html, body {
  touch-action: manipulation; /* Or 'none', but 'manipulation' is safer */
}
body {
  background: #000;
  color: #FFD700;
  font-family: monospace, Arial, sans-serif;
  margin: 0;
  padding: 0;
}

#main {
  width: 400px;
  margin: 40px auto;
  background: #111;
  border-radius: 12px;
  padding: 32px 24px 32px 24px;
  box-shadow: 0 3px 20px #222;
}

h1, h2 {
  text-align: center;
  color: #FFD700;
  margin-bottom: 20px;
}

#btc-display {
  font-size: 2.2em;
  text-align: center;
  margin-bottom: 20px;
}

#click-btn, #save-btn, #load-btn, #reset-btn {
  background: #FFD700;
  color: #000;
  border: none;
  border-radius: 8px;
  font-size: 1.2em;
  font-weight: bold;
  padding: 10px 20px;
  margin: 10px auto 20px auto;
  display: block;
  cursor: pointer;
  transition: background 0.2s;
}
#click-btn:hover, #save-btn:hover, #load-btn:hover, #reset-btn:hover {
  background: #ffe066;
}

#per-sec {
  text-align: center;
  margin-bottom: 20px;
}

#shop {
  margin-top: 8px;
}

.upgrade {
  background: #222;
  border: 1px solid #FFD700;
  border-radius: 8px;
  padding: 12px 10px 10px 10px;
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.upgrade-name {
  font-size: 1.12em;
  color: #FFD700;
  font-weight: bold;
}

.upgrade-desc {
  font-size: 0.85em;
  color: #FFD700;
  padding-top: 2px;
}

.upgrade-cost {
  color: #FFD700;
  font-size: 1em;
}

.upgrade-btn {
  background: #FFD700;
  color: #000;
  border: none;
  border-radius: 6px;
  padding: 7px 15px;
  font-weight: bold;
  margin-left: 8px;
  cursor: pointer;
  transition: background 0.2s;
}
.upgrade-btn:disabled {
  background: #444;
  color: #FFD700;
  cursor: not-allowed;
}
.upgrade-btn:hover:not(:disabled) {
  background: #ffe066;
}