/* ==========================================================
   HUZIHUB DESIGN SYSTEM & GLOBAL VARIABLES
   ========================================================== */
:root {
  --ink: #15132b;
  --ink-soft: #4d4a6b;
  --ink-faint: #8985a8;

  --bg: #fcfbff;
  --bg-soft: #f4f2ff;

  --line: #e7e4f6;
  --line-soft: #f0eefb;

  --primary: #4f46e5;
  --primary-dark: #3b33c4;
  --primary-light: #eeebff;

  --accent: #7c3aed;
  --white: #ffffff;

  --font-heading: "Lexend", sans-serif;
  --font-body: "Inter", sans-serif;

  --shadow-sm: 0 4px 12px rgba(21, 19, 43, 0.04);
  --shadow-md: 0 10px 30px rgba(79, 70, 229, 0.08);
  --shadow-lg: 0 20px 50px rgba(21, 19, 43, 0.1);

  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 24px;
  --radius-full: 9999px;

  --transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html,
body {
  width: 100%;
  margin: 0;
  padding: 0;
  min-width: 0;
  background-color: var(--bg);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

h1,
h2,
h3,
h4,
h5,
h6 {
  font-family: var(--font-heading);
  color: var(--ink);
  margin: 0;
  font-weight: 600;
}

a {
  color: inherit;
  text-decoration: none;
}

ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

.container {
  width: min(calc(100% - 32px), 1200px);
  margin-inline: auto;
}

/* Skip Navigation Link */
.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--primary);
  color: var(--white);
  padding: 8px 16px;
  z-index: 1000;
  transition: top 0.3s;
}
.skip-link:focus {
  top: 0;
}

/* ==========================================================
   GLOBAL NAVBAR
   ========================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 900;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--line);
  height: 72px;
  display: flex;
  align-items: center;
}

.navbar-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
}

.logo-link {
  display: flex;
  align-items: center;
  gap: 10px;
}

.logo-img {
  object-fit: contain;
}

.logo-text {
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--ink);
}
.logo-text.white {
  color: var(--white);
}

.desktop-nav {
  display: none;
}

@media (min-width: 1200px) {
  .desktop-nav {
    display: block;
  }
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 8px;
}

.nav-item {
  position: relative;
}

.nav-link,
.dropdown-toggle {
  font-size: 0.925rem;
  font-weight: 500;
  color: var(--ink-soft);
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  transition: var(--transition);
  display: flex;
  align-items: center;
  gap: 4px;
}

.nav-link:hover,
.dropdown-toggle:hover,
.dropdown-toggle[aria-expanded="true"] {
  color: var(--primary);
  background: var(--bg-soft);
}

.dropdown-toggle .arrow {
  font-size: 0.65rem;
  transition: transform 0.3s;
}

.dropdown-toggle[aria-expanded="true"] .arrow {
  transform: rotate(180deg);
}

/* Dropdown Menus */
.dropdown-menu {
  position: absolute;
  top: calc(100% + 12px);
  left: 0;
  width: 220px;
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  padding: 8px;
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: var(--transition);
  z-index: 950;
}

.dropdown.active .dropdown-menu,
.dropdown:hover .dropdown-menu {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.dropdown-menu a {
  display: block;
  padding: 8px 12px;
  font-size: 0.875rem;
  color: var(--ink-soft);
  border-radius: 6px;
  transition: var(--transition);
}

.dropdown-menu a:hover,
.dropdown-menu a.active {
  color: var(--primary);
  background: var(--primary-light);
  font-weight: 500;
}

/* Navbar Actions */
.navbar-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

.search-trigger-btn {
  display: flex;
  align-items: center;
  gap: 8px;
  background: var(--bg-soft);
  border: 1px solid var(--line);
  padding: 8px 14px;
  border-radius: var(--radius-full);
  color: var(--ink-faint);
  font-size: 0.85rem;
  transition: var(--transition);
}

.search-trigger-btn:hover {
  border-color: var(--primary);
  color: var(--primary);
}

.search-shortcut {
  background: var(--white);
  border: 1px solid var(--line);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 0.7rem;
  color: var(--ink-faint);
}

.hamburger-btn {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  width: 28px;
  height: 20px;
  padding: 0;
  cursor: pointer;
}

@media (min-width: 1200px) {
  .hamburger-btn {
    display: none;
  }
}

.hamburger-btn .bar {
  width: 100%;
  height: 2px;
  background: var(--ink);
  border-radius: 2px;
  transition: var(--transition);
}

/* ==========================================================
   MOBILE DRAWER & SEARCH MODAL
   ========================================================== */
.mobile-drawer {
  position: fixed;
  top: 0;
  right: -100%;
  width: 100%;
  max-width: 380px;
  height: 100vh;
  background: var(--white);
  box-shadow: -10px 0 30px rgba(0, 0, 0, 0.1);
  z-index: 1100;
  transition: right 0.4s cubic-bezier(0.16, 1, 0.3, 1);
  display: flex;
  flex-direction: column;
}

.mobile-drawer.open {
  right: 0;
}

.mobile-drawer-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px;
  border-bottom: 1px solid var(--line);
}

.close-drawer-btn {
  font-size: 1.75rem;
  color: var(--ink-soft);
  cursor: pointer;
}

.mobile-drawer-content {
  flex: 1;
  overflow-y: auto;
  padding: 20px;
}

.mobile-accordion-item {
  border-bottom: 1px solid var(--line-soft);
  margin-bottom: 8px;
}

.mobile-accordion-toggle {
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 12px 0;
  font-family: var(--font-heading);
  font-weight: 600;
  color: var(--ink);
  font-size: 1rem;
}

.mobile-accordion-panel {
  display: none;
  padding-bottom: 12px;
  padding-left: 12px;
}

.mobile-accordion-panel a {
  display: block;
  padding: 8px 0;
  font-size: 0.925rem;
  color: var(--ink-soft);
}

.mobile-accordion-panel a:hover {
  color: var(--primary);
}

.mobile-direct-links {
  margin-top: 20px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.mobile-direct-links a {
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 1.1rem;
  color: var(--ink);
}

.drawer-backdrop {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: rgba(21, 19, 43, 0.5);
  backdrop-filter: blur(4px);
  z-index: 1050;
  opacity: 0;
  visibility: hidden;
  transition: var(--transition);
}

.drawer-backdrop.active {
  opacity: 1;
  visibility: visible;
}

/* Search Modal */
.search-modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: rgba(21, 19, 43, 0.6);
  backdrop-filter: blur(6px);
  z-index: 1200;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding-top: 10vh;
  opacity: 0;
  visibility: hidden;
  transition: var(--transition);
}

.search-modal-overlay.active {
  opacity: 1;
  visibility: visible;
}

.search-modal-container {
  width: min(calc(100% - 32px), 640px);
  background: var(--white);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
  transform: translateY(-20px);
  transition: transform 0.3s;
}

.search-modal-overlay.active .search-modal-container {
  transform: translateY(0);
}

.search-input-wrapper {
  display: flex;
  align-items: center;
  padding: 16px 20px;
  border-bottom: 1px solid var(--line);
  gap: 12px;
  color: var(--ink-faint);
}

.search-input-wrapper input {
  flex: 1;
  border: none;
  outline: none;
  font-size: 1.1rem;
  color: var(--ink);
  background: transparent;
}

.search-close-btn {
  font-size: 1.5rem;
  color: var(--ink-soft);
  cursor: pointer;
}

.search-results-list {
  max-height: 360px;
  overflow-y: auto;
  padding: 12px;
}

.search-hint {
  padding: 16px;
  text-align: center;
  color: var(--ink-faint);
  font-size: 0.9rem;
}

.search-result-item {
  display: block;
  padding: 12px 16px;
  border-radius: var(--radius-sm);
  color: var(--ink);
  font-weight: 500;
  transition: var(--transition);
}

.search-result-item:hover {
  background: var(--bg-soft);
  color: var(--primary);
}

/* ==========================================================
   BREADCRUMBS
   ========================================================== */
.breadcrumb-nav {
  padding: 24px 0 0;
}

.breadcrumb-list {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.85rem;
  color: var(--ink-faint);
}

.breadcrumb-list a {
  color: var(--ink-soft);
  transition: var(--transition);
}

.breadcrumb-list a:hover {
  color: var(--primary);
}

.breadcrumb-list .separator {
  color: var(--ink-faint);
}

.breadcrumb-list .current {
  color: var(--primary);
  font-weight: 500;
}

/* ==========================================================
   HERO SECTION
   ========================================================== */
.hero-section {
  padding: 40px 0 60px;
  position: relative;
  overflow: hidden;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 40px;
  align-items: center;
}

@media (min-width: 992px) {
  .hero-grid {
    grid-template-columns: 1.1fr 0.9fr;
  }
}

.eyebrow-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--primary-light);
  color: var(--primary);
  padding: 6px 14px;
  border-radius: var(--radius-full);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.5px;
  margin-bottom: 20px;
}

.pulse-dot {
  width: 8px;
  height: 8px;
  background: var(--primary);
  border-radius: 50%;
  box-shadow: 0 0 0 0 rgba(79, 70, 229, 0.4);
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0% {
    transform: scale(0.95);
    box-shadow: 0 0 0 0 rgba(79, 70, 229, 0.4);
  }
  70% {
    transform: scale(1);
    box-shadow: 0 0 0 8px rgba(79, 70, 229, 0);
  }
  100% {
    transform: scale(0.95);
    box-shadow: 0 0 0 0 rgba(79, 70, 229, 0);
  }
}

.hero-content h1 {
  font-size: clamp(2.4rem, 5vw, 4rem);
  line-height: 1.15;
  margin-bottom: 20px;
  letter-spacing: -0.02em;
}

.hero-desc {
  font-size: 1.125rem;
  color: var(--ink-soft);
  margin-bottom: 32px;
  max-width: 560px;
}

.hero-cta-group {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 28px;
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: 0.95rem;
  transition: var(--transition);
  cursor: pointer;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
  color: var(--white);
  box-shadow: 0 8px 20px rgba(79, 70, 229, 0.25);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 28px rgba(79, 70, 229, 0.35);
}

.btn-secondary {
  background: var(--bg-soft);
  color: var(--primary);
  border: 1px solid var(--line);
}

.btn-secondary:hover {
  background: var(--primary-light);
  border-color: var(--primary);
}

.btn-outline {
  background: var(--white);
  color: var(--ink-soft);
  border: 1px solid var(--line);
}

.btn-outline:hover {
  background: var(--bg-soft);
  color: var(--ink);
}

/* Hero 3D Visual */
.hero-visual-wrapper {
  perspective: 1200px;
  display: flex;
  justify-content: center;
}

.hero-3d-card {
  width: 100%;
  max-width: 440px;
  background: linear-gradient(
    145deg,
    rgba(255, 255, 255, 0.9) 0%,
    rgba(244, 242, 255, 0.8) 100%
  );
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 28px;
  box-shadow: var(--shadow-lg);
  position: relative;
  transform-style: preserve-3d;
  transition: transform 0.1s ease-out;
}

.card-glass-content {
  position: relative;
  z-index: 2;
}

.visual-header {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 24px;
}

.visual-header .dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
}
.dot.red {
  background: #ff5f56;
}
.dot.yellow {
  background: #ffbd2e;
}
.dot.green {
  background: #27c93f;
}

.visual-title {
  margin-left: auto;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--ink-faint);
  text-transform: uppercase;
}

.visual-main-display {
  display: flex;
  align-items: center;
  gap: 24px;
  background: var(--white);
  padding: 20px;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--line-soft);
}

.circular-progress-preview {
  position: relative;
  width: 80px;
  height: 80px;
}

.circular-progress-preview svg {
  width: 100%;
  height: 100%;
  transform: rotate(-90deg);
}

.circular-progress-preview .track {
  fill: none;
  stroke: var(--line-soft);
  stroke-width: 8;
}

.circular-progress-preview .progress {
  fill: none;
  stroke: var(--primary);
  stroke-width: 8;
  stroke-linecap: round;
  transition: stroke-dashoffset 1s ease;
}

.preview-number {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--ink);
}

.preview-info {
  display: flex;
  flex-direction: column;
}

.preview-info .label {
  font-size: 0.8rem;
  color: var(--ink-faint);
}

.preview-info .value {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--primary);
}

.floating-badge {
  position: absolute;
  background: var(--white);
  padding: 8px 16px;
  border-radius: var(--radius-full);
  font-size: 0.8rem;
  font-weight: 700;
  box-shadow: var(--shadow-md);
  border: 1px solid var(--line);
  color: var(--ink);
}

.floating-badge.badge-1 {
  top: -16px;
  right: 20px;
  color: #10b981;
}

.floating-badge.badge-2 {
  bottom: -16px;
  left: 20px;
  color: #ef4444;
}

/* ==========================================================
   CALCULATOR SECTION
   ========================================================== */
.calculator-section {
  padding: 40px 0 80px;
}

.calculator-card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  padding: 32px 24px;
}

@media (min-width: 768px) {
  .calculator-card {
    padding: 48px;
  }
}

.calculator-header {
  text-align: center;
  max-width: 600px;
  margin: 0 auto 36px;
}

.sub-heading {
  display: block;
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--primary);
  letter-spacing: 1px;
  margin-bottom: 8px;
}

.calculator-header h2 {
  font-size: clamp(1.8rem, 3vw, 2.4rem);
  margin-bottom: 12px;
}

.calculator-header p {
  color: var(--ink-soft);
  font-size: 1rem;
}

/* Mode Tabs */
.calc-tabs-wrapper {
  display: flex;
  gap: 8px;
  overflow-x: auto;
  padding-bottom: 12px;
  margin-bottom: 36px;
  border-bottom: 1px solid var(--line);
  scrollbar-width: thin;
}

.calc-tab {
  padding: 10px 18px;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--ink-soft);
  background: var(--bg-soft);
  border-radius: var(--radius-sm);
  white-space: nowrap;
  transition: var(--transition);
}

.calc-tab:hover,
.calc-tab.active {
  color: var(--white);
  background: var(--primary);
}

/* Calculator Grid Layout */
.calculator-grid-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 40px;
}

@media (min-width: 992px) {
  .calculator-grid-layout {
    grid-template-columns: 1.2fr 0.8fr;
    align-items: start;
  }
}

.calc-inputs-panel {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.input-group {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.input-group label {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--ink);
}

.input-group label .req {
  color: #ef4444;
}

.input-with-icon {
  position: relative;
  display: flex;
  align-items: center;
}

.input-with-icon input,
.calc-select {
  width: 100%;
  height: 54px;
  padding: 0 16px;
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  font-family: var(--font-body);
  font-size: 1rem;
  color: var(--ink);
  outline: none;
  transition: var(--transition);
}

.input-with-icon input:focus,
.calc-select:focus {
  border-color: var(--primary);
  background: var(--white);
  box-shadow: 0 0 0 4px var(--primary-light);
}

.input-unit {
  position: absolute;
  right: 16px;
  font-weight: 600;
  color: var(--ink-faint);
  font-size: 0.9rem;
}

.error-msg {
  font-size: 0.8rem;
  color: #ef4444;
  min-height: 18px;
}

.calc-action-buttons {
  display: flex;
  gap: 12px;
  margin-top: 12px;
}

.btn-full {
  flex: 1;
}

/* Results Panel */
.calc-results-panel {
  background: var(--bg-soft);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 28px;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
}

.result-header-label {
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 1px;
  color: var(--primary);
  margin-bottom: 16px;
}

.result-display-box {
  margin-bottom: 24px;
}

.result-number-large {
  font-family: var(--font-heading);
  font-size: 3rem;
  font-weight: 700;
  color: var(--ink);
  line-height: 1;
  margin-bottom: 8px;
}

.result-explanation {
  font-size: 0.95rem;
  color: var(--ink-soft);
}

/* Result SVG Ring */
.result-ring-container {
  position: relative;
  width: 160px;
  height: 160px;
  margin-bottom: 24px;
}

.result-ring-container svg {
  width: 100%;
  height: 100%;
  transform: rotate(-90deg);
}

.ring-bg {
  fill: none;
  stroke: var(--line);
  stroke-width: 10;
}

.ring-fill {
  fill: none;
  stroke: var(--primary);
  stroke-width: 10;
  stroke-linecap: round;
  transition: stroke-dashoffset 0.8s cubic-bezier(0.16, 1, 0.3, 1);
}

.ring-inner-text {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--ink);
}

.result-actions {
  display: flex;
  gap: 10px;
  width: 100%;
}

.btn-action-sm {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  background: var(--white);
  border: 1px solid var(--line);
  padding: 10px;
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--ink-soft);
  transition: var(--transition);
}

.btn-action-sm:hover {
  background: var(--primary-light);
  color: var(--primary);
  border-color: var(--primary);
}

/* ==========================================================
   ADSENSE PLACEHOLDER
   ========================================================== */
.ad-container {
  padding: 20px 0 60px;
}

.ad-placeholder {
  width: 100%;
  min-height: 100px;
  background: var(--bg-soft);
  border: 2px dashed var(--line);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--ink-faint);
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 0.5px;
}

/* ==========================================================
   SECTIONS: FORMULAS, EXAMPLES, EDU, FAQ, RELATED
   ========================================================== */
.section-title-wrapper {
  text-align: center;
  max-width: 600px;
  margin: 0 auto 40px;
}

.section-title-wrapper h2 {
  font-size: clamp(1.8rem, 3vw, 2.2rem);
  margin-bottom: 12px;
}

.section-title-wrapper p {
  color: var(--ink-soft);
}

/* Formulas Grid */
.formulas-section {
  padding: 40px 0 80px;
}

.formulas-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}

.formula-card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  padding: 24px;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}

.formula-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: var(--primary);
}

.formula-card h3 {
  font-size: 1.1rem;
  margin-bottom: 12px;
}

.formula-box {
  background: var(--bg-soft);
  padding: 14px;
  border-radius: var(--radius-sm);
  text-align: center;
  font-family: var(--font-heading);
  font-weight: 600;
  color: var(--primary);
  margin-bottom: 12px;
  font-size: 1.1rem;
}

.formula-card p {
  font-size: 0.9rem;
  color: var(--ink-soft);
}

/* Examples Grid */
.examples-section {
  padding: 0 0 80px;
}

.examples-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 24px;
}

.example-card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  padding: 24px;
  box-shadow: var(--shadow-sm);
}

.example-card h4 {
  font-size: 1.1rem;
  margin-bottom: 8px;
  color: var(--primary);
}

.example-card p {
  font-size: 0.925rem;
  color: var(--ink-soft);
  margin-bottom: 16px;
}

.example-result {
  background: var(--primary-light);
  color: var(--primary);
  padding: 10px 14px;
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  font-weight: 600;
}

/* Educational Content */
.educational-section {
  padding: 0 0 80px;
}

.edu-content-box {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 40px;
  box-shadow: var(--shadow-sm);
}

.edu-content-box h2 {
  font-size: 2rem;
  margin-bottom: 24px;
}

.edu-content-box h3 {
  font-size: 1.3rem;
  margin-top: 28px;
  margin-bottom: 12px;
  color: var(--primary);
}

.edu-content-box p,
.edu-content-box li {
  color: var(--ink-soft);
  margin-bottom: 16px;
  font-size: 1rem;
}

.edu-content-box ul {
  list-style: disc;
  padding-left: 20px;
}

/* FAQ Accordion */
.faq-section {
  padding: 0 0 80px;
}

.faq-accordion-wrapper {
  max-width: 800px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.faq-item {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.faq-question {
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 1.05rem;
  color: var(--ink);
  text-align: left;
  cursor: pointer;
}

.faq-question .arrow {
  font-size: 0.75rem;
  transition: transform 0.3s;
}

.faq-item.active .faq-question .arrow {
  transform: rotate(180deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  padding: 0 20px;
  transition:
    max-height 0.3s ease,
    padding 0.3s ease;
}

.faq-item.active .faq-answer {
  max-height: 200px;
  padding: 0 20px 20px;
}

.faq-answer p {
  color: var(--ink-soft);
  font-size: 0.95rem;
}

/* Related Tools */
.related-tools-section {
  padding: 0 0 80px;
}

.related-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 20px;
}

.tool-card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  padding: 24px;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  display: block;
}

.tool-card:hover {
  transform: translateY(-4px);
  border-color: var(--primary);
  box-shadow: var(--shadow-md);
}

.tool-card h3 {
  font-size: 1.1rem;
  margin-bottom: 8px;
  color: var(--ink);
}

.tool-card:hover h3 {
  color: var(--primary);
}

.tool-card p {
  font-size: 0.875rem;
  color: var(--ink-faint);
}

/* ==========================================================
   FOOTER
   ========================================================== */
.site-footer {
  background: var(--ink);
  color: var(--white);
  padding: 60px 0 30px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 40px;
  margin-bottom: 40px;
}

@media (min-width: 768px) {
  .footer-grid {
    grid-template-columns: 2fr repeat(4, 1fr);
  }
}

.footer-col.brand-col {
  grid-column: span 1;
}

@media (min-width: 768px) {
  .footer-col.brand-col {
    grid-column: span 2;
  }
}

.footer-desc {
  color: var(--ink-faint);
  font-size: 0.925rem;
  margin-top: 16px;
  max-width: 360px;
}

.footer-col h4 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--white);
  margin-bottom: 16px;
}

.footer-col ul {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-col ul a {
  font-size: 0.875rem;
  color: var(--ink-faint);
  transition: var(--transition);
}

.footer-col ul a:hover {
  color: var(--white);
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding-top: 24px;
  text-align: center;
  color: var(--ink-faint);
  font-size: 0.85rem;
}

/* ==========================================================
   TOAST NOTIFICATION
   ========================================================== */
.toast-notification {
  position: fixed;
  bottom: 30px;
  right: 30px;
  background: var(--ink);
  color: var(--white);
  padding: 12px 24px;
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-lg);
  font-size: 0.9rem;
  font-weight: 500;
  z-index: 1300;
  opacity: 0;
  visibility: hidden;
  transform: translateY(20px);
  transition: var(--transition);
}

.toast-notification.show {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

/* ==========================================================
   RESPONSIVE OVERRIDES & REDUCED MOTION
   ========================================================== */
@media (max-width: 600px) {
  .calc-action-buttons {
    flex-direction: column;
  }
  .edu-content-box {
    padding: 20px;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  ::before,
  ::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}