/* ===== Design Tokens ===== */
:root {
  --color-primary: #005c55;
  --color-primary-container: #0f766e;
  --color-on-primary: #ffffff;
  --color-on-primary-container: #a3faef;
  --color-secondary: #006a61;
  --color-secondary-container: #86f2e4;
  --color-on-secondary-container: #006f66;
  --color-tertiary: #495167;
  --color-error: #ba1a1a;
  --color-error-container: #ffdad6;
  --color-background: #f7f9fb;
  --color-surface: #f7f9fb;
  --color-surface-bright: #f7f9fb;
  --color-surface-dim: #d8dadc;
  --color-surface-container-lowest: #ffffff;
  --color-surface-container-low: #f2f4f6;
  --color-surface-container: #eceef0;
  --color-surface-container-high: #e6e8ea;
  --color-surface-container-highest: #e0e3e5;
  --color-on-surface: #191c1e;
  --color-on-surface-variant: #3e4947;
  --color-outline: #6e7977;
  --color-outline-variant: #bdc9c6;
  --color-primary-fixed: #9cf2e8;

  --radius: 0.25rem;
  --radius-lg: 0.5rem;
  --radius-xl: 0.75rem;
  --radius-full: 9999px;

  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 16px;
  --space-lg: 24px;
  --space-xl: 32px;
  --space-2xl: 48px;
  --space-3xl: 64px;
  --space-4xl: 80px;
  --max-width: 1200px;

  --font-family: "Noto Sans Bengali", sans-serif;

  --fs-label-md: 14px;
  --fs-body-lg: 18px;
  --fs-display: 48px;
  --fs-headline-lg-mobile: 28px;
  --fs-body-md: 16px;
  --fs-label-sm: 12px;
  --fs-headline-lg: 32px;
  --fs-headline-md: 24px;
}

/* ===== Reset ===== */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--font-family);
  background-color: var(--color-background);
  color: var(--color-on-surface);
  -webkit-font-smoothing: antialiased;
}

a {
  text-decoration: none;
  color: inherit;
}
button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
}
ul {
  list-style: none;
}
img {
  max-width: 100%;
  display: block;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

.hidden {
  display: none !important;
}

/* Consistent, visible keyboard focus across every interactive element */
a:focus-visible,
button:focus-visible,
input:focus-visible,
summary:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
  border-radius: var(--radius);
}

/* ===== Header / Navbar ===== */
header {
  background-color: var(--color-surface-container-lowest);
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.05);
  position: sticky;
  top: 0;
  z-index: 50;
}
.navbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  width: 100%;
  height: 72px;
  flex-wrap: wrap;
}
.logo {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  font-size: var(--fs-headline-md);
  font-weight: 700;
  color: var(--color-primary);
}
.logo i {
  font-style: normal;
}

.mobile-toggle {
  display: block;
  color: var(--color-primary);
  font-size: 24px;
}

.nav-links {
  display: none;
  width: 100%;
  flex-direction: column;
  gap: var(--space-xs);
  list-style: none;
  padding: var(--space-sm) 0 var(--space-md);
}
.nav-links.open {
  display: flex;
}

.nav-links li {
  position: relative;
}
.nav-links > li > a {
  display: block;
  color: var(--color-on-surface-variant);
  font-size: var(--fs-label-md);
  font-weight: 500;
  padding: var(--space-xs) 0;
  transition: color 0.2s;
}
.nav-links > li > a:hover {
  color: var(--color-primary);
}

.dropdown-menu {
  display: none;
  list-style: none;
  padding-left: var(--space-md);
}
.dropdown:hover .dropdown-menu,
.dropdown.open .dropdown-menu {
  display: block;
}
.dropdown-menu a {
  display: block;
  color: var(--color-on-surface-variant);
  font-size: var(--fs-label-sm);
  padding: 6px 0;
}
.dropdown-menu a:hover {
  color: var(--color-primary);
}

@media (min-width: 768px) {
  .mobile-toggle {
    display: none;
  }
  .nav-links {
    display: flex !important;
    flex-direction: row;
    align-items: center;
    width: auto;
    gap: var(--space-lg);
    padding: 0;
  }
  .dropdown-menu {
    position: absolute;
    top: 100%;
    left: 0;
    min-width: 200px;
    background-color: var(--color-surface-container-lowest);
    border: 1px solid var(--color-outline-variant);
    border-radius: var(--radius-lg);
    box-shadow: 0px 4px 6px -1px rgba(15, 23, 42, 0.08);
    padding: var(--space-sm) var(--space-md);
    z-index: 60;
  }
  .dropdown-menu a {
    padding: var(--space-xs) 0;
  }
}

/* ===== Breadcrumb ===== */
.breadcrumb {
  background-color: var(--color-surface-container-low);
  padding: var(--space-sm) 0;
}
.breadcrumb-list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  list-style: none;
  font-size: var(--fs-label-md);
}
.breadcrumb-item a {
  color: var(--color-on-surface-variant);
  transition: color 0.2s;
}
.breadcrumb-item a:hover {
  color: var(--color-primary);
}
.breadcrumb-item.active {
  color: var(--color-primary);
  font-weight: 500;
}
.breadcrumb-item:not(:last-child)::after {
  content: "›";
  margin-left: 6px;
  color: var(--color-outline);
}

/* ===== Hero ===== */
.hero {
  background-color: #f7f9fb;
  background-image:
    radial-gradient(at 10% 20%, hsla(170, 100%, 94%, 1) 0px, transparent 50%),
    radial-gradient(at 80% 0%, hsla(168, 100%, 89%, 1) 0px, transparent 50%),
    radial-gradient(at 0% 50%, hsla(174, 100%, 90%, 1) 0px, transparent 50%),
    radial-gradient(at 80% 50%, hsla(173, 100%, 93%, 1) 0px, transparent 50%),
    radial-gradient(at 0% 100%, hsla(169, 100%, 92%, 1) 0px, transparent 50%),
    radial-gradient(at 80% 100%, hsla(175, 100%, 88%, 1) 0px, transparent 50%),
    radial-gradient(at 0% 0%, hsla(171, 100%, 91%, 1) 0px, transparent 50%);
  padding: var(--space-3xl) 0;
  position: relative;
  overflow: hidden;
}
@media (min-width: 768px) {
  .hero {
    padding: var(--space-4xl) 0;
  }
}

.hero-head {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-lg);
  text-align: center;
  margin-bottom: var(--space-xl);
  position: relative;
  z-index: 10;
}
.hero-head h1 {
  font-size: var(--fs-headline-lg-mobile);
  font-weight: 600;
  color: var(--color-on-surface);
  margin-bottom: var(--space-md);
}
@media (min-width: 768px) {
  .hero-head h1 {
    font-size: var(--fs-display);
    font-weight: 700;
  }
}
.hero-head p {
  font-size: var(--fs-body-lg);
  color: var(--color-on-surface-variant);
  max-width: 640px;
  margin: 0 auto;
}

/* ===== Calculator Card ===== */
.calc-wrap {
  max-width: 768px;
  margin: 0 auto;
  padding: 0 var(--space-lg);
  position: relative;
  z-index: 10;
}
.calc-card {
  background-color: var(--color-surface-container-lowest);
  border-radius: var(--radius-xl);
  box-shadow:
    0px 4px 6px -1px rgba(15, 23, 42, 0.05),
    0px 10px 15px -3px rgba(15, 23, 42, 0.1);
  padding: var(--space-lg);
}
@media (min-width: 768px) {
  .calc-card {
    padding: var(--space-xl);
  }
}

.field-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-lg);
  margin-bottom: var(--space-lg);
}
@media (min-width: 768px) {
  .field-grid {
    grid-template-columns: 1fr 1fr;
  }
}

.field label {
  display: block;
  font-size: var(--fs-label-md);
  font-weight: 500;
  color: var(--color-on-surface-variant);
  margin-bottom: var(--space-sm);
}
.field input[type="date"] {
  width: 100%;
  height: 48px;
  padding: 0 var(--space-md);
  border: 1px solid var(--color-outline-variant);
  border-radius: var(--radius-lg);
  background-color: var(--color-surface-container-lowest);
  font-size: var(--fs-body-md);
  font-family: inherit;
  color: var(--color-on-surface);
  transition: border-color 0.2s;
}
.field input[type="date"]:hover {
  border-color: var(--color-outline);
}
.field input[type="date"]:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px var(--color-primary-fixed);
}
.field input[type="date"]::-webkit-calendar-picker-indicator {
  filter: invert(20%) sepia(40%) saturate(600%) hue-rotate(130deg);
}

/* Day / Month / Year select group — replaces the native date input so the
   display order always matches the day-month-year convention used in
   Bangladesh, regardless of the visitor's browser/OS locale. */
.date-select-group {
  display: flex;
  gap: var(--space-sm);
}
.date-select-group select {
  flex: 1 1 0;
  min-width: 0;
  height: 48px;
  padding: 0 var(--space-sm);
  border: 1px solid var(--color-outline-variant);
  border-radius: var(--radius-lg);
  background-color: var(--color-surface-container-lowest);
  font-size: var(--fs-body-md);
  font-family: inherit;
  color: var(--color-on-surface);
  transition: border-color 0.2s;
}
.date-select-group select.day-select,
.date-select-group select.year-select {
  flex: 0 0 30%;
}
.date-select-group select.month-select {
  flex: 1 1 auto;
}
.date-select-group select:hover {
  border-color: var(--color-outline);
}
.date-select-group select:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px var(--color-primary-fixed);
}

.error-msg {
  color: var(--color-error);
  font-size: var(--fs-label-md);
  font-weight: 500;
  margin-bottom: var(--space-md);
}

.calc-btn {
  width: 100%;
  background-color: var(--color-primary-container);
  color: var(--color-on-primary);
  height: 48px;
  border-radius: var(--radius-lg);
  font-size: var(--fs-label-md);
  font-weight: 500;
  transition:
    background-color 0.2s,
    transform 0.15s;
  margin-bottom: var(--space-xl);
}
.calc-btn:hover {
  background-color: var(--color-secondary);
}
.calc-btn:active {
  transform: scale(0.98);
}

.result-block {
  padding-top: var(--space-lg);
  border-top: 1px solid var(--color-surface-container-highest);
}
.result-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--space-lg);
}
.result-head h3 {
  font-size: var(--fs-headline-md);
  font-weight: 600;
  color: var(--color-on-surface);
}
.copy-btn {
  font-size: var(--fs-label-md);
  font-weight: 500;
  color: var(--color-primary);
  display: flex;
  align-items: center;
  gap: 4px;
  transition: opacity 0.2s;
}
.copy-btn:hover {
  opacity: 0.7;
}

.result-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-sm);
}
@media (min-width: 768px) {
  .result-grid {
    gap: var(--space-md);
  }
}

.result-cell {
  background-color: var(--color-surface-container);
  padding: var(--space-md);
  border-radius: var(--radius-lg);
  text-align: center;
  border: 1px solid var(--color-outline-variant);
  transition: border-color 0.2s;
}
.result-cell:hover {
  border-color: var(--color-primary-container);
}
@media (min-width: 768px) {
  .result-cell {
    padding: var(--space-lg);
  }
}

.result-cell .value {
  font-size: 24px;
  font-weight: 700;
  color: var(--color-primary-container);
  margin-bottom: var(--space-xs);
}
@media (min-width: 768px) {
  .result-cell .value {
    font-size: var(--fs-display);
  }
}

.result-cell .unit {
  font-size: var(--fs-label-md);
  font-weight: 500;
  color: var(--color-on-surface-variant);
}

.extra-info {
  text-align: center;
  font-size: var(--fs-body-md);
  color: var(--color-on-surface-variant);
  margin-top: var(--space-lg);
}

/* ===== Trust Badges ===== */
.trust {
  background-color: var(--color-secondary-container);
  padding: var(--space-lg) 0;
}
.trust-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-md);
}
@media (min-width: 768px) {
  .trust-grid {
    grid-template-columns: repeat(4, 1fr);
  }
}
.trust-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: var(--space-xs);
}
.trust-item .icon {
  color: var(--color-primary);
  font-size: 22px;
}
.trust-item span.label {
  font-size: var(--fs-label-md);
  font-weight: 500;
  color: var(--color-on-secondary-container);
}

/* ===== Generic Sections ===== */
.section {
  padding: var(--space-3xl) 0;
}
.section.bg-alt {
  background-color: var(--color-surface-container-low);
}
.section h2 {
  font-size: var(--fs-headline-lg);
  font-weight: 600;
  text-align: center;
  color: var(--color-on-surface);
  margin-bottom: var(--space-sm);
}
.section > .container > p.lead {
  font-size: var(--fs-body-md);
  color: var(--color-on-surface-variant);
  text-align: center;
  max-width: 640px;
  margin: 0 auto var(--space-xl);
}

/* ===== Year Grid ===== */
/* ===== Year Grid ===== */
.year-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-sm);
  min-height: 1560px; /* ~৩৩টা JS-injected year-card এর জন্য জায়গা রিজার্ভ — CLS ঠেকায় */
}
@media (min-width: 640px) {
  .year-grid {
    grid-template-columns: repeat(3, 1fr);
    min-height: 1010px;
  }
}
@media (min-width: 768px) {
  .year-grid {
    grid-template-columns: repeat(5, 1fr);
    gap: var(--space-md);
    min-height: 690px;
  }
}
.year-card {
  background-color: var(--color-surface-container-lowest);
  padding: var(--space-md);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-outline-variant);
  text-align: center;
  transition: border-color 0.2s;
}
.year-card:hover {
  border-color: var(--color-primary-container);
}
.year-card .yr {
  font-size: var(--fs-headline-md);
  font-weight: 600;
  color: var(--color-primary-container);
}
.year-card .age {
  font-size: var(--fs-label-md);
  font-weight: 500;
  color: var(--color-on-surface-variant);
  margin-top: var(--space-xs);
}

/* ===== Ad Slot ===== */
.ad-slot {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--space-lg);
}
.ad-box {
  border: 1px dashed var(--color-outline-variant);
  border-radius: var(--radius-lg);
  height: 96px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-on-surface-variant);
  font-size: var(--fs-label-md);
  font-weight: 500;
  background-color: var(--color-surface-container-low);
}

/* ===== How it works / Use Cases cards ===== */
.card-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-lg);
}
@media (min-width: 768px) {
  .card-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.info-card {
  background-color: var(--color-surface-container-lowest);
  padding: var(--space-lg);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-outline-variant);
  transition: border-color 0.2s;
}
.info-card:hover {
  border-color: var(--color-primary-container);
}
.info-card.centered {
  text-align: center;
}

.step-icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-full);
  background-color: var(--color-primary-container);
  color: var(--color-on-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto var(--space-md);
  font-size: 22px;
}
.info-card h3 {
  font-size: var(--fs-headline-md);
  font-weight: 600;
  margin-bottom: var(--space-xs);
}
.info-card p {
  font-size: var(--fs-body-md);
  color: var(--color-on-surface-variant);
}
.info-card .icon-lead {
  color: var(--color-primary);
  font-size: 22px;
  display: block;
  margin-bottom: var(--space-sm);
}

/* ===== FAQ =====
   Styles the native <details>/<summary> markup used in the HTML
   directly (no JS-generated .faq-toggle/.faq-panel wrapper anymore —
   that duplicate structure was the source of the schema/visible/DOM
   mismatch). The chevron is drawn in pure CSS so it never depends on
   an icon font being loaded. */
.faq-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  max-width: 768px;
  margin: 0 auto;
}
.faq-item {
  background-color: var(--color-surface-container-lowest);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-outline-variant);
  overflow: hidden;
  transition: border-color 0.2s;
}
.faq-item:hover {
  border-color: var(--color-primary-container);
}
.faq-item[open] {
  border-color: var(--color-primary-container);
}

.faq-question {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-md);
  font-size: var(--fs-body-lg);
  font-weight: 500;
  color: var(--color-on-surface);
  cursor: pointer;
  list-style: none;
  -webkit-tap-highlight-color: transparent;
}
@media (min-width: 768px) {
  .faq-question {
    padding: var(--space-lg);
  }
}
.faq-question::-webkit-details-marker {
  display: none;
}
.faq-question::marker {
  content: "";
}
.faq-question::after {
  content: "";
  flex-shrink: 0;
  width: 9px;
  height: 9px;
  margin-top: -3px;
  border-right: 2px solid var(--color-primary);
  border-bottom: 2px solid var(--color-primary);
  transform: rotate(45deg);
  transition: transform 0.2s ease;
}
.faq-item[open] .faq-question::after {
  margin-top: 3px;
  transform: rotate(-135deg);
}

.faq-answer {
  padding: 0 var(--space-md) var(--space-md);
  font-size: var(--fs-body-md);
  color: var(--color-on-surface-variant);
}
@media (min-width: 768px) {
  .faq-answer {
    padding: 0 var(--space-lg) var(--space-lg);
  }
}

/* ===== Related Tools ===== */
.tools-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-md);
  max-width: 768px;
  margin: 0 auto;
}
@media (min-width: 768px) {
  .tools-grid {
    grid-template-columns: repeat(4, 1fr);
  }
}
.tool-card {
  background-color: var(--color-surface-container-lowest);
  padding: var(--space-md);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-outline-variant);
  text-align: center;
  transition: border-color 0.2s;
}
.tool-card:hover {
  border-color: var(--color-primary);
}
.tool-card .icon {
  color: var(--color-primary);
  font-size: 22px;
  margin-bottom: var(--space-xs);
}
.tool-card .label {
  font-size: var(--fs-label-md);
  font-weight: 500;
  color: var(--color-on-surface);
}

/* ===== Footer ===== */
footer {
  background-color: var(--color-surface-container-low);
}
.footer-content {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-lg);
  padding: var(--space-2xl) 0 var(--space-lg);
}
@media (min-width: 640px) {
  .footer-content {
    grid-template-columns: repeat(2, 1fr);
  }
}
@media (min-width: 1024px) {
  .footer-content {
    grid-template-columns: 2fr repeat(3, 1fr);
  }
}

.footer-column h3 {
  font-size: var(--fs-headline-md);
  font-weight: 600;
  color: var(--color-on-surface);
  margin-bottom: var(--space-md);
}
.footer-column p {
  font-size: var(--fs-body-md);
  color: var(--color-on-surface-variant);
}
.footer-links {
  list-style: none;
}
.footer-links li {
  margin-bottom: var(--space-sm);
}
.footer-links a {
  font-size: var(--fs-label-md);
  color: var(--color-on-surface-variant);
  transition: color 0.2s;
}
.footer-links a:hover {
  color: var(--color-primary);
}

.copyright {
  text-align: center;
  padding: var(--space-lg) 0;
  border-top: 1px solid var(--color-surface-container-highest);
  font-size: var(--fs-label-md);
  color: var(--color-on-surface-variant);
}