:root {
  /* Color Palette */
  --primary-color: #333;
  --gray-border: lightgray;

  /* Font Families */
  --font-sans: 'Segoe UI', Roboto, sans-serif;
  --font-heading: 'Inter', sans-serif;

  /* Layout */
  --container-width: 800px;
}

* {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  padding: 0;
  font-family: var(--font-sans);
  color: var(--primary-color);
}

main {
  display: flex;
}

h1 {
  font-family: var(--font-heading);
  margin-top: 0;
}

.container {
  padding: 1rem;
  display: grid;
  grid-template-columns: 1fr min(var(--container-width), 100%) 1fr;
}
.container > * {
  grid-column: 2;
}

.row {
  display: flex;
  justify-content: stretch;
  margin-bottom: 0.25rem;
}
.row > * + * {
  margin-left: 0.25rem;
}

.column {
  display: flex;
  flex-direction: column;
}

.grow {
  flex-grow: 1;
}

input.narrow {
  width: 1.5rem;
}

form {
  flex-shrink: 0;
  width: 15rem;
  padding-right: 1rem;
  margin-right: 1rem;
  border-right: 1px solid var(--gray-border);
}

label {
  display: block;
  margin-bottom: 1rem;
}

input {
  display: block;
  width: 100%;
  font-size: 14pt;
}
input[type="number"] {
  width: 4rem;
}

select {
  display: block;
  width: 100%;
  font-size: 14pt;
}

button {
  background: hsl(210, 70%, 40%);
  font-size: 14pt;
  cursor: pointer;
  color: white;
  border: none;
  border-radius: 4px;
  width: 100%;
}
button.add {
  background: hsl(150, 70%, 40%);
}
button.delete {
  background: none;
  color: hsl(355, 65%, 50%);
  width: 1.5rem;
  min-width: 1.5rem;
}

.mobile {
  display: none;
}

@media (max-width: 600px) {
  form {
    width: 100%;
    margin-right: 0;
    padding-right: 0;
    border-right: none;
    border-bottom: 1px solid var(--gray-border);
  }
  main {
    flex-direction: column;
  }
  .mobile {
    display: block;
  }
}