* { box-sizing: border-box; }

body {
  margin: 0;
  height: 100vh;
  background: #0f0f0f;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: system-ui, sans-serif;
  color: #fff;
}

.app {
  width: 300px;
}

.mode {
  display: flex;
  gap: 8px;
  margin-bottom: 10px;
}

.mode button {
  flex: 1;
  height: 36px;
  font-size: 14px;
  border: none;
  border-radius: 10px;
  background: #333;
  color: #fff;
  cursor: pointer;
}

.calc, .golf {
  background: #1c1c1c;
  padding: 16px;
  border-radius: 18px;
}

#screen {
  width: 100%;
  height: 60px;
  margin-bottom: 12px;
  background: #000;
  color: #00ff88;
  font-size: 28px;
  text-align: right;
  padding: 10px;
  border: none;
  border-radius: 10px;
}

.keys {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
}

button {
  height: 52px;
  font-size: 18px;
  border: none;
  border-radius: 10px;
  background: #333;
  color: #fff;
  cursor: pointer;
}

button:hover { background: #444; }

.wide { grid-column: span 2; }

.eq {
  grid-column: span 4;
  background: #0a84ff;
}

.golf input {
  width: 100%;
  height: 44px;
  margin-bottom: 8px;
  padding: 8px;
  font-size: 16px;
  border-radius: 8px;
  border: none;
}

#golfResult {
  margin-top: 10px;
  font-size: 14px;
  color: #00ff88;
}