* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

.hidden {
    display: none !important;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    background: #1a1a2e;
    color: #e0e0e0;
    min-height: 100vh;
}

/* Header bar */
header {
    display: flex;
    align-items: baseline;
    gap: 1rem;
    padding: 1rem 2rem;
    background: #12122a;
    border-bottom: 1px solid #2a2a4a;
}

header h1 {
    font-size: 1.3rem;
    color: #fff;
}

header .subtitle {
    color: #666;
    font-size: 0.85rem;
}

/* Main content */
main {
    padding: 1.5rem 2rem;
}

/* Drop zone */
.drop-zone {
    max-width: 600px;
    margin: 4rem auto;
    border: 2px dashed #444;
    border-radius: 8px;
    padding: 3rem;
    text-align: center;
    cursor: pointer;
    transition: border-color 0.2s, background 0.2s;
}

.drop-zone:hover,
.drop-zone.dragover {
    border-color: #6c63ff;
    background: rgba(108, 99, 255, 0.05);
}

.drop-zone p {
    color: #888;
    font-size: 1rem;
}

/* File bar */
.file-bar {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.6rem 1rem;
    background: #16213e;
    border-radius: 6px;
    margin-bottom: 1.25rem;
}

#file-name {
    flex: 1;
    font-size: 0.9rem;
}

.file-bar-actions {
    display: flex;
    gap: 0.5rem;
}

.btn-action {
    background: #6c63ff;
    border: none;
    color: #fff;
    padding: 0.3rem 0.7rem;
    border-radius: 4px;
    cursor: pointer;
    font-size: 0.8rem;
    transition: background 0.2s;
}

.btn-action:hover {
    background: #5a52d5;
}

.btn-muted {
    background: none;
    border: 1px solid #555;
    color: #aaa;
}

.btn-muted:hover {
    border-color: #888;
    color: #fff;
    background: none;
}

/* MIDI Player */
#midi-player {
    flex: 0 1 360px;
    min-width: 200px;
    --primary-color: #6c63ff;
}

#midi-player::part(control-panel) {
    background: #12122a;
    border: 1px solid #2a2a4a;
    border-radius: 4px;
    padding: 0.2rem 0.5rem;
}

#midi-player::part(play-button) {
    color: #e0e0e0;
    border: none;
}

#midi-player::part(time) {
    color: #888;
    font-family: inherit;
    font-size: 0.75rem;
}

#midi-player::part(seek-bar) {
    accent-color: #6c63ff;
}

#midi-player::part(loading-overlay) {
    background: #12122a;
}

/* Two-column layout */
.columns {
    display: grid;
    grid-template-columns: 1fr 360px;
    gap: 1.25rem;
    align-items: start;
}

.panel {
    background: #12122a;
    border: 1px solid #2a2a4a;
    border-radius: 8px;
    padding: 1.25rem;
}

.panel h2 {
    font-size: 1rem;
    color: #ccc;
    margin-bottom: 1rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-weight: 600;
}

.panel h3 {
    font-size: 0.85rem;
    color: #888;
    margin-bottom: 0.6rem;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    font-weight: 600;
}

/* Analysis panel */
.analysis-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
    gap: 0.6rem;
    margin-bottom: 1.25rem;
}

.metric-card {
    background: #1a1a2e;
    border-radius: 6px;
    padding: 0.65rem 0.85rem;
    border-left: 3px solid #6c63ff;
}

.metric-card .label {
    font-size: 0.7rem;
    color: #888;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    margin-bottom: 0.15rem;
}

.metric-card .value {
    font-size: 1.05rem;
    color: #fff;
    font-weight: 500;
}

.track-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 0.5rem;
}

.track-card {
    background: #1a1a2e;
    border-radius: 6px;
    padding: 0.65rem 0.85rem;
}

.track-card .track-header {
    font-size: 0.9rem;
    color: #fff;
    font-weight: 500;
    margin-bottom: 0.35rem;
    display: flex;
    align-items: center;
    gap: 0.4rem;
    flex-wrap: wrap;
}

.channel-badge {
    font-size: 0.65rem;
    background: #6c63ff33;
    color: #a9a4ff;
    padding: 0.1rem 0.35rem;
    border-radius: 3px;
    font-weight: 400;
}

.track-card .detail-row {
    display: flex;
    justify-content: space-between;
    font-size: 0.8rem;
    padding: 0.12rem 0;
    color: #777;
}

.track-card .detail-row .detail-value {
    color: #bbb;
}

.hint {
    font-size: 0.7rem;
    color: #555;
    font-weight: 400;
    text-transform: none;
    letter-spacing: 0;
}

/* Tracks header with merge button */
.tracks-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 0.6rem;
}

.tracks-header h3 {
    margin-bottom: 0;
}

.track-card .merge-checkbox {
    position: absolute;
    top: 0.5rem;
    right: 0.5rem;
    accent-color: #6c63ff;
    width: 14px;
    height: 14px;
}

.track-card {
    position: relative;
}

/* Track detail panel */
.track-detail {
    margin-top: 1.25rem;
    padding-top: 1rem;
    border-top: 1px solid #2a2a4a;
}

.track-detail-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 0.75rem;
}

.track-detail-header h3 {
    margin-bottom: 0;
}

.track-detail-actions {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.btn-danger {
    background: #e03131;
}

.btn-danger:hover {
    background: #c92a2a;
}

.track-edit-controls {
    margin-bottom: 0.75rem;
}

.track-edit-row {
    display: flex;
    align-items: flex-end;
    gap: 0.75rem;
}

.track-edit-row .param-group {
    flex: 1;
}

.track-edit-row .param-group select {
    width: 100%;
    padding: 0.4rem 0.5rem;
    background: #1a1a2e;
    color: #e0e0e0;
    border: 1px solid #333;
    border-radius: 6px;
    font-size: 0.85rem;
}

.track-edit-row .btn-action {
    margin-bottom: 0;
    white-space: nowrap;
}

.graph-container {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.graph-card {
    background: #1a1a2e;
    border-radius: 6px;
    padding: 0.6rem 0.75rem;
}

.graph-card .graph-label {
    font-size: 0.75rem;
    color: #888;
    margin-bottom: 0.35rem;
    font-weight: 500;
}

.graph-card canvas {
    width: 100%;
    height: 80px;
    display: block;
    border-radius: 4px;
}

.graph-card canvas.piano-roll {
    height: 300px;
}

.graph-card .graph-range {
    display: flex;
    justify-content: space-between;
    font-size: 0.65rem;
    color: #555;
    margin-top: 0.2rem;
}

.track-card {
    cursor: pointer;
    transition: border-color 0.15s;
    border: 1px solid transparent;
}

.track-card:hover {
    border-color: #6c63ff55;
}

.track-card.selected {
    border-color: #6c63ff;
}

/* Tool panel */
.tool-select select {
    width: 100%;
    padding: 0.5rem;
    background: #1a1a2e;
    color: #e0e0e0;
    border: 1px solid #333;
    border-radius: 6px;
    font-size: 0.9rem;
}

.tool-description {
    color: #777;
    font-size: 0.8rem;
    margin-top: 0.6rem;
    line-height: 1.4;
}

/* Channel selection */
.channel-section {
    margin-top: 1rem;
}

.channel-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 0.4rem;
}

.channel-header label {
    font-size: 0.8rem;
    color: #aaa;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.04em;
}

.btn-link {
    background: none;
    border: none;
    color: #6c63ff;
    cursor: pointer;
    font-size: 0.75rem;
    padding: 0;
}

.btn-link:hover {
    color: #a9a4ff;
}

.channel-checkboxes {
    display: flex;
    flex-wrap: wrap;
    gap: 0.3rem;
}

.channel-checkboxes label {
    display: flex;
    align-items: center;
    gap: 0.25rem;
    font-size: 0.8rem;
    color: #ccc;
    background: #1a1a2e;
    padding: 0.25rem 0.5rem;
    border-radius: 4px;
    cursor: pointer;
    user-select: none;
    border: 1px solid transparent;
    transition: border-color 0.15s;
}

.channel-checkboxes label:has(input:checked) {
    border-color: #6c63ff55;
    background: #6c63ff15;
}

.channel-checkboxes input[type="checkbox"] {
    accent-color: #6c63ff;
    width: 14px;
    height: 14px;
}

/* Params */
.params {
    margin-top: 1rem;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.param-group {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.param-group label {
    font-size: 0.8rem;
    color: #aaa;
    font-weight: 500;
}

.param-group input {
    padding: 0.45rem 0.6rem;
    background: #1a1a2e;
    color: #e0e0e0;
    border: 1px solid #333;
    border-radius: 6px;
    font-size: 0.9rem;
}

.vel-range-row {
    display: flex;
    align-items: center;
    gap: 0.4rem;
}

.vel-range-row input {
    flex: 1;
}

.vel-range-sep {
    color: #666;
    font-size: 0.9rem;
}

.param-hint {
    font-size: 0.7rem;
    color: #555;
}

.btn-primary {
    margin-top: 1rem;
    width: 100%;
    padding: 0.65rem;
    background: #6c63ff;
    color: #fff;
    border: none;
    border-radius: 6px;
    font-size: 0.95rem;
    cursor: pointer;
    transition: background 0.2s;
}

.btn-primary:hover:not(:disabled) {
    background: #5a52d5;
}

.btn-primary:disabled {
    opacity: 0.4;
    cursor: not-allowed;
}

.status {
    margin-top: 0.75rem;
    padding: 0.6rem 0.85rem;
    border-radius: 6px;
    font-size: 0.85rem;
}

.status.loading {
    background: #16213e;
    color: #6c63ff;
}

.status.error {
    background: #2e1a1a;
    color: #ff6b6b;
}

.status.success {
    background: #1a2e1a;
    color: #69db7c;
}

/* History */
.history-section {
    margin-top: 1.25rem;
    padding-top: 1rem;
    border-top: 1px solid #2a2a4a;
}

.history-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 0.5rem;
}

.history-header h3 {
    margin-bottom: 0;
}

.btn-undo {
    background: #e8590c;
    font-size: 0.75rem;
    padding: 0.25rem 0.6rem;
}

.btn-undo:hover {
    background: #d9480f;
}

.btn-undo:disabled {
    opacity: 0.4;
    cursor: not-allowed;
    background: #e8590c;
}

.history-list {
    list-style: none;
    counter-reset: history;
}

.history-list li {
    counter-increment: history;
    font-size: 0.8rem;
    color: #aaa;
    padding: 0.3rem 0;
    border-bottom: 1px solid #1a1a2e;
}

.history-list li::before {
    content: counter(history) ". ";
    color: #555;
}