*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: 'Inter', sans-serif;
  background: linear-gradient(135deg, #0f0c29, #302b63, #24243e);
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
}

.container {
  width: 100%;
  max-width: 420px;
  padding: 1.5rem;
}

.card {
  background: rgba(255, 255, 255, 0.05);
  backdrop-filter: blur(16px);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 24px;
  padding: 3rem 2.5rem;
  text-align: center;
  box-shadow: 0 24px 64px rgba(0, 0, 0, 0.4);
}

.title {
  font-size: 1.1rem;
  font-weight: 600;
  color: rgba(255, 255, 255, 0.5);
  letter-spacing: 0.15em;
  text-transform: uppercase;
  margin-bottom: 2rem;
}

.display {
  font-size: 6rem;
  font-weight: 900;
  color: #ffffff;
  line-height: 1;
  margin-bottom: 2.5rem;
  transition: transform 0.1s ease, color 0.3s ease;
  user-select: none;
}

.display.positive {
  color: #6ee7b7;
}

.display.negative {
  color: #fca5a5;
}

.display.bump {
  transform: scale(1.12);
}

.controls {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
}

.btn {
  border: none;
  border-radius: 14px;
  font-family: 'Inter', sans-serif;
  font-weight: 700;
  cursor: pointer;
  transition: transform 0.12s ease, box-shadow 0.12s ease, opacity 0.12s ease;
  outline: none;
}

.btn:active {
  transform: scale(0.93);
}

.btn:focus-visible {
  box-shadow: 0 0 0 3px rgba(255, 255, 255, 0.4);
}

.btn-decrement {
  width: 64px;
  height: 64px;
  font-size: 2rem;
  background: rgba(252, 165, 165, 0.15);
  color: #fca5a5;
  border: 1px solid rgba(252, 165, 165, 0.25);
}

.btn-decrement:hover {
  background: rgba(252, 165, 165, 0.25);
  box-shadow: 0 4px 20px rgba(252, 165, 165, 0.2);
}

.btn-increment {
  width: 64px;
  height: 64px;
  font-size: 2rem;
  background: rgba(110, 231, 183, 0.15);
  color: #6ee7b7;
  border: 1px solid rgba(110, 231, 183, 0.25);
}

.btn-increment:hover {
  background: rgba(110, 231, 183, 0.25);
  box-shadow: 0 4px 20px rgba(110, 231, 183, 0.2);
}

.btn-reset {
  width: 80px;
  height: 44px;
  font-size: 0.8rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  background: rgba(255, 255, 255, 0.08);
  color: rgba(255, 255, 255, 0.5);
  border: 1px solid rgba(255, 255, 255, 0.12);
}

.btn-reset:hover {
  background: rgba(255, 255, 255, 0.14);
  color: rgba(255, 255, 255, 0.8);
}

@media (max-width: 480px) {
  .display {
    font-size: 5rem;
  }

  .card {
    padding: 2.5rem 1.75rem;
  }
}