:root {
  /* core brand colors for this project */
  --page-bg: #0a0a0a;
  --panel-bg: #161b22;
  --display-bg: #0a2342;

  --pad-bg: #eceff1;
  --pad-hover: #10b981;
  --pad-active: #0fa371;

  --text-main: #f8fafc;
  --text-dark: #000000;
  --text-display: #f8fafc;

  --border-color: #555555;
  --shadow-color: rgba(0, 0, 0, 0.35);

  /* font sizes */
  --root-font-size: 16px;
  font-size: var(--root-font-size);

  /* font-families */
  --font-headline: 'Roboto Mono', monospace;
  --font-family: 'Lato', sans-serif;
}

*,
*::after,
*::before {
  box-sizing: border-box;
}

body {
  font-family: var(--font-family);
  background-color: var(--page-bg);
  color: var(--text-main);
  display: flex;
  width: 100%;
  height: 100vh;
  text-align: center;
  justify-content: center;
  align-items: center;
  margin: 0;
}

#drum-machine {
  background-color: var(--panel-bg);
  padding: 1rem;
  border: 2px solid var(--border-color);
  border-radius: 8px;
}

#pad-bank {
  display: grid;
  width: 100%;
  height: auto;
  grid-template-columns: repeat(3, 100px);
  grid-template-rows: repeat(3, 100px);
  justify-content: center;
  padding: 1rem;
  gap: 1rem;
}

#display {
  background-color: var(--display-bg);
  color: var(--text-display);
  border: 2px solid var(--border-color);
  border-radius: 8px;
  padding: 0.5rem;
  min-height: 50px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 1rem;
}

.drum-pad {
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--pad-bg);
  color: var(--text-dark);
  font-family: var(--font-headline);
  font-size: 1.5rem;
  font-weight: 700;
  cursor: pointer;
  border: 2px solid var(--border-color);
  border-radius: 8px;
  box-shadow: 0 6px 12px var(--shadow-color);
  transition:
    background-color 0.2s ease,
    transform 0.08s ease,
    box-shadow 0.08s ease;
}

.drum-pad:hover {
  background-color: var(--pad-hover);
  color: var(--text-display);
  transform: translateY(-2px);
  box-shadow: 0 10px 18px var(--shadow-color);
}

.drum-pad:active {
  background-color: var(--pad-active);
  color: var(--text-display);
  transform: translateY(2px);
  box-shadow: 0 2px 4px var(--shadow-color);
}