* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: Arial, sans-serif;
}

body {
  background: #d7dfee;
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: flex-start;
  padding: 36px 16px;
  color: #111827;
}

.container {
  width: 100%;
  max-width: 460px;
}

h1 {
  text-align: center;
  margin-bottom: 22px;
  font-size: 30px;
  color: #111827;
}

.converter-box {
  background: #ffffff;
  border-radius: 16px;
  padding: 22px;
  box-shadow: 0 10px 26px rgba(0, 0, 0, 0.08);
}

.input-group {
  margin-bottom: 18px;
}

label {
  display: block;
  font-size: 14px;
  font-weight: bold;
  margin-bottom: 6px;
}

input,
select {
  width: 100%;
  height: 46px;
  padding: 0 12px;
  border: 1px solid #d1d5db;
  border-radius: 10px;
  font-size: 14px;
  background: #fff;
  color: #111827;
  outline: none;
}

input:focus,
select:focus {
  border-color: #111827;
}

.currency-row {
  display: grid;
  grid-template-columns: 1fr 52px 1fr;
  gap: 12px;
  align-items: end;
  margin-bottom: 18px;
}

.select-box {
  width: 100%;
}

#swapBtn {
  width: 42px;
  height: 42px;
  margin: 0 auto 2px;
  border: none;
  border-radius: 50%;
  background: #1f2937;
  color: #ffffff;
  font-size: 18px;
  cursor: pointer;
  transition:
    transform 0.2s ease,
    background 0.2s ease;
}

#swapBtn:hover {
  background: #111827;
  transform: rotate(180deg);
}

#convertBtn {
  width: 100%;
  height: 46px;
  border: none;
  border-radius: 10px;
  background: #1f2937;
  color: #ffffff;
  font-size: 15px;
  font-weight: bold;
  cursor: pointer;
  transition: background 0.2s ease;
}

#convertBtn:hover {
  background: #111827;
}

#message {
  min-height: 20px;
  text-align: center;
  margin-top: 14px;
  font-size: 13px;
  color: #dc2626;
  font-weight: bold;
}

#result {
  margin-top: 18px;
  text-align: center;
  font-size: 22px;
  font-weight: bold;
  color: #111827;
}

@media (max-width: 600px) {
  .currency-row {
    grid-template-columns: 1fr;
    gap: 14px;
  }

  #swapBtn {
    margin: 0 auto;
  }

  h1 {
    font-size: 26px;
  }

  .converter-box {
    padding: 18px;
  }
}