@font-face {
    font-family: 'Bravura';
    src: url('https://cdn.jsdelivr.net/gh/steinbergmedia/bravura@master/redist/woff/Bravura.woff2') format('woff2');
    font-display: swap;
}

:root {
    --color-sharp: #ff4136;
    --color-flat: #800080;
    --color-perfect: #2ecc40;
    --color-staff: #2c2f33;
    --color-leger: #b8bdc4;
    --color-indicator-line: #d8dde3;
    --color-score-ring: #f5c542;
    --transition-speed: 0.1s;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background-color: #f0f0f0;
    color: #333;
    margin: 0;
}

.container {
    text-align: center;
    background-color: #fff;
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
    width: 90%;
    max-width: 640px;
}

h1 {
    margin-top: 0;
    color: #555;
}

/* --- Staff visualization --- */

.staff-container {
    position: relative;
    width: 100%;
    aspect-ratio: 5 / 2;
    margin: 24px 0 8px;
}

#staff {
    width: 100%;
    height: 100%;
    display: block;
    overflow: hidden;
}

.staff-line {
    stroke: var(--color-staff);
    stroke-width: 2.6;
    stroke-linecap: butt;
    shape-rendering: geometricPrecision;
}

.leger-line {
    stroke: var(--color-leger);
    stroke-width: 1.8;
    stroke-linecap: butt;
    shape-rendering: geometricPrecision;
}

.treble-clef {
    fill: var(--color-staff);
    pointer-events: none;
    font-family: 'Bravura', serif;
    font-size: 154.67px;
}

.indicator-axis {
    stroke: var(--color-indicator-line);
    stroke-width: 1;
    stroke-dasharray: 3 4;
}

.indicator {
    transition: opacity 120ms ease-out;
}

.indicator.hidden {
    opacity: 0;
}

.indicator-dot {
    fill: var(--color-perfect);
    transition: fill var(--transition-speed) ease-out;
    filter: drop-shadow(0 0 4px rgba(0, 0, 0, 0.18));
}

.indicator-label {
    fill: #333;
    font-size: 22px;
    font-weight: 700;
    font-family: 'Iowan Old Style', 'Palatino Linotype', Georgia, serif;
    dominant-baseline: middle;
}

.score-ring {
    fill: none;
    stroke: var(--color-score-ring);
    stroke-width: 3;
    opacity: 0;
    transform-origin: center;
    transform-box: fill-box;
}

.score-ring.pulse {
    animation: ring-pulse 0.55s ease-out;
}

@keyframes ring-pulse {
    0%   { transform: scale(1);   opacity: 1;   stroke-width: 3; }
    100% { transform: scale(4.5); opacity: 0;   stroke-width: 0.6; }
}

.oor-arrow {
    fill: var(--color-leger);
    transition: opacity 120ms ease-out;
}

.oor-arrow.hidden {
    opacity: 0;
}

.cents-readout {
    position: absolute;
    bottom: 6px;
    right: 10px;
    font-size: 13px;
    font-variant-numeric: tabular-nums;
    color: #888;
    transition: color var(--transition-speed) ease-out;
    pointer-events: none;
}

/* --- Score & controls --- */

.score-display {
    font-size: 50px;
    font-weight: bold;
    color: #444;
    margin: 25px 0;
    font-variant-numeric: tabular-nums;
}

.controls {
    margin-top: 20px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 15px;
}

.controls button {
    padding: 12px 25px;
    font-size: 16px;
    cursor: pointer;
    border: none;
    border-radius: 5px;
    background-color: #007bff;
    color: white;
    transition: background-color 0.2s ease;
    min-width: 150px;
}

.controls button:hover {
    background-color: #0056b3;
}

.controls button#start-stop-button.detecting {
    background-color: #28a745;
}
.controls button#start-stop-button.detecting:hover {
    background-color: #218838;
}

.status-message {
    margin-top: 20px;
    font-size: 14px;
    color: #888;
    min-height: 20px;
}