/* =========================================
   1. GLOBAL VARIABLES & RESET
   ========================================= */
:root {
  --primary: #2563eb;
  --bg-color: #f8fafc;
  --card-bg: #ffffff;
  --text-main: #0f172a;
  --text-muted: #64748b;
  --border: #e2e8f0;
  --success: #16a34a;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-family:
    -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial,
    sans-serif;
}

body {
  background-color: var(--bg-color);
  color: var(--text-main);
  line-height: 1.6;
  /* NEW: Flexbox rules to force full screen height */
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.ad-container-grid {
  background-color: #e2e8f0;
  display: grid;
  place-items: center; /* This single line handles both horizontal and vertical centering */
  width: 100%;
  margin-top: 40px;
  margin-bottom: 40px;
}

/* =========================================
   2. HEADER & NAVIGATION (DESKTOP)
   ========================================= */
.navbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 2rem;
  background: var(--card-bg);
  border-bottom: 1px solid var(--border);
  position: relative; /* Anchors the mobile dropdown */
  z-index: 100;
}

.logo a {
  font-size: 1.5rem;
  font-weight: bold;
  color: var(--primary);
  text-decoration: none;
  letter-spacing: -0.5px;
}

.nav-menu {
  display: flex;
  gap: 1.5rem;
}

.nav-menu a {
  text-decoration: none;
  color: var(--text-main);
  font-weight: 500;
  transition: color 0.2s ease;
}

.nav-menu a:hover,
.nav-menu a.active {
  color: var(--primary);
}

/* Hidden Checkbox & Label for Mobile */
.nav-toggle,
.nav-toggle-label {
  display: none;
}

/* =========================================
   3. MAIN LAYOUT & TYPOGRAPHY
   ========================================= */
.container {
  max-width: 1100px;
  margin: 2rem auto;
  padding: 0 1rem;
  /* NEW: Tells the container to grow and push the footer down */
  flex: 1;
  width: 100%;
}

.header-text {
  text-align: center;
  margin-bottom: 2rem;
}

.header-text h1 {
  font-size: 2.2rem;
  margin-bottom: 0.5rem;
}

.subtitle {
  color: var(--text-muted);
  font-weight: 500;
}

/* =========================================
   4. CALCULATOR GRID & CARDS
   ========================================= */
.calculator-grid {
  display: grid;
  grid-template-columns: 1fr 1.1fr;
  gap: 2rem;
  align-items: start;
}

.input-card,
.result-card {
  background: var(--card-bg);
  padding: 2rem;
  border-radius: 12px;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
}

h2 {
  font-size: 1.25rem;
  margin-bottom: 1.2rem;
  border-bottom: 2px solid var(--bg-color);
  padding-bottom: 0.5rem;
}

/* =========================================
   5. FORM INPUTS
   ========================================= */
.input-group {
  margin-bottom: 1.2rem;
}

.input-group label {
  display: block;
  font-weight: 600;
  margin-bottom: 0.4rem;
  font-size: 0.95rem;
}

.input-group input {
  width: 100%;
  padding: 0.75rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 1rem;
  transition:
    border 0.2s,
    box-shadow 0.2s;
}

.input-group input:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

/* Reset Button Styling */
.reset-btn {
  width: 100%;
  padding: 0.85rem;
  margin-top: 1rem;
  background: transparent;
  border: 2px solid var(--border);
  color: var(--text-muted);
  border-radius: 6px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
}

.reset-btn:hover {
  border-color: #ef4444; /* Subtle red border */
  color: #ef4444; /* Subtle red text */
  background: #fef2f2; /* Very light red background */
}

.reset-btn:focus {
  outline: none;
  box-shadow: 0 0 0 3px rgba(239, 68, 68, 0.1);
}

/* =========================================
   6. ITEMIZED RECEIPT OUTPUT (RESULTS)
   ========================================= */
.result-row {
  display: flex;
  justify-content: space-between;
  padding: 0.5rem 0;
  font-size: 0.95rem;
}

.main-row {
  font-weight: 600;
  color: var(--text-main);
  padding-top: 0.75rem;
}

.sub-row {
  padding-left: 1.5rem;
  color: var(--text-muted);
  font-size: 0.9rem;
}

.text-muted {
  color: var(--text-muted);
}

.highlight-green {
  color: var(--success);
  font-weight: 600;
  border-top: 1px solid var(--border);
  padding-top: 1rem;
}

.subtotal {
  font-weight: 600;
  margin-top: 0.5rem;
  border-top: 1px dashed var(--border);
  padding-top: 0.5rem;
}

.grand-total {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--primary);
  padding-top: 1rem;
}

hr {
  border: 0;
  border-top: 1px solid var(--border);
  margin: 1rem 0;
}

/* =========================================
   7. CONTENT & FOOTER
   ========================================= */
.content-section {
  margin-top: 3rem;
}

/* Modern Disclaimer Card */
.disclaimer-card {
  display: flex;
  gap: 1.2rem;
  background: var(--card-bg);
  padding: 1.5rem;
  border-radius: 12px;
  border: 1px solid var(--border);
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.02);
  margin-bottom: 2rem;
  align-items: flex-start;
  transition: box-shadow 0.2s ease;
}

.disclaimer-card:hover {
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
}

.disclaimer-icon {
  flex-shrink: 0;
  color: var(--primary);
  background: rgba(37, 99, 235, 0.1); /* Very subtle blue background */
  padding: 0.6rem;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
}

.disclaimer-content strong {
  display: block;
  font-size: 0.95rem;
  color: var(--text-main);
  margin-bottom: 0.4rem;
}

.disclaimer-content p {
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 1.7;
  margin: 0;
}

/* How to Use Guide Styling */
.guide-container {
  margin-top: 3rem;
  background: var(--card-bg);
  padding: 2rem;
  border-radius: 12px;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
}

.guide-container h2 {
  font-size: 1.5rem;
  margin-bottom: 1.5rem;
  border-bottom: none;
  padding-bottom: 0;
}

.guide-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
}

.guide-step {
  display: flex;
  gap: 1rem;
  align-items: flex-start;
  background: var(--bg-color);
  padding: 1.5rem;
  border-radius: 8px;
  border: 1px solid var(--border);
}

.step-number {
  background: var(--primary);
  color: white;
  width: 28px;
  height: 28px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  font-weight: bold;
  font-size: 0.9rem;
  flex-shrink: 0;
}

.step-content h3 {
  font-size: 1.05rem;
  margin-bottom: 0.4rem;
  border-bottom: none;
  padding-bottom: 0;
  color: var(--text-main);
}

.step-content p {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.6;
  margin: 0;
}

/* FAQ Container & Styling */
.faq-container {
  margin-top: 3rem;
  background: var(--card-bg);
  padding: 2rem;
  border-radius: 12px;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
}

.faq-container h2 {
  font-size: 1.5rem;
  margin-bottom: 1.5rem;
  border-bottom: none;
  padding-bottom: 0;
}

.faq-item {
  border-bottom: 1px solid var(--border);
  padding: 1rem 0;
}

.faq-item:last-child {
  border-bottom: none;
}

/* The clickable question */
.faq-item summary {
  font-weight: 600;
  font-size: 1.05rem;
  cursor: pointer;
  list-style: none; /* Hides default arrow in some browsers */
  position: relative;
  padding-right: 2rem;
  outline: none;
  color: var(--text-main);
  transition: color 0.2s ease;
}

.faq-item summary:hover {
  color: var(--primary);
}

/* Custom Dropdown Arrow */
.faq-item summary::after {
  content: "+";
  position: absolute;
  right: 0;
  top: 50%;
  transform: translateY(-50%);
  font-size: 1.5rem;
  color: var(--text-muted);
  transition: transform 0.3s ease;
}

/* Change arrow to minus when open */
.faq-item[open] summary::after {
  content: "−";
  transform: translateY(-50%) rotate(180deg);
  color: var(--primary);
}

/* Hide default marker in webkit browsers */
.faq-item summary::-webkit-details-marker {
  display: none;
}

/* The hidden answer text */
.faq-content {
  margin-top: 1rem;
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.7;
  padding-right: 1rem;
  animation: fadeDown 0.3s ease-in-out;
}

/* Smooth fade-in animation for the answer */
@keyframes fadeDown {
  from {
    opacity: 0;
    transform: translateY(-10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.site-footer {
  text-align: center;
  padding: 1.5rem;
  /* NEW: Auto pushes it away from the content above it */
  margin-top: auto;
  background: var(--card-bg);
  border-top: 1px solid var(--border);
  color: var(--text-muted);
  font-size: 0.95rem;
}

/* =========================================
   8. MOBILE & TABLET RESPONSIVENESS
   ========================================= */
@media (max-width: 768px) {
  /* Stack the calculator cards */
  .calculator-grid {
    grid-template-columns: 1fr;
  }

  /* --- Hamburger Menu Logic --- */

  /* Show the hamburger icon container */
  .nav-toggle-label {
    display: block;
    cursor: pointer;
    padding: 0.5rem;
  }

  /* Draw the 3 hamburger lines */
  .nav-toggle-label span,
  .nav-toggle-label span::before,
  .nav-toggle-label span::after {
    display: block;
    background: var(--text-main);
    height: 3px;
    width: 24px;
    border-radius: 3px;
    position: relative;
    transition:
      transform 0.3s ease-in-out,
      background 0.3s ease-in-out;
  }

  .nav-toggle-label span::before,
  .nav-toggle-label span::after {
    content: "";
    position: absolute;
    width: 100%;
  }

  .nav-toggle-label span::before {
    top: -8px;
  }
  .nav-toggle-label span::after {
    bottom: -8px;
  }

  /* Hide the desktop menu links */
  .nav-menu {
    position: absolute;
    top: 100%;
    left: 0;
    width: 100%;
    background: var(--card-bg);
    flex-direction: column;
    gap: 0;
    max-height: 0; /* Squished completely flat */
    overflow: hidden; /* Hides the links */
    transition: max-height 0.3s ease-out;
    border-bottom: 1px solid var(--border);
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
  }

  .nav-menu a {
    padding: 1rem 2rem;
    border-top: 1px solid var(--bg-color);
    width: 100%;
    display: block;
  }

  /* The Trigger: Expand menu when invisible checkbox is checked */
  .nav-toggle:checked ~ .nav-menu {
    max-height: 300px;
  }

  /* The Trigger: Animate Hamburger into an 'X' */
  .nav-toggle:checked ~ .nav-toggle-label span {
    background: transparent; /* Hide middle line */
  }
  .nav-toggle:checked ~ .nav-toggle-label span::before {
    transform: rotate(45deg);
    top: 0;
  }
  .nav-toggle:checked ~ .nav-toggle-label span::after {
    transform: rotate(-45deg);
    bottom: 0;
  }
}