/* RESET */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

/* BODY */
body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  background: linear-gradient(135deg, #1f2933, #111827);
  color: #f9fafb;
}

/* MAIN CONTAINER */
.container {
  width: 100%;
  max-width: 420px;
  padding: 2.2rem;
  background: rgba(255, 255, 255, 0.06);
  border-radius: 18px;
  text-align: center;
  backdrop-filter: blur(10px);
  box-shadow: 0 15px 40px rgba(0, 0, 0, 0.35);
}

/* HEADING */
.container h1 {
  font-size: 2.3rem;
  margin-bottom: 1.8rem;
  letter-spacing: 0.5px;
  color: #e5e7eb;
}

/* COUNTER DISPLAY */
.input {
  font-size: 4rem;
  font-weight: 700;
  margin-bottom: 2rem;
  padding: 1.2rem;
  background: #0f172a;
  color: #38bdf8;
  border-radius: 14px;
  box-shadow: inset 0 0 12px rgba(0, 0, 0, 0.6);
}

/* BUTTON BASE */
button {
  width: 100%;
  padding: 0.75rem 1rem;
  font-size: 1rem;
  margin-bottom: 0.8rem;
  border: none;
  border-radius: 10px;
  cursor: pointer;
  font-weight: 600;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

/* BUTTON COLORS */
.btn1 {
  background-color: #22c55e;
  color: #052e16;
}

.btn2 {
  background-color: #64748b;
  color: #020617;
}

.btn3 {
  background-color: #ef4444;
  color: #450a0a;
}

/* HOVER EFFECT */
button:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(0, 0, 0, 0.35);
}

/* RESPONSIVE - MOBILE */
@media (max-width: 480px) {
  body {
    padding: 1rem;
  }

  .container {
    padding: 1.6rem;
  }

  .container h1 {
    font-size: 1.7rem;
    margin-bottom: 1.4rem;
  }

  .input {
    font-size: 3rem;
    padding: 1rem;
    margin-bottom: 1.6rem;
  }

  button {
    font-size: 0.95rem;
    padding: 0.7rem;
  }
}