:root {
  --ink: #1f2759;
  --purple: #7257e8;
  --purple-dark: #553cc3;
  --yellow: #ffca3a;
  --mint: #c7f6e8;
  --pink: #ffecf2;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-width: 320px;
  min-height: 100vh;
  color: var(--ink);
  font-family: "Fredoka", ui-rounded, system-ui, sans-serif;
  background:
    radial-gradient(circle at 6% 10%, #fff2b5 0 7px, transparent 8px),
    radial-gradient(circle at 92% 17%, #ffcfde 0 10px, transparent 11px),
    radial-gradient(circle at 11% 89%, #d0f7ef 0 13px, transparent 14px),
    linear-gradient(135deg, #e8fbff, #f8efff 48%, #fff8dc);
}

.celebration {
  position: fixed; inset: 0; z-index: 20; pointer-events: none; overflow: hidden;
  opacity: 0; background: rgba(95, 238, 153, .38);
}
.celebration.playing { animation: celebration-flash 1.8s ease-out forwards; }
.confetti {
  position: absolute; top: -8vh; left: var(--left); width: var(--size); height: calc(var(--size) * 1.65);
  background: var(--color); border-radius: 3px; transform: rotate(var(--tilt));
  animation: confetti-fall 1.65s cubic-bezier(.1,.7,.3,1) var(--delay) forwards;
}
.firework {
  position: absolute; left: var(--x); top: var(--y); width: 14px; height: 14px;
  border-radius: 50%; background: var(--color); box-shadow: 0 0 18px 8px var(--color);
  animation: firework-pop .85s ease-out var(--delay) both;
}
.firework::before, .firework::after {
  content: ""; position: absolute; inset: -3px; border: 4px dotted var(--color); border-radius: 50%;
}
.firework::after { transform: rotate(45deg); }

@keyframes celebration-flash {
  0%, 100% { opacity: 0; }
  12%, 35%, 58% { opacity: 1; }
  23%, 46% { opacity: .08; }
}
@keyframes confetti-fall {
  0% { opacity: 0; transform: translate3d(0, 0, 0) rotate(var(--tilt)); }
  8% { opacity: 1; }
  100% { opacity: 1; transform: translate3d(var(--drift), 115vh, 0) rotate(calc(var(--tilt) + 720deg)); }
}
@keyframes firework-pop {
  0% { opacity: 0; transform: scale(.1); }
  25% { opacity: 1; transform: scale(1.5); }
  100% { opacity: 0; transform: scale(7); }
}

.app-shell {
  min-height: 100vh;
  max-width: 1280px;
  margin: auto;
  padding: clamp(18px, 3vw, 42px) clamp(18px, 5vw, 70px) 24px;
  display: flex;
  flex-direction: column;
}

header, footer { display: flex; align-items: center; justify-content: space-between; gap: 16px; }

.brand { font-size: clamp(1.5rem, 3vw, 2.2rem); font-weight: 700; letter-spacing: .2px; }
.brand-icon { color: #ff9f1c; margin-right: 8px; }

.score-card {
  display: flex; align-items: center; gap: 8px;
  background: #fff; border: 3px solid #fff5c9; border-radius: 999px;
  padding: 9px 16px; box-shadow: 0 5px 0 #e7d9ff; font-size: 1.05rem;
}
.score-card .star { color: #ffb400; font-size: 1.4rem; }
.score-card strong { font-size: 1.35rem; min-width: 1.3em; text-align: center; }

.game-area { flex: 1; width: min(100%, 820px); margin: clamp(20px, 4vh, 45px) auto 20px; }
.mode-picker { display: grid; grid-template-columns: repeat(4, 1fr); gap: 10px; margin-bottom: 18px; }
.mode {
  border: 0; cursor: pointer; font: inherit; font-size: clamp(.8rem, 1.8vw, 1rem); color: var(--ink);
  padding: 10px 8px; border-radius: 16px; background: #ffffffa9; transition: transform .15s, background .15s;
}
.mode span { font-size: 1.3em; font-weight: 700; margin-right: 4px; }
.mode:hover, .mode.active { background: var(--purple); color: white; transform: translateY(-2px); }
.settings-panel { display: flex; justify-content: center; gap: 12px; margin: 0 0 18px; flex-wrap: wrap; }
.setting { display: flex; align-items: center; gap: 8px; color: #5e5583; font-weight: 600; font-size: .95rem; }
.setting select {
  max-width: 260px; border: 2px solid #ded8ff; border-radius: 12px; padding: 8px 31px 8px 10px;
  color: var(--ink); background: white; font: 500 .95rem "Fredoka", sans-serif;
}

.progressive-indicator {
  display: flex;
  align-items: center;
  gap: 8px;
  background: #ffffffeb;
  border: 2px solid #ded8ff;
  border-radius: 12px;
  padding: 6px 12px;
  font-weight: 600;
  box-shadow: 0 4px 10px rgba(114, 87, 232, 0.08);
}

.progressive-badge {
  color: var(--purple-dark);
  font-size: 0.95rem;
  font-weight: 700;
  letter-spacing: 0.2px;
  white-space: nowrap;
}

.streak-dots {
  display: inline-flex;
  gap: 5px;
  align-items: center;
  margin: 0 2px;
}

.streak-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: #e2dcfa;
  border: 1.5px solid #c7bbf8;
  transition: all 0.25s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.streak-dot.active {
  background: #ffb400;
  border-color: #ff9f1c;
  box-shadow: 0 0 8px #ffca3a;
  transform: scale(1.2);
}

.level-reset-btn {
  border: 0;
  background: #f0ecff;
  color: var(--purple);
  cursor: pointer;
  font: 600 0.8rem "Fredoka", sans-serif;
  padding: 3px 8px;
  border-radius: 8px;
  transition: background 0.15s, transform 0.1s;
}

.level-reset-btn:hover {
  background: #ded6ff;
  transform: translateY(-1px);
}

.question-card {
  background: #fff; border-radius: 32px; text-align: center; padding: clamp(22px, 5vw, 42px) 15px 20px;
  box-shadow: 0 10px 0 #d9d3f8, 0 16px 30px #553cc326;
}
.prompt { color: #765bc9; font-size: clamp(1rem, 2vw, 1.25rem); font-weight: 600; margin: 0 0 8px; }
.question { display: flex; justify-content: center; align-items: center; gap: clamp(8px, 2.5vw, 25px); font-size: clamp(2.7rem, 9vw, 6.3rem); font-weight: 600; line-height: 1.1; }
.answer-blank { min-width: 1.1em; color: var(--purple); border-bottom: 6px solid #bbaefa; padding: 0 .15em .06em; }
.answer-blank.waiting { animation: answer-waiting 1s ease-in-out infinite; }
.feedback { min-height: 1.4em; margin: 20px 0 0; color: #687091; font-size: 1.15rem; }
.feedback.success { color: #14976e; font-weight: 600; }
.feedback.try-again { color: #d15267; font-weight: 600; }

@keyframes answer-waiting {
  0%, 100% { border-color: #bbaefa; transform: translateY(0); }
  50% { border-color: #ff9f1c; transform: translateY(-3px); }
}

.calculator { margin: clamp(22px, 4vw, 36px) auto 0; width: min(100%, 590px); }
.key-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; }
.key {
  border: 0; border-radius: 20px; min-height: clamp(55px, 9vh, 82px); cursor: pointer;
  color: var(--ink); font: 600 clamp(1.65rem, 4vw, 2.4rem)/1 "Fredoka", sans-serif;
  background: #fff; box-shadow: 0 6px 0 #d6d8ed; transition: transform .1s, box-shadow .1s;
}
.key:hover { background: #fbfaff; }
.key:active { transform: translateY(5px); box-shadow: 0 1px 0 #d6d8ed; }
.key.clear { background: #ffdae2; color: #c24158; }
.key.backspace { background: var(--mint); color: #18866b; }
.auto-check { margin: 17px 0 0; text-align: center; color: #7068a3; font-size: 1.05rem; }

footer { color: #737895; font-size: 1rem; }
.footer-actions { display: flex; align-items: center; gap: 8px; }
.new-question { border: 0; background: transparent; color: #654acf; cursor: pointer; font: 600 1rem "Fredoka", sans-serif; padding: 8px; }

@media (max-width: 520px) {
  .app-shell { padding: 16px 15px; }
  .mode-picker { gap: 6px; }
  .mode { padding: 9px 4px; border-radius: 12px; }
  .mode span { display: block; }
  .settings-panel { flex-direction: column; align-items: stretch; }
  .setting { justify-content: space-between; }
  .setting select { max-width: none; }
  .question-card { border-radius: 24px; }
  footer span { display: none; }
  footer { justify-content: center; }
}