body {
  font-family: Arial, sans-serif;
  background: #0d1117;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  margin: 0;
  color: #c9d1d9;
}

.container {
  background: #161b22;
  padding: 30px;
  border-radius: 10px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.5);
  width: 600px;
  max-width: 90%;
  text-align: center;
}

h1 {
  margin-bottom: 20px;
  color: #ffffff;
}

.tabs {
  display: flex;
  justify-content: center;
  margin-bottom: 20px;
}

.tabs button {
  padding: 10px 20px;
  border: none;
  background: #21262d;
  margin: 0 5px;
  cursor: pointer;
  border-radius: 5px;
  font-size: 1rem;
  color: #c9d1d9;
  transition: background 0.2s;
}

.tabs button.active {
  background: #30363d;
  color: #ffffff;
}

.tabs button:hover {
  background: #30363d;
}

.converter {
  display: none;
}

.converter.active {
  display: block;
}

.converter-box {
  display: flex;
  justify-content: center;
  align-items: stretch;
  gap: 20px;
}

.category-select select {
  padding: 10px 15px;
  font-size: 16px;
  border-radius: 6px;
  border: 1px solid #30363d;
  background: #0d1117;
  color: #c9d1d9;
  cursor: pointer;
  margin-bottom: 20px;
}

.unit-row {
  display: flex;
  align-items: stretch;
  justify-content: center;
  gap: 20px;
}

.unit-row span {
  font-size: 2rem;
  font-weight: bold;
  margin: 0 10px;
  color: #ffffff;
}

.unit-box {
  background: #21262d;
  padding: 20px;
  border-radius: 8px;
  width: 250px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  box-sizing: border-box;
}

.unit-box input {
  font-size: 1.4rem;
  font-weight: bold;
  padding: 10px;
  text-align: center;
  width: 100%;
  border: none;
  background: transparent;
  outline: none;
  margin-bottom: 10px;
  color: #ffffff;
}

.unit-box select {
  padding: 6px;
  font-size: 1rem;
  border-radius: 4px;
  border: 1px solid #30363d;
  width: 100%;
  text-align: center;
  background: #0d1117;
  color: #c9d1d9;
}

.unit-box input::placeholder {
  color: #8b949e;
  font-style: italic;
}

#currencyNote {
  margin-top: 15px;
  font-size: 0.9rem;
  color: #f85149;
  transition: opacity 0.5s ease-in-out;
}

.equals {
  font-size: 24px;
  display: flex;
  align-items: center;
  color: #ffffff;
}