/* ============================================================
   EasyGPAConverter.online — Main Stylesheet
   Clean, educational, professional design
   ============================================================ */

/* ---------- CSS Custom Properties ---------- */
:root {
  --clr-bg:        #f8f9fb;
  --clr-surface:   #ffffff;
  --clr-surface2:  #f1f3f7;
  --clr-border:    #e2e6ed;
  --clr-text:      #1a202c;
  --clr-text-mute: #5a6474;
  --clr-primary:   #2563eb;
  --clr-primary-h: #1d4ed8;
  --clr-primary-lt:#eff6ff;
  --clr-accent:    #0ea5e9;
  --clr-success:   #16a34a;
  --clr-warning:   #d97706;
  --clr-danger:    #dc2626;
  --clr-shadow:    rgba(37,99,235,0.10);

  --radius-sm:  6px;
  --radius-md:  12px;
  --radius-lg:  18px;
  --radius-xl:  24px;

  --shadow-sm: 0 1px 3px rgba(0,0,0,0.07), 0 1px 2px rgba(0,0,0,0.05);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.08), 0 2px 4px rgba(0,0,0,0.04);
  --shadow-lg: 0 10px 30px rgba(0,0,0,0.10), 0 4px 8px rgba(0,0,0,0.04);

  --font-sans: 'Plus Jakarta Sans', 'Segoe UI', system-ui, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  --max-width: 1140px;
  --transition: 0.22s ease;
}

/* Dark Mode */
[data-theme="dark"] {
  --clr-bg:        #0f1117;
  --clr-surface:   #1a1d27;
  --clr-surface2:  #252836;
  --clr-border:    #2e3244;
  --clr-text:      #e8eaf0;
  --clr-text-mute: #8b95a8;
  --clr-primary:   #3b82f6;
  --clr-primary-h: #60a5fa;
  --clr-primary-lt:#1e3a5f;
  --clr-shadow:    rgba(59,130,246,0.12);
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.3);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.35);
  --shadow-lg: 0 10px 30px rgba(0,0,0,0.40);
}

/* ---------- Reset & Base ---------- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  scroll-behavior: smooth;
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  background-color: var(--clr-bg);
  color: var(--clr-text);
  line-height: 1.7;
  transition: background-color 0.3s, color 0.3s;
  min-height: 100vh;
}

img { max-width: 100%; height: auto; display: block; }
a { color: var(--clr-primary); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--clr-primary-h); }

/* ---------- Typography ---------- */
h1, h2, h3, h4, h5, h6 {
  line-height: 1.25;
  font-weight: 700;
  color: var(--clr-text);
  letter-spacing: -0.02em;
}
h1 { font-size: clamp(1.8rem, 4vw, 2.8rem); }
h2 { font-size: clamp(1.4rem, 3vw, 2rem); }
h3 { font-size: clamp(1.1rem, 2vw, 1.4rem); }
h4 { font-size: 1.1rem; }
p  { max-width: 70ch; color: var(--clr-text-mute); }
p.wide { max-width: 100%; }

strong { color: var(--clr-text); font-weight: 600; }
code {
  font-family: var(--font-mono);
  background: var(--clr-surface2);
  padding: 2px 7px;
  border-radius: 4px;
  font-size: 0.88em;
  color: var(--clr-primary);
}

/* ---------- Layout Utilities ---------- */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 20px;
}

.section { padding: 56px 0; }
.section-sm { padding: 32px 0; }
.section-lg { padding: 80px 0; }

.grid-2 { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 24px; }
.grid-3 { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 20px; }
.grid-4 { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 16px; }

.flex    { display: flex; }
.flex-col { flex-direction: column; }
.items-center { align-items: center; }
.justify-between { justify-content: space-between; }
.gap-1 { gap: 8px; }
.gap-2 { gap: 16px; }
.gap-3 { gap: 24px; }

.text-center { text-align: center; }
.text-mute   { color: var(--clr-text-mute); }
.mt-1 { margin-top: 8px; }
.mt-2 { margin-top: 16px; }
.mt-3 { margin-top: 24px; }
.mt-4 { margin-top: 40px; }
.mb-1 { margin-bottom: 8px; }
.mb-2 { margin-bottom: 16px; }
.mb-3 { margin-bottom: 24px; }

/* ---------- Cards ---------- */
.card {
  background: var(--clr-surface);
  border: 1px solid var(--clr-border);
  border-radius: var(--radius-lg);
  padding: 28px;
  box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition), transform var(--transition);
}
.card:hover { box-shadow: var(--shadow-md); }
.card-sm { padding: 18px 20px; border-radius: var(--radius-md); }

.tool-card {
  background: var(--clr-surface);
  border: 1px solid var(--clr-border);
  border-radius: var(--radius-lg);
  padding: 24px;
  transition: box-shadow var(--transition), transform var(--transition), border-color var(--transition);
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.tool-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-3px);
  border-color: var(--clr-primary);
}
.tool-card .icon {
  width: 44px; height: 44px;
  background: var(--clr-primary-lt);
  border-radius: var(--radius-md);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.3rem;
  flex-shrink: 0;
}
.tool-card h3 { font-size: 1rem; margin-top: 4px; }
.tool-card p  { font-size: 0.88rem; margin: 0; }
.tool-card .card-link {
  margin-top: auto;
  padding-top: 12px;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--clr-primary);
  display: flex;
  align-items: center;
  gap: 4px;
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 22px;
  font-size: 0.9rem;
  font-weight: 600;
  border-radius: var(--radius-md);
  border: none;
  cursor: pointer;
  transition: background-color var(--transition), transform var(--transition), box-shadow var(--transition);
  font-family: var(--font-sans);
  text-decoration: none;
}
.btn:active { transform: scale(0.97); }

.btn-primary {
  background: var(--clr-primary);
  color: #fff;
}
.btn-primary:hover {
  background: var(--clr-primary-h);
  box-shadow: 0 4px 14px var(--clr-shadow);
  color: #fff;
}

.btn-outline {
  background: transparent;
  color: var(--clr-primary);
  border: 1.5px solid var(--clr-primary);
}
.btn-outline:hover {
  background: var(--clr-primary-lt);
}

.btn-ghost {
  background: transparent;
  color: var(--clr-text-mute);
  border: 1.5px solid var(--clr-border);
}
.btn-ghost:hover {
  background: var(--clr-surface2);
  color: var(--clr-text);
  border-color: var(--clr-text-mute);
}

.btn-sm { padding: 7px 15px; font-size: 0.82rem; }
.btn-lg { padding: 13px 30px; font-size: 1rem; }
.btn-full { width: 100%; }

.btn-danger {
  background: #fef2f2;
  color: var(--clr-danger);
  border: 1.5px solid #fecaca;
}
.btn-danger:hover { background: #fee2e2; }

/* ---------- Form Elements ---------- */
.form-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-bottom: 16px;
}
label {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--clr-text);
}
input[type="text"],
input[type="number"],
input[type="email"],
input[type="tel"],
textarea,
select {
  width: 100%;
  padding: 10px 14px;
  border: 1.5px solid var(--clr-border);
  border-radius: var(--radius-sm);
  background: var(--clr-surface);
  color: var(--clr-text);
  font-size: 0.92rem;
  font-family: var(--font-sans);
  transition: border-color var(--transition), box-shadow var(--transition);
  outline: none;
}
input:focus, textarea:focus, select:focus {
  border-color: var(--clr-primary);
  box-shadow: 0 0 0 3px rgba(37,99,235,0.12);
}
input::placeholder, textarea::placeholder { color: var(--clr-text-mute); }
select { appearance: none; background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%235a6474' stroke-width='2'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E"); background-repeat: no-repeat; background-position: right 12px center; padding-right: 36px; }
textarea { resize: vertical; min-height: 100px; }

.input-error { border-color: var(--clr-danger) !important; }
.error-msg { font-size: 0.8rem; color: var(--clr-danger); margin-top: 3px; }
.helper-text { font-size: 0.8rem; color: var(--clr-text-mute); }

/* ---------- Result Box ---------- */
.result-box {
  background: var(--clr-primary-lt);
  border: 1.5px solid var(--clr-primary);
  border-radius: var(--radius-md);
  padding: 20px 24px;
  margin-top: 20px;
  display: none;
}
.result-box.show { display: block; }
.result-box .result-label {
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--clr-primary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 4px;
}
.result-box .result-value {
  font-size: 2rem;
  font-weight: 800;
  color: var(--clr-primary);
  letter-spacing: -0.03em;
}
.result-box .result-sub {
  font-size: 0.85rem;
  color: var(--clr-text-mute);
  margin-top: 4px;
}

/* ---------- Formula Box ---------- */
.formula-box {
  background: var(--clr-surface2);
  border-left: 3px solid var(--clr-primary);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  padding: 14px 18px;
  margin: 16px 0;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  color: var(--clr-text);
  overflow-x: auto;
}

/* ---------- Alert / Info Box ---------- */
.alert {
  padding: 14px 18px;
  border-radius: var(--radius-md);
  font-size: 0.88rem;
  display: flex;
  gap: 10px;
  align-items: flex-start;
}
.alert-info  { background: #eff6ff; border: 1px solid #bfdbfe; color: #1d4ed8; }
.alert-warn  { background: #fffbeb; border: 1px solid #fde68a; color: #92400e; }
.alert-success { background: #f0fdf4; border: 1px solid #bbf7d0; color: #15803d; }

[data-theme="dark"] .alert-info    { background: #1e3a5f; border-color: #3b5f9e; color: #93c5fd; }
[data-theme="dark"] .alert-warn    { background: #2d2210; border-color: #7c5a1a; color: #fcd34d; }
[data-theme="dark"] .alert-success { background: #0d2818; border-color: #166534; color: #86efac; }

/* ---------- Navbar ---------- */
.navbar {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: var(--clr-surface);
  border-bottom: 1px solid var(--clr-border);
  box-shadow: var(--shadow-sm);
  transition: background-color 0.3s, border-color 0.3s;
}
.navbar-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
  gap: 16px;
}
.navbar-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  flex-shrink: 0;
}
.logo-badge {
  width: 34px; height: 34px;
  background: var(--clr-primary);
  color: #fff;
  border-radius: 8px;
  display: flex; align-items: center; justify-content: center;
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.03em;
}
.logo-text {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--clr-text);
  line-height: 1.2;
}
.logo-text span { color: var(--clr-primary); }

.navbar-nav {
  display: flex;
  align-items: center;
  gap: 2px;
  list-style: none;
}
.navbar-nav a {
  padding: 6px 12px;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--clr-text-mute);
  border-radius: var(--radius-sm);
  transition: color var(--transition), background var(--transition);
  white-space: nowrap;
}
.navbar-nav a:hover,
.navbar-nav a.active {
  color: var(--clr-primary);
  background: var(--clr-primary-lt);
}

/* Dropdown */
.nav-dropdown { position: relative; }
.nav-dropdown > a::after { content: ' ▾'; font-size: 0.7em; }
.dropdown-menu {
  position: absolute;
  top: calc(100% + 6px);
  left: 0;
  min-width: 200px;
  background: var(--clr-surface);
  border: 1px solid var(--clr-border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  padding: 6px;
  display: none;
  z-index: 100;
}
.nav-dropdown:hover .dropdown-menu { display: block; }
.dropdown-menu a {
  display: block;
  padding: 8px 12px;
  font-size: 0.85rem;
  color: var(--clr-text-mute);
  border-radius: var(--radius-sm);
}
.dropdown-menu a:hover { background: var(--clr-primary-lt); color: var(--clr-primary); }

.navbar-actions { display: flex; align-items: center; gap: 8px; }

/* Dark mode toggle */
.dark-toggle {
  width: 36px; height: 36px;
  border: 1.5px solid var(--clr-border);
  border-radius: var(--radius-sm);
  background: var(--clr-surface);
  cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  font-size: 1rem;
  color: var(--clr-text-mute);
  transition: all var(--transition);
}
.dark-toggle:hover { background: var(--clr-surface2); color: var(--clr-text); }

/* Mobile menu toggle */
.hamburger {
  display: none;
  width: 36px; height: 36px;
  border: 1.5px solid var(--clr-border);
  border-radius: var(--radius-sm);
  background: var(--clr-surface);
  cursor: pointer;
  align-items: center; justify-content: center;
  flex-direction: column;
  gap: 5px;
  padding: 8px;
}
.hamburger span {
  display: block;
  width: 100%; height: 2px;
  background: var(--clr-text);
  border-radius: 2px;
  transition: all var(--transition);
}

/* Mobile nav */
.mobile-nav {
  display: none;
  flex-direction: column;
  background: var(--clr-surface);
  border-bottom: 1px solid var(--clr-border);
  padding: 12px 20px;
  gap: 2px;
}
.mobile-nav.open { display: flex; }
.mobile-nav a {
  padding: 10px 12px;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--clr-text-mute);
  border-radius: var(--radius-sm);
  transition: all var(--transition);
}
.mobile-nav a:hover { color: var(--clr-primary); background: var(--clr-primary-lt); }
.mobile-nav-group-label {
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--clr-text-mute);
  padding: 10px 12px 2px;
}

/* ---------- Hero Section ---------- */
.hero {
  padding: 60px 0 48px;
  background: var(--clr-surface);
  border-bottom: 1px solid var(--clr-border);
}
.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--clr-primary-lt);
  color: var(--clr-primary);
  border: 1px solid #bfdbfe;
  border-radius: 100px;
  padding: 4px 12px;
  font-size: 0.78rem;
  font-weight: 600;
  margin-bottom: 16px;
}
.hero h1 { margin-bottom: 12px; }
.hero p.lead {
  font-size: 1.05rem;
  max-width: 60ch;
  margin-bottom: 28px;
  color: var(--clr-text-mute);
}
.hero-tools-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 24px;
}
.hero-tool-chip {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 5px 12px;
  background: var(--clr-surface2);
  border: 1px solid var(--clr-border);
  border-radius: 100px;
  font-size: 0.8rem;
  color: var(--clr-text-mute);
  text-decoration: none;
  transition: all var(--transition);
}
.hero-tool-chip:hover {
  background: var(--clr-primary-lt);
  border-color: var(--clr-primary);
  color: var(--clr-primary);
}

/* ---------- Section Headers ---------- */
.section-header { margin-bottom: 32px; }
.section-header h2 { margin-bottom: 8px; }
.section-header p { font-size: 1rem; }
.section-eyebrow {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--clr-primary);
  margin-bottom: 6px;
  display: block;
}

/* ---------- GPA Calculator (Main Tool) ---------- */
.calc-wrapper {
  background: var(--clr-surface);
  border: 1px solid var(--clr-border);
  border-radius: var(--radius-xl);
  padding: 32px;
  box-shadow: var(--shadow-md);
}
.calc-title {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 20px;
  display: flex;
  align-items: center;
  gap: 8px;
}
.calc-title .icon { font-size: 1.2rem; }

/* Subject rows table */
.subjects-table {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
  margin-bottom: 16px;
}
.subjects-table th {
  font-size: 0.78rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--clr-text-mute);
  padding: 0 8px 10px;
  text-align: left;
}
.subjects-table td {
  padding: 5px 8px;
  vertical-align: middle;
}
.subjects-table td input,
.subjects-table td select {
  margin-bottom: 0;
  padding: 8px 10px;
  font-size: 0.88rem;
}
.subjects-table td:last-child { width: 44px; }
.remove-row-btn {
  width: 30px; height: 30px;
  background: none;
  border: 1.5px solid var(--clr-border);
  border-radius: 6px;
  cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  color: var(--clr-text-mute);
  font-size: 1rem;
  transition: all var(--transition);
}
.remove-row-btn:hover {
  background: #fef2f2;
  border-color: #fecaca;
  color: var(--clr-danger);
}
.calc-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 16px;
}

/* ---------- FAQ Accordion ---------- */
.faq-list { list-style: none; display: flex; flex-direction: column; gap: 8px; }
.faq-item {
  border: 1px solid var(--clr-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: border-color var(--transition);
}
.faq-item.open { border-color: var(--clr-primary); }
.faq-question {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 16px 20px;
  cursor: pointer;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--clr-text);
  background: var(--clr-surface);
  gap: 12px;
  transition: background var(--transition);
  user-select: none;
  list-style: none;
}
.faq-question:hover { background: var(--clr-surface2); }
.faq-chevron {
  width: 20px; height: 20px;
  flex-shrink: 0;
  transition: transform var(--transition);
  color: var(--clr-text-mute);
}
.faq-item.open .faq-chevron { transform: rotate(180deg); }
.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s ease, padding 0.35s ease;
  background: var(--clr-surface);
}
.faq-answer-inner {
  padding: 0 20px 18px;
  font-size: 0.9rem;
  color: var(--clr-text-mute);
  line-height: 1.75;
}
.faq-item.open .faq-answer { max-height: 600px; }

/* ---------- Breadcrumb ---------- */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.82rem;
  color: var(--clr-text-mute);
  padding: 14px 0;
  flex-wrap: wrap;
}
.breadcrumb a { color: var(--clr-text-mute); }
.breadcrumb a:hover { color: var(--clr-primary); }
.breadcrumb-sep { color: var(--clr-border); }
.breadcrumb .current { color: var(--clr-text); font-weight: 500; }

/* ---------- Related Tools ---------- */
.related-tools {
  background: var(--clr-surface2);
  border-radius: var(--radius-lg);
  padding: 28px;
  margin-top: 40px;
}
.related-tools h3 { margin-bottom: 16px; }
.related-tools-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 12px;
}
.related-tool-link {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 12px 14px;
  background: var(--clr-surface);
  border: 1px solid var(--clr-border);
  border-radius: var(--radius-md);
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--clr-text);
  text-decoration: none;
  transition: all var(--transition);
}
.related-tool-link:hover {
  border-color: var(--clr-primary);
  color: var(--clr-primary);
  background: var(--clr-primary-lt);
}
.related-tool-link .icon { font-size: 1.1rem; }

/* ---------- Steps / How-To ---------- */
.steps-list { list-style: none; display: flex; flex-direction: column; gap: 16px; counter-reset: step-counter; }
.step-item {
  display: flex;
  gap: 14px;
  align-items: flex-start;
}
.step-number {
  width: 32px; height: 32px;
  background: var(--clr-primary);
  color: #fff;
  border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-size: 0.82rem;
  font-weight: 700;
  flex-shrink: 0;
  margin-top: 2px;
}
.step-content h4 { font-size: 0.95rem; margin-bottom: 2px; }
.step-content p { font-size: 0.88rem; margin: 0; }

/* ---------- Grade Table ---------- */
.grade-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
  margin: 12px 0;
}
.grade-table th {
  background: var(--clr-surface2);
  padding: 10px 14px;
  text-align: left;
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--clr-text-mute);
}
.grade-table td {
  padding: 10px 14px;
  border-bottom: 1px solid var(--clr-border);
  color: var(--clr-text);
}
.grade-table tr:last-child td { border-bottom: none; }
.grade-table tr:hover td { background: var(--clr-surface2); }
.grade-badge {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 100px;
  font-size: 0.78rem;
  font-weight: 700;
}
.grade-a { background: #dcfce7; color: #166534; }
.grade-b { background: #dbeafe; color: #1e40af; }
.grade-c { background: #fef9c3; color: #854d0e; }
.grade-d { background: #ffedd5; color: #9a3412; }
.grade-f { background: #fee2e2; color: #991b1b; }

[data-theme="dark"] .grade-a { background: #14532d; color: #86efac; }
[data-theme="dark"] .grade-b { background: #1e3a5f; color: #93c5fd; }
[data-theme="dark"] .grade-c { background: #42350a; color: #fde68a; }
[data-theme="dark"] .grade-d { background: #431407; color: #fdba74; }
[data-theme="dark"] .grade-f { background: #450a0a; color: #fca5a5; }

/* ---------- Copy Button ---------- */
.copy-btn {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 5px 12px;
  font-size: 0.8rem;
  font-weight: 500;
  background: var(--clr-surface2);
  border: 1px solid var(--clr-border);
  border-radius: 6px;
  cursor: pointer;
  color: var(--clr-text-mute);
  transition: all var(--transition);
  font-family: var(--font-sans);
}
.copy-btn:hover { background: var(--clr-surface); color: var(--clr-primary); border-color: var(--clr-primary); }
.copy-btn.copied { background: #dcfce7; color: #166534; border-color: #86efac; }

/* ---------- Footer ---------- */
.footer {
  background: var(--clr-surface);
  border-top: 1px solid var(--clr-border);
  padding: 48px 0 24px;
  margin-top: 60px;
}
.footer-grid {
  display: grid;
  grid-template-columns: 1.5fr repeat(3, 1fr);
  gap: 40px;
  margin-bottom: 40px;
}
.footer-brand p {
  font-size: 0.88rem;
  margin-top: 10px;
  max-width: 28ch;
}
.footer-col h4 {
  font-size: 0.82rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--clr-text-mute);
  margin-bottom: 12px;
}
.footer-col ul { list-style: none; display: flex; flex-direction: column; gap: 7px; }
.footer-col ul li a {
  font-size: 0.875rem;
  color: var(--clr-text-mute);
  transition: color var(--transition);
}
.footer-col ul li a:hover { color: var(--clr-primary); }
.footer-bottom {
  border-top: 1px solid var(--clr-border);
  padding-top: 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 10px;
}
.footer-bottom p { font-size: 0.82rem; max-width: 100%; }
.footer-legal-links { display: flex; gap: 16px; flex-wrap: wrap; }
.footer-legal-links a { font-size: 0.82rem; color: var(--clr-text-mute); }
.footer-legal-links a:hover { color: var(--clr-primary); }

/* ---------- Back to Top ---------- */
.back-to-top {
  position: fixed;
  bottom: 24px;
  right: 24px;
  width: 40px; height: 40px;
  background: var(--clr-primary);
  color: #fff;
  border-radius: var(--radius-md);
  display: flex; align-items: center; justify-content: center;
  cursor: pointer;
  opacity: 0;
  transform: translateY(12px);
  transition: opacity var(--transition), transform var(--transition), box-shadow var(--transition);
  pointer-events: none;
  box-shadow: var(--shadow-md);
  font-size: 1.1rem;
  border: none;
  z-index: 999;
}
.back-to-top.visible { opacity: 1; transform: translateY(0); pointer-events: all; }
.back-to-top:hover { background: var(--clr-primary-h); box-shadow: var(--shadow-lg); }

/* ---------- Scroll Reveal ---------- */
.reveal {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}
.reveal.visible { opacity: 1; transform: translateY(0); }

/* ---------- Responsive ---------- */
@media (max-width: 900px) {
  .navbar-nav  { display: none; }
  .hamburger   { display: flex; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 640px) {
  .hero { padding: 40px 0 32px; }
  .calc-wrapper { padding: 20px; }
  .footer-grid { grid-template-columns: 1fr; gap: 24px; }
  .footer-bottom { flex-direction: column; text-align: center; }
  .subjects-table thead { display: none; }
  .subjects-table, .subjects-table tbody,
  .subjects-table tr, .subjects-table td { display: block; }
  .subjects-table tr {
    background: var(--clr-surface2);
    border-radius: var(--radius-md);
    padding: 10px;
    margin-bottom: 10px;
    border: 1px solid var(--clr-border);
  }
  .subjects-table td { padding: 4px 0; }
  .subjects-table td::before {
    content: attr(data-label);
    display: block;
    font-size: 0.72rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--clr-text-mute);
    margin-bottom: 2px;
  }
}

/* ---------- Ad Slots ---------- */
.ad-slot {
  min-height: 90px;
  background: var(--clr-surface2);
  border: 1px dashed var(--clr-border);
  border-radius: var(--radius-md);
  display: flex; align-items: center; justify-content: center;
  font-size: 0.75rem;
  color: var(--clr-text-mute);
  margin: 24px 0;
}

/* ---------- Page Hero (inner pages) ---------- */
.page-hero {
  padding: 40px 0 32px;
  background: var(--clr-surface);
  border-bottom: 1px solid var(--clr-border);
}
.page-hero h1 { margin-bottom: 8px; font-size: clamp(1.5rem, 3vw, 2.2rem); }
.page-hero p.lead { font-size: 1rem; margin-bottom: 0; }

/* ---------- Stat Strip ---------- */
.stat-strip {
  display: flex;
  flex-wrap: wrap;
  gap: 24px;
  padding: 24px 0;
}
.stat-item { display: flex; flex-direction: column; }
.stat-value { font-size: 1.6rem; font-weight: 800; color: var(--clr-primary); letter-spacing: -0.03em; }
.stat-label { font-size: 0.78rem; color: var(--clr-text-mute); font-weight: 500; }

/* ---------- Prose Content ---------- */
.prose h2 { margin: 36px 0 12px; font-size: 1.4rem; }
.prose h3 { margin: 28px 0 10px; font-size: 1.15rem; }
.prose p  { margin-bottom: 14px; }
.prose ul, .prose ol {
  padding-left: 22px;
  margin-bottom: 14px;
  display: flex;
  flex-direction: column;
  gap: 5px;
}
.prose ul li, .prose ol li {
  font-size: 0.93rem;
  color: var(--clr-text-mute);
  line-height: 1.7;
}
.prose table {
  width: 100%;
  border-collapse: collapse;
  margin: 16px 0;
  font-size: 0.9rem;
  overflow-x: auto;
  display: block;
}
.prose table th, .prose table td {
  padding: 10px 14px;
  border: 1px solid var(--clr-border);
  text-align: left;
}
.prose table th {
  background: var(--clr-surface2);
  font-weight: 600;
  font-size: 0.82rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

/* ---------- Two-col layout for tool + content ---------- */
.tool-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
  align-items: start;
}
@media (max-width: 860px) {
  .tool-layout { grid-template-columns: 1fr; }
}

/* ---------- Contact Form ---------- */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1.5fr;
  gap: 40px;
  align-items: start;
}
@media (max-width: 740px) { .contact-grid { grid-template-columns: 1fr; } }

.contact-info-item {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  margin-bottom: 20px;
}
.contact-info-item .icon {
  width: 38px; height: 38px;
  background: var(--clr-primary-lt);
  border-radius: var(--radius-sm);
  display: flex; align-items: center; justify-content: center;
  font-size: 1rem;
  flex-shrink: 0;
}
.contact-info-item h4 { font-size: 0.88rem; margin-bottom: 2px; }
.contact-info-item p  { font-size: 0.85rem; margin: 0; }