* {
  box-sizing: border-box;
  font-family: "Poppins", sans-serif;
}
body {
  font-family: Arial, sans-serif;
  margin: 0;
  background: #f4f4f4;
  color: #333;
}

header {
  background: #004aad;
  color: #fff;
  padding: 15px 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
nav a {
  color: #fff;
  margin: 0 10px;
  text-decoration: none;
}

nav a:hover {
  text-decoration: underline;
}


main {
  padding: 20px;
  display: grid;
  gap: 20px;
  grid-template-columns: 1fr;
}

.card {
  background: white;
  border-radius: 12px;
  padding: 20px;
  box-shadow: 0 4px 8px rgba(0,0,0,0.1);
  
}

h2 {
  color: #0077b6;
  border-bottom: 2px solid #0077b6;
  padding-bottom: 5px;
  margin-bottom: 15px;
}

.charts {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
}

.chart-container {
  flex: 1;
  min-width: 300px;
}

table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 10px;
}

th, td {
  border: 1px solid #ddd;
  padding: 10px;
  text-align: left;
}

th {
  background-color: #0077b6;
  color: white;
}

form {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 10px;
}

input, button {
  padding: 10px;
  border-radius: 6px;
  border: 1px solid #ccc;
}

button {
  background-color: #0077b6;
  color: white;
  border: none;
  cursor: pointer;
}

button:hover {
  background-color: #023e8a;
}

footer {
  text-align: center;
  padding: 10px;
  background: #0077b6;
  color: white;
  margin-top: 20px;
}

.container {
  width: 100%;
  min-height: 100vh;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding-top: 40px;
  padding-bottom: 20px;
}

.calculator {
  background: #3a4452;
  padding: 25px;
  border-radius: 15px;
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.3);
  width: 360px;
  max-width: 95%;
}

form .display {
  display: flex;
  width: 100%;
  justify-content: flex-end;
  margin: 20px 0;
}

form .display input {
  flex: 1;
  text-align: right;
  font-size: 45px;
  height: 80px;
  box-shadow: none;
  
  width: 100%;
  background: #222;
  color: #33ffd8;
  padding-right: 50px;
  border-radius: 10px;
  border: none;
}

.button-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
  justify-items: center;
}

.calculator form input {
  border: 0;
  outline: 0;
  height: 70px;
  width: 70px;
  border-radius: 10px;
  box-shadow: -8px -8px 15px rgba(255, 255, 255, 0.1),
 5px 5px 15px rgba(0, 0, 0, 0.3);
  background-color: aliceblue;
  font-size: 22px;
  color: black;
  cursor: pointer;
  transition: 0.2s;
}

.calculator form input:hover {
  background: rgba(255,255,255,0.3);
}

.calculator form input.equal {
  grid-column: span 2;
  width: 100%;
  background-color: #33ffd8 ;
  color: #000;
  font-weight: bold;
  font-size: 24px;
}
.calculator form input.equal:hover {
  background-color: #1affb0;
}

form input.kev {
  color: #33ffd8;
}

marquee.kev {
  color: #33ffd8;
  font-size: 18px;
  margin-bottom: 10px;
}

/* ✅ Responsive design */
@media (max-width: 600px) {
  .calculator {
    width: 90%;
    padding: 20px;
  }

  .calculator form input {
    width: 60px;
    height: 60px;
    font-size: 20px;
  }

  .calculator form input.equal {
    font-size: 22px;
  }

  form .display input {
    font-size: 30px;
    height: 70px;
  }
}

@media (max-width: 400px) {
  .calculator form input {
    width: 50px;
    height: 50px;
    font-size: 18px;
  }
}