/* Hz to Note Converter — frequency-to-note matcher with mini-piano and cents meter */
.tool-grid { display: grid; grid-template-columns: 1fr 1fr; gap: var(--space-lg); margin-bottom: var(--space-xl); }
.tool-panel { background: var(--color-surface); border: 1px solid var(--color-border); border-radius: var(--radius-lg); padding: var(--space-lg); }
.panel-title { font-family: var(--font-display); font-size: var(--fs-base); color: var(--color-primary); margin: 0 0 var(--space-md); text-transform: uppercase; letter-spacing: 0.05em; }

.input-group { margin-bottom: var(--space-md); }
.input-label { display: block; font-size: var(--fs-sm); color: var(--color-text-muted); margin-bottom: var(--space-xs); font-family: var(--font-mono); }
.input-field { width: 100%; background: var(--color-bg); border: 1px solid var(--color-border); border-radius: var(--radius-md); color: var(--color-text); font-family: var(--font-mono); font-size: var(--fs-lg); padding: var(--space-sm) var(--space-md); box-sizing: border-box; transition: border-color 0.2s; }
.input-field:focus { outline: none; border-color: var(--color-primary); box-shadow: var(--glow-sm); }
.input-with-unit { display: flex; gap: var(--space-xs); align-items: stretch; }
.input-with-unit .input-field { flex: 1; }
.unit-badge { display: flex; align-items: center; padding: 0 var(--space-md); background: var(--color-bg); border: 1px solid var(--color-border); border-radius: var(--radius-md); font-family: var(--font-mono); font-size: var(--fs-base); color: var(--color-secondary); font-weight: 600; }

.slider-wrap { margin-top: var(--space-xs); }
.slider { width: 100%; accent-color: var(--color-primary); cursor: pointer; }
.slider-labels { display: flex; justify-content: space-between; font-size: var(--fs-xs); color: var(--color-text-muted); font-family: var(--font-mono); margin-top: 2px; }
.a4-display-row { font-family: var(--font-mono); font-size: var(--fs-sm); color: var(--color-text-muted); margin-top: var(--space-xs); }
.a4-display-row strong { color: var(--color-secondary); font-weight: 600; }

.presets-section { margin-top: var(--space-md); }
.presets-label { font-size: var(--fs-xs); color: var(--color-text-muted); text-transform: uppercase; letter-spacing: 0.1em; margin-bottom: var(--space-xs); font-family: var(--font-mono); }
.presets-list { display: flex; flex-wrap: wrap; gap: var(--space-xs); }
.preset-btn { padding: var(--space-xs) var(--space-sm); border: 1px solid var(--color-border); border-radius: var(--radius-full); background: var(--color-bg); color: var(--color-text); font-family: var(--font-mono); font-size: var(--fs-xs); cursor: pointer; transition: all 0.2s; }
.preset-btn:hover { border-color: var(--color-primary); color: var(--color-primary); box-shadow: var(--glow-sm); }

.action-row { display: grid; grid-template-columns: 1fr 1fr; gap: var(--space-sm); margin-top: var(--space-md); }
.action-row--single { grid-template-columns: 1fr; }
.play-btn { padding: var(--space-sm) var(--space-md); border: 1px solid var(--color-primary); border-radius: var(--radius-md); background: color-mix(in srgb, var(--color-primary) 10%, var(--color-bg)); color: var(--color-primary); font-family: var(--font-mono); font-size: var(--fs-sm); font-weight: 600; cursor: pointer; transition: all 0.2s; }
.play-btn:hover { background: color-mix(in srgb, var(--color-primary) 20%, var(--color-bg)); box-shadow: var(--glow-sm); }
.play-btn.playing { background: color-mix(in srgb, var(--color-accent) 15%, var(--color-bg)); border-color: var(--color-accent); color: var(--color-accent); animation: play-pulse 1s ease-in-out infinite; }
@keyframes play-pulse { 50% { box-shadow: 0 0 16px color-mix(in srgb, var(--color-accent) 40%, transparent); } }

.result-note-row { text-align: center; margin-bottom: var(--space-sm); }
.result-note { font-family: var(--font-display); font-size: var(--fs-2xl); color: var(--color-secondary); }
.result-hero { text-align: center; padding: var(--space-lg); background: var(--color-bg); border-radius: var(--radius-lg); border: 1px solid var(--color-primary); margin-bottom: var(--space-md); box-shadow: 0 0 24px color-mix(in srgb, var(--color-primary) 15%, transparent); }
.result-label { font-size: var(--fs-sm); color: var(--color-text-muted); font-family: var(--font-mono); text-transform: uppercase; letter-spacing: 0.1em; margin-bottom: var(--space-xs); }
.result-value { font-family: var(--font-display); font-size: 2.5rem; color: var(--color-primary); line-height: 1.1; text-shadow: 0 0 16px var(--color-primary-glow); word-break: break-all; }
.result-unit { font-family: var(--font-mono); color: var(--color-text-muted); font-size: var(--fs-sm); margin-top: var(--space-xs); }

/* Cents meter — horizontal bar with center notch and needle */
.cents-meter-wrap { margin-bottom: var(--space-md); }
.cents-meter-label { display: flex; justify-content: space-between; font-family: var(--font-mono); font-size: var(--fs-xs); color: var(--color-text-muted); margin-bottom: 4px; }
.cents-meter { position: relative; height: 24px; background: var(--color-bg); border: 1px solid var(--color-border); border-radius: var(--radius-full); overflow: hidden; }
.cents-meter-center { position: absolute; left: 50%; top: 0; bottom: 0; width: 2px; background: var(--color-primary); opacity: 0.5; }
.cents-meter-needle { position: absolute; top: 2px; bottom: 2px; left: 50%; width: 4px; background: var(--color-primary); border-radius: 2px; transform: translateX(-50%); transition: left 0.2s ease; box-shadow: 0 0 8px var(--color-primary-glow); }
.cents-value-row { text-align: center; font-family: var(--font-mono); font-size: var(--fs-base); color: var(--color-secondary); margin-top: var(--space-xs); font-weight: 600; }

/* Tuning quality badges */
.tune-badge { display: inline-block; padding: var(--space-xs) var(--space-md); border-radius: var(--radius-full); font-family: var(--font-mono); font-size: var(--fs-xs); font-weight: 600; margin: 0 auto var(--space-sm); text-align: center; border: 1px solid currentColor; }
.tune-perfect { background: color-mix(in srgb, #00ff41 15%, transparent); color: #00ff41; }
.tune-close   { background: color-mix(in srgb, #00e5ff 15%, transparent); color: #00e5ff; }
.tune-off     { background: color-mix(in srgb, #ffe000 15%, transparent); color: #ffe000; }
.tune-bad     { background: color-mix(in srgb, #ffb300 15%, transparent); color: #ffb300; }
.tune-wrong   { background: color-mix(in srgb, #ff4444 15%, transparent); color: #ff4444; }

/* Octave band badge (audio bands) */
.band-badge { display: inline-block; padding: var(--space-xs) var(--space-md); border-radius: var(--radius-full); font-family: var(--font-mono); font-size: var(--fs-sm); font-weight: 600; margin: 0 auto var(--space-md); text-align: center; border: 1px solid currentColor; }
.band-subbass    { background: color-mix(in srgb, #b266ff 15%, transparent); color: #b266ff; }
.band-bass       { background: color-mix(in srgb, #6699ff 15%, transparent); color: #6699ff; }
.band-lomid      { background: color-mix(in srgb, #00e5ff 15%, transparent); color: #00e5ff; }
.band-mid        { background: color-mix(in srgb, #00ff41 15%, transparent); color: #00ff41; }
.band-umid       { background: color-mix(in srgb, #ffe000 15%, transparent); color: #ffe000; }
.band-presence   { background: color-mix(in srgb, #ffb300 15%, transparent); color: #ffb300; }
.band-brilliance { background: color-mix(in srgb, #ff4488 15%, transparent); color: #ff4488; }
.band-ultra      { background: color-mix(in srgb, #ff66cc 15%, transparent); color: #ff66cc; }

/* Mini piano — single octave */
.piano-wrap { margin: var(--space-md) 0; }
.piano-wrap__label { font-family: var(--font-mono); font-size: var(--fs-xs); color: var(--color-text-muted); text-transform: uppercase; letter-spacing: 0.1em; margin-bottom: var(--space-xs); text-align: center; }
.mini-piano { position: relative; height: 130px; max-width: 480px; margin: 0 auto; padding: var(--space-xs); background: var(--color-bg); border: 1px solid var(--color-border); border-radius: var(--radius-md); }
.mp-whites { display: grid; grid-template-columns: repeat(7, 1fr); height: 100%; gap: 0; }
.mp-blacks { position: absolute; top: var(--space-xs); left: var(--space-xs); right: var(--space-xs); height: 66%; pointer-events: none; }

.mp-key { position: relative; display: flex; align-items: flex-end; justify-content: center; padding-bottom: 8px; border-radius: 0 0 var(--radius-sm) var(--radius-sm); transition: all 0.2s; font-family: var(--font-mono); font-weight: 600; font-size: var(--fs-xs); }
.mp-white { background: linear-gradient(to bottom, #fafafa, #e2e2e2); color: #333; border: 1px solid #444; }
.mp-white.mp-active { background: linear-gradient(to bottom, #66ff88, #00ff41); color: #003311; box-shadow: 0 0 18px var(--color-primary-glow), inset 0 0 8px rgba(0,0,0,0.2); border-color: var(--color-primary); }

.mp-black { position: absolute; width: 8.57%; height: 100%; background: linear-gradient(to bottom, #2a2a2a, #0a0a0a); color: #ccc; font-size: 0.65rem; border: 1px solid #000; border-radius: 0 0 var(--radius-sm) var(--radius-sm); }
/* Position black keys at the boundaries of the white-key grid */
.mp-black:nth-child(1) { left: 10.00%; }   /* C# between C and D */
.mp-black:nth-child(2) { left: 24.28%; }   /* D# between D and E */
.mp-black:nth-child(3) { left: 52.86%; }   /* F# between F and G */
.mp-black:nth-child(4) { left: 67.14%; }   /* G# between G and A */
.mp-black:nth-child(5) { left: 81.43%; }   /* A# between A and B */
.mp-black.mp-active { background: linear-gradient(to bottom, #00cc33, #00801f); color: #fff; box-shadow: 0 0 18px var(--color-primary-glow); border-color: var(--color-primary); }

.result-grid { display: grid; grid-template-columns: 1fr 1fr; gap: var(--space-sm); margin-bottom: var(--space-md); }
.result-card { background: var(--color-bg); border: 1px solid var(--color-border); border-radius: var(--radius-md); padding: var(--space-sm) var(--space-md); }
.result-card__label { font-size: var(--fs-xs); color: var(--color-text-muted); font-family: var(--font-mono); text-transform: uppercase; letter-spacing: 0.08em; }
.result-card__value { font-family: var(--font-mono); font-size: var(--fs-base); color: var(--color-secondary); font-weight: 600; margin-top: 2px; word-break: break-all; }

.formula-box { background: var(--color-bg); border: 1px solid var(--color-border); border-left: 3px solid var(--color-primary); border-radius: var(--radius-md); padding: var(--space-sm) var(--space-md); margin-bottom: var(--space-md); }
.formula-title { font-size: var(--fs-xs); color: var(--color-text-muted); text-transform: uppercase; letter-spacing: 0.1em; margin-bottom: var(--space-xs); }
.formula-text { font-family: var(--font-mono); font-size: var(--fs-sm); color: var(--color-text); margin: 2px 0; word-break: break-word; }

.comparison-section { margin-top: var(--space-xl); }
.table-wrap { overflow-x: auto; }
.data-table { width: 100%; border-collapse: collapse; font-family: var(--font-mono); font-size: var(--fs-sm); }
.data-table th { background: var(--color-surface); color: var(--color-primary); padding: var(--space-xs) var(--space-sm); text-align: left; border-bottom: 1px solid var(--color-border); font-size: var(--fs-xs); text-transform: uppercase; letter-spacing: 0.06em; }
.data-table td { padding: var(--space-xs) var(--space-sm); border-bottom: 1px solid color-mix(in srgb, var(--color-border) 50%, transparent); color: var(--color-text); }
.data-table td:nth-child(2), .data-table td:nth-child(3) { color: var(--color-secondary); }
.data-table tr:hover td { background: color-mix(in srgb, var(--color-primary) 5%, transparent); }

.content-section { max-width: 800px; margin: 0 auto var(--space-lg); color: var(--color-text); line-height: 1.7; }
.content-section h3 { color: var(--color-secondary); font-family: var(--font-display); margin-top: var(--space-lg); margin-bottom: var(--space-xs); font-size: var(--fs-md); }
.content-section p { margin-bottom: var(--space-sm); }

.faq-list { max-width: 800px; margin: 0 auto; }
.faq-item { border: 1px solid var(--color-border); border-radius: var(--radius-md); margin-bottom: var(--space-sm); overflow: hidden; }
.faq-question { padding: var(--space-md); cursor: pointer; font-weight: 600; list-style: none; display: flex; justify-content: space-between; align-items: center; color: var(--color-text-bright); }
.faq-question::-webkit-details-marker { display: none; }
.faq-question::after { content: '+'; color: var(--color-primary); font-size: 1.3em; font-weight: 700; }
details[open] .faq-question::after { content: '−'; }
.faq-answer { padding: 0 var(--space-md) var(--space-md); color: var(--color-text-muted); line-height: 1.75; border-top: 1px solid var(--color-border); padding-top: var(--space-sm); }

.related-tools-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: var(--space-md); max-width: 800px; margin: 0 auto; }
.related-tool-card { display: block; background: var(--color-surface); border: 1px solid var(--color-border); border-radius: var(--radius-md); padding: var(--space-md); text-decoration: none; transition: border-color 0.2s, transform 0.2s; text-align: left; }
.related-tool-card:hover { border-color: var(--color-primary); transform: translateY(-2px); }
.related-tool-card__title { font-family: var(--font-display); font-size: var(--fs-sm); color: var(--color-primary); margin-bottom: var(--space-xs); }
.related-tool-card__desc { font-size: var(--fs-xs); color: var(--color-text-muted); line-height: 1.5; }

@media (max-width: 768px) {
  .tool-grid { grid-template-columns: 1fr !important; }
  .result-value { font-size: 2rem; }
  .result-grid { grid-template-columns: 1fr 1fr; }
  .related-tools-grid { grid-template-columns: 1fr; }
  .mini-piano { height: 110px; }
}