* {
  box-sizing: border-box;
}

body {
  min-height: 100vh;
  margin: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: #f4f7fb;
  color: #162033;
  font-family: Arial, Helvetica, sans-serif;
}

.calculator {
  width: min(760px, calc(100vw - 32px));
  padding: 32px;
  background: #ffffff;
  border: 1px solid #d8dee9;
  border-radius: 8px;
  box-shadow: 0 16px 40px rgba(22, 32, 51, 0.12);
}

h1 {
  margin: 0 0 24px;
  font-size: 28px;
  line-height: 1.2;
}

form {
  display: grid;
  grid-template-columns: max-content minmax(0, 1fr);
  gap: 14px 16px;
  align-items: center;
}

label {
  font-weight: 700;
}

textarea {
  width: 100%;
  min-width: min(100%, 50ch);
  height: 58px;
  padding: 10px 12px 20px;
  border: 1px solid #9aa8bb;
  border-radius: 6px;
  color: #162033;
  font: 16px/1.4 Consolas, "Courier New", monospace;
  overflow-x: auto;
  overflow-y: hidden;
  resize: none;
  white-space: nowrap;
}

textarea:focus {
  border-color: #225ea8;
  outline: 3px solid rgba(34, 94, 168, 0.2);
}

textarea[readonly] {
  background: #eef2f7;
}

.message {
  grid-column: 2;
  min-height: 20px;
  margin: 0;
  color: #a34000;
  font-size: 14px;
}

.actions {
  grid-column: 2;
  display: flex;
  gap: 12px;
  margin-top: 18px;
}

button {
  min-width: 112px;
  padding: 10px 18px;
  border: 1px solid #6e7f97;
  border-radius: 6px;
  background: #ffffff;
  color: #162033;
  cursor: pointer;
  font-size: 16px;
  font-weight: 700;
}

button:hover:not(:disabled),
button:focus-visible:not(:disabled) {
  background: #e8eef6;
}

button:disabled {
  background: #d3d7de;
  border-color: #b8bec8;
  color: #737b88;
  cursor: not-allowed;
}

#compute:not(:disabled) {
  background: #225ea8;
  border-color: #225ea8;
  color: #ffffff;
}

#compute:hover:not(:disabled),
#compute:focus-visible:not(:disabled) {
  background: #174778;
}

@media (max-width: 620px) {
  .calculator {
    padding: 24px;
  }

  form {
    grid-template-columns: 1fr;
  }

  .message,
  .actions {
    grid-column: 1;
  }

  .actions {
    flex-wrap: wrap;
  }

  button {
    flex: 1 1 140px;
  }
}