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

:root {
  color-scheme: light;
  --bg: #f6f1e8;
  --bg-strong: #f0e6d8;
  --panel: #ffffff;
  --panel-muted: #fcf8f2;
  --text: #1d2226;
  --muted: #51616d;
  --brand: #0f766e;
  --brand-strong: #0b5f58;
  --accent: #f97316;
  --border: #e1d7c7;
  --shadow: 0 24px 60px rgba(15, 23, 42, 0.12);
  --radius: 18px;
  --radius-small: 12px;
  --font-heading: "Fraunces", "Georgia", serif;
  --font-body: "Manrope", "Helvetica Neue", Arial, sans-serif;
  --font-math: "STIX Two Math", "Cambria Math", "Latin Modern Math", serif;
}

body[data-theme="dark"] {
  color-scheme: dark;
  --bg: #0b1212;
  --bg-strong: #101a1a;
  --panel: #141c1c;
  --panel-muted: #111818;
  --text: #f3f4f6;
  --muted: #b0c0c5;
  --brand: #4fd1c5;
  --brand-strong: #38b2ac;
  --accent: #fb923c;
  --border: #27303a;
  --shadow: 0 24px 60px rgba(0, 0, 0, 0.4);
}

body {
  margin: 0;
  font-family: var(--font-body);
  color: var(--text);
  background: radial-gradient(circle at top left, #ffffff 0%, transparent 45%),
    linear-gradient(130deg, var(--bg) 0%, #e9f3f1 45%, #fff3e2 100%);
  min-height: 100vh;
  overflow-x: hidden;
}

body[data-theme="dark"] {
  background: radial-gradient(circle at top left, #1b2a2a 0%, transparent 40%),
    linear-gradient(135deg, var(--bg) 0%, #0c1718 55%, #132322 100%);
}

.bg-orbit {
  position: fixed;
  inset: -20% -10% auto auto;
  width: 360px;
  height: 360px;
  background: radial-gradient(circle, rgba(249, 115, 22, 0.28), transparent 65%);
  filter: blur(10px);
  opacity: 0.7;
  z-index: 0;
  pointer-events: none;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 18px 6vw;
  background: color-mix(in srgb, var(--bg) 78%, transparent);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid color-mix(in srgb, var(--border) 80%, transparent);
  gap: 20px;
  flex-wrap: wrap;
}

.logo {
  font-family: var(--font-heading);
  font-size: 1.5rem;
  letter-spacing: 0.03em;
}

.header-actions {
  display: flex;
  gap: 12px;
  align-items: center;
}

.menu-toggle {
  display: none;
  border-radius: 999px;
  padding: 8px 14px;
  font-weight: 700;
  font-family: var(--font-body);
  font-size: 0.9rem;
  cursor: pointer;
  border: 1px solid var(--border);
  background: var(--panel);
  color: var(--text);
}

.site-nav {
  display: flex;
  gap: 10px;
  align-items: center;
  flex-wrap: wrap;
}

.nav-link {
  color: var(--text);
  text-decoration: none;
  font-weight: 600;
  font-size: 0.92rem;
  padding: 6px 2px;
  border-bottom: 2px solid transparent;
  transition: all 0.2s ease;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.nav-link:hover {
  color: var(--brand);
  border-color: var(--brand);
}

.nav-item {
  position: relative;
}

.nav-item summary {
  list-style: none;
  cursor: pointer;
}

.nav-item summary::-webkit-details-marker {
  display: none;
}

.nav-caret {
  font-size: 0.75rem;
  opacity: 0.7;
}

.nav-dropdown {
  position: absolute;
  top: 100%;
  left: 0;
  min-width: 220px;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 8px;
  box-shadow: var(--shadow);
  display: none;
  z-index: 20;
}

.nav-item[open] .nav-dropdown {
  display: grid;
  gap: 4px;
}

.nav-dropdown-link {
  display: block;
  padding: 8px 10px;
  border-radius: 8px;
  color: var(--text);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 600;
  transition: all 0.2s ease;
}

.nav-dropdown-link:hover {
  background: var(--panel-muted);
  color: var(--brand);
}

main {
  position: relative;
  z-index: 1;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 40px 6vw 80px;
  width: 100%;
}

.hero {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 32px;
  padding: 48px 6vw 20px;
  align-items: center;
  max-width: 1200px;
  margin: 0 auto;
}

.hero-text h1 {
  font-family: var(--font-heading);
  font-size: clamp(2.2rem, 4vw, 3.4rem);
  margin: 12px 0;
}

.eyebrow {
  text-transform: uppercase;
  font-size: 0.8rem;
  letter-spacing: 0.25em;
  color: var(--accent);
  margin: 0;
}

.lead {
  font-size: 1.05rem;
  color: var(--muted);
}

.hero-actions {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-top: 20px;
  flex-wrap: wrap;
}

.hero-note {
  font-size: 0.9rem;
  color: var(--muted);
}

.hero-card {
  min-width: 0;
  background: var(--panel);
  border-radius: var(--radius);
  padding: 22px;
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
  display: grid;
  gap: 14px;
}

.stat {
  display: grid;
  gap: 4px;
}

.stat-label {
  font-size: 0.85rem;
  color: var(--muted);
}

.stat-value {
  font-weight: 600;
}

.converter {
  display: grid;
  gap: 20px;
  padding: 16px 6vw 40px;
  max-width: 1200px;
  margin: 0 auto;
}

.converter-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 20px;
  align-items: start;
}

.panel {
  min-width: 0;
  background: var(--panel);
  border-radius: var(--radius);
  padding: 20px;
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
  display: grid;
  gap: 16px;
}

.panel-header h2 {
  margin: 0 0 6px;
  font-family: var(--font-heading);
  font-size: 1.5rem;
}

.panel-header p {
  margin: 0;
  color: var(--muted);
}

.tab-row {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.input-tabs {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 10px;
}

.input-tabs .tab-button {
  width: 100%;
  justify-content: center;
}

.tab-button {
  border: 1px solid var(--border);
  background: var(--panel-muted);
  color: var(--text);
  padding: 6px 12px;
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.92rem;
  cursor: pointer;
  transition: all 0.2s ease;
}

.tab-button.active {
  background: var(--brand);
  border-color: var(--brand);
  color: #ffffff;
}

.input-area {
  display: grid;
  gap: 12px;
}

.math-textarea {
  width: 100%;
  min-height: 120px;
  border-radius: var(--radius-small);
  border: 1px solid var(--border);
  padding: 12px;
  font-size: 0.95rem;
  font-family: var(--font-body);
  background: var(--panel-muted);
  color: var(--text);
  resize: vertical;
}

.math-textarea:focus {
  outline: 2px solid color-mix(in srgb, var(--brand) 60%, transparent);
  border-color: var(--brand);
}

.math-field {
  min-height: 120px;
  padding: 10px 12px;
  border-radius: var(--radius-small);
  border: 1px solid var(--border);
  font-size: 1rem;
  background: var(--panel-muted);
  color: var(--text);
}

.math-field:focus-within {
  outline: 2px solid color-mix(in srgb, var(--brand) 60%, transparent);
  border-color: var(--brand);
}

.toolbar {
  display: grid;
  gap: 12px;
}

.toolbar-row {
  display: grid;
  gap: 8px;
}

.toolbar-top {
  grid-template-columns: repeat(auto-fit, minmax(56px, 1fr));
}

.toolbar-bottom {
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  align-items: center;
}

.tool-button {
  border: 1px solid var(--border);
  background: var(--panel-muted);
  padding: 6px 8px;
  border-radius: 10px;
  cursor: pointer;
  font-weight: 600;
  font-size: 0.85rem;
  transition: all 0.2s ease;
}

.tool-button:hover {
  border-color: var(--brand);
  transform: translateY(-1px);
}

.select-wrap select {
  width: 100%;
  padding: 8px 10px;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: var(--panel-muted);
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--text);
}

.select-wrap select:disabled,
.ghost-button:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

.option-row {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
  align-items: center;
}

.segmented {
  display: inline-flex;
  background: var(--panel-muted);
  padding: 4px;
  border-radius: 999px;
  border: 1px solid var(--border);
  gap: 4px;
}

.segment {
  border: none;
  background: transparent;
  padding: 6px 14px;
  border-radius: 999px;
  font-weight: 600;
  cursor: pointer;
  color: var(--text);
}

.segment.active {
  background: var(--brand);
  color: #ffffff;
}

.toggle-wrap {
  display: inline-flex;
  gap: 8px;
  align-items: center;
  font-weight: 600;
  color: var(--muted);
}

.toggle {
  width: 44px;
  height: 24px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--panel-muted);
  position: relative;
  cursor: pointer;
  transition: all 0.2s ease;
}

.toggle::after {
  content: "";
  position: absolute;
  top: 3px;
  left: 4px;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--brand);
  transition: transform 0.2s ease;
}

.toggle[aria-pressed="true"]::after {
  transform: translateX(18px);
  background: var(--accent);
}

.checkbox {
  font-weight: 600;
  display: inline-flex;
  gap: 8px;
  align-items: center;
  color: var(--muted);
}

.preview-card {
  background: var(--panel-muted);
  border-radius: var(--radius-small);
  border: 1px solid var(--border);
  padding: 16px;
  min-height: 160px;
  display: grid;
  gap: 12px;
}

.preview-body {
  font-family: var(--font-math);
  font-size: 1.2rem;
  line-height: 1.7;
  min-height: 120px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.preview-body.inline-mode {
  justify-content: flex-start;
}

.preview-body.numbered {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 12px;
  justify-items: stretch;
}

.preview-body.numbered::after {
  content: "(1)";
  font-family: var(--font-body);
  font-size: 0.95rem;
  color: var(--muted);
  justify-self: end;
}

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

.preview-error {
  color: #b42318;
  font-weight: 600;
  font-size: 0.95rem;
}

.output-panel-body {
  display: grid;
  gap: 12px;
}

.output-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
}

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

.output-code {
  background: #101725;
  color: #e2e8f0;
  padding: 18px;
  border-radius: 12px;
  min-height: 160px;
  font-size: 0.9rem;
  max-height: 320px;
  overflow: auto;
  white-space: pre-wrap;
  word-break: break-word;
}

body[data-theme="dark"] .output-code {
  background: #0a0f16;
}

.output-actions {
  display: flex;
  justify-content: flex-end;
}

.seo-content {
  padding: 40px 6vw 80px;
  display: grid;
  gap: 24px;
  max-width: 1200px;
  margin: 0 auto;
}

.seo-card {
  min-width: 0;
  background: var(--panel);
  border-radius: var(--radius);
  padding: 24px;
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
}

.seo-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 20px;
}

.seo-block {
  min-width: 0;
  background: var(--panel);
  border-radius: var(--radius);
  padding: 22px;
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
}

.seo-block h3 {
  margin-top: 0;
  font-family: var(--font-heading);
}

.seo-block ul,
.seo-block ol {
  padding-left: 18px;
  color: var(--muted);
}

.seo-card p,
.seo-card li,
.seo-card code,
.faq summary,
.faq p {
  overflow-wrap: anywhere;
  word-break: break-word;
}

.faq details {
  padding: 12px 0;
  border-bottom: 1px solid var(--border);
}

.faq summary {
  font-weight: 600;
  cursor: pointer;
}

.faq p {
  color: var(--muted);
}


.faq-layout {
  display: grid;
  gap: 24px;
}

.faq-cta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}

.primary-button,
.secondary-button,
.ghost-button {
  border-radius: 999px;
  padding: 8px 14px;
  font-weight: 700;
  font-family: var(--font-body);
  font-size: 0.92rem;
  cursor: pointer;
  border: 1px solid transparent;
  transition: all 0.2s ease;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
}

.primary-button {
  background: var(--brand);
  color: #ffffff;
  border-color: var(--brand);
}

.primary-button:hover {
  background: var(--brand-strong);
}

.secondary-button {
  background: color-mix(in srgb, var(--accent) 20%, var(--panel));
  border-color: color-mix(in srgb, var(--accent) 40%, var(--border));
  color: var(--text);
}

.ghost-button {
  background: transparent;
  border-color: var(--border);
  color: var(--text);
}

.ghost-button.compact {
  padding: 6px 12px;
  font-size: 0.85rem;
}

.ghost-button.small {
  padding: 6px 10px;
  font-size: 0.8rem;
}

.hidden {
  display: none !important;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}

#toast {
  position: fixed;
  bottom: 28px;
  right: 28px;
  background: var(--text);
  color: var(--panel);
  padding: 12px 16px;
  border-radius: 12px;
  opacity: 0;
  pointer-events: none;
  transform: translateY(8px);
  transition: all 0.25s ease;
  z-index: 20;
}

#toast.show {
  opacity: 1;
  transform: translateY(0);
}

.site-footer {
  border-top: 1px solid var(--border);
  padding: 24px 6vw 32px;
  background: var(--panel);
}

.footer-inner {
  max-width: 1200px;
  margin: 0 auto;
  display: grid;
  gap: 18px;
}

.footer-brand {
  font-family: var(--font-heading);
  font-size: 1.2rem;
}

.footer-links {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 16px;
}

.footer-bottom {
  border-top: 1px solid var(--border);
  padding: 16px 6vw 20px;
  font-size: 0.85rem;
  color: var(--muted);
  text-align: center;
}

.footer-bottom a {
  color: var(--text);
  font-weight: 600;
  text-decoration: none;
}

.footer-bottom a:hover {
  color: var(--brand);
}

.footer-col h4 {
  margin: 0 0 8px;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
}

.footer-link {
  display: block;
  color: var(--text);
  text-decoration: none;
  font-weight: 600;
  font-size: 0.9rem;
  padding: 4px 0;
  transition: color 0.2s ease;
}

.footer-link:hover {
  color: var(--brand);
}

[data-reveal] {
  opacity: 0;
  transform: translateY(16px);
  animation: rise 0.6s ease forwards;
  animation-delay: var(--delay);
}

@keyframes rise {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (max-width: 720px) {
  .site-header {
    flex-direction: column;
    gap: 10px;
    align-items: flex-start;
  }

  .menu-toggle {
    display: inline-flex;
  }

  .site-nav {
    width: 100%;
    justify-content: flex-start;
    display: none;
    flex-direction: column;
    align-items: flex-start;
    gap: 6px;
    padding: 8px 0;
    border-top: 1px solid var(--border);
  }

  .site-nav.is-open {
    display: flex;
  }

  .header-actions {
    width: 100%;
    justify-content: flex-start;
    flex-wrap: wrap;
  }

  .hero {
    padding: 40px 5vw 16px;
  }

  .container {
    padding: 32px 5vw 56px;
  }

  .converter {
    padding: 16px 5vw 40px;
  }

  .output-actions {
    justify-content: flex-start;
  }

  .nav-dropdown {
    position: static;
    width: 100%;
    box-shadow: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  * {
    animation: none !important;
    transition-duration: 0.01ms !important;
  }
}


@media (max-width: 520px) {
  .seo-grid {
    grid-template-columns: 1fr;
  }

  .hero {
    grid-template-columns: 1fr;
  }

  .converter-grid {
    grid-template-columns: 1fr;
  }

  .faq-cta {
    flex-direction: column;
    align-items: flex-start;
  }

  .faq-cta .primary-button {
    width: 100%;
  }
}