* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "Poppins", sans-serif;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background-color: #f0f4f8; 
  background-image: url("grey.jpg");
  background-size: cover;
  background-position: center;
  text-align: center;
}


#heading {
  font-size: 56px;
  color: #1e3a8a; 
  font-weight: 700;
  text-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
  margin-bottom: 40px;
  letter-spacing: 1px;
}

/* ⏱️ Stopwatch Container */
.stopwatch {
  width: 500px;
  height:350px;
  max-width: 90%;
  padding: 50px 20px;
  border-radius: 20px;
background: linear-gradient(135deg, #efd7d9ff, #e8edf4ff);


  backdrop-filter: blur(15px);
  border: 2px solid rgba(0, 0, 0, 0.1);
  box-shadow:
    0 6px 25px rgba(0, 0, 0, 0.2),
    inset 0 0 10px rgba(255, 255, 255, 0.3);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.stopwatch:hover {
  transform: scale(1.02);
  box-shadow: 0 8px 35px rgba(0, 0, 0, 0.3);
}

/* 🕰️ Time Display */
#displayTime {
  color: #1d4ed8; /* strong blue */
  font-size: 72px;
  font-weight: 700;
  margin-bottom: 25px;
  text-shadow: 0 0 15px rgba(29, 78, 216, 0.3);
}

/* 🎛️ Buttons Container */
.btn {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 20px;
}

/* 🔘 Base Button Style */
.btn1,
.btn2,
.btn3 {
  width: 120px;
  height: 55px;
  font-size: 20px;
  font-weight: 600;
  border-radius: 10px;
  border: none;
  outline: none;
  color: #fff;
  background-color: #2563eb; /* primary blue */
  cursor: pointer;
  box-shadow: 0 5px 15px rgba(37, 99, 235, 0.4);
  transition: all 0.3s ease;
}

/* 🎨 Button Color Variants */
.btn1 {
  background-color: #dc2626; /* red */
}
.btn2 {
  background-color: #059669; /* green */
}
.btn3 {
  background-color: #f59e0b; /* yellow */
  color: #222;
  font-weight: 700;
}

/* 💫 Hover Effects */
.btn1:hover,
.btn2:hover,
.btn3:hover {
  transform: scale(1.08);
  filter: brightness(1.1);
}

/* ⚡ Active State */
.btn1:active,
.btn2:active,
.btn3:active {
  transform: scale(0.95);
  filter: brightness(0.9);
}

/* 🌙 Theme Button */
.theme {
  position: absolute;
  top: 25px;
  right: 25px;
  background-color: #1e293b; /* dark navy */
  color: #f8fafc;
  border: none;
  border-radius: 8px;
  padding: 10px 20px;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.25);
  transition: all 0.3s ease;
}

.theme:hover {
  background-color: #334155;
  transform: scale(1.08);
}

/* 📱 Responsive */
@media (max-width: 480px) {
  #heading {
    font-size: 42px;
  }

  .stopwatch {
    width: 90%;
    padding: 25px 15px;
  }

  #displayTime {
    font-size: 52px;
  }

  .btn1,
  .btn2,
  .btn3 {
    width: 100px;
    height: 50px;
    font-size: 18px;
  }

  .theme {
    top: 15px;
    right: 15px;
    padding: 8px 16px;
    font-size: 14px;
  }
}