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

body {
  background: #f4f7fb;
  color: #333;
}

/* ===== HEADER ===== */
header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: linear-gradient(90deg, #1e3c72, #2a5298);
  color: white;
  padding: 12px 30px;
  border-bottom: 4px solid #3498db;
  box-shadow: 0 4px 8px rgba(0,0,0,0.2);
}

.header-left img {
  width: 70px;
  background: white;
  border-radius: 12px;
  padding: 6px;
  transition: transform 0.3s ease;
}
.header-left img:hover {
  transform: scale(1.08);
}

.header-center {
  flex: 1;
  text-align: center;
}

.header-center h1 {
  font-size: 26px;
  font-weight: bold;
  letter-spacing: 1px;
}

/* ===== MAIN ===== */
main {
  display: flex;
  justify-content: center;
  padding: 40px 20px;
}

.calculator {
  background: #fff;
  padding: 25px;
  border-radius: 14px;
  box-shadow: 0px 6px 15px rgba(0,0,0,0.1);
  width: 100%;
  max-width: 850px;
  text-align: center;
  overflow-x: auto;
}

.calculator h2 {
  margin-bottom: 20px;
  color: #2a5298;
}

/* ===== TABLE ===== */
table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 20px;
}

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

table th {
  background: #2a5298;
  color: white;
}

table input {
  width: 95%;
  padding: 6px;
  border: 1px solid #ccc;
  border-radius: 8px; /* Rounded input boxes */
  text-align: center;
  outline: none;
  transition: border 0.3s ease;
}

table input:focus {
  border-color: #2a5298;
}

/* ===== BUTTONS ===== */
.buttons {
  display: flex;
  justify-content: center;
  gap: 15px;
}

button {
  padding: 10px 18px;
  border: none;
  border-radius: 8px;
  background: #2a5298;
  color: white;
  font-size: 16px;
  cursor: pointer;
  transition: transform 0.2s, background 0.3s ease;
}

button:hover {
  background: #1e3c72;
  transform: scale(1.05);
}

/* ===== RESULT ===== */
#result {
  margin-top: 20px;
  padding: 15px;
  background: #eef4ff;
  border-left: 6px solid #2a5298;
  border-radius: 8px;
  text-align: left;
  font-size: 16px;
  font-weight: bold;
}

/* ===== FOOTER ===== */
footer {
  background: linear-gradient(90deg, #1e3c72, #2a5298);
  color: white;
  text-align: center;
  padding: 20px 10px;
  margin-top: 40px;
  font-size: 14px;
  border-top: 3px solid #3498db;
  box-shadow: 0 -3px 8px rgba(0,0,0,0.2);
}

footer p {
  margin: 5px 0;
}

footer a {
  color: #4cd137;
  font-weight: bold;
  text-decoration: none;
  transition: color 0.3s ease, transform 0.2s ease;
}

footer a:hover {
  color: #f1c40f;
  transform: scale(1.05);
}