:root {
  font-family: "Inter", "Hiragino Kaku Gothic ProN", "Yu Gothic", sans-serif;
  color: #0f172a;
  background-color: #f8fafc;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100dvh;
  background: linear-gradient(180deg, #e2e8f0, #f8fafc 40%);
}

body.is-special-shaking .app {
  animation: appShake 400ms ease-in-out infinite;
}

.app {
  min-height: 100dvh;
  display: grid;
  grid-template-rows: minmax(160px, 30vh) 1fr;
  gap: 12px;
  padding: 12px;
  position: relative;
  z-index: 1;
}

.display {
  background: #ffffff;
  border-radius: 16px;
  padding: 16px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 8px;
  box-shadow: 0 8px 24px rgb(15 23 42 / 0.08);
}

.display__label {
  margin: 0;
  font-size: 0.9rem;
  color: #475569;
}

.display__input {
  margin: 0;
  font-size: clamp(2rem, 8vw, 3.5rem);
  line-height: 1.1;
  font-weight: 700;
  min-height: 1.1em;
}

.display__result {
  margin: 0;
  font-size: 1rem;
  font-weight: 600;
  color: #1d4ed8;
  font-family: "JetBrains Mono", "SFMono-Regular", "Consolas", monospace;
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.01em;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
}

.display__result sup {
  font-size: 0.72em;
  vertical-align: super;
}

.display__result--special {
  color: #9a3412;
}


.keys {
  display: grid;
  grid-template-columns: repeat(3, minmax(44px, 1fr));
  gap: 10px;
  align-content: stretch;
}

.key {
  border: none;
  border-radius: 14px;
  min-height: 56px;
  font-size: 1.2rem;
  font-weight: 700;
  background: #1e293b;
  color: #f8fafc;
  touch-action: manipulation;
}

.key:active {
  transform: scale(0.98);
}

.key--clear {
  background: #dc2626;
}

.special-overlay {
  position: fixed;
  inset: 0;
  z-index: 3;
  pointer-events: none;
  opacity: 0;
  transition: opacity 320ms ease;
}

.special-overlay--active {
  opacity: 1;
}

.special-overlay__canvas,
.special-overlay__glow,
.special-overlay__ripples {
  position: absolute;
  inset: 0;
}

.special-overlay__glow {
  background: radial-gradient(circle at center, rgb(255 215 0 / 0.45), rgb(0 0 0 / 0.7));
  mix-blend-mode: screen;
}

.special-overlay--rama .special-overlay__glow {
  background: radial-gradient(circle at center, rgb(34 211 238 / 0.35), rgb(0 0 0 / 0.72));
}

.special-overlay__ripples {
  display: grid;
  place-items: center;
}

.special-overlay__ripple {
  position: absolute;
  width: 10vmin;
  aspect-ratio: 1;
  border-radius: 999px;
  border: 3px solid rgb(255 255 255 / 0.5);
  animation: ripple 1.3s ease-out infinite;
}

.special-overlay__content {
  position: absolute;
  inset: 0;
  display: grid;
  place-content: center;
  text-align: center;
  gap: 8px;
  color: #fff7ed;
  text-shadow: 0 0 14px rgb(254 240 138 / 0.9), 0 0 36px rgb(245 158 11 / 0.85);
  animation: zoomPulse 700ms ease-in-out infinite alternate;
}

.special-overlay--rama .special-overlay__content {
  color: #ecfeff;
  text-shadow: 0 0 14px rgb(34 211 238 / 0.95), 0 0 36px rgb(192 132 252 / 0.8);
}

.special-overlay__tag {
  margin: 0;
  letter-spacing: 0.18em;
  font-size: clamp(0.75rem, 2vw, 1rem);
}

.special-overlay__title {
  margin: 0;
  font-size: clamp(1.7rem, 8vw, 4.4rem);
  line-height: 1.1;
  letter-spacing: 0.06em;
}

@keyframes appShake {
  0% { transform: translate(0, 0) rotate(0deg); }
  25% { transform: translate(1px, -1px) rotate(0.3deg); }
  50% { transform: translate(-1px, 1px) rotate(-0.3deg); }
  75% { transform: translate(1px, 1px) rotate(0.2deg); }
  100% { transform: translate(0, 0) rotate(0deg); }
}

@keyframes ripple {
  from { transform: scale(0.2); opacity: 0.9; }
  to { transform: scale(8); opacity: 0; }
}

@keyframes zoomPulse {
  from { transform: scale(0.95); }
  to { transform: scale(1.05); }
}

@media (min-width: 768px) {
  .app {
    max-width: 760px;
    margin: 0 auto;
    grid-template-rows: minmax(200px, 35vh) 1fr;
    padding: 20px;
    gap: 16px;
  }

  .keys {
    grid-template-columns: repeat(5, minmax(44px, 1fr));
  }

  .key {
    min-height: 72px;
    font-size: 1.35rem;
  }
}