* {
  box-sizing: border-box;
}

body {
  font-family: Arial, sans-serif;
  background: #0b0c14;
  color: white;
  margin: 0;
}

.container {
  max-width: 980px;
  margin: auto;
  padding: 28px 20px 40px;
}

h1 {
  text-align: center;
  margin-bottom: 28px;
}

input, select {
  width: 100%;
  padding: 14px 15px;
  margin: 10px 0;
  border-radius: 10px;
  border: none;
  outline: none;
  font-size: 15px;
}

.song {
  background: linear-gradient(90deg, #171926, #1a1c2b);
  padding: 14px;
  margin: 8px 0;
  border-radius: 10px;
  cursor: pointer;
  transition: 0.2s ease;
  border: 1px solid rgba(255,255,255,0.04);
}

.song:hover {
  background: #24273a;
  transform: translateY(-1px);
}

.hidden {
  display: none !important;
}

#player {
  margin-top: 22px;
  padding: 18px;
  background: #171925;
  border-radius: 14px;
  border: 1px solid rgba(255,255,255,0.05);
}

.player-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}

#songTitle {
  margin: 0 0 6px;
  font-size: 22px;
}

.muted {
  margin: 0;
  color: #9ea3bf;
}

#playBtn {
  padding: 12px 22px;
  border: none;
  border-radius: 10px;
  background: #5573ff;
  color: white;
  cursor: pointer;
  font-size: 15px;
  font-weight: 700;
  transition: 0.2s ease;
}

#playBtn:hover {
  filter: brightness(1.08);
}

#playBtn:disabled {
  opacity: 0.55;
  cursor: not-allowed;
}

.status {
  margin: 14px 0 16px;
  color: #cfd3ea;
  min-height: 22px;
}

.sheet-wrap {
  margin: 10px 0 18px;
  border-radius: 12px;
  overflow: hidden;
  background: #0f111a;
  border: 1px solid rgba(255,255,255,0.05);
}

#sheetImage {
  display: block;
  width: 100%;
  max-height: 520px;
  object-fit: contain;
  background: #111;
}

#notesContainer {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.note {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 44px;
  padding: 10px 12px;
  border-radius: 8px;
  background: #2a2d43;
  color: white;
  font-weight: 700;
  transition: 0.2s ease;
  border: 1px solid rgba(255,255,255,0.05);
}

.note.active {
  background: #d9d11e;
  color: #131313;
  transform: scale(1.08);
  box-shadow: 0 0 18px rgba(255, 238, 0, 0.55);
}

.note.correct {
  background: #18b56a;
  color: white;
  box-shadow: 0 0 16px rgba(24, 181, 106, 0.45);
}

.note.wrong {
  background: #d63b3b;
  color: white;
  box-shadow: 0 0 16px rgba(214, 59, 59, 0.45);
}

@media (max-width: 640px) {
  .player-top {
    align-items: flex-start;
  }

  #playBtn {
    width: 100%;
  }
}