:root {
  color-scheme: light;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: #f7f7f2;
  color: #25272b;
  font-synthesis: none;
}

* { box-sizing: border-box; }
body { margin: 0; min-height: 100vh; min-height: 100svh; display: grid; place-items: center; padding: 24px 16px; }
button, input { font: inherit; -webkit-tap-highlight-color: transparent; }
button:focus-visible, input:focus-visible { outline: 3px solid #8890ff; outline-offset: 4px; }
.player { position: relative; width: min(100%, 400px); padding: 28px; background: #fff; border: 1px solid #e7e7e4; border-radius: 20px; }
.volume-row { display: flex; align-items: center; justify-content: space-between; color: #9396a0; font-size: 12px; font-variant-numeric: tabular-nums; }
#volume-level { color: #444ee7; font-weight: 600; }
.frequency-control { margin: 28px 0 24px; }
.frequency-options { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 6px; margin-top: 24px; }
.frequency-option { min-width: 0; min-height: 44px; padding: 6px 2px; background: #f8f8fb; border: 1px solid transparent; border-radius: 7px; color: #565b66; cursor: pointer; font-size: 12px; font-variant-numeric: tabular-nums; white-space: nowrap; }
.frequency-option:hover:enabled { background: #eceeff; color: #444ee7; }
.frequency-option:disabled { cursor: wait; opacity: .6; }
.frequency-option[aria-pressed="true"] { background: #eceeff; border-color: #b9bef8; color: #444ee7; }
.frequency-display { display: flex; align-items: baseline; justify-content: center; gap: 7px; margin: 0; font-size: clamp(50px, 11vw, 68px); line-height: 1.1; font-weight: 500; letter-spacing: -3px; font-variant-numeric: tabular-nums; }
.frequency-unit { font-size: 18px; font-weight: 400; color: #9396a0; letter-spacing: 0; }
.play-button { position: relative; overflow: hidden; display: block; width: 100%; min-height: 56px; padding: 14px; border: 0; border-radius: 10px; background: #444ee7; color: #fff; cursor: pointer; font-size: 14px; font-weight: 500; transition: background .15s, transform .15s; }
.play-button:hover:enabled { background: #3640d9; }
.play-button:active:enabled { transform: translateY(1px); }
.play-button:disabled { background: #5660eb; cursor: wait; }
.play-button::after { content: ''; position: absolute; inset: 0; background: #ffffff18; transform: scaleX(0); transform-origin: left; pointer-events: none; }
.play-button.is-playing::after { animation: playback var(--tone-duration, 1000ms) linear forwards; }
.duration-control { display: flex; align-items: center; justify-content: space-between; gap: 16px; margin-top: 24px; }
.duration-control label { font-size: 13px; color: #727680; }
.duration-input-wrap { display: flex; align-items: center; gap: 7px; padding: 10px 12px; background: #f8f8fb; border: 1px solid #e8e8ef; border-radius: 8px; }
.duration-input-wrap input { appearance: textfield; -moz-appearance: textfield; width: 66px; padding: 0; background: transparent; color: #444856; border: 0; text-align: right; font-size: 14px; font-variant-numeric: tabular-nums; }
.duration-input-wrap input::-webkit-inner-spin-button, .duration-input-wrap input::-webkit-outer-spin-button { -webkit-appearance: none; margin: 0; }
.duration-input-wrap span { font-size: 12px; color: #9396a0; }
.error-message { margin: 20px 0 0; color: #a83c3c; font-size: 12px; line-height: 1.5; }
.sr-only { position: absolute; height: 1px; width: 1px; margin: -1px; padding: 0; overflow: hidden; clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0; }
noscript { font-size: 13px; }
@keyframes playback { to { transform: scaleX(1); } }
@media (max-width: 360px) { .player { padding: 24px; } }
@media (prefers-reduced-motion: reduce) { *, *::before, *::after { animation: none !important; transition: none !important; } }