:root {
  --primary-color: #00796b;
  --primary-dark: #004d40;
  --background-color: #f4f6f8;
  --container-bg: #fff;
  --table-bg: #e0f2f1;
  --text-color: #333;
  --border-color: #ccc;
  --footer-color: #888;
  --border-radius: 6px;
  --container-margin: 30px;
}

body {
  font-family: 'Segoe UI', Roboto, sans-serif;
  background-color: var(--background-color);
  color: var(--text-color);
  transition: background-color 0.3s ease, color 0.3s ease;
  padding: 20px;
  overflow-x: hidden;
  max-width: 100%;
}

.container {
  max-width: 720px;
  margin: var(--container-margin) auto;
  padding: 30px;
  background: var(--container-bg);
  border-radius: var(--border-radius);
  box-shadow: 0 6px 18px rgba(0, 0, 0, 0.08);
}

h1 {
  font-size: 1.8rem;
  color: var(--primary-color);
  margin: 0 0 20px 0;
  text-align: center;
}

.h1-icon {
  width: 32px;
  height: 32px;
  margin-right: 10px;
  vertical-align: middle;
}

.table-with-total {
  margin-bottom: 16px;
  border-radius: var(--border-radius);
  overflow: hidden;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
  background-color: var(--table-bg);
}

table {
  width: 100%;
  border-collapse: collapse;
  table-layout: fixed;
}

th, td {
  padding: 8px;
  text-align: center;
  vertical-align: middle;
  font-size: 0.95rem;
  width: 25%;
}

th {
  background-color: var(--primary-color);
  color: #fff;
  font-weight: 600;
}

td {
  background-color: var(--table-bg);
  color: var(--text-color);
  font-weight: 500;
}

tfoot td {
  font-weight: bold;
}

.total-incurred-row td {
  font-weight: 800;
  font-size: 1.1rem;
  padding: 12px;
}

#incurredTotal {
  color: red;
  font-size: 1.2rem;
  margin-left: 5px;
  font-weight: 800;
}

input[type="number"],
.balance-value {
  -moz-appearance: textfield;
  appearance: textfield;
  width: 100%;
  padding: 6px 8px;
  box-sizing: border-box;
  font-size: 1rem;
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  background-color: #fff;
  color: #333;
  max-width: 100%;
  text-align: center;
  font-weight: 500;
}

input[type="number"]::-webkit-outer-spin-button,
input[type="number"]::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

.balance-value {
  min-height: 1.5em;
}

.copy-icon {
  font-size: 0.8em;
  margin-left: 4px;
  color: var(--primary-color);
  cursor: pointer;
  opacity: 0.7;
  transition: opacity 0.2s;
}

.copy-icon:hover {
  opacity: 1;
}

.controls-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 20px;
  flex-wrap: wrap;
  gap: 10px;
}

.button-group {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.button-group button,
#themeToggle {
  color: white;
  border: none;
  padding: 8px 12px;
  border-radius: var(--border-radius);
  font-size: 0.9rem;
  cursor: pointer;
  transition: all 0.3s ease;
  min-width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
}

.button-group button:hover,
#themeToggle:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
}

.button-group button .btn-text {
  font-weight: 500;
}

#calculateBtn { background-color: #2196F3; }
#calculateBtn:hover { background-color: #1976D2; }
#addRowBtn { background-color: #4CAF50; }
#addRowBtn:hover { background-color: #388E3C; }
#delRowBtn { background-color: #F44336; }
#delRowBtn:hover { background-color: #D32F2F; }
#printPDFBtn { background-color: #9C27B0; }
#printPDFBtn:hover { background-color: #7B1FA2; }
#themeToggle { background-color: #FF9800; }
#themeToggle:hover { background-color: #F57C00; }
#clearTableBtn { background-color: #607D8B; }
#clearTableBtn:hover { background-color: #455A64; }

.danger-btn { color: white !important; }

footer {
  text-align: center;
  margin-top: 30px;
  font-size: 0.9rem;
  color: var(--footer-color);
}

footer a {
  color: teal;
  text-decoration: none;
}

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

footer span {
  opacity: 0.8;
}

/* Dark Mode */
body.dark-mode {
  background-color: #121212;
  color: #e0e0e0;
}

body.dark-mode .container {
  background-color: #1a1a1a;
  box-shadow: 0 6px 18px rgba(0, 0, 0, 0.3);
}

body.dark-mode input[type="number"],
body.dark-mode .balance-value {
  background-color: #2a2a2a;
  color: #e0e0e0;
  border-color: #444;
}

body.dark-mode th {
  background-color: var(--primary-dark);
}

body.dark-mode .table-with-total,
body.dark-mode td,
body.dark-mode tfoot td,
body.dark-mode .total-incurred-row td {
  background-color: #121212;
  color: #e0e0e0;
}

body.dark-mode .copy-icon {
  color: #4db6ac;
}

body.dark-mode #incurredTotal {
  color: #ff6b6b;
}

/* Feedback */
.copied-feedback {
  position: fixed;
  background: var(--primary-color);
  color: white;
  padding: 8px 16px;
  border-radius: var(--border-radius);
  font-size: 14px;
  font-weight: 600;
  pointer-events: none;
  z-index: 10000;
  animation: fadeOut 1s ease-in-out forwards;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
  text-align: center;
  min-width: 120px;
  transform: translateX(-50%);
  left: 50%;
  top: 20px;
}

body.dark-mode .copied-feedback {
  background: var(--primary-dark);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

@keyframes fadeOut {
  0% { opacity: 1; transform: translateX(-50%) translateY(0); }
  70% { opacity: 1; transform: translateX(-50%) translateY(10px); }
  100% { opacity: 0; transform: translateX(-50%) translateY(20px); }
}

/* Print */
@media print {
  * { print-color-adjust: exact; -webkit-print-color-adjust: exact; }
  body, .container, table, th, td, .balance-value, input[type="number"] {
    color: #000 !important;
    background: white !important;
    box-shadow: none !important;
  }
  .controls-container, footer, .copy-icon, .copied-feedback {
    display: none !important;
  }
  .container { padding: 0.25in !important; margin: 0 auto !important; }
  table { width: 100%; border-collapse: collapse; }
  th, td { border: 1px solid #000; padding: 8px; }
  .balance-value, input[type="number"] {
    border: none !important;
    background: transparent !important;
  }
  @page { margin: 0.5in; }
}

/* Mobile */
@media (max-width: 768px) {
  .container { padding: 15px; margin: 15px auto; }
  h1 { font-size: 1.4rem; }
  input[type="number"], .balance-value { font-size: 16px; padding: 8px 6px; }
  
  .controls-container {
    display: grid;
    grid-template-columns: repeat(3, 1fr); /* Three columns, equal width */
    gap: 8px; /* Space between buttons */
    width: 100%;
    justify-items: center; /* Center items in the grid cells */
  }

  .button-group {
    display: contents; /* Allows buttons to be direct grid items */
  }

  .button-group button, 
  #themeToggle {
    width: 100%; /* Take full width of grid cell */
    height: auto; /* Allow height to adjust based on content */
    min-height: 44px; /* Ensure a minimum touch target size */
    padding: 10px 5px; /* Adjust padding for better text fit */
    font-size: 0.85rem; /* Slightly smaller font for mobile */
  }

  .button-group button .btn-text { 
    display: inline; /* Show button text */
  }
}