(180deg, #FFFFFF 0%, #EDF2FC 55%, #D7E1F5 100%);
  border: 4px solid #B9C6E0;
  border-radius: var(--radius-lg);
  padding: 22px 10px;
  font-family: var(--font-heading);
  font-size: 1.9rem;
  font-weight: 800;
  color: var(--color-primary);
  box-shadow: var(--gloss-shadow);
  transition: transform 150ms ease-out, box-shadow 150ms ease-out, background 150ms, border-color 150ms;
  min-height: 44px;
}
.answer-btn:hover:not(:disabled) { transform: translateY(-3px); }
.answer-btn:active:not(:disabled) {
  transform: translateY(4px) scale(0.98);
  box-shadow: 0 2px 0 rgba(15,23,42,0.3), inset 0 2px 2px rgba(255,255,255,0.5), inset 0 -3px 6px rgba(15,23,42,0.2);
}
.answer-btn:disabled { cursor: default; }
.answer-btn.correct {
  background: var(--gloss-shine-strong), linear-gradient(180deg, #8CF0AE 0%, #22C55E 55%, #0F6B31 100%);
  border-color: #0B4A22;
  color: #fff;
  text-shadow: 0 1px 2px rgba(0,0,0,0.3);
  animation: pop-in 220ms ease-out;
}
.answer-btn.wrong {
  background: var(--gloss-shine-strong), linear-gradient(180deg, #FCA5A5 0%, #EF4444 55%, #8A1414 100%);
  border-color: #7F1D1D;
  color: #fff;
  animation: shake 420ms ease-in-out;
}
.answer-btn.dim { opacity: 0.5; }
.answer-btn.reveal {
  animation: btn-pop-in 320ms ease-out backwards;
}

@keyframes btn-pop-in {
  0% { transform: scale(0.7) translateY(10px); opacity: 0; }
  70% { transform: scale(1.04) translateY(0); opacity: 1; }
  100% { transform: scale(1) translateY(0); }
}

/* ==== Thinking dots ==== */
.thinking-dots {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 12px 0;
}
.thinking-dots span {
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: linear-gradient(180deg, #7DAEFF 0%, #2563EB 100%);
  box-shadow: var(--gloss-shadow-sm);
  animation: dot-bounce 1s ease-in-out infinite;
}
.thinking-dots span:nth-child(2) { animation-delay: 0.15s; background: linear-gradient(180deg, #F472B6, var(--color-accent)); }
.thinking-dots span:nth-child(3) { animation-delay: 0.3s; background: linear-gradient(180deg, #FFD98F 0%, #F59E0B 100%); }
@keyframes dot-bounce {
  0%, 60%, 100% { transform: translateY(0); opacity: 0.6; }
  30% { transform: translateY(-14px); opacity: 1; }
}

/* ==== Question card entrance variety ==== */
.question-card.anim-pop { animation: qc-pop 380ms ease-out; }
.question-card.anim-slide-up { animation: qc-slide-up 380ms ease-out; }
.question-card.anim-slide-side { animation: qc-slide-side 380ms ease-out; }
@keyframes qc-pop {
  0% { transform: scale(0.8); opacity: 0; }
  100% { transform: scale(1); opacity: 1; }
}
@keyframes qc-slide-up {
  0% { transform: translateY(28px); opacity: 0; }
  100% { transform: translateY(0); opacity: 1; }
}
@keyframes qc-slide-side {
  0% { transform: translateX(-32px); opacity: 0; }
  100% { transform: translateX(0); opacity: 1; }
}

@keyframes shake {
  10%, 90% { transform: translateX(-4px); }
  20%, 80% { transform: translateX(6px); }
  30%, 50%, 70% { transform: translateX(-9px); }
  40%, 60% { transform: translateX(9px); }
}
@keyframes pop-in {
  0% { transform: scale(0.85); }
  60% { transform: scale(1.05); }
  100% { transform: scale(1); }
}

.solution-box {
  width: 100%;
  background: var(--gloss-shine), linear-gradient(180deg, #FFFFFF 0%, #DFFBE7 100%);
  border: 3px dashed var(--color-success);
  border-radius: var(--radius-lg);
  padding: 18px 20px;
  text-align: center;
  box-shadow: var(--gloss-shadow-sm);
  animation: pop-in 250ms ease-out;
}
.solution-tag {
  display: inline-block;
  background: var(--gloss-shine-strong), linear-gradient(180deg, #8CF0AE 0%, #22C55E 55%, #0F6B31 100%);
  color: #fff;
  text-shadow: 0 1px 2px rgba(0,0,0,0.3);
  font-family: var(--font-heading);
  font-weight: 800;
  padding: 4px 14px;
  border-radius: 999px;
  font-size: 0.85rem;
  margin-bottom: 10px;
  box-shadow: var(--gloss-shadow-sm);
}
.solution-text {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--color-success-dark);
  margin: 0 0 14px;
  line-height: 1.5;
}
#btnNextWord { width: 100%; }

/* ==== Result screen ==== */
.result-wrap {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 100%;
  padding: 40px 20px;
  gap: 10px;
  text-align: center;
}
.result-title {
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 2.2rem;
  color: var(--color-primary);
  margin: 4px 0 0;
}
.stars-row { font-size: 3rem; letter-spacing: 8px; line-height: 1; margin: 8px 0 4px; }
.star { color: var(--color-border); transition: color 200ms, transform 200ms; display: inline-block; }
.star.on { color: var(--color-secondary); text-shadow: 0 2px 0 #B45F06, 0 0 14px rgba(245,158,11,0.7); animation: pop-in 300ms ease-out; }

.result-stats {
  display: flex;
  gap: 14px;
  margin: 18px 0 6px;
  flex-wrap: wrap;
  justify-content: center;
}
.stat-box {
  background: var(--gloss-shine), linear-gradient(180deg, #FFFFFF 0%, #EDF2FC 55%, #D7E1F5 100%);
  border: 3px solid #B9C6E0;
  border-radius: var(--radius-md);
  padding: 16px 22px;
  min-width: 110px;
  box-shadow: var(--gloss-shadow-sm);
}
.stat-num {
  display: block;
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 1.8rem;
  color: var(--color-primary);
}
.stat-label { font-family: var(--font-heading); font-size: 0.85rem; color: var(--color-muted-foreground); font-weight: 800; }

.new-record-badge {
  display: flex;
  align-items: center;
  gap: 8px;
  background: var(--gloss-shine-strong), linear-gradient(180deg, #FFD98F 0%, #F59E0B 55%, #B45F06 100%);
  color: var(--color-on-secondary);
  font-family: var(--font-heading);
  font-weight: 800;
  padding: 8px 18px;
  border-radius: 999px;
  border: 2px solid #6B3A02;
  box-shadow: var(--gloss-shadow-sm);
  margin: 4px 0 10px;
}

.share-fb-btn {
  font-size: 0.95rem;
  padding: 10px 20px;
  margin-top: 18px;
}
.result-actions { display: flex; gap: 16px; margin-top: 14px; flex-wrap: wrap; justify-content: center; }

/* ==== Modal ==== */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, 0.45);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
  padding: 20px;
}
.modal-box {
  position: relative;
  background: var(--gloss-shine), linear-gradient(180deg, #FFFFFF 0%, #EDF2FC 55%, #D7E1F5 100%);
  border: 4px solid #B9C6E0;
  border-radius: var(--radius-xl);
  max-width: 480px;
  width: 100%;
  padding: 32px 28px 28px;
  box-shadow: var(--gloss-shadow);
  max-height: 85vh;
  overflow-y: auto;
}
.modal-box h2 {
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 1.6rem;
  color: var(--color-primary);
  margin-top: 0;
}
.modal-close { position: absolute; top: 14px; right: 14px; width: 40px; height: 40px; }
.howto-list { padding-left: 20px; line-height: 1.7; font-weight: 700; color: var(--color-foreground); }
.howto-list strong { color: var(--color-primary); }
.howto-list li { margin-bottom: 8px; }
#btnHowToGotIt { width: 100%; margin-top: 10px; }

/* ==== Browser picker modal ==== */
.btn-install {
  background: var(--gloss-shine-strong), linear-gradient(180deg, #8CF0AE 0%, #22C55E 55%, #0F6B31 100%);
  color: #fff;
  border-color: #0B4A22;
  margin: 4px 0 18px;
  animation: pop-in 300ms ease-out;
}

.ios-install-overlay {
  align-items: flex-start;
  padding-top: 6vh;
}
.ios-install-box { max-width: 420px; }
.ios-arrow-hint {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  margin: 18px 0 10px;
  color: var(--color-primary);
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 1.05rem;
  text-align: center;
}
.ios-arrow-hint svg { animation: bounce-down 1.1s ease-in-out infinite; }
@keyframes bounce-down {
  0%, 100% { transform: translateY(0); opacity: 0.6; }
  50% { transform: translateY(10px); opacity: 1; }
}

.browser-picker-desc {
  color: var(--color-muted-foreground);
  font-weight: 700;
  margin: 0 0 16px;
}
.browser-picker-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.browser-pick-btn {
  display: flex;
  align-items: center;
  gap: 12px;
  width: 100%;
  text-align: left;
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 1rem;
  color: var(--color-foreground);
  background: var(--gloss-shine), linear-gradient(180deg, #FFFFFF 0%, #EDF2FC 55%, #D7E1F5 100%);
  border: 3px solid #B9C6E0;
  border-radius: var(--radius-md);
  padding: 12px 16px;
  box-shadow: var(--gloss-shadow-sm);
  transition: transform 150ms ease-out;
}
.browser-pick-btn:hover { transform: translateY(-2px); }
.browser-pick-btn:active { transform: translateY(1px) scale(0.98); }
.browser-pick-btn svg { flex-shrink: 0; color: var(--color-primary); }

/* ==== Fun break overlay ==== */
.break-overlay { background: rgba(15, 23, 42, 0.6); overflow: hidden; }

.break-tiles {
  position: absolute;
  inset: 0;
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  opacity: 0.16;
  pointer-events: none;
}
.break-tiles span {
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-heading);
  font-size: 4rem;
  color: #fff;
  border: 2px solid rgba(255,255,255,0.25);
}

.break-box {
  text-align: center;
  max-width: 460px;
  border-color: #6B3A02;
  background: var(--gloss-shine), linear-gradient(180deg, #FFFFFF 0%, #FFF3DC 55%, #FCE3B0 100%);
}
.break-mascot { width: 80px; height: 80px; margin: -12px auto 0; }
.break-tag {
  display: inline-block;
  background: var(--gloss-shine-strong), linear-gradient(180deg, #FF9FCB 0%, #EC4899 55%, #A3175C 100%);
  color: #fff;
  text-shadow: 0 1px 2px rgba(0,0,0,0.3);
  font-family: var(--font-heading);
  font-weight: 800;
  padding: 5px 16px;
  border-radius: 999px;
  font-size: 0.9rem;
  margin-bottom: 8px;
  box-shadow: var(--gloss-shadow-sm);
}
.break-heading {
  font-family: var(--font-heading);
  font-weight: 800;
  color: var(--color-primary);
  margin: 4px 0 14px;
  font-size: 1.45rem;
}
.break-joke-q {
  font-family: var(--font-heading);
  font-size: 1.2rem;
  font-weight: 800;
  color: var(--color-foreground);
  margin: 0 0 10px;
  line-height: 1.5;
}
.break-joke-a {
  font-family: var(--font-heading);
  font-size: 1.1rem;
  color: var(--color-success-dark);
  font-weight: 800;
  background: var(--gloss-shine), linear-gradient(180deg, #FFFFFF 0%, #DFFBE7 100%);
  border: 2px dashed var(--color-success);
  border-radius: var(--radius-md);
  padding: 12px 16px;
  margin: 0 0 16px;
  animation: pop-in 250ms ease-out;
}
#btnRevealJoke, #btnContinueGame { width: 100%; }

.break-quiz-grid {
  display: flex;
  flex-direction: column;
  gap: 10px;
  width: 100%;
  margin: 0 0 16px;
}
.break-quiz-btn {
  background: var(--gloss-shine), linear-gradient(180deg, #FFFFFF 0%, #EDF2FC 55%, #D7E1F5 100%);
  border: 3px solid #B9C6E0;
  border-radius: var(--radius-md);
  padding: 13px 16px;
  font-family: var(--font-heading);
  font-size: 1.05rem;
  font-weight: 800;
  color: var(--color-primary);
  box-shadow: var(--gloss-shadow-sm);
  transition: transform 150ms ease-out, box-shadow 150ms ease-out, background 150ms, border-color 150ms;
  text-align: center;
}
.break-quiz-btn:hover:not(:disabled) { transform: translateY(-2px); }
.break-quiz-btn:active:not(:disabled) { transform: translateY(3px) scale(0.98); }
.break-quiz-btn:disabled { cursor: default; }
.break-quiz-btn.correct {
  background: var(--gloss-shine-strong), linear-gradient(180deg, #8CF0AE 0%, #22C55E 55%, #0F6B31 100%);
  border-color: #0B4A22;
  color: #fff;
  text-shadow: 0 1px 2px rgba(0,0,0,0.3);
  animation: pop-in 220ms ease-out;
}
.break-quiz-btn.wrong {
  background: var(--gloss-shine-strong), linear-gradient(180deg, #FCA5A5 0%, #EF4444 55%, #8A1414 100%);
  border-color: #7F1D1D;
  color: #fff;
  animation: shake 420ms ease-in-out;
}
.break-quiz-btn.dim { opacity: 0.5; }
.break-quiz-btn.reveal { animation: btn-pop-in 320ms ease-out backwards; }

/* ==== Confetti ==== */
#confettiLayer {
  position: fixed;
  inset: 0;
  pointer-events: none;
  overflow: hidden;
  z-index: 200;
}
.confetti-piece {
  position: absolute;
  top: -20px;
  border-radius: 3px;
  animation: confetti-fall linear forwards;
}
@keyframes confetti-fall {
  to { transform: translateY(110vh) rotate(540deg); opacity: 0.9; }
}

/* ==== Homework helper ==== */
.btn-homework {
  background: var(--gloss-shine-strong), linear-gradient(180deg, #C9A7FF 0%, #8B5CF6 55%, #5B21B6 100%);
  color: #fff;
  border-color: #3B1470;
  font-size: 0.95rem;
  padding: 12px 22px;
  margin-top: 4px;
}
.homework-wrap {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 100%;
  padding: 40px 20px;
  gap: 12px;
  text-align: center;
}
.homework-back-btn { top: calc(18px + env(safe-area-inset-top, 0px)); left: calc(18px + env(safe-area-inset-left, 0px)); right: auto; }
.homework-title {
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 1.6rem;
  color: var(--color-on-bg);
  margin: 6px 0 0;
}
#homeworkStepPick,
#homeworkStepPreview,
#homeworkStepLoading,
#homeworkStepResult,
#homeworkStepError {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 14px;
  width: 100%;
  max-width: 480px;
  margin-top: 10px;
}
.homework-preview-img {
  width: 100%;
  max-width: 320px;
  max-height: 320px;
  object-fit: contain;
  border-radius: var(--radius-md);
  border: 3px solid var(--color-border);
  background: #fff;
  box-shadow: var(--gloss-shadow-sm);
}
.btn-toggle-struggling {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 0.9rem;
  color: var(--color-primary);
  background: var(--gloss-shine), linear-gradient(180deg, #FFFFFF 0%, #EDF2FC 55%, #D7E1F5 100%);
  border: 3px solid #B9C6E0;
  border-radius: 999px;
  padding: 10px 18px;
  box-shadow: var(--gloss-shadow-sm);
  transition: all 150ms ease-out;
}
.btn-toggle-struggling[aria-pressed="true"] {
  color: #fff;
  background: var(--gloss-shine-strong), linear-gradient(180deg, #FF9FCB 0%, #EC4899 55%, #A3175C 100%);
  border-color: #6B0F3A;
  text-shadow: 0 1px 2px rgba(0,0,0,0.3);
}
.homework-actions {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
  justify-content: center;
}
.homework-loading-text {
  font-family: var(--font-heading);
  font-weight: 700;
  color: var(--color-on-bg-muted);
}
.homework-progress-row {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  margin: 0 0 6px;
}
.homework-slide-progress {
  font-family: var(--font-heading);
  font-weight: 800;
  color: var(--color-primary);
  margin: 0;
}
.btn-speak {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 34px;
  height: 34px;
  border-radius: 50%;
  border: 2px solid #B9C6E0;
  background: var(--gloss-shine-strong), linear-gradient(180deg, #FFFFFF 0%, #E4EBFA 55%, #C6D4F0 100%);
  color: var(--color-primary);
  box-shadow: var(--gloss-shadow-sm);
  transition: transform 150ms ease-out;
}
.btn-speak:active { transform: scale(0.92); }
.btn-speak.is-speaking {
  color: #fff;
  background: var(--gloss-shine-strong), linear-gradient(180deg, #8CF0AE 0%, #22C55E 55%, #0F6B31 100%);
  border-color: #0B4A22;
  animation: speak-pulse 1s ease-in-out infinite;
}
@keyframes speak-pulse {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.08); }
}
.btn-download {
  border-color: #E0C088;
  background: var(--gloss-shine-strong), linear-gradient(180deg, #FFF7E6 0%, #FBE4B0 55%, #E8BE6E 100%);
  color: #7C4A1E;
}
.btn-download.is-saved {
  color: #fff;
  background: var(--gloss-shine-strong), linear-gradient(180deg, #8CF0AE 0%, #22C55E 55%, #0F6B31 100%);
  border-color: #0B4A22;
}
.homework-answer-box {
  background: var(--gloss-shine), linear-gradient(180deg, #FFFFFF 0%, #F1F5FD 100%);
  border: 3px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 20px;
  text-align: left;
  color: var(--color-foreground);
  font-weight: 600;
  line-height: 1.6;
  max-height: 50vh;
  overflow-y: auto;
  white-space: pre-wrap;
  box-shadow: var(--gloss-shadow-sm);
  touch-action: pan-y;
}
.homework-dots {
  display: flex;
  gap: 8px;
  justify-content: center;
  margin: 14px 0 4px;
}
.homework-dots .dot {
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--color-border);
  transition: background 150ms ease-out, transform 150ms ease-out;
}
.homework-dots .dot.current {
  background: var(--color-primary);
  transform: scale(1.3);
}
.homework-error-text {
  font-family: var(--font-heading);
  font-weight: 700;
  color: var(--color-destructive);
}

/* ==== Responsive ==== */
@media (max-width: 700px) {
  .grade-row { grid-template-columns: repeat(5, 1fr); gap: 8px; }
  .op-row { grid-template-columns: repeat(3, 1fr); gap: 8px; }
  .grade-card, .op-card { padding: 10px 4px; font-size: 0.75rem; }
  .grade-num { width: 34px; height: 34px; font-size: 1.05rem; }
  .op-sym { font-size: 1.3rem; }
  .mode-row { grid-template-columns: 1fr; }
  .answers-grid { grid-template-columns: 1fr 1fr; }
  .title-hero { font-size: 2.4rem; }
}