/* ========================================
   NusMusic Notation Studio - Frontend CSS
   ======================================== */

/* --- Variables --- */
:root {
    --nus-primary: #FF6B00;
    --nus-dark: #1a1a1a;
    --nus-text: #333;
    --nus-bg: #ffffff;
    --nus-border: #e0e0e0;
    --nus-badge-bg: #f0f0f0;
    --nus-section-bg: #fafafa;
    --nus-highlight: rgba(255, 107, 0, 0.12);
    --nus-font: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --nus-mono: 'SF Mono', 'Fira Code', 'Consolas', monospace;
}

/* --- Top Bar (Shared) --- */
.nus-top-bar {
    background: var(--nus-dark);
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 10px 20px;
    border-radius: 8px 8px 0 0;
    flex-wrap: wrap;
    gap: 10px;
}

.nus-top-bar .nus-song-header {
    display: flex;
    flex-direction: column;
    gap: 2px;
}

.nus-top-bar .nus-song-name {
    font-size: 16px;
    font-weight: 700;
    margin: 0;
}

.nus-top-bar .nus-song-artist-label {
    font-size: 12px;
    color: #aaa;
    margin: 0;
}

.nus-controls {
    display: flex;
    align-items: center;
    gap: 8px;
    flex-wrap: wrap;
}

.nus-btn {
    background: rgba(255,255,255,0.15);
    border: 1px solid rgba(255,255,255,0.25);
    color: #fff;
    padding: 6px 14px;
    border-radius: 20px;
    cursor: pointer;
    font-size: 13px;
    font-family: var(--nus-font);
    transition: all 0.2s;
    display: inline-flex;
    align-items: center;
    gap: 5px;
}

.nus-btn:hover {
    background: rgba(255,255,255,0.25);
}

.nus-btn.active {
    background: var(--nus-primary);
    border-color: var(--nus-primary);
}

.nus-btn-play {
    background: var(--nus-primary);
    border-color: var(--nus-primary);
    font-weight: 600;
}

.nus-bpm-control {
    display: flex;
    align-items: center;
    gap: 4px;
    background: rgba(255,255,255,0.1);
    border-radius: 20px;
    padding: 4px 8px;
}

.nus-bpm-control .nus-bpm-btn {
    background: none;
    border: none;
    color: #fff;
    cursor: pointer;
    font-size: 16px;
    width: 24px;
    height: 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    transition: background 0.2s;
}

.nus-bpm-control .nus-bpm-btn:hover {
    background: rgba(255,255,255,0.2);
}

.nus-bpm-control .nus-bpm-value {
    font-size: 14px;
    font-weight: 700;
    min-width: 36px;
    text-align: center;
}

.nus-bpm-control .nus-bpm-label {
    font-size: 11px;
    color: #aaa;
    margin-left: 2px;
}

/* --- Chord Chart Styles --- */
.nus-chord-container {
    border: 1px solid var(--nus-border);
    border-radius: 8px;
    overflow: hidden;
    margin: 20px 0;
    font-family: var(--nus-font);
}

.nus-chord-body {
    background: var(--nus-bg);
    padding: 20px;
    max-height: 80vh;
    overflow-y: auto;
    scroll-behavior: smooth;
}

.nus-section {
    margin-bottom: 24px;
}

.nus-section-header {
    font-size: 14px;
    font-weight: 700;
    color: var(--nus-primary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    padding: 6px 12px;
    background: var(--nus-section-bg);
    border-left: 3px solid var(--nus-primary);
    border-radius: 0 4px 4px 0;
    margin-bottom: 12px;
    cursor: pointer;
    transition: background 0.2s;
}

.nus-section-header:hover {
    background: var(--nus-highlight);
}

.nus-section-header.nus-loop-active {
    background: var(--nus-highlight);
    border-left-color: #ff0000;
}

.nus-chord-line {
    margin-bottom: 8px;
    line-height: 1.8;
    position: relative;
}

.nus-chord-line .nus-chord-row {
    font-family: var(--nus-mono);
    font-size: 15px;
    font-weight: 700;
    color: var(--nus-primary);
    letter-spacing: 0.3px;
    white-space: pre;
    min-height: 22px;
}

.nus-chord-line .nus-lyric-row {
    font-size: 15px;
    color: var(--nus-text);
    white-space: pre-wrap;
}

.nus-chord-highlight {
    background: var(--nus-highlight);
    border-radius: 3px;
    padding: 1px 3px;
    transition: background 0.15s;
}

.nus-chord-highlight.nus-active {
    background: var(--nus-primary);
    color: #fff;
    border-radius: 3px;
}

/* --- Chord Diagrams --- */
.nus-chord-diagrams {
    display: flex;
    flex-wrap: wrap;
    gap: 16px;
    padding: 16px 20px;
    background: var(--nus-section-bg);
    border-top: 1px solid var(--nus-border);
}

.nus-chord-diagram {
    text-align: center;
    width: 72px;
}

.nus-chord-diagram .nus-chord-name {
    font-size: 13px;
    font-weight: 700;
    margin-bottom: 4px;
    color: var(--nus-text);
}

.nus-chord-diagram svg {
    display: block;
    margin: 0 auto;
}

/* --- Key/Transpose Bar --- */
.nus-key-bar {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px 20px;
    background: var(--nus-section-bg);
    border-bottom: 1px solid var(--nus-border);
    font-size: 13px;
}

.nus-key-bar .nus-key-label {
    font-weight: 600;
    color: var(--nus-text);
}

.nus-key-bar .nus-transpose-btn {
    background: var(--nus-badge-bg);
    border: 1px solid var(--nus-border);
    color: var(--nus-text);
    width: 28px;
    height: 28px;
    border-radius: 50%;
    cursor: pointer;
    font-size: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s;
}

.nus-key-bar .nus-transpose-btn:hover {
    background: var(--nus-primary);
    color: #fff;
    border-color: var(--nus-primary);
}

.nus-key-value {
    font-weight: 700;
    color: var(--nus-primary);
    min-width: 30px;
    text-align: center;
}

/* --- Notation Container --- */
.nus-notation-container {
    border: 1px solid var(--nus-border);
    border-radius: 8px;
    overflow: hidden;
    margin: 20px 0;
    font-family: var(--nus-font);
}

.nus-notation-body {
    background: var(--nus-bg);
    padding: 20px;
    overflow-x: auto;
    overflow-y: auto;
    max-height: 80vh;
    position: relative;
}

.nus-notation-body svg {
    display: block;
}

/* Playback cursor */
.nus-cursor {
    position: absolute;
    top: 0;
    width: 2px;
    background: var(--nus-primary);
    box-shadow: 0 0 6px rgba(255, 107, 0, 0.5);
    pointer-events: none;
    transition: left 0.05s linear;
    z-index: 10;
}

/* --- Progress Bar --- */
.nus-progress-bar {
    height: 3px;
    background: rgba(255,255,255,0.2);
    position: relative;
    overflow: hidden;
}

.nus-progress-fill {
    height: 100%;
    background: var(--nus-primary);
    width: 0%;
    transition: width 0.1s linear;
}

/* --- Song Grid (List) --- */
.nus-song-grid {
    display: grid;
    grid-template-columns: repeat(var(--nus-cols, 3), 1fr);
    gap: 20px;
    margin: 20px 0;
}

.nus-song-card {
    display: block;
    background: var(--nus-bg);
    border: 1px solid var(--nus-border);
    border-radius: 8px;
    overflow: hidden;
    text-decoration: none;
    color: var(--nus-text);
    transition: transform 0.2s, box-shadow 0.2s;
}

.nus-song-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

.nus-song-card .nus-song-thumb {
    width: 100%;
    height: 160px;
    object-fit: cover;
    display: block;
}

.nus-song-thumb-placeholder {
    width: 100%;
    height: 160px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    font-size: 40px;
}

.nus-song-info {
    padding: 12px 16px;
}

.nus-song-info .nus-song-title {
    font-size: 15px;
    font-weight: 700;
    margin: 0 0 4px;
    color: var(--nus-text);
}

.nus-song-info .nus-song-artist {
    font-size: 13px;
    color: #888;
    margin: 0 0 8px;
}

.nus-song-meta {
    display: flex;
    gap: 6px;
    flex-wrap: wrap;
}

.nus-badge {
    font-size: 11px;
    padding: 2px 8px;
    border-radius: 10px;
    background: var(--nus-badge-bg);
    color: #666;
}

.nus-badge-type {
    background: var(--nus-primary);
    color: #fff;
}

/* --- Dark Theme --- */
[data-theme="dark"] .nus-chord-body,
[data-theme="dark"] .nus-notation-body {
    background: #1a1a1a;
    color: #e0e0e0;
}

[data-theme="dark"] .nus-chord-line .nus-lyric-row {
    color: #e0e0e0;
}

[data-theme="dark"] .nus-section-header {
    background: #2a2a2a;
    color: var(--nus-primary);
}

[data-theme="dark"] .nus-key-bar {
    background: #222;
    border-color: #444;
}

[data-theme="dark"] .nus-chord-diagrams {
    background: #222;
    border-color: #444;
}

/* --- Responsive --- */
@media (max-width: 768px) {
    .nus-top-bar {
        padding: 8px 12px;
    }

    .nus-controls {
        gap: 5px;
    }

    .nus-btn {
        padding: 5px 10px;
        font-size: 12px;
    }

    .nus-chord-body,
    .nus-notation-body {
        padding: 12px;
    }

    .nus-song-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 480px) {
    .nus-song-grid {
        grid-template-columns: 1fr;
    }

    .nus-top-bar {
        flex-direction: column;
        align-items: flex-start;
    }
}

/* --- Empty state --- */
.nus-empty {
    text-align: center;
    padding: 40px 20px;
    color: #999;
    font-style: italic;
}

/* --- Auto-scroll indicator --- */
.nus-autoscroll-indicator {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background: var(--nus-primary);
    color: #fff;
    padding: 8px 16px;
    border-radius: 20px;
    font-size: 13px;
    z-index: 1000;
    opacity: 0;
    transition: opacity 0.3s;
    pointer-events: none;
}

.nus-autoscroll-indicator.visible {
    opacity: 1;
}