* { box-sizing: border-box; margin: 0; padding: 0; }
body { font-family: system-ui, -apple-system, sans-serif; font-size: 13px; background: #f8f8f8; min-height: 100vh; }

.app { max-width: 720px; margin: 0 auto; background: #fff; height: 100vh; border-left: 1px solid #e0e0e0; border-right: 1px solid #e0e0e0; display: flex; flex-direction: column; overflow: hidden; }

.transport { display: flex; align-items: center; gap: 2px; padding: 6px 12px; background: linear-gradient(to bottom, #fafafa, #f0f0f0); border-bottom: 1px solid #ddd; flex-shrink: 0; height: 42px; }
.transport-section { display: flex; align-items: center; gap: 4px; padding: 0 8px; border-right: 1px solid #e0e0e0; }
.transport-section:last-child { border-right: none; }
.transport-section.grow { flex: 1; justify-content: flex-end; }

#start-btn { width: 28px; height: 28px; padding: 0; font-size: 12px; border: 1px solid #aaa; background: linear-gradient(to bottom, #fff, #eee); border-radius: 3px; cursor: pointer; }
#start-btn:hover { background: linear-gradient(to bottom, #fff, #e0e0e0); border-color: #888; }
#start-btn:active { background: #ddd; }
#start-btn.playing { background: linear-gradient(to bottom, #e8f5e9, #c8e6c9); border-color: #4caf50; }

.mini-btn { width: 22px; height: 22px; padding: 0; font-size: 10px; border: 1px solid #bbb; background: #fff; border-radius: 2px; cursor: pointer; display: flex; align-items: center; justify-content: center; }
.mini-btn:hover { background: #f5f5f5; border-color: #999; }
.mini-btn:active { background: #eee; }

.toggle-btn { padding: 3px 8px; font-size: 11px; border: 1px solid #bbb; background: #fff; border-radius: 2px; cursor: pointer; }
.toggle-btn:hover { background: #f5f5f5; }
.toggle-btn.active { background: linear-gradient(to bottom, #e3f2fd, #bbdefb); border-color: #2196f3; color: #1565c0; }

.param-group { display: flex; align-items: center; gap: 3px; }
.param-label { font-size: 9px; color: #888; text-transform: uppercase; letter-spacing: 0.5px; }

select { padding: 3px 6px; font-size: 11px; border: 1px solid #bbb; border-radius: 2px; background: #fff; cursor: pointer; }
select:hover { border-color: #999; }

.mixer { display: flex; gap: 6px; }
.mixer-ch { display: flex; align-items: center; gap: 3px; }
.mixer-ch label { font-size: 9px; color: #666; text-transform: uppercase; width: 18px; }
.mixer-ch input[type="range"] { width: 40px; height: 16px; -webkit-appearance: none; background: transparent; cursor: pointer; }
.mixer-ch input[type="range"]::-webkit-slider-runnable-track { height: 4px; background: #ddd; border-radius: 2px; }
.mixer-ch input[type="range"]::-webkit-slider-thumb { -webkit-appearance: none; width: 10px; height: 10px; background: #666; border-radius: 50%; margin-top: -3px; }
.mixer-ch input[type="range"]::-moz-range-track { height: 4px; background: #ddd; border-radius: 2px; }
.mixer-ch input[type="range"]::-moz-range-thumb { width: 10px; height: 10px; background: #666; border-radius: 50%; border: none; }

.display-panel { display: flex; align-items: stretch; border-bottom: 1px solid #e0e0e0; background: #fafafa; flex-shrink: 0; height: 120px; }
.chord-info { display: flex; flex-direction: column; justify-content: center; align-items: center; padding: 12px 20px; min-width: 100px; border-right: 1px solid #e0e0e0; }
.chord-name { font-size: 32px; font-weight: 300; font-family: Georgia, serif; line-height: 1; }
.chord-info.inactive .chord-name { color: #ccc; }
.history-row { display: flex; gap: 4px; margin-top: 6px; }
.history-chip { font-size: 11px; font-family: Georgia, serif; color: #999; padding: 2px 6px; background: #eee; border-radius: 2px; cursor: pointer; border: none; }
.history-chip:hover { background: #e0e0e0; color: #666; }

.sheet-music { flex: 1; display: flex; align-items: center; justify-content: center; padding: 8px; overflow: hidden; }
.sheet-music svg { display: block; }

.keyboard-panel { padding: 8px 12px; background: #f0f0f0; border-bottom: 1px solid #ddd; display: flex; justify-content: center; align-items: center; gap: 6px; flex-shrink: 0; height: 118px; }
.keyboard-shift { width: 20px; height: 60px; border: 1px solid #bbb; background: #e8e8e8; border-radius: 2px; cursor: pointer; display: flex; align-items: center; justify-content: center; font-size: 10px; color: #666; }
.keyboard-shift:hover { background: #ddd; }
.keyboard-shift:disabled { opacity: 0.3; cursor: default; }
.piano { display: flex; position: relative; }
.white-key { width: 24px; height: 100px; background: linear-gradient(to bottom, #fff, #f8f8f8); border: 1px solid #444; border-radius: 0 0 3px 3px; cursor: pointer; }
.white-key:hover { background: linear-gradient(to bottom, #f5f5f5, #eee); }
.white-key.active { background: linear-gradient(to bottom, #ffcdd2, #ef9a9a); }
.white-key.playing { background: linear-gradient(to bottom, #ef5350, #e53935); }
.black-key { width: 14px; height: 60px; background: linear-gradient(to bottom, #333, #111); border: none; border-radius: 0 0 2px 2px; position: absolute; z-index: 1; cursor: pointer; }
.black-key:hover { background: linear-gradient(to bottom, #444, #222); }
.black-key.active { background: linear-gradient(to bottom, #d32f2f, #b71c1c); }
.black-key.playing { background: linear-gradient(to bottom, #ff5252, #ff1744); }
.white-key.active, .black-key.active { cursor: ew-resize; }

.chord-browser { padding: 12px; flex: 1; overflow-y: auto; }
.chord-row { display: flex; align-items: flex-start; gap: 8px; padding: 6px 0; border-bottom: 1px solid #f0f0f0; }
.chord-row:last-child { border-bottom: none; }
.chord-row-label { width: 70px; flex-shrink: 0; font-size: 10px; font-weight: 600; text-transform: uppercase; letter-spacing: 0.5px; color: #666; padding-top: 6px; }
.chord-row-buttons { display: flex; flex-wrap: wrap; gap: 4px; flex: 1; }

.chord-btn { padding: 6px 10px; font-size: 14px; font-family: Georgia, serif; border: 1px solid #ccc; background: #fff; border-radius: 2px; cursor: pointer; min-width: 44px; text-align: center; }
.chord-btn:hover { border-color: #888; background: #fafafa; }
.chord-btn:active { background: #f0f0f0; }
.chord-btn.hint-classic { border-color: #64b5f6; background: linear-gradient(to bottom, #fff, #e3f2fd); }
.chord-btn.hint-classic:hover { background: #e3f2fd; }
.chord-btn.hint-safe { border-color: #81c784; background: linear-gradient(to bottom, #fff, #e8f5e9); }
.chord-btn.hint-safe:hover { background: #e8f5e9; }
.chord-btn.hint-interesting { border-color: #ffb74d; background: linear-gradient(to bottom, #fff, #fff3e0); }
.chord-btn.hint-interesting:hover { background: #fff3e0; }

.hint-legend { display: flex; justify-content: center; gap: 16px; padding: 8px; font-size: 10px; color: #888; border-top: 1px solid #eee; flex-shrink: 0; height: 28px; }
.hint-legend span { display: flex; align-items: center; gap: 4px; }
.hint-dot { width: 8px; height: 8px; border-radius: 1px; }
.hint-dot.classic { background: #e3f2fd; border: 1px solid #64b5f6; }
.hint-dot.safe { background: #e8f5e9; border: 1px solid #81c784; }
.hint-dot.interesting { background: #fff3e0; border: 1px solid #ffb74d; }

.status-bar { display: flex; justify-content: center; gap: 12px; padding: 8px 12px; font-size: 10px; color: #999; background: #f5f5f5; border-top: 1px solid #e0e0e0; flex-shrink: 0; height: 30px; }
kbd { padding: 1px 4px; font-family: inherit; font-size: 9px; background: #fff; border: 1px solid #ddd; border-radius: 2px; }

.history-modal { display: none; position: fixed; inset: 0; background: rgba(0,0,0,0.4); z-index: 100; align-items: center; justify-content: center; }
.history-modal.open { display: flex; }
.history-modal-content { background: #fff; border-radius: 4px; padding: 16px; max-width: 360px; width: 90%; max-height: 70vh; overflow-y: auto; }
.history-modal h3 { font-size: 14px; font-weight: 600; margin-bottom: 12px; }
.history-modal-list { display: flex; flex-wrap: wrap; gap: 6px; }
.history-modal-item { font-family: Georgia, serif; font-size: 14px; color: #666; padding: 6px 10px; background: #f0f0f0; border: none; border-radius: 2px; cursor: pointer; }
.history-modal-item:hover { background: #e0e0e0; }
.history-modal-close { margin-top: 12px; padding: 8px; width: 100%; border: 1px solid #ccc; background: #fff; border-radius: 2px; cursor: pointer; }

@media (max-width: 600px) {
  .transport { flex-wrap: wrap; padding: 6px 8px; height: auto; }
  .transport-section { padding: 4px; border-right: none; }
  .transport-section.grow { width: 100%; justify-content: center; margin-top: 4px; }
  .mixer { gap: 12px; }
  .display-panel { height: 100px; }
  .keyboard-panel { height: 98px; }
  .white-key { width: calc((100vw - 80px) / 15); height: 80px; }
  .black-key { width: calc((100vw - 80px) / 22); height: 48px; }
  .keyboard-shift { height: 50px; }
  .chord-row { flex-direction: column; gap: 4px; }
  .chord-row-label { width: auto; padding-top: 0; }
}