/* ===== General Layout ===== */
body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  margin: 0;
  background: #f9fafc;
  color: #333;
}

.container {
  max-width: 1000px;
  margin: 40px auto;
  padding: 20px;
  background: #fff;
  border-radius: 12px;
  box-shadow: 0 4px 16px rgba(0,0,0,0.08);
}

h1 {
  text-align: center;
  color: #016db7;
  margin-bottom: 10px;
}

p {
  text-align: center;
  color: #6d6964;
}

/* ===== Global Unit Selector ===== */
.unit-switcher {
  text-align: center;
  margin-bottom: 20px;
  font-weight: 600;
  color: #016db7;
}
.unit-switcher select {
  margin-left: 8px;
  padding: 6px 8px;
  border-radius: 6px;
  border: 1px solid #d1e7ff;
  background: #fff;
  color: #016db7;
  font-weight: 600;
}
.unit-switcher span {
  margin-left: 10px;
  color: #6d6964;
  font-weight: normal;
}
@media (max-width: 600px) {
  .unit-switcher {
    display: block;
    text-align: left;
  }
}

/* ===== Tabs ===== */
.tabs {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  margin: 20px 0;
  gap: 10px;
}
.tab-button {
  padding: 10px 18px;
  border: 2px solid #016db7;
  border-radius: 8px;
  background: #fff;
  color: #016db7;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
}
.tab-button:hover {
  background: #016db7;
  color: #fff;
}
.tab-button.active {
  background: #016db7;
  color: #fff;
}

/* ===== Tab Content ===== */
.tab-content {
  display: none;
  padding: 20px;
  background: #fdfdfd;
  border: 1px solid #eee;
  border-radius: 10px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.05);
}
.tab-content.active {
  display: block;
  animation: fadeIn 0.4s ease;
}
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ===== Form Elements ===== */
label {
  display: block;
  margin: 12px 0 6px;
  font-weight: 500;
  color: #016db7;
}
input[type="number"], select {
  width: 100%;
  padding: 10px;
  border: 1px solid #ccc;
  border-radius: 8px;
  font-size: 14px;
}
button {
  display: inline-block;
  margin-top: 12px;
  padding: 10px 20px;
  background: #016db7;
  color: #fff;
  font-weight: 600;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  transition: background 0.3s ease;
}
button:hover {
  background: #025892;
}

/* ===== Results ===== */
.result-box {
  margin-top: 15px;
  padding: 12px;
  border-left: 5px solid #016db7;
  background: #f0f8ff;
  border-radius: 8px;
  font-size: 15px;
  color: #333;
}

/* ===== Export Buttons ===== */
.export-buttons {
  margin-top: 10px;
  display: flex;
  gap: 10px;
}
.export-btn {
  padding: 8px 14px;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  font-size: 14px;
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 6px;
}
.export-btn.pdf {
  background: #e63946;
  color: #fff;
}
.export-btn.excel {
  background: #2a9d8f;
  color: #fff;
}
.export-btn:hover {
  opacity: 0.9;
}