:root {
    --bg-color: #f5f5f7;
    --card-bg-color: #ffffff;
    --text-color: #1d1d1f;
    --secondary-text-color: #6e6e73;
    --accent-color: #007aff;
    --border-color: #d2d2d7;
    --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

body {
    font-family: var(--font-family);
    background-color: var(--bg-color);
    color: var(--text-color);
    margin: 0;
    padding: 20px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

header {
    text-align: center;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 20px;
}

header h1 {
    font-size: 28px;
    font-weight: 600;
    margin-bottom: 8px;
}

header p {
    font-size: 16px;
    color: var(--secondary-text-color);
}

.main-content {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.controls-area, .pcm-list-container, .split-section {
    background-color: var(--card-bg-color);
    border-radius: 12px;
    padding: 20px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.05);
}

.drop-zone {
    border: 2px dashed var(--border-color);
    border-radius: 12px;
    padding: 40px;
    text-align: center;
    cursor: pointer;
    transition: background-color 0.2s, border-color 0.2s;
}

.drop-zone.dragover {
    background-color: #e9e9eb;
    border-color: var(--accent-color);
}

.drop-zone p {
    margin: 0;
    color: var(--secondary-text-color);
}

#file-input {
    display: none;
}

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

label {
    font-weight: 500;
}

select, input[type="number"], button {
    padding: 8px 12px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    background-color: #fff;
    font-family: var(--font-family);
    font-size: 14px;
    transition: border-color 0.2s, box-shadow 0.2s;
}

select:focus, input[type="number"]:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 2px rgba(0, 122, 255, 0.3);
}

button {
    background-color: var(--accent-color);
    color: #fff;
    border: none;
    cursor: pointer;
    font-weight: 500;
    transition: background-color 0.2s;
}

button:hover {
    background-color: #006adc;
}

button:active {
    background-color: #005bb5;
}

#zoom-in-btn, #zoom-out-btn, #reset-zoom-btn {
    background-color: #e9e9eb;
    color: var(--text-color);
}
#zoom-in-btn:hover, #zoom-out-btn:hover, #reset-zoom-btn:hover {
    background-color: #dcdce0;
}

#zoom-level-display {
    font-size: 14px;
    color: var(--secondary-text-color);
    font-variant-numeric: tabular-nums;
    margin-left: 5px;
}

.waveform-container {
    position: relative;
    width: 100%;
    height: 300px;
    background-color: var(--card-bg-color);
    border-radius: 12px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.05);
    cursor: grab;
}

.waveform-container:hover {
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

.waveform-container:active {
    cursor: grabbing;
}

#waveform-canvas {
    width: 100%;
    height: 100%;
    border-radius: 12px;
}

.info-tooltip {
    position: absolute;
    display: none;
    background-color: rgba(0,0,0,0.7);
    color: #fff;
    padding: 5px 10px;
    border-radius: 4px;
    font-size: 12px;
    pointer-events: none;
    white-space: nowrap;
}

#pcm-list-container h2, .split-section h2 {
    margin-top: 0;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 10px;
    margin-bottom: 15px;
    font-size: 18px;
    font-weight: 600;
}

#pcm-list {
    list-style: none;
    padding: 0;
    margin: 0;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.pcm-item {
    display: flex;
    align-items: center;
    gap: 15px;
    padding: 10px;
    border-radius: 8px;
    transition: background-color 0.2s;
}

.pcm-item:hover {
    background-color: var(--bg-color);
}

.pcm-color-indicator {
    width: 15px;
    height: 15px;
    border-radius: 4px;
    flex-shrink: 0;
}

.pcm-name {
    flex-grow: 1;
    font-weight: 500;
}

.pcm-actions button {
    background: none;
    border: none;
    cursor: pointer;
    font-size: 18px;
    color: var(--secondary-text-color);
    padding: 5px;
}
.pcm-actions button:hover {
    color: var(--text-color);
}

.split-controls {
    display: grid;
    grid-template-columns: auto 1fr;
    gap: 15px;
    align-items: center;
}

.range-wrapper {
    display: flex;
    align-items: center;
    gap: 10px;
}

.range-wrapper input[type="range"] {
    flex-grow: 1;
}

#threshold-value {
    font-variant-numeric: tabular-nums;
    min-width: 45px;
    text-align: right;
}

.split-controls button {
    grid-column: 1 / -1;
    justify-self: end;
    width: auto;
    min-width: 120px;
}

input[type="range"] {
    -webkit-appearance: none;
    appearance: none;
    width: 100%;
    height: 8px;
    background: #ddd;
    border-radius: 5px;
    outline: none;
    opacity: 0.7;
    transition: opacity .2s;
}

input[type="range"]:hover {
    opacity: 1;
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 20px;
    height: 20px;
    background: var(--accent-color);
    border-radius: 50%;
    cursor: pointer;
}

input[type="range"]::-moz-range-thumb {
    width: 20px;
    height: 20px;
    background: var(--accent-color);
    border-radius: 50%;
    cursor: pointer;
}

#split-results {
    margin-top: 20px;
}

.split-results-list {
    list-style: none;
    padding: 0;
    margin-top: 10px;
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.split-item {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    align-items: center;
    gap: 10px;
    padding: 8px 12px;
    background-color: var(--bg-color);
    border-radius: 6px;
}

.split-item-name {
    font-weight: 500;
}

.split-item-info {
    font-size: 12px;
    color: var(--secondary-text-color);
    flex-shrink: 0;
}

.split-item-actions {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-left: auto;
}

.icon-btn {
    background-color: transparent;
    border: none;
    padding: 0;
    cursor: pointer;
    width: 28px;
    height: 28px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    color: var(--secondary-text-color);
    background-repeat: no-repeat;
    background-position: center center;
    background-size: 55%;
    transition: background-color 0.2s;
    flex-shrink: 0;
}

.icon-btn:hover {
    background-color: #e9e9eb;
}

.icon-btn.play-icon {
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='%236e6e73'%3E%3Cpath d='M8 5v14l11-7z'/%3E%3C/svg%3E");
}
.icon-btn.pause-icon {
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='%236e6e73'%3E%3Cpath d='M6 19h4V5H6v14zm8-14v14h4V5h-4z'/%3E%3C/svg%3E");
}
.icon-btn.info-icon {
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='%236e6e73'%3E%3Cpath d='M12 2C6.48 2 2 6.48 2 12s4.48 10 10 10 10-4.48 10-10S17.52 2 12 2zm1 15h-2v-6h2v6zm0-8h-2V7h2v2z'/%3E%3C/svg%3E");
}
.icon-btn.delete-icon {
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='%236e6e73'%3E%3Cpath d='M19 6.41L17.59 5 12 10.59 6.41 5 5 6.41 10.59 12 5 17.59 6.41 19 12 13.41 17.59 19 19 17.59 13.41 12z'/%3E%3C/svg%3E");
}
.icon-btn.download-icon {
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='%236e6e73'%3E%3Cpath d='M19 9h-4V3H9v6H5l7 7 7-7zM5 18v2h14v-2H5z'/%3E%3C/svg%3E");
}

.download-all-btn {
    margin-top: 0;
    float: none;
}

.btn-secondary {
    background-color: #e9e9eb;
    color: var(--text-color);
}
.btn-secondary:hover {
    background-color: #dcdce0;
}

.split-results-actions {
    margin-top: 15px;
    display: flex;
    justify-content: flex-end;
    gap: 10px;
}