/* ═══════════════════════════════════════
   MusicGo — 暗色賽博風設計系統
   ═══════════════════════════════════════ */

:root {
    --bg: #070710;
    --bg-2: #0c0c1a;
    --surface: #111122;
    --surface-2: #181830;
    --surface-3: #1f1f40;
    --border: rgba(255, 255, 255, 0.06);
    --border-hover: rgba(255, 255, 255, 0.12);

    --accent: #00e5ff;
    --accent-dim: rgba(0, 229, 255, 0.12);
    --accent-glow: rgba(0, 229, 255, 0.3);
    --purple: #a855f7;
    --purple-dim: rgba(168, 85, 247, 0.12);
    --pink: #ec4899;
    --orange: #f97316;
    --gold: #f59e0b;
    --success: #22c55e;
    --success-dim: rgba(34, 197, 94, 0.15);
    --error: #ef4444;
    --error-dim: rgba(239, 68, 68, 0.15);

    --text: #f0f0f8;
    --text-2: #9ca3b8;
    --text-3: #5a5f7a;

    --font: -apple-system, 'Segoe UI', 'Microsoft JhengHei', 'PingFang SC', sans-serif;
    --font-mono: 'SF Mono', 'Cascadia Code', 'Consolas', monospace;
    --radius: 12px;
    --radius-sm: 8px;
    --radius-xs: 4px;
    --shadow: 0 4px 24px rgba(0, 0, 0, 0.4);
    --shadow-glow: 0 0 20px var(--accent-glow);
    --transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ═══ 主題變體 ═══ */
body.theme-ocean {
    --bg: #060d14; --bg-2: #0a1520; --surface: #0f1e2e; --surface-2: #142838; --surface-3: #1a3347;
    --accent: #38bdf8; --accent-dim: rgba(56, 189, 248, 0.12); --accent-glow: rgba(56, 189, 248, 0.3);
    --purple: #818cf8; --gold: #67e8f9;
}
body.theme-forest {
    --bg: #060e08; --bg-2: #0a1a0e; --surface: #0f2215; --surface-2: #142d1c; --surface-3: #1a3823;
    --accent: #4ade80; --accent-dim: rgba(74, 222, 128, 0.12); --accent-glow: rgba(74, 222, 128, 0.3);
    --purple: #86efac; --gold: #fbbf24;
}
body.theme-sunset {
    --bg: #120808; --bg-2: #1a0d0a; --surface: #231410; --surface-2: #2d1a14; --surface-3: #38201a;
    --accent: #fb923c; --accent-dim: rgba(251, 146, 60, 0.12); --accent-glow: rgba(251, 146, 60, 0.3);
    --purple: #f87171; --gold: #fbbf24;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
    font-family: var(--font);
    background: var(--bg);
    color: var(--text);
    min-height: 100vh;
    overflow-x: hidden;
    -webkit-tap-highlight-color: transparent;
}
::selection { background: var(--accent-dim); color: var(--accent); }
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg-2); }
::-webkit-scrollbar-thumb { background: var(--surface-3); border-radius: 3px; }

/* ═══ 按鈕系統 ═══ */
.btn {
    padding: 10px 20px;
    border: none;
    border-radius: var(--radius-sm);
    font: 600 14px var(--font);
    cursor: pointer;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    gap: 6px;
    color: var(--text);
    background: var(--surface-2);
    border: 1px solid var(--border);
    user-select: none;
}
.btn:hover { transform: translateY(-1px); border-color: var(--border-hover); background: var(--surface-3); }
.btn:active { transform: translateY(0); }
.btn-glow {
    background: linear-gradient(135deg, var(--accent), #0088aa);
    color: #000;
    border: none;
    box-shadow: 0 0 16px var(--accent-glow);
    font-weight: 700;
}
.btn-glow:hover { box-shadow: 0 0 24px var(--accent-glow), 0 0 48px rgba(0, 229, 255, 0.15); }
.btn-outline { background: transparent; border: 1px solid var(--accent); color: var(--accent); }
.btn-outline:hover { background: var(--accent-dim); }
.btn-ghost { background: transparent; border: 1px solid var(--border); }
.btn-ghost:hover { background: var(--surface); border-color: var(--border-hover); }
.btn-sm { padding: 6px 12px; font-size: 12px; border-radius: 6px; }
.btn-xs { padding: 3px 8px; font-size: 11px; border-radius: 4px; }
.btn-danger { background: var(--error); color: #fff; border: none; }
.btn:disabled { opacity: 0.4; pointer-events: none; }

/* ═══ 頂部導航 ═══ */
#app-header {
    position: sticky;
    top: 0;
    z-index: 100;
    display: flex;
    align-items: center;
    height: 56px;
    padding: 0 16px;
    background: rgba(7, 7, 16, 0.85);
    backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border);
}
.header-left { display: flex; align-items: center; }
.nav-logo {
    display: flex;
    align-items: center;
    gap: 8px;
    background: none;
    border: none;
    cursor: pointer;
    color: var(--text);
    padding: 4px 8px;
}
.logo-icon { font-size: 24px; }
.logo-text { font-size: 18px; font-weight: 800; background: linear-gradient(135deg, var(--accent), var(--purple)); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }
.header-nav {
    flex: 1;
    display: flex;
    justify-content: center;
    gap: 2px;
}
.nav-btn {
    background: none;
    border: none;
    color: var(--text-3);
    padding: 8px 16px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font: 500 13px var(--font);
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 6px;
}
.nav-btn:hover { color: var(--text); background: var(--surface); }
.nav-btn.active { color: var(--accent); background: var(--accent-dim); }
.nav-icon { font-size: 16px; }
.header-right { display: flex; align-items: center; gap: 8px; }
.nav-btn-icon {
    background: none;
    border: none;
    color: var(--text-3);
    font-size: 18px;
    cursor: pointer;
    padding: 6px;
    border-radius: 6px;
    transition: var(--transition);
}
.nav-btn-icon:hover { color: var(--text); background: var(--surface); }

/* XP 徽章 */
.xp-badge { display: flex; align-items: center; gap: 6px; padding: 4px 10px; background: var(--surface); border-radius: 20px; border: 1px solid var(--border); }
.xp-level { font: 700 11px var(--font); color: var(--gold); }
.xp-bar { width: 48px; height: 4px; background: var(--surface-3); border-radius: 2px; overflow: hidden; }
.xp-fill { height: 100%; background: linear-gradient(90deg, var(--gold), var(--orange)); border-radius: 2px; transition: width 0.5s ease; }

/* ═══ Section 系統 ═══ */
#app-main { min-height: calc(100vh - 56px); }
.section { display: none; padding: 24px; max-width: 1400px; margin: 0 auto; animation: fadeIn 0.3s ease; }
.section.active { display: block; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: translateY(0); } }
.section-header { text-align: center; margin-bottom: 32px; }
.section-header h2 { font-size: 28px; font-weight: 800; margin-bottom: 8px; }
.section-header p { color: var(--text-2); font-size: 15px; }
.instrument-section, .tool-section { max-width: 1200px; }

/* ═══ Hero 首頁 ═══ */
.hero {
    text-align: center;
    padding: 60px 20px 40px;
    position: relative;
}
.hero-title {
    font-size: 42px;
    font-weight: 900;
    line-height: 1.2;
    margin-bottom: 12px;
}
.accent { color: var(--accent); }
.glow { filter: drop-shadow(0 0 12px var(--accent-glow)); }
.hero-sub { font-size: 18px; color: var(--text-2); margin-bottom: 8px; }
.hero-desc { font-size: 14px; color: var(--text-3); margin-bottom: 28px; letter-spacing: 2px; }
.hero-actions { display: flex; gap: 12px; justify-content: center; }

/* ═══ 首頁功能卡片 ═══ */
.home-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
    gap: 12px;
    margin: 40px auto;
    max-width: 900px;
}
.feature-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 20px 16px;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
}
.feature-card:hover {
    border-color: var(--accent);
    transform: translateY(-4px);
    box-shadow: var(--shadow-glow);
}
.fc-icon { font-size: 36px; margin-bottom: 8px; }
.fc-title { font-size: 14px; font-weight: 700; margin-bottom: 4px; }
.fc-desc { font-size: 11px; color: var(--text-3); }

/* 統計條 */
.stats-bar {
    display: flex;
    justify-content: center;
    gap: 32px;
    padding: 24px;
    margin: 20px auto;
    max-width: 600px;
    background: var(--surface);
    border-radius: var(--radius);
    border: 1px solid var(--border);
}
.stat { text-align: center; }
.stat-num { display: block; font: 700 22px var(--font-mono); color: var(--accent); }
.stat-label { font-size: 11px; color: var(--text-3); }

/* ═══ 樂器選擇頁 ═══ */
.instrument-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
    gap: 16px;
}
.inst-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
    cursor: pointer;
    transition: var(--transition);
}
.inst-card:hover { border-color: var(--accent); transform: translateY(-4px); box-shadow: var(--shadow-glow); }
.inst-visual {
    height: 120px;
    background: var(--surface-2);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 48px;
}
.piano-preview::after { content: '🎹'; }
.guitar-preview::after { content: '🎸'; }
.bass-preview::after { content: '🎸'; }
.uke-preview::after { content: '🪕'; }
.drums-preview::after { content: '🥁'; }
.dm-preview::after { content: '🎛️'; }
.xylo-preview::after { content: '🪘'; }
.loop-preview::after { content: '🔁'; }
.inst-info { padding: 16px; }
.inst-info h3 { font-size: 16px; font-weight: 700; margin-bottom: 4px; }
.inst-info p { font-size: 12px; color: var(--text-3); }

/* ═══ 樂器工具列 ═══ */
.instrument-toolbar {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 16px;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--border);
}
.instrument-toolbar h2 { font-size: 18px; font-weight: 700; flex: 1; }
.toolbar-actions { display: flex; gap: 8px; align-items: center; }

/* ═══ 鋼琴 ═══ */
.piano-container {
    display: flex;
    justify-content: center;
    padding: 20px 0;
    overflow-x: auto;
    position: relative;
}
.piano-keys {
    display: flex;
    position: relative;
    height: 200px;
}
.piano-key {
    position: relative;
    cursor: pointer;
    transition: transform 0.08s ease, background 0.08s ease, box-shadow 0.08s ease;
    user-select: none;
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
    align-items: center;
    padding-bottom: 12px;
}
.piano-key.white {
    width: 48px;
    height: 200px;
    background: linear-gradient(to bottom, #ffffff 0%, #f0f0f0 85%, #dcdcdc 100%);
    border: 1px solid #aaa;
    border-radius: 0 0 6px 6px;
    z-index: 1;
    color: #555;
    font-size: 10px;
    box-shadow: inset 0 1px 1px #fff, inset 0 -5px 8px rgba(0,0,0,0.2), 0 3px 6px rgba(0,0,0,0.4);
    transform-origin: top;
}
.piano-key.white:hover { 
    background: linear-gradient(to bottom, #ffffff 0%, #f4f4f4 85%, #e0e0e0 100%); 
}
.piano-key.white.active { 
    background: linear-gradient(to bottom, #e0faff 0%, #00e5ff 100%); 
    color: #004455; 
    box-shadow: inset 0 2px 4px rgba(0,0,0,0.1), inset 0 -2px 4px rgba(0,0,0,0.3), 0 1px 2px rgba(0,0,0,0.2);
    transform: perspective(400px) rotateX(-2deg) translateY(4px);
    border-color: #00d2eb;
}
.piano-key.black {
    width: 30px;
    height: 125px;
    background: linear-gradient(to bottom, #3a3a3a 0%, #222 75%, #050505 100%);
    border: 1px solid #000;
    border-radius: 0 0 4px 4px;
    margin-left: -15px;
    margin-right: -15px;
    z-index: 2;
    color: #999;
    font-size: 8px;
    box-shadow: inset 0 1px 2px rgba(255,255,255,0.2), inset 0 -6px 8px rgba(0,0,0,0.8), 2px 4px 8px rgba(0,0,0,0.6);
    transform-origin: top;
}
.piano-key.black:hover { 
    background: linear-gradient(to bottom, #4a4a4a 0%, #2a2a2a 75%, #0a0a0a 100%); 
}
.piano-key.black.active { 
    background: linear-gradient(to bottom, #5a2a8a 0%, var(--purple) 100%); 
    color: #fff; 
    box-shadow: inset 0 2px 4px rgba(0,0,0,0.4), inset 0 -2px 4px rgba(0,0,0,0.9), 1px 2px 3px rgba(0,0,0,0.5);
    transform: perspective(400px) rotateX(-3deg) translateY(3px) scaleY(0.98);
    border-color: #4a1a7a;
}
.piano-key .key-label { pointer-events: none; font-weight: 600; text-shadow: 0 1px 0 rgba(255,255,255,0.6); }
.piano-key.black .key-label { text-shadow: 0 1px 1px rgba(0,0,0,0.8); }
.piano-key .key-shortcut { pointer-events: none; font-size: 9px; opacity: 0.5; margin-top: 2px; }
.piano-controls {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 16px;
    padding: 12px;
    margin-top: 8px;
    background: var(--surface);
    border-radius: var(--radius-sm);
}
.toggle-label { font-size: 12px; color: var(--text-2); display: flex; align-items: center; gap: 4px; cursor: pointer; }
.toggle-label input { cursor: pointer; }

/* 音效面板 */
.fx-panel {
    display: flex;
    gap: 24px;
    padding: 16px 20px;
    background: var(--surface);
    border-radius: var(--radius-sm);
    margin-bottom: 12px;
    border: 1px solid var(--border);
}
.fx-control { flex: 1; }
.fx-control label { display: block; font-size: 12px; color: var(--text-2); margin-bottom: 6px; }
.fx-control label span { color: var(--accent); font-weight: 600; }
.fx-control input[type="range"] { width: 100%; accent-color: var(--accent); }

/* ═══ 鼓組 ═══ */
.drums-container {
    display: flex;
    justify-content: center;
    padding: 20px;
    min-height: 400px;
}
.drum-kit {
    position: relative;
    width: 700px;
    height: 400px;
}
.drum-pad {
    position: absolute;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    transition: transform 0.05s cubic-bezier(0.18, 0.89, 0.32, 1.28), box-shadow 0.1s;
    user-select: none;
    border: 4px solid #333;
    box-shadow: inset 0 0 20px rgba(0,0,0,0.8), 0 8px 16px rgba(0,0,0,0.6), 0 2px 4px rgba(255,255,255,0.1) inset;
    background-clip: padding-box;
}
.drum-pad:hover { 
    border-color: #555; 
    box-shadow: inset 0 0 20px rgba(0,0,0,0.6), 0 10px 20px rgba(0,0,0,0.8), 0 2px 4px rgba(255,255,255,0.2) inset; 
}
.drum-pad.hit { 
    transform: scale(0.95) translateY(4px); 
    box-shadow: inset 0 0 30px rgba(0,0,0,0.9), 0 2px 4px rgba(0,0,0,0.6), 0 1px 2px rgba(255,255,255,0.05) inset;
    border-color: var(--accent);
}
.drum-pad .pad-label { font-size: 11px; font-weight: 600; color: rgba(255,255,255,0.8); margin-top: 4px; text-shadow: 0 1px 2px rgba(0,0,0,0.8); }
.drum-pad .pad-key { font: 600 10px var(--font-mono); color: #fff; padding: 2px 6px; background: rgba(0,0,0,0.5); border-radius: 3px; margin-top: 2px; }

/* 鼓色與光影 */
.drum-kick { background: radial-gradient(circle at 30% 30%, #4a3a5a, #1a0d2a); width: 140px; height: 140px; }
.drum-snare { background: radial-gradient(circle at 30% 30%, #f8f0e0, #a8a090 80%, #666); width: 100px; height: 100px; }
.drum-hihat { background: radial-gradient(circle at 30% 30%, #e0d080, #908030 70%, #554411); width: 90px; height: 90px; }
.drum-tom1 { background: radial-gradient(circle at 30% 30%, #5a3a3a, #2a0d0d); width: 80px; height: 80px; }
.drum-tom2 { background: radial-gradient(circle at 30% 30%, #3a5a3a, #0d2a0d); width: 85px; height: 85px; }
.drum-floor { background: radial-gradient(circle at 30% 30%, #3a3a5a, #0d0d2a); width: 110px; height: 110px; }
.drum-crash { background: radial-gradient(circle at 50% 50%, #fff 0%, #e0d060 20%, #a09030 80%, #554411); width: 100px; height: 100px; border-radius: 50%; }
.drum-ride { background: radial-gradient(circle at 50% 50%, #fff 0%, #d0c878 20%, #807828 80%, #444015); width: 110px; height: 110px; border-radius: 50%; }

/* ═══ 鼓機 ═══ */
.dm-container { padding: 20px; }
.dm-grid {
    display: grid;
    gap: 2px;
    background: var(--surface);
    border-radius: var(--radius);
    padding: 16px;
    border: 1px solid var(--border);
}
.dm-row {
    display: flex;
    align-items: center;
    gap: 4px;
}
.dm-label {
    width: 80px;
    font-size: 11px;
    font-weight: 600;
    color: var(--text-2);
    text-align: right;
    padding-right: 8px;
    flex-shrink: 0;
}
.dm-cell {
    width: 32px;
    height: 32px;
    border-radius: var(--radius-xs);
    background: var(--surface-2);
    border: 1px solid var(--border);
    cursor: pointer;
    transition: all 0.1s;
}
.dm-cell:hover { border-color: var(--accent); }
.dm-cell.on { background: var(--accent); border-color: var(--accent); }
.dm-cell.playing { box-shadow: 0 0 8px var(--accent-glow); }
.dm-cell.beat-marker { border-bottom: 2px solid var(--text-3); }
.bpm-control { display: flex; align-items: center; gap: 6px; font: 600 13px var(--font-mono); color: var(--accent); }

/* ═══ 習題系統 ═══ */
.exercise-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
    gap: 12px;
}
.ex-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 20px;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
    position: relative;
}
.ex-card:hover { border-color: var(--accent); transform: translateY(-3px); box-shadow: var(--shadow-glow); }
.ex-icon { font-size: 32px; margin-bottom: 8px; }
.ex-card h3 { font-size: 14px; font-weight: 700; margin-bottom: 8px; }
.ex-level { font: 700 11px var(--font); color: var(--gold); margin-bottom: 6px; }
.ex-bar { height: 4px; background: var(--surface-3); border-radius: 2px; overflow: hidden; }
.ex-fill { height: 100%; background: linear-gradient(90deg, var(--accent), var(--purple)); border-radius: 2px; width: 0%; transition: width 0.5s; }

/* 每日挑戰 */
.daily-challenge {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 16px 24px;
    background: linear-gradient(135deg, var(--surface), var(--surface-2));
    border: 1px solid var(--gold);
    border-radius: var(--radius);
    margin-bottom: 24px;
    box-shadow: 0 0 16px rgba(245, 158, 11, 0.1);
}
.dc-badge { font: 700 13px var(--font); color: var(--gold); white-space: nowrap; }
.dc-info { flex: 1; }
.dc-info span { display: block; }
#dc-title { font-size: 14px; font-weight: 600; }
#dc-reward { font-size: 12px; color: var(--gold); }

/* 習題遊玩區 */
.exercise-area {
    min-height: 400px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 24px;
    padding: 20px;
}
.score-display-inline { font: 600 14px var(--font-mono); color: var(--accent); display: flex; align-items: center; gap: 8px; }
.divider { color: var(--text-3); }

/* 習題互動 */
.question-display {
    font-size: 32px;
    font-weight: 800;
    text-align: center;
    padding: 40px;
    min-height: 200px;
    display: flex;
    align-items: center;
    justify-content: center;
}
.answer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
    gap: 10px;
    max-width: 600px;
    width: 100%;
}
.answer-btn {
    padding: 14px;
    background: var(--surface);
    border: 2px solid var(--border);
    border-radius: var(--radius-sm);
    color: var(--text);
    font: 600 14px var(--font);
    cursor: pointer;
    transition: var(--transition);
    text-align: center;
}
.answer-btn:hover { border-color: var(--accent); background: var(--accent-dim); }
.answer-btn.correct { border-color: var(--success); background: var(--success-dim); animation: pulse 0.3s ease; }
.answer-btn.wrong { border-color: var(--error); background: var(--error-dim); animation: shake 0.3s ease; }
@keyframes pulse { 50% { transform: scale(1.05); } }
@keyframes shake { 0%, 100% { transform: translateX(0); } 25% { transform: translateX(-6px); } 75% { transform: translateX(6px); } }

/* ═══ 工具頁 ═══ */
.tool-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 16px;
}
.tool-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 32px 20px;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
}
.tool-card:hover { border-color: var(--purple); transform: translateY(-3px); box-shadow: 0 0 16px var(--purple-dim); }
.tc-icon { font-size: 36px; display: block; margin-bottom: 8px; }
.tool-card h3 { font-size: 15px; font-weight: 700; }

/* ═══ 節拍器 ═══ */
.metronome-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 24px;
    padding: 40px 20px;
}
.metro-bpm-display {
    font: 900 72px var(--font-mono);
    color: var(--accent);
    text-shadow: 0 0 20px var(--accent-glow);
}
.metro-bpm-label { font-size: 14px; color: var(--text-3); margin-top: -8px; }
.metro-slider { width: 300px; accent-color: var(--accent); }
.metro-beats {
    display: flex;
    gap: 12px;
}
.metro-beat {
    width: 24px;
    height: 24px;
    border-radius: 50%;
    background: var(--surface-2);
    border: 2px solid var(--border);
    transition: all 0.1s;
}
.metro-beat.active { background: var(--accent); border-color: var(--accent); box-shadow: 0 0 12px var(--accent-glow); transform: scale(1.2); }
.metro-beat.accent-beat { border-color: var(--gold); }
.metro-controls { display: flex; gap: 12px; align-items: center; }
.metro-time-sig {
    display: flex;
    gap: 4px;
}
.ts-btn {
    padding: 6px 12px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 6px;
    color: var(--text-2);
    font: 600 12px var(--font);
    cursor: pointer;
    transition: var(--transition);
}
.ts-btn.active { background: var(--accent-dim); border-color: var(--accent); color: var(--accent); }

/* ═══ 吉他指板 ═══ */
.guitar-container { overflow-x: auto; padding: 20px; }
.guitar-fretboard {
    display: flex;
    gap: 0;
    min-width: 900px;
    background: linear-gradient(90deg, #3d2314 0%, #2b180d 50%, #3d2314 100%); /* 木紋質感 */
    border-radius: var(--radius);
    padding: 16px;
    border: 1px solid #1a0f08;
    box-shadow: inset 0 0 30px rgba(0,0,0,0.9), 0 10px 24px rgba(0,0,0,0.6);
}
.guitar-string-labels {
    display: flex;
    flex-direction: column;
    gap: 4px;
    padding: 0 12px 0 4px;
    justify-content: center;
}
.guitar-string-name {
    height: 28px;
    display: flex;
    align-items: center;
    font: 600 12px var(--font-mono);
    color: var(--gold);
    text-shadow: 0 1px 2px rgba(0,0,0,0.8);
}
.guitar-fret {
    display: flex;
    flex-direction: column;
    gap: 4px;
    border-right: 3px solid #bba; /* 金屬琴桁 */
    box-shadow: 2px 0 3px rgba(0,0,0,0.6);
    padding: 0 2px;
    position: relative;
    min-width: 48px;
    align-items: center;
}
.guitar-fret.open-fret {
    border-right: 6px solid #e0dfd5; /* 琴枕 Nut */
    box-shadow: 4px 0 6px rgba(0,0,0,0.8);
    background: rgba(0,0,0,0.3);
}
.guitar-cell {
    width: 44px;
    height: 28px;
    border-radius: 4px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.1s;
    position: relative;
}
.guitar-cell::before {
    content: '';
    position: absolute;
    width: 100%;
    height: 3px;
    background: linear-gradient(to bottom, #eee 0%, #999 50%, #555 100%); /* 金屬琴弦質感 */
    box-shadow: 0 3px 4px rgba(0,0,0,0.5);
    top: 50%;
    transform: translateY(-50%);
    z-index: 1;
}
.guitar-cell:hover { background: rgba(255,255,255,0.05); }
.guitar-cell.plucked::before {
    animation: string-vibrate 0.3s ease-in-out;
    box-shadow: 0 0 10px var(--accent-glow);
    background: linear-gradient(to bottom, #fff 0%, var(--accent) 50%, #0088aa 100%);
}
@keyframes string-vibrate {
    0%, 100% { transform: translateY(-50%); }
    25% { transform: translateY(-70%); }
    75% { transform: translateY(-30%); }
}
.guitar-cell.chord-highlight::after {
    content: '';
    position: absolute;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: var(--accent);
    z-index: 1;
}
.fret-marker {
    position: absolute;
    bottom: -8px;
    left: 50%;
    transform: translateX(-50%);
}
.fret-marker.single::after {
    content: '●';
    color: var(--text-3);
    font-size: 8px;
}
.fret-marker.double::after {
    content: '● ●';
    color: var(--gold);
    font-size: 8px;
}
.fret-number {
    font: 600 9px var(--font-mono);
    color: var(--text-3);
    margin-top: 4px;
}
.guitar-strum-bar {
    display: flex;
    justify-content: center;
    gap: 12px;
    padding: 16px;
    margin-top: 12px;
}

/* ═══ 五度圈 ═══ */
.cof-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 40px;
    gap: 24px;
}
.cof-info { text-align: center; }
.cof-detail { padding: 16px; }

/* ═══ 設定面板 ═══ */
.settings-panel {
    position: fixed;
    right: 0;
    top: 56px;
    width: 280px;
    height: calc(100vh - 56px);
    background: var(--surface);
    border-left: 1px solid var(--border);
    z-index: 200;
    animation: slideInRight 0.3s ease;
}
@keyframes slideInRight { from { transform: translateX(100%); } }
.sp-header { display: flex; justify-content: space-between; align-items: center; padding: 16px 20px; border-bottom: 1px solid var(--border); }
.sp-header h3 { font-size: 15px; }
.sp-close { background: none; border: none; color: var(--text-2); font-size: 18px; cursor: pointer; }
.sp-body { padding: 20px; }
.sp-group { margin-bottom: 16px; }
.sp-group label { display: block; font-size: 13px; color: var(--text-2); margin-bottom: 6px; cursor: pointer; }
.sp-group input[type="range"] { width: 100%; accent-color: var(--accent); }
.sp-group select { width: 100%; padding: 8px; background: var(--bg); border: 1px solid var(--border); border-radius: 6px; color: var(--text); font: 400 13px var(--font); }

/* ═══ Toast ═══ */
#toast-container { position: fixed; top: 64px; right: 16px; z-index: 2000; display: flex; flex-direction: column; gap: 8px; }
.toast {
    padding: 12px 20px;
    border-radius: var(--radius-sm);
    font: 500 13px var(--font);
    color: #fff;
    animation: slideIn 0.3s ease;
    box-shadow: var(--shadow);
}
.toast.success { background: var(--success); color: #000; }
.toast.error { background: var(--error); }
.toast.info { background: var(--surface-2); border: 1px solid var(--accent); color: var(--accent); }
@keyframes slideIn { from { opacity: 0; transform: translateX(40px); } }

/* ═══ 成就彈出 ═══ */
.achievement-popup {
    position: fixed;
    top: 80px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 16px 24px;
    background: linear-gradient(135deg, var(--surface), #2a2a40);
    border: 1px solid var(--gold);
    border-radius: var(--radius);
    z-index: 2000;
    box-shadow: 0 0 32px rgba(245, 158, 11, 0.2);
    animation: popIn 0.5s cubic-bezier(0.68, -0.55, 0.265, 1.55);
}
@keyframes popIn { from { opacity: 0; transform: translateX(-50%) scale(0.5); } }
.ap-icon { font-size: 32px; }
.ap-title { font: 700 14px var(--font); color: var(--gold); }
.ap-desc { font-size: 12px; color: var(--text-2); }

/* ═══ 升級動畫 ═══ */
.levelup-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.7);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 3000;
    animation: fadeIn 0.3s ease;
}
.lu-content { text-align: center; animation: popIn 0.6s cubic-bezier(0.68, -0.55, 0.265, 1.55); }
.lu-text { font: 800 24px var(--font); color: var(--gold); text-shadow: 0 0 20px rgba(245, 158, 11, 0.5); margin-bottom: 8px; }
.lu-level { font: 900 64px var(--font-mono); color: var(--accent); text-shadow: 0 0 32px var(--accent-glow); }

/* ═══ 粒子畫布 ═══ */
#particle-canvas {
    position: fixed;
    inset: 0;
    pointer-events: none;
    z-index: 1500;
}

/* ═══ 課程卡片 ═══ */
.course-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 16px;
}
.course-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 24px;
    transition: var(--transition);
}
.course-card:hover { border-color: var(--accent); transform: translateY(-2px); }
.cc-badge {
    display: inline-block;
    font: 600 11px var(--font);
    color: var(--success);
    background: var(--success-dim);
    padding: 3px 8px;
    border-radius: 4px;
    margin-bottom: 8px;
}
.cc-badge.cc-intermediate { color: var(--accent); background: var(--accent-dim); }
.cc-badge.cc-advanced { color: var(--orange); background: rgba(249, 115, 22, 0.12); }
.course-card h3 { font-size: 16px; font-weight: 700; margin-bottom: 8px; }
.course-card p { font-size: 13px; color: var(--text-2); margin-bottom: 12px; line-height: 1.5; }
.cc-progress { display: flex; align-items: center; gap: 8px; margin-bottom: 12px; }
.cc-bar { flex: 1; height: 4px; background: var(--surface-3); border-radius: 2px; overflow: hidden; }
.cc-fill { height: 100%; background: linear-gradient(90deg, var(--accent), var(--purple)); border-radius: 2px; transition: width 0.5s; }
.cc-progress span { font: 600 11px var(--font); color: var(--text-3); white-space: nowrap; }

/* ═══ Hero 音波動畫 ═══ */
#hero-wave-canvas {
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    opacity: 0.3;
    pointer-events: none;
}
.hero { position: relative; overflow: hidden; }

/* ═══ 隱藏 ═══ */
.hidden { display: none !important; }

/* ═══ 響應式 ═══ */
@media (max-width: 768px) {
    .header-nav { display: none; }
    .hero-title { font-size: 28px; }
    .home-grid { grid-template-columns: repeat(2, 1fr); }
    .instrument-grid { grid-template-columns: repeat(2, 1fr); }
    .exercise-grid { grid-template-columns: repeat(2, 1fr); }
    .stats-bar { flex-wrap: wrap; gap: 16px; }
    .piano-key.white { width: 36px; height: 160px; }
    .piano-key.black { width: 24px; height: 100px; margin-left: -12px; margin-right: -12px; }
    .inst-visual { height: 80px; }
    .fx-panel { flex-direction: column; gap: 12px; }
}
@media (max-width: 480px) {
    .hero-title { font-size: 22px; }
    .hero-actions { flex-direction: column; }
    .home-grid { grid-template-columns: 1fr 1fr; gap: 8px; }
    .feature-card { padding: 14px 10px; }
    .fc-icon { font-size: 28px; }
    .piano-key.white { width: 28px; height: 130px; }
    .piano-key.black { width: 20px; height: 80px; margin-left: -10px; margin-right: -10px; }
}

/* ═══ 漢堡選單 ═══ */
.hamburger { display: none; font-size: 20px; }
@media (max-width: 768px) {
    .hamburger { display: flex; }
    .header-nav { 
        display: none; 
        position: absolute; 
        top: 100%; left: 0; right: 0;
        background: var(--bg);
        border-bottom: 1px solid var(--border);
        flex-direction: column;
        padding: 8px;
        z-index: 100;
    }
    .header-nav.mobile-open { display: flex; }
}

/* ═══ 鍵盤快捷鍵 Modal ═══ */
.keyboard-help-overlay {
    position: fixed; inset: 0;
    background: rgba(0,0,0,0.7);
    z-index: 2000;
    display: flex; align-items: center; justify-content: center;
}
.keyboard-help-modal {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 24px;
    max-width: 520px; width: 90%;
    max-height: 80vh; overflow-y: auto;
}
.kb-row {
    font: 600 12px var(--font-mono);
    color: var(--text);
    padding: 4px 0;
    display: flex; gap: 6px; align-items: center;
}
.kb-hint {
    font: 400 11px var(--font);
    color: var(--text-3);
    margin-left: auto;
}

/* ═══ 撥弦動畫 ═══ */
.guitar-cell.plucked {
    background: var(--accent) !important;
    box-shadow: 0 0 12px var(--accent-glow);
    transition: background 0.05s;
}
.guitar-cell.chord-highlight {
    background: rgba(168, 85, 247, 0.3);
    box-shadow: inset 0 0 0 2px var(--purple);
}

/* ═══════════════════════════════════════
   AbsolutePitch 宇宙級 Styles
   ═══════════════════════════════════════ */

.ap-rank-bar { display: flex; align-items: center; gap: 16px; margin-bottom: 16px; padding: 12px 16px; background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); }
.ap-rank-badge { display: flex; flex-direction: column; align-items: center; gap: 2px; padding: 8px 12px; border: 2px solid; border-radius: var(--radius-sm); min-width: 72px; }
.ap-rank-progress { flex: 1; }

.ap-mode-strip { display: flex; gap: 6px; justify-content: center; margin-bottom: 12px; flex-wrap: wrap; }
.ap-mode-btn { display: flex; flex-direction: column; align-items: center; gap: 2px; padding: 8px 14px; background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius-sm); cursor: pointer; transition: var(--transition); color: var(--text-2); font-size: 11px; }
.ap-mode-btn:hover { border-color: var(--border-hover); background: var(--surface-2); }
.ap-mode-btn.active { border-color: var(--accent); background: var(--accent-dim); color: var(--accent); box-shadow: 0 0 12px var(--accent-glow); }
.ap-mode-emoji { font-size: 20px; }
.ap-mode-name { font-weight: 600; }

.ap-level-strip { display: flex; gap: 6px; justify-content: center; margin-bottom: 12px; flex-wrap: wrap; }
.ap-level-btn { padding: 6px 14px; background: var(--surface); border: 1px solid var(--border); border-radius: 20px; cursor: pointer; transition: var(--transition); color: var(--text-2); font-size: 12px; font-weight: 600; }
.ap-level-btn:hover { background: var(--surface-2); border-color: var(--border-hover); }
.ap-level-btn.active { color: #fff; }

.ap-settings-row { display: flex; gap: 16px; justify-content: center; margin-bottom: 16px; flex-wrap: wrap; }
.ap-setting { display: flex; flex-direction: column; align-items: center; gap: 4px; }

.ap-score-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(90px, 1fr)); gap: 8px; margin-bottom: 16px; }
.ap-score-card { padding: 10px; background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius-sm); text-align: center; }
.ap-score-val { font: 900 18px var(--font-mono); }
.ap-score-label { font-size: 10px; color: var(--text-3); margin-top: 2px; }

/* Mini Piano */
.ap-piano-visual { margin-bottom: 16px; overflow-x: auto; }
.ap-piano-keys { display: flex; position: relative; height: 56px; max-width: 100%; justify-content: center; gap: 1px; }
.ap-pkey { position: relative; display: flex; align-items: flex-end; justify-content: center; border-radius: 0 0 4px 4px; cursor: default; transition: all 0.2s; }
.ap-pkey.white { width: 40px; height: 56px; background: #ddd; border: 1px solid #999; }
.ap-pkey.black { width: 28px; height: 36px; background: #222; border: 1px solid #111; margin: 0 -14px; z-index: 2; }
.ap-pkey-label { font: 600 8px var(--font-mono); color: #666; padding-bottom: 3px; }
.ap-pkey.black .ap-pkey-label { color: #888; }
.ap-pkey.ap-correct { background: var(--success) !important; border-color: var(--success) !important; box-shadow: 0 0 12px rgba(34,197,94,0.5); animation: ap-key-glow 0.6s ease; }
.ap-pkey.ap-correct .ap-pkey-label { color: #fff !important; }
.ap-pkey.ap-wrong { background: var(--error) !important; border-color: var(--error) !important; box-shadow: 0 0 12px rgba(239,68,68,0.5); animation: ap-shake 0.3s ease; }
.ap-pkey.ap-wrong .ap-pkey-label { color: #fff !important; }

@keyframes ap-key-glow { 0% { transform: scaleY(1); } 30% { transform: scaleY(1.08); } 100% { transform: scaleY(1); } }
@keyframes ap-shake { 0%, 100% { transform: translateX(0); } 25% { transform: translateX(-4px); } 75% { transform: translateX(4px); } }

/* Game Area */
.ap-game-area { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 24px; margin-bottom: 16px; }
.ap-start-zone { text-align: center; padding: 20px 0; }
.ap-start-btn { animation: ap-pulse 2s infinite; }
@keyframes ap-pulse { 0%, 100% { box-shadow: 0 0 0 0 var(--accent-glow); } 50% { box-shadow: 0 0 20px 6px var(--accent-glow); } }
.ap-replay-btn { margin: 0 8px; }

.ap-options-grid { display: grid; gap: 8px; }
.ap-note-grid { grid-template-columns: repeat(auto-fill, minmax(60px, 1fr)); }
.ap-chord-grid { grid-template-columns: repeat(auto-fill, minmax(110px, 1fr)); }
.ap-compare-grid { grid-template-columns: repeat(3, 1fr); max-width: 400px; margin: 0 auto; }
.ap-option-btn { padding: 12px 8px; background: var(--surface-2); border: 1px solid var(--border); border-radius: var(--radius-sm); cursor: pointer; transition: var(--transition); color: var(--text); font: 700 14px var(--font-mono); text-align: center; }
.ap-option-btn:hover { background: var(--accent-dim); border-color: var(--accent); color: var(--accent); transform: translateY(-2px); box-shadow: 0 4px 12px rgba(0,0,0,0.3); }
.ap-compare-btn { font-size: 16px !important; padding: 16px !important; }

.ap-result { text-align: center; padding: 16px 0; }
.ap-result-text { font: 900 28px var(--font); margin: 8px 0; }
.ap-correct-result .ap-result-text { color: var(--success); }
.ap-wrong-result .ap-result-text { color: var(--error); }
.ap-correct-result { animation: ap-celebrate 0.5s ease; }
.ap-wrong-result { animation: ap-shake 0.3s ease; }
@keyframes ap-celebrate { 0% { transform: scale(1); } 30% { transform: scale(1.05); } 100% { transform: scale(1); } }
.ap-result-answer { font: 600 16px var(--font-mono); color: var(--accent); }
.ap-result-actions { display: flex; gap: 12px; justify-content: center; margin-top: 16px; }

/* Weakness */
.ap-weakness-panel { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 16px; margin-bottom: 16px; }
.ap-weakness-row { display: flex; align-items: center; gap: 8px; margin-bottom: 6px; }
.ap-weakness-note { font: 700 12px var(--font-mono); color: var(--error); width: 36px; }
.ap-weakness-bar-bg { flex: 1; height: 8px; background: var(--surface-3); border-radius: 4px; overflow: hidden; }
.ap-weakness-bar-fill { height: 100%; background: linear-gradient(90deg, var(--error), var(--orange)); border-radius: 4px; transition: width 0.3s; }
.ap-weakness-count { font: 600 10px var(--font-mono); color: var(--text-3); width: 32px; text-align: right; }

/* History */
.ap-history-panel { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 16px; }
.ap-history-row { display: flex; align-items: center; gap: 8px; padding: 5px 8px; background: var(--surface-2); border-radius: 6px; font-size: 12px; margin-bottom: 4px; }
.ap-history-time { margin-left: auto; font: 600 10px var(--font-mono); color: var(--text-3); }

/* Homepage AP Banner */
.ap-hero-banner { background: linear-gradient(135deg, rgba(168,85,247,0.15), rgba(0,229,255,0.1)); border: 1px solid rgba(168,85,247,0.3); border-radius: var(--radius); padding: 20px 24px; margin-top: 16px; cursor: pointer; transition: var(--transition); display: flex; align-items: center; gap: 20px; }
.ap-hero-banner:hover { border-color: var(--purple); box-shadow: 0 0 20px rgba(168,85,247,0.2); transform: translateY(-2px); }
.ap-hero-icon { font-size: 44px; animation: ap-ear-bounce 2s infinite; }
@keyframes ap-ear-bounce { 0%, 100% { transform: rotate(0deg); } 25% { transform: rotate(-8deg); } 75% { transform: rotate(8deg); } }
.ap-hero-text h3 { font: 900 18px var(--font); color: var(--purple); margin-bottom: 4px; }
.ap-hero-text p { font-size: 12px; color: var(--text-2); }
.ap-hero-badges { display: flex; gap: 6px; margin-top: 6px; flex-wrap: wrap; }
.ap-hero-badge { font-size: 9px; padding: 2px 8px; background: var(--purple-dim); border: 1px solid rgba(168,85,247,0.3); border-radius: 12px; color: var(--purple); font-weight: 600; }

/* ═══════════════════════════════════════
   Loading Splash Screen
   ═══════════════════════════════════════ */
#app-loader {
    position: fixed; inset: 0; z-index: 100000;
    background: var(--bg);
    display: flex; align-items: center; justify-content: center;
    transition: opacity 0.5s, visibility 0.5s;
}
#app-loader.hidden { opacity: 0; visibility: hidden; pointer-events: none; }
.loader-content { text-align: center; }
.loader-icon { font-size: 56px; animation: loader-bounce 1.2s ease infinite; }
@keyframes loader-bounce { 0%, 100% { transform: translateY(0); } 50% { transform: translateY(-12px); } }
.loader-title { font: 900 28px var(--font); color: var(--accent); margin: 8px 0 16px; letter-spacing: 2px; }
.loader-bar { width: 200px; height: 4px; background: var(--surface-3); border-radius: 2px; margin: 0 auto 10px; overflow: hidden; }
.loader-fill { height: 100%; width: 0%; background: linear-gradient(90deg, var(--accent), var(--purple)); border-radius: 2px; animation: loader-progress 1.2s ease-out forwards; }
@keyframes loader-progress { 0% { width: 0%; } 100% { width: 100%; } }
.loader-text { font-size: 12px; color: var(--text-3); }

/* ═══════════════════════════════════════
   Onboarding Tour
   ═══════════════════════════════════════ */
#onboarding-overlay { display: none; }
.ob-backdrop { position: fixed; inset: 0; z-index: 99998; background: rgba(0,0,0,0.75); backdrop-filter: blur(4px); display: flex; align-items: center; justify-content: center; animation: ob-fadein 0.3s ease; }
@keyframes ob-fadein { from { opacity: 0; } to { opacity: 1; } }
.ob-card { background: var(--surface); border: 1px solid var(--border); border-radius: 16px; padding: 32px; max-width: 440px; width: 90%; text-align: center; animation: ob-slidein 0.4s ease; }
@keyframes ob-slidein { from { transform: translateY(20px) scale(0.95); opacity: 0; } to { transform: translateY(0) scale(1); opacity: 1; } }
.ob-progress { height: 4px; background: var(--surface-3); border-radius: 2px; margin-bottom: 8px; overflow: hidden; }
.ob-progress-fill { height: 100%; background: linear-gradient(90deg, var(--accent), var(--purple)); border-radius: 2px; transition: width 0.3s; }
.ob-step { font: 600 10px var(--font-mono); color: var(--text-3); margin-bottom: 16px; }
.ob-emoji { font-size: 56px; margin-bottom: 12px; }
.ob-title { font: 900 22px var(--font); color: var(--text); margin-bottom: 8px; }
.ob-desc { font-size: 13px; color: var(--text-2); line-height: 1.6; margin-bottom: 20px; }
.ob-actions { display: flex; gap: 12px; justify-content: center; }

/* ═══════════════════════════════════════
   Practice Streak Badge
   ═══════════════════════════════════════ */
.streak-badge {
    position: fixed; top: 20px; right: -300px; z-index: 9999;
    padding: 12px 20px; background: linear-gradient(135deg, var(--surface), var(--surface-2));
    border: 1px solid rgba(249,115,22,0.3); border-radius: var(--radius);
    color: var(--orange); font: 700 14px var(--font);
    box-shadow: 0 4px 20px rgba(249,115,22,0.2);
    transition: right 0.4s cubic-bezier(0.4,0,0.2,1);
    cursor: pointer;
}
.streak-badge.show { right: 20px; }

/* ═══════════════════════════════════════
   Mobile Bottom Navigation
   ═══════════════════════════════════════ */
.mobile-bottom-nav {
    display: none; position: fixed; bottom: 0; left: 0; right: 0; z-index: 9990;
    background: var(--surface); border-top: 1px solid var(--border);
    padding: 6px 0 env(safe-area-inset-bottom, 6px);
    flex-direction: row; justify-content: space-around;
}
.mob-nav-btn {
    display: flex; flex-direction: column; align-items: center; gap: 2px;
    background: none; border: none; cursor: pointer; padding: 6px 0;
    color: var(--text-3); transition: var(--transition); min-width: 56px;
}
.mob-nav-btn.active { color: var(--accent); }
.mob-nav-icon { font-size: 20px; }
.mob-nav-label { font: 600 9px var(--font); }

@media (max-width: 768px) {
    .mobile-bottom-nav { display: flex; }
    #app-header { position: sticky; top: 0; z-index: 999; }
    body { padding-bottom: 64px; }
}

/* ═══════════════════════════════════════
   Rhythm Tap Beats
   ═══════════════════════════════════════ */
.rt-visual { margin-bottom: 16px; overflow-x: auto; }
.rt-beats { display: flex; gap: 6px; justify-content: center; flex-wrap: wrap; }
.rt-beat { width: 36px; height: 36px; display: flex; align-items: center; justify-content: center; border-radius: 8px; background: var(--surface-2); border: 1px solid var(--border); transition: all 0.2s; font-size: 14px; color: var(--text-3); }
.rt-beat-on { border-color: var(--accent); color: var(--accent); }
.rt-beat-active { background: var(--accent-dim); border-color: var(--accent); box-shadow: 0 0 12px var(--accent-glow); transform: scale(1.15); }
.rt-beat-hit { background: var(--success-dim) !important; border-color: var(--success) !important; color: var(--success) !important; }
.rt-beat-miss { background: var(--error-dim) !important; border-color: var(--error) !important; color: var(--error) !important; }
.rt-tap-btn { font-size: 24px !important; min-width: 160px; min-height: 80px; border-radius: 50%; animation: ap-pulse 1s infinite; }

/* ═══════════════════════════════════════
   Weekly Practice Calendar
   ═══════════════════════════════════════ */
.week-calendar { margin-top: 16px; }
.wc-row { display: flex; gap: 8px; justify-content: center; }
.wc-day { display: flex; flex-direction: column; align-items: center; gap: 2px; padding: 6px 10px; background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius-sm); min-width: 40px; }
.wc-day.wc-done { border-color: var(--success); background: var(--success-dim); }
.wc-dot { font-size: 16px; }
.wc-label { font: 600 10px var(--font); color: var(--text-3); }

/* ═══════════════════════════════════════
   Exercise Card Tag
   ═══════════════════════════════════════ */
.ex-tag { position: absolute; top: 8px; right: 8px; font: 700 9px var(--font); padding: 2px 8px; border-radius: 10px; }
.ex-card { position: relative; }

/* ═══════════════════════════════════════
   Simon Says Pads
   ═══════════════════════════════════════ */
.ss-pads { display: flex; gap: 8px; justify-content: center; flex-wrap: wrap; margin-top: 16px; }
.ss-pad {
    width: 64px; height: 64px; border-radius: 50%; border: 3px solid var(--pad-color);
    background: color-mix(in srgb, var(--pad-color) 15%, transparent); cursor: pointer;
    display: flex; align-items: center; justify-content: center; transition: all 0.15s;
    position: relative;
}
.ss-pad:hover:not(:disabled) { transform: scale(1.1); background: color-mix(in srgb, var(--pad-color) 30%, transparent); }
.ss-pad:disabled { opacity: 0.4; cursor: default; }
.ss-pad-note { font: 900 18px var(--font); color: var(--pad-color); }
.ss-pad-flash {
    background: var(--pad-color) !important; transform: scale(1.15) !important;
    box-shadow: 0 0 24px var(--pad-color);
}
.ss-pad-flash .ss-pad-note { color: #fff !important; }

@keyframes ss-flash { 0%,100% { opacity:0.3 } 50% { opacity:1 } }

/* ═══════════════════════════════════════
   Music Quiz Options
   ═══════════════════════════════════════ */
.mq-question { text-align: center; margin-bottom: 20px; }
.mq-options { display: flex; flex-direction: column; gap: 8px; max-width: 480px; margin: 0 auto; }
.mq-option-btn {
    display: flex; align-items: center; gap: 12px; padding: 12px 16px; text-align: left;
    background: var(--surface-2); border: 1px solid var(--border); border-radius: var(--radius);
    color: var(--text); font: 500 14px var(--font); cursor: pointer;
    transition: var(--transition);
}
.mq-option-btn:hover { border-color: var(--accent); background: var(--accent-dim); transform: translateX(4px); }
.mq-opt-letter {
    width: 28px; height: 28px; display: flex; align-items: center; justify-content: center;
    background: var(--surface-3); border-radius: 50%; font: 800 12px var(--font-mono);
    color: var(--accent); flex-shrink: 0;
}

/* ═══════════════════════════════════════
   Achievement Toast
   ═══════════════════════════════════════ */
.ach-toast-container {
    position: fixed; top: 20px; right: 20px; z-index: 99999;
    display: flex; flex-direction: column; gap: 8px;
    pointer-events: none;
}
.ach-toast {
    display: flex; align-items: center; gap: 12px; padding: 14px 18px;
    background: linear-gradient(135deg, var(--surface), var(--surface-2));
    border: 1px solid var(--gold); border-radius: var(--radius);
    box-shadow: 0 8px 32px rgba(255,215,0,0.2);
    transform: translateX(120%); transition: transform 0.4s cubic-bezier(0.4,0,0.2,1);
    pointer-events: auto; cursor: pointer; min-width: 260px;
}
.ach-toast.show { transform: translateX(0); }
.ach-toast.hide { transform: translateX(120%); }
.ach-toast-icon { font-size: 32px; flex-shrink: 0; }
.ach-toast-body { flex: 1; }
.ach-toast-title { font: 700 10px var(--font); color: var(--gold); text-transform: uppercase; letter-spacing: 1px; }
.ach-toast-name { font: 800 14px var(--font); color: var(--text); margin-top: 2px; }
.ach-toast-desc { font: 500 11px var(--font); color: var(--text-3); margin-top: 2px; }

/* ═══════════════════════════════════════
   Wave Background Canvas
   ═══════════════════════════════════════ */
.hero { position: relative; overflow: hidden; }
.wave-bg {
    position: absolute; top: 0; left: 0; width: 100%; height: 100%;
    pointer-events: none; z-index: 0;
}
.hero-content { position: relative; z-index: 1; }

/* ═══════════════════════════════════════
   Global Micro-Animations
   ═══════════════════════════════════════ */
.btn { transition: all 0.2s cubic-bezier(0.4,0,0.2,1); }
.btn:active { transform: scale(0.95); }
.nav-btn:active { transform: scale(0.92); }
.feature-card:hover { transform: translateY(-4px); }
.ex-card:hover { transform: translateY(-3px); box-shadow: 0 8px 24px rgba(0,0,0,0.3); }
.tool-card:hover { transform: translateY(-3px); }
.stat:hover { transform: scale(1.05); }

/* ═══════════════════════════════════════
   Responsive Final Polish
   ═══════════════════════════════════════ */
@media (max-width: 768px) {
    .hero-title { font-size: 24px !important; }
    .hero-sub { font-size: 13px !important; }
    .hero-actions { flex-direction: column; gap: 8px; }
    .hero-actions .btn { width: 100%; }
    .feature-grid { grid-template-columns: repeat(2, 1fr) !important; gap: 8px !important; }
    .ex-grid { grid-template-columns: repeat(2, 1fr) !important; }
    .tool-grid { grid-template-columns: repeat(2, 1fr) !important; }
    .ap-mode-strip { flex-wrap: wrap; }
    .ap-score-grid { grid-template-columns: repeat(2, 1fr) !important; }
    .ss-pads { gap: 6px; }
    .ss-pad { width: 48px; height: 48px; }
    .mq-option-btn { padding: 10px 12px; font-size: 13px; }
    .stats-bar { flex-wrap: wrap; gap: 8px; }
    .wc-row { gap: 4px; }
    .wc-day { padding: 4px 6px; min-width: 32px; }
    .ach-toast-container { left: 12px; right: 12px; top: auto; bottom: 72px; }
    .ach-toast { min-width: auto; }
    footer { padding-bottom: 72px !important; }
}

@media (max-width: 480px) {
    .feature-grid { grid-template-columns: 1fr !important; }
    .ap-level-strip { flex-wrap: wrap; justify-content: center; }
    .hero { padding: 24px 16px !important; }
}