:root {
  --bg-1: #e3f8ff;
  --bg-2: #fff6d9;
  --card: #ffffff;
  --ink: #0f2940;
  --accent: #ff7a59;
  --accent-2: #2db7ff;
  --good: #2fbf71;
  --shadow: 0 12px 28px rgba(15, 41, 64, 0.16);
  --radius-xl: 28px;
  --radius-lg: 20px;
  --radius-md: 16px;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Trebuchet MS", "Arial Rounded MT Bold", Arial, sans-serif;
  color: var(--ink);
  background:
    radial-gradient(circle at 12% 18%, rgba(255, 122, 89, 0.22) 0 60px, transparent 61px),
    radial-gradient(circle at 90% 8%, rgba(45, 183, 255, 0.23) 0 70px, transparent 71px),
    radial-gradient(circle at 80% 85%, rgba(47, 191, 113, 0.2) 0 78px, transparent 79px),
    linear-gradient(145deg, var(--bg-1), var(--bg-2));
}

.app {
  max-width: 980px;
  margin: 0 auto;
  min-height: 100vh;
  padding: 16px 14px 22px;
  display: grid;
  grid-template-rows: auto auto auto auto 1fr;
  gap: 14px;
}

.top h1 {
  margin: 0;
  text-align: center;
  font-size: clamp(1.6rem, 4.5vw, 2.6rem);
  letter-spacing: 0.08em;
  color: #04436e;
}

.card-wrap {
  position: relative;
}

.hint {
  position: absolute;
  top: -8px;
  left: 50%;
  transform: translateX(-50%);
  background: #fff3a1;
  border: 3px solid #f5b100;
  border-radius: 999px;
  padding: 8px 18px;
  font-weight: 800;
  letter-spacing: 0.06em;
  font-size: clamp(0.95rem, 2.7vw, 1.15rem);
  z-index: 3;
  box-shadow: var(--shadow);
}

.hint.hide {
  display: none;
}

.card {
  background: var(--card);
  border-radius: var(--radius-xl);
  padding: 30px 18px 22px;
  box-shadow: var(--shadow);
  text-align: center;
  border: 4px solid rgba(45, 183, 255, 0.25);
  transform-origin: center;
}

.card.bounce {
  animation: bounce 0.42s ease;
}

.big-letter {
  font-weight: 900;
  font-size: clamp(5rem, 20vw, 10rem);
  line-height: 1;
  color: #0a5f95;
  text-shadow: 0 4px 0 rgba(10, 95, 149, 0.12);
}

.word-line {
  margin-top: 6px;
  font-weight: 800;
  font-size: clamp(1.4rem, 5vw, 2.4rem);
  letter-spacing: 0.04em;
}

.emoji {
  margin-top: 6px;
  font-size: clamp(3rem, 10vw, 4.8rem);
}

.sparkles {
  position: absolute;
  inset: 0;
  pointer-events: none;
  overflow: hidden;
}

.sparkle {
  position: absolute;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  opacity: 0;
  animation: sparkle 0.8s ease-out;
}

.controls {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.nav-btn {
  min-height: 66px;
  border: 0;
  border-radius: var(--radius-lg);
  font-weight: 800;
  font-size: clamp(1.1rem, 3.5vw, 1.4rem);
  letter-spacing: 0.05em;
  color: #ffffff;
  cursor: pointer;
  box-shadow: var(--shadow);
}

#back-btn {
  background: #36a8e0;
}

#next-btn {
  background: #ff7a59;
}

.toggles {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: center;
}

.toggle {
  min-height: 60px;
  border-radius: var(--radius-md);
  background: #ffffff;
  border: 2px solid rgba(15, 41, 64, 0.14);
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 10px 14px;
  box-shadow: 0 6px 14px rgba(15, 41, 64, 0.1);
  font-weight: 800;
  letter-spacing: 0.04em;
}

.toggle.small {
  min-height: 50px;
  font-size: 0.95rem;
}

.toggle input {
  width: 24px;
  height: 24px;
  accent-color: var(--good);
}

.letters-panel {
  min-height: 0;
}

.letters-grid {
  display: grid;
  grid-template-columns: repeat(6, minmax(44px, 1fr));
  gap: 8px;
}

.letter-btn {
  min-height: 60px;
  border: 0;
  border-radius: 14px;
  background: #ffffff;
  font-size: clamp(1.3rem, 4vw, 1.7rem);
  font-weight: 900;
  color: #0b4d78;
  box-shadow: 0 4px 10px rgba(15, 41, 64, 0.15);
  cursor: pointer;
}

.letter-btn.active {
  background: #2db7ff;
  color: #ffffff;
  transform: translateY(-2px);
}

.nav-btn:active,
.letter-btn:active {
  transform: scale(0.98);
}

@keyframes bounce {
  0% { transform: scale(0.95); }
  40% { transform: scale(1.05); }
  70% { transform: scale(0.98); }
  100% { transform: scale(1); }
}

@keyframes sparkle {
  0% {
    opacity: 0.95;
    transform: translateY(0) scale(0.8);
  }
  100% {
    opacity: 0;
    transform: translateY(-34px) scale(1.5);
  }
}

@media (max-width: 720px) {
  .app {
    grid-template-rows: auto auto auto auto auto;
  }

  .letters-grid {
    grid-template-columns: repeat(4, minmax(56px, 1fr));
    gap: 10px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .card.bounce,
  .sparkle {
    animation: none;
  }
}