:root {
  --bg: #FFE4EF;
  --bg2: #FFD1E3;
  --card: #FFF5F9;
  --accent: #FF6FA8;
  --deep: #B03A6B;
  --border: #FFB6D3;
  --glow: rgba(255, 111, 168, 0.35);
  --shadow: 0 8px 24px rgba(255, 111, 168, 0.25), 0 0 40px rgba(255, 111, 168, 0.3), inset 0 0 18px rgba(255, 255, 255, 0.7);
}

* { box-sizing: border-box; }

html { touch-action: manipulation; height: 100%; overflow: hidden; overscroll-behavior: none; background: var(--bg); }

body {
  margin: 0;
  height: 100dvh;
  overflow: hidden;
  overscroll-behavior: none;
  font-family: ui-rounded, "SF Pro Rounded", "Nunito", "Quicksand", system-ui, sans-serif;
  color: var(--deep);
  background: var(--bg);
  padding: max(24px, env(safe-area-inset-top)) max(16px, env(safe-area-inset-right))
           max(24px, env(safe-area-inset-bottom)) max(16px, env(safe-area-inset-left));
}

.app { max-width: 420px; margin: 0 auto; }

header { text-align: center; margin-bottom: 20px; }
h1 { margin: 0; font-size: 2.2rem; letter-spacing: 0.5px; display: flex; align-items: center; justify-content: center; gap: 10px; }
.peony { height: 1.4em; width: auto; flex: none; }
.tagline { margin: 4px 0 0; font-size: 1rem; opacity: 0.85; }

.card {
  background: var(--card);
  border: 2px solid var(--border);
  border-radius: 24px;
  box-shadow: var(--shadow);
  padding: 20px;
  margin-bottom: 20px;
}
.card h2 { margin: 0 0 14px; font-size: 1.1rem; text-align: center; }

.row { display: flex; align-items: center; gap: 12px; }
.unit { min-width: 2.2rem; font-size: 1.25rem; font-weight: 700; }

input, .result {
  flex: 1;
  min-width: 0;
  min-height: 56px;
  font: inherit;
  font-size: 1.6rem;
  font-weight: 700;
  text-align: center;
  color: var(--deep);
  background: #fff;
  border: 2px solid var(--border);
  border-radius: 16px;
  padding: 8px 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: border-color 0.2s, box-shadow 0.2s;
}
input::placeholder { color: var(--border); }
input:focus, .result:focus-visible {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 5px var(--glow);
}

.result { background: #FFEAF3; cursor: pointer; user-select: all; }
.result.pop { animation: pop 0.25s ease; }

.body { display: flex; align-items: center; gap: 12px; }
.rows { flex: 1; min-width: 0; display: flex; flex-direction: column; gap: 12px; }

.swap {
  flex: none;
  width: 48px;
  height: 48px;
  font: inherit;
  font-size: 1.5rem;
  line-height: 1;
  color: #fff;
  background: var(--accent);
  border: none;
  border-radius: 50%;
  box-shadow: 0 4px 10px var(--glow);
  cursor: pointer;
  transition: transform 0.2s, box-shadow 0.2s;
}
.swap:hover { transform: scale(1.08); }
.swap:focus-visible { outline: none; box-shadow: 0 0 0 5px var(--glow); }
.swap.flip { transform: rotate(180deg); }

.toast {
  position: fixed;
  left: 50%;
  bottom: max(24px, env(safe-area-inset-bottom));
  transform: translate(-50%, 20px);
  background: var(--deep);
  color: #fff;
  padding: 10px 18px;
  border-radius: 999px;
  font-weight: 700;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s, transform 0.2s;
}
.toast.show { opacity: 1; transform: translate(-50%, 0); }

@keyframes pop {
  50% { transform: scale(1.06); }
}

@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; animation: none !important; }
}