:root {
  --digit-height: 6.5rem;
  --digit-width: 5rem;
  --roll-duration: 360ms;
  --roll-ease: cubic-bezier(0.22, 1, 0.36, 1);
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
}

body {
  min-height: 100vh;
  font-family: var(--font-display);
  color: var(--ink);
  background: var(--paper);
  display: flex;
  flex-direction: column;
  align-items: stretch;
  padding: 0;
}

.odometer-app {
  width: 100%;
  max-width: 56rem;
  text-align: center;
  margin: 0 auto;
  padding: 1rem 1.25rem 3rem;
  flex: 1;
}

h1 {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(2rem, 2.5vw + 1rem, 2.75rem);
  margin: 0 0 2rem;
  color: var(--ink-strong);
  letter-spacing: -0.015em;
}

.odometer {
  display: flex;
  justify-content: center;
  align-items: flex-start;
  gap: 1.25rem;
  flex-wrap: wrap;
  margin-bottom: 2rem;
}

.column {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.75rem;
  padding: 1rem;
  border-radius: var(--radius-lg);
  background: var(--panel);
  box-shadow: var(--shadow-md);
  border: 3px solid transparent;
  transition:
    border-color 180ms ease,
    background-color 180ms ease,
    transform 180ms ease;
  outline: none;
}

.column:hover {
  transform: translateY(-2px);
}

.column.focused,
.column:focus-visible {
  border-color: var(--coral);
  background: var(--coral-soft);
}

.btn {
  font: inherit;
  font-family: var(--font-display);
  font-size: 1.5rem;
  font-weight: 700;
  line-height: 1;
  width: var(--digit-width);
  height: 3rem;
  border: 2px solid var(--ink);
  border-radius: var(--radius-md);
  background: var(--accent);
  color: var(--ink);
  cursor: pointer;
  transition:
    background-color 120ms ease,
    border-color 120ms ease,
    transform 80ms ease;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.btn:hover:not(:disabled) {
  background: var(--accent-dark);
}

.btn:active:not(:disabled) {
  transform: scale(0.96);
}

.btn:disabled {
  opacity: 0.35;
  cursor: not-allowed;
}

.btn:focus-visible {
  outline: 3px solid var(--coral);
  outline-offset: 2px;
}

.window {
  position: relative;
  width: var(--digit-width);
  height: var(--digit-height);
  overflow: hidden;
  border-radius: var(--radius-md);
  background: linear-gradient(180deg, #2e2b2b 0%, #3a3535 50%, #2e2b2b 100%);
  box-shadow:
    inset 0 10px 14px rgba(0, 0, 0, 0.55),
    inset 0 -10px 14px rgba(0, 0, 0, 0.55),
    0 1px 0 rgba(255, 255, 255, 0.4);
}

.window::before,
.window::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  height: 1.1rem;
  pointer-events: none;
  z-index: 1;
}

.window::before {
  top: 0;
  background: linear-gradient(180deg, rgba(0, 0, 0, 0.55), rgba(0, 0, 0, 0));
}

.window::after {
  bottom: 0;
  background: linear-gradient(0deg, rgba(0, 0, 0, 0.55), rgba(0, 0, 0, 0));
}

.strip {
  display: flex;
  flex-direction: column;
  transform: translateY(calc(var(--offset, 1) * var(--digit-height) * -1));
  transition: transform var(--roll-duration) var(--roll-ease);
  will-change: transform;
}

.strip.no-transition {
  transition: none;
}

.digit {
  height: var(--digit-height);
  width: var(--digit-width);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-display);
  font-size: calc(var(--digit-height) * 0.72);
  font-weight: 800;
  color: #ffffff;
  font-variant-numeric: tabular-nums;
  line-height: 1;
  user-select: none;
}

.label {
  font-family: var(--font-display);
  font-size: 0.8125rem;
  font-weight: 700;
  color: var(--ink-soft);
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.total {
  font-family: var(--font-display);
  font-size: clamp(2.25rem, 3vw + 1rem, 3.25rem);
  font-weight: 800;
  font-variant-numeric: tabular-nums;
  color: var(--ink-strong);
  margin: 0 0 1.75rem;
  letter-spacing: -0.01em;
}

.reset {
  font: inherit;
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: 0.85rem 2rem;
  border-radius: var(--radius-md);
  border: 2px solid var(--ink);
  background: var(--accent);
  color: var(--ink);
  cursor: pointer;
  transition:
    background-color 120ms ease,
    transform 80ms ease;
}

.reset:hover {
  background: var(--accent-dark);
}

.reset:active {
  transform: scale(0.97);
}

.reset:focus-visible {
  outline: 3px solid var(--coral);
  outline-offset: 3px;
}

@media (max-width: 560px) {
  :root {
    --digit-width: max(2.25rem, calc((100vw - 6.5rem) / 4));
    --digit-height: calc(var(--digit-width) * 1.3);
  }

  body {
    padding: 0;
  }

  .odometer-app {
    max-width: 100%;
    padding: 0.5rem 0.5rem 2rem;
  }

  h1 {
    margin-bottom: 1.5rem;
  }

  .odometer {
    gap: 0.4rem;
    flex-wrap: nowrap;
    margin-bottom: 1.5rem;
  }

  .column {
    padding: 0.35rem;
    gap: 0.35rem;
    border-width: 2px;
  }

  .btn {
    height: calc(var(--digit-width) * 0.6);
    min-height: 2.5rem;
    font-size: 1.125rem;
    border-radius: var(--radius-sm);
    border-width: 1.5px;
  }

  .window {
    border-radius: var(--radius-sm);
  }

  .label {
    font-size: 0.625rem;
    letter-spacing: 0.08em;
    white-space: nowrap;
  }

  .total {
    margin-bottom: 1.25rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  .strip {
    transition: none;
  }

  .column {
    transition: none;
  }

  .column:hover {
    transform: none;
  }
}