body {
  display: flex;
  font-family: Arial, sans-serif;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  padding-top: 100px;
  margin: 0;
  background: linear-gradient(135deg, #2b0a14, #4a0e1f, #2b0a14);
  background-size: 200% 200%;
  animation: gradientShift 10s ease infinite;
}
.calculator-box {
  background-color: white;
  padding: 30px;
  border-radius: 20px;
  box-shadow: rgba(0, 0, 0, 0.35) 0px 5px 15px;
  display: flex;
  flex-direction: column;
  gap: 15px;
}
input,
button {
  padding: 10px;
  font-size: 16px;
  border-radius: 5px;
}
button {
  background-color: #15428c;
  color: white;
  border: none;
  cursor: pointer;
  transition: all 0.3s ease;
}
button:hover {
  background-color: #6dd5ef;
  color: black;
  transform: scale(1.1);
}
@keyframes slideDown {
  0% {
    opacity: 0;
    transform: translateY(-50px);
  }
  100% {
    opacity: 1;
    transform: translateY(0);
  }
}
h1 {
  animation: fadeIn 2s;
  animation: slideDown 1s ease-out;
}
@keyframes gradientShift {
  0% {
    background-position: 0% 50%;
  }
  50% {
    background-position: 100% 50%;
  }
  100% {
    background-position: 0% 50%;
  }
}
.calculator-box {
  position: relative;
}
.calculator-box::before {
  content: "";
  position: absolute;
  inset: -2px;
  border-radius: 22px;
  padding: 2px;
  background: linear-gradient(120deg, #ff3b3b, #8b0000, #ff6b6b, #ff3b3b);
  background-size: 300% 300%;
  animation: borderGlow 6s linear infinite;
  -webkit-mask:
    linear-gradient(#fff 0 0) content-box,
    linear-gradient(#fff 0 0);
  -webkit-mask-composite: xor;
  mask-composite: exclude;
  z-index: -1;
}
@keyframes borderGlow {
  0% {
    background-position: 0% 50%;
  }
  100% {
    background-position: 300% 50%;
  }
}
.calculator-box {
  animation:
    cardEntrance 0.7s ease-out,
    boxGlow 3s ease-in-out infinite;
}

@keyframes cardEntrance {
  0% {
    opacity: 0;
    transform: translateY(30px) scale(0.96);
  }
  100% {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}
.calculator-box {
  transition:
    transform 0.3s ease,
    box-shadow 0.3s ease;
}
.calculator-box:hover {
  transform: translateY(-4px);
  box-shadow: 120px 80px 40px 20px rgb(225, 69, 69);
}
input {
  border: 1.5px solid #d7dcec;
  transition:
    border-color 0.25s ease,
    box-shadow 0.25s ease,
    transform 0.25s ease;
}
input:hover {
  border-color: #6dd5ef;
}
input:focus {
  border-color: #15428c;
  box-shadow: 0 0 0 4px rgba(21, 66, 140, 0.15);
  transform: scale(1.02);
}
button {
  background: linear-gradient(135deg, #15428c, #0b1740);
  transition:
    transform 0.25s ease,
    box-shadow 0.25s ease,
    background 0.4s ease;
}
button:hover {
  background: linear-gradient(135deg, #6dd5ef, #15428c);
  box-shadow: 0 8px 20px rgba(21, 66, 140, 0.35);
}
button:active {
  transform: scale(0.97);
}
label {
  font-size: 13px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.6px;
  color: #4a5a8a;
}

h1 {
  animation:
    fadeIn 2s,
    slideDown 1s ease-out;
}
@keyframes boxGlow {
  0%,
  100% {
    box-shadow:
      rgba(0, 0, 0, 0.35) 0px 5px 15px,
      0 0 20px rgba(220, 20, 20, 0.4),
      0 0 40px rgba(255, 80, 80, 0.2);
  }
  50% {
    box-shadow:
      rgba(0, 0, 0, 0.35) 0px 5px 15px,
      0 0 35px rgba(220, 20, 20, 0.7),
      0 0 60px rgba(255, 80, 80, 0.4);
  }
}