.piano-container {
    perspective: 1000px;
}

.key {
    position: relative;
    border-radius: 0 0 4px 4px;
    transition: all 0.1s;
    cursor: pointer;
    user-select: none;
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
    align-items: center;
    padding-bottom: 10px;
    font-weight: bold;
    font-size: 14px;
}

.key-white {
    width: 60px;
    height: 240px;
    background: linear-gradient(to bottom, #fff 0%, #eee 100%);
    z-index: 1;
    border: 1px solid #ccc;
    border-top: none;
    box-shadow: 0 4px 5px rgba(0,0,0,0.2), inset 0 0 2px #fff;
    color: #999;
}

.key-white:active, .key-white.active {
    background: linear-gradient(to bottom, #fff 0%, #ddd 100%);
    transform: rotateX(-5deg) translateY(2px);
    box-shadow: 0 2px 2px rgba(0,0,0,0.2), inset 0 0 2px #fff;
    border-bottom: 4px solid #ddd;
}

.key-black {
    width: 40px;
    height: 150px;
    background: linear-gradient(45deg, #222 0%, #444 100%);
    z-index: 2;
    margin-left: -20px;
    margin-right: -20px;
    border-radius: 0 0 4px 4px;
    box-shadow: 2px 2px 4px rgba(0,0,0,0.4), inset 0 1px 2px rgba(255,255,255,0.2);
    color: #fff;
    padding-bottom: 8px;
    font-size: 12px;
}

.key-black:active, .key-black.active {
    background: linear-gradient(45deg, #111 0%, #333 100%);
    transform: rotateX(-5deg) translateY(2px);
    box-shadow: 1px 1px 2px rgba(0,0,0,0.4), inset 0 1px 2px rgba(255,255,255,0.1);
}

.note-char {
    display: block;
    margin-bottom: 4px;
    text-transform: uppercase;
    font-family: monospace;
}

.note-name {
    font-size: 10px;
    opacity: 0.7;
}

/* Sheet Music Highlight */
.sheet-note {
    width: 40px;
    height: 50px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    border-radius: 8px;
    transition: all 0.2s;
    background-color: white;
    border: 1px solid #E2E8F0;
}

.note-main {
    font-size: 14px;
    font-weight: bold;
    color: #2D3748;
}

.note-sub {
    font-size: 10px;
    color: #A0AEC0;
    margin-top: 2px;
}

.sheet-note.current {
    background-color: #D53F8C; /* Pink Brand */
    border-color: #D53F8C;
    transform: scale(1.15);
    box-shadow: 0 4px 6px rgba(213, 63, 140, 0.3);
    z-index: 10;
}

.sheet-note.current .note-main,
.sheet-note.current .note-sub {
    color: white;
}

.sheet-note.matched {
    background-color: #F0FFF4; /* Green-50 */
    border-color: #667eea; /* Brand Accent Blue-Purple for border indicating done */
}

.sheet-note.matched .note-main {
    color: #667eea;
}

.sheet-note.matched .note-sub {
    color: #A0AEC0;
}

.sheet-spacer {
    width: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #CBD5E0;
    height: 50px;
}